odot
CC member # 17,----- DUP member # 7, mensa club m
You probably need a new battery.
The Really, Definitely Completely Un-Authorized TBS
- Thread starter Fred W
- Start date
Help Support Yamaha FJR Motorcycle Forum:
Yes. Everything that you've said is correct.
Here's what I would do on a 2nd gen:
Adjust your idle speed first, before closing down the air screws, then don't touch it (until the very end).
Next, close down all 4 air screws and use the throttle itself, possible with a throttle locking device of some kind to hold it, maintain a decent idle speed while adjusting the throttle plates. The idle speed for the throttle plate adjustment isn't critical.
After you are happy with that vacuum balance, open each of the 4 air screws an equal amount. Try 1 turn first.
If the idle is too high, close each of the 4 air screws an equal (small) amount. Conversely, if the idle is too low open the 4 an equal amount. Either way, don't worry about the balance until you get your speed to ~1100 rpm.
Finally make adjustments to the individual air screws to balance them. They should be very close already.
Note, that even after adjustment, there will be some amount of engine vibration present, so your last observation about the cause being the thing between your ears is entirely possible.
Last edited by a moderator:
ABQFJR
Well-known member
Hi Fred,Yes. Everything that you've said is correct.
Here's what I would do on a 2nd gen:
Adjust your idle speed first, before closing down the air screws, then don't touch it (until the very end).
Next, close down all 4 air screws and use the throttle itself, possible with a throttle locking device of some kind to hold it, maintain a decent idle speed while adjusting the throttle plates. The idle speed for the throttle plate adjustment isn't critical.
After you are happy with that vacuum balance, open each of the 4 air screws an equal amount. Try 1 turn first.
If the idle is too high, close each of the 4 air screws an equal (small) amount. Conversely, if the idle is too low open the 4 an equal amount. Either way, don't worry about the balance until you get your speed to ~1100 rpm.
Finally make adjustments to the individual air screws to balance them. They should be very close already.
Note, that even after adjustment, there will be some amount of engine vibration present, so your last observation about the cause being the thing between your ears is entirely possible.
I'm glad to hear that, as I just got back from the garage doing almost this exact procedure, based on my suppositions in the previous post. The only difference is that I backed out the idle adjust screw as far as I could to eliminate its bypass effects, then I closed down the cylinders' idle air screws. This, of course, made the bike not want to run, but I used a combination of a GoCruise and a zip-tie to keep the idle at 1000 throughout the procedure. Needless to say, there was syncing to be done. It sure is a PITA chasing the sync from cylinder to cylinder using the throttle plate screws, but I finally got it. Tried the whole revving thing but it seemed to look different each time I revved the engine. I think you're right when you say that that particular method does not really accomplish much.
Anyway, I think I had actually taken my bike further out of balance during the previous sync due to not having backed out the main idle adjuster screw (without it dropping out, assuming it even CAN drop out on the Gen 2 bike). It would seem that the crux of this procedure (either on a Gen 1 or Gen 2 bike) is to remove (or at least minimize) the effects of air bypass from the idle adjust screw and the idle air screws. Only THEN can one know if the throttle plates are truly synchronized.
On a side note, here's an interesting story: The FJR is my first inline-4 motorcycle. My previous bikes consisted of two parallel twins, a 90-degree V-twin, and a thumper. Those bikes all vibrated, though at a lower frequency. Last week Thursday, out of curiosity, I went by the BMW dealership and test rode an R1200RT. It was the first boxer twin I've ridden, and damn, that thing vibrates. All the RT veterans are gushing about how smooth the 1200's are... I can't imagine how bad the older bikes shook. Anyway, when the test ride was over, and I got back on my bike, it felt so smoooooooth. Methinks a lot of the buzziness/vibration in the FJR is a matter of perception. It would make sense since a lot of people (including me) seem to feel the vibes are stronger some days than others. Every inline-4 engined car I've driven buzzed to a certain extent, but those engines are always rubber-mounted, and there is a lot more mass to dissipate the vibrations that DO make it through the rubber mounts. In the end, the fact is, the engine on the FJR is rigidly mounted to a frame which is rigidly mounted to the handlebars, footpegs, and seat. We're lucky these bikes are as smooth as they are.
In any case, I'm done worrying about it. It's time to ride!
I don't think that backing the idle speed adjust all the way out is the right thing either. You'd ideally want it to be providing the exact same air leak that it will when running normally, so that you are balancing the cylinders around that leak. The way to do that is to not adjust it at all for the closed down air screws, just leave it in the normal position. At least that is the way I have done several 2nd gens successfully.
But if your results are OK, the 2nd gen idle adjust may not matter all that much.
But if your results are OK, the 2nd gen idle adjust may not matter all that much.
ABQFJR
Well-known member
Hi Fred,
I see your point, and that's actually pretty much how I did it last time. But what inspired me to try it with the idle screw backed out is that on the Gen 2, the idle screw basically acts like a master air leak for idle, while the air screws on the throttle bodies are used to create four separate, secondary air leaks which can be balanced against the main idle adjuster's air leak. At least, that's the way the system seems to work. I noticed that, even with all the air screws closed, the bike would still idle, just at a lower RPM. That told me that the idle adjust screw was acting independently of the TB air screws. It was only after I backed out the idle screw that the bike wouldn't run. In that case, I theorized that backing out the idle screw all the way would maximize the effects of throttle plate sync on the balance at idle (or 1200, or 2000, or wherever you choose to lock the throttle). If there is no air leak allowed, you know the only air getting through is past the throttle plates, and you can balance them more accurately. This thread has some interesting discussion on the 2nd gen idle circuit and its various screws. I believe constant mesh's post (#3) has the correct explanation.
Ah, hell, I feel like I'm splitting hairs at this point. In all honesty, I really don't think all the time I've spent in the garage messing with balancing the throttle bodies has made much of a difference, one way or the other. If it has made a difference, it's an intangible one. The first sync I did back when I first got the bike - the "authorized" sync - did smooth out my bike's idle, but that's it.
In any case, thanks for your willingness to discuss this ad nauseum!
I see your point, and that's actually pretty much how I did it last time. But what inspired me to try it with the idle screw backed out is that on the Gen 2, the idle screw basically acts like a master air leak for idle, while the air screws on the throttle bodies are used to create four separate, secondary air leaks which can be balanced against the main idle adjuster's air leak. At least, that's the way the system seems to work. I noticed that, even with all the air screws closed, the bike would still idle, just at a lower RPM. That told me that the idle adjust screw was acting independently of the TB air screws. It was only after I backed out the idle screw that the bike wouldn't run. In that case, I theorized that backing out the idle screw all the way would maximize the effects of throttle plate sync on the balance at idle (or 1200, or 2000, or wherever you choose to lock the throttle). If there is no air leak allowed, you know the only air getting through is past the throttle plates, and you can balance them more accurately. This thread has some interesting discussion on the 2nd gen idle circuit and its various screws. I believe constant mesh's post (#3) has the correct explanation.
Ah, hell, I feel like I'm splitting hairs at this point. In all honesty, I really don't think all the time I've spent in the garage messing with balancing the throttle bodies has made much of a difference, one way or the other. If it has made a difference, it's an intangible one. The first sync I did back when I first got the bike - the "authorized" sync - did smooth out my bike's idle, but that's it.
In any case, thanks for your willingness to discuss this ad nauseum!
No problem. I've got the time... Unlike last year, true winter has set in on New England. Temps in the teens accompanied by regular doses of the white stuff is making it hard to a get a day ride in. I did manage to quell my PMS on Sunday afternoon with a short ride on the V-strom (with heated gear buzzing) but my next one looks to be a while away.
ULEWZ
Well-known member
Great procedure Fred, but I have a few questions that I did not see in your first writeup:
1. Is it recommended to have a baseline rpm of 1,100 first?
2. Should the plugs be changed before starting this procedure?
3. Should the engine be warmed up before starting the procedure?
Thanks for a great writeup.
1. Is it recommended to have a baseline rpm of 1,100 first?
2. Should the plugs be changed before starting this procedure?
3. Should the engine be warmed up before starting the procedure?
Thanks for a great writeup.
Yes!
Should not matter.
Yes, for sure. I've started with a cold engine and the gauge hooked up and watched the vacuums as the bike warmed up fully, and it does seem to matter. So since you usually ride it warmed up, that is where you'll want to adjust it.
You're welcome.
Last edited by a moderator:
Fred
also wanted to say thanks for the great writeup - did it today and im not 100% happy with MY adjustments but im happy, pleased with myself, I was able to do it and save a few bucks in the process
BTW getting to the 2-3 adjustment screw (I have kept all the pair stuff as its still under warranty) looked close to impossible - throttle open or not ! - but my 2-3 were close enough for me for my first attempt - I did post some pictures in neprt "what I did to my FJR today " thread,
https://www.fjrforum.com/forum//index.php/topic/144039-what-did-you-do-to-your-fjr-today/page-124?do=findComment&comment=1104477
Also As ABQFJR pointed out closing all the Air screws the bike still idled at 1100 - which threw me a bit ! - but I kept going.
also wanted to say thanks for the great writeup - did it today and im not 100% happy with MY adjustments but im happy, pleased with myself, I was able to do it and save a few bucks in the process
BTW getting to the 2-3 adjustment screw (I have kept all the pair stuff as its still under warranty) looked close to impossible - throttle open or not ! - but my 2-3 were close enough for me for my first attempt - I did post some pictures in neprt "what I did to my FJR today " thread,
https://www.fjrforum.com/forum//index.php/topic/144039-what-did-you-do-to-your-fjr-today/page-124?do=findComment&comment=1104477
Also As ABQFJR pointed out closing all the Air screws the bike still idled at 1100 - which threw me a bit ! - but I kept going.
I'm glad folks are using this procedure successfully. I still believe that the premise of the adjustment (aligning the throttle plates at idle) is valid, but I've recently determined that it only works for relatively clean / new, low mileage throttle plates.
My old 1st gen ('05 w/ 85k miles) for which this procedure had worked so nicely on in the past was no longer delivering the smooth results I had come to expect in the past couple of go 'rounds. I began to theorize that maybe the throttle plates have non-uniformly built up some crud which may be impacting the vacuum levels at idle but not so much when they are open. This could result in their angles not being aligned correctly to each other when set at idle.
So what I did this time was to close all 4 air screws down and then pay attention to the vacuums while revving the engine to ~4k rpm. I found that #1 vacuum was much higher than the others and #4 a little lower, while 2 and 3 were pretty close to each other. I adjusted the linkages to make them all closer together at 4k, which made the vacuums at 1100 rpm idle way off.
I then opened all 4 air screws 3/4 turn and re-balanced their vacuums at idle using those screws and the idle adjuster to keep it at 1100 rpm. The trick here is to open the ones with high vacuum and close down the ones with low vacuum, regardless of which cylinder it happens to be (don't use #3 as a reference)
The result was a balanced vacuum at idle and also a fairly closely balanced vacuum at 4k rpm as compared to how it was previously. The net result was reduced vibration FELT at 4-5k rpm, which was exactly what I was looking for. I think I could have been more meticulous with the adjustments at 4k. I just wanted to see if this was going to make things at all better or worse. It did seem a bit better to me.
So, if you've done the RDCUA TBS as per the prior procedure and not got the smooth results you expected, and if your bike is a bit older and you haven't removed the air box to clean the throttle bodies yet (I still have not done this, but plan to this winter) this tweak to the procedure may be worth trying. If it doesn't pan out you can always go back to the original way.
My old 1st gen ('05 w/ 85k miles) for which this procedure had worked so nicely on in the past was no longer delivering the smooth results I had come to expect in the past couple of go 'rounds. I began to theorize that maybe the throttle plates have non-uniformly built up some crud which may be impacting the vacuum levels at idle but not so much when they are open. This could result in their angles not being aligned correctly to each other when set at idle.
So what I did this time was to close all 4 air screws down and then pay attention to the vacuums while revving the engine to ~4k rpm. I found that #1 vacuum was much higher than the others and #4 a little lower, while 2 and 3 were pretty close to each other. I adjusted the linkages to make them all closer together at 4k, which made the vacuums at 1100 rpm idle way off.
I then opened all 4 air screws 3/4 turn and re-balanced their vacuums at idle using those screws and the idle adjuster to keep it at 1100 rpm. The trick here is to open the ones with high vacuum and close down the ones with low vacuum, regardless of which cylinder it happens to be (don't use #3 as a reference)
The result was a balanced vacuum at idle and also a fairly closely balanced vacuum at 4k rpm as compared to how it was previously. The net result was reduced vibration FELT at 4-5k rpm, which was exactly what I was looking for. I think I could have been more meticulous with the adjustments at 4k. I just wanted to see if this was going to make things at all better or worse. It did seem a bit better to me.
So, if you've done the RDCUA TBS as per the prior procedure and not got the smooth results you expected, and if your bike is a bit older and you haven't removed the air box to clean the throttle bodies yet (I still have not done this, but plan to this winter) this tweak to the procedure may be worth trying. If it doesn't pan out you can always go back to the original way.
leclairk
Well-known member
I had the opportunity this afternoon to perform the Unauthorized TBS on my new to me 06. Let me just say HOLY CRAP!! What a difference! When I first hooked up the TBS tool my numbers were not too bad, my mechanic had done a TBS 500 miles ago. I went ahead and performed the unauthorized anyway. Very simple to to do. I have never done a TBS before and just bought a sync tool this week. I took it out for a short spin and oh my God what a difference. Like other people have said, the bike runs like a different machine. Riding at 75mph, 5th gear, approx 3800 rpm, almost zero vibration. I could feel a tiny bit of vibration in my feet but other than that, nothing! The bike is so smooth and SO AWESOME!!! I don't see how you could own this bike and not do this to your bike. It makes a huge difference. I was a little worried that some people might think it runs smoother even thought it really is the same, but there is no question the bike is smoother. Fred, you are a genius!
ABQFJR
Well-known member
I must be one of the only people on this forum who noticed none, nada, zilch difference after doing the TBS, authorized or not. All these posts about people having a whole different bike after doing the RDCUATBS really depress me. I should stop reading them.
Carry on.
Carry on.
It would kind of depend on how far out of sync it was before the adjustment. If it was already good before hand it would be harder to make it much better, right?
That and how sensitive you are to things like vibration. Not everyone senses things like that in the same way.
HotRodZilla
GOD BLESS AMERICA
I used to know a girl that was "sensitive to vibrations." She was crazy, but dayum!!
On a related note, I have some maintenance coming up. I may try this, just for the Hell of it.
On a related note, I have some maintenance coming up. I may try this, just for the Hell of it.
MajBach
Well-known member
I'm going to add my observations to this rather old thread.
I ordered a Motion Sync Pro recently (as a side note, I wouldn't buy another. This unit does work but it doesn't show specific vacuums/pressure, it shows relative pressures. That is, you cannot tell when you're pulling say 10 mm Hg or 200 mm, only that #1 is higher/lower than #2 etc.) so I could start doing my own sync. I just turned 50,000 miles on mine and the last sync was, well....pre-10,000 miles.
This thread was rather lengthy and hard to read what with all the updates,links and references too differences between Gen I and Gen II. I was just going to do a sync at idle but after pulling everything apart, I went ahead and did the entire thing. Well, halfway through the anxiety was peaking as I had wished I had just left well enough alone and did the sync at idle. I seemed to knock everything out of whack and couldn't get things back to what they were when I started. At this point, I'm pot-committed obviously.
After several back-and-forths - not to mention a dozen or so re-reads of this thread, I somehow managed get all four synced within a mm of each other at both 4k rpm and at idle, I wasn't sure if it was due to being meticulous or just plain lucky but I was happy with the results and anxious to get out for a test run. Thats when the sh*t hit the fan...as it always seems to do.
Since we were having a record breaking heat wave here on Vanc Is, I was anxious to close my garage door that I had open to vent the exhaust. Well, one of the bungee cords I had attached to the tank to hold it up was on the slide bar of the garage door opener and while my back was turned, the garage door was pulling on the tank as it tried to close. The only thing holding it back were the wires for the fuel pump and fuel gauge. I don't need to tell you who won that battle.
I got the wires reattached and everything back together and didn't have the time for a ride, so...tomorrow.
Well, sorry to tell you, ABQFJR, but the results were truly unbelievable for me as well! And, it wasn't some expected or placebo observation either. This bike truly felt like a different bike and I would have noticed this in 100 feet of riding if had someone else had done the same thing to it without me knowing. Aside from it being long overdue the main reason I was motivated to perform this maintenance because I noticed a subtle/distinct unevenness at idle. This was remedied immediately and I observed the change as I was performing the sync itself. But the next thing I noticed was the surge was eliminated. My FJ always seemed to lurch forward or back whenever I rolled on the fuel or came off it. I just assumed it was the nature of the beast over the years and was accustomed to it. That was gone! Completely smooth transitions during power on or power off. *Smile on my face*
Next came shifting. How did this procedure make shifting from 5th to 4th at highway speeds approaching a stop(or ANY other shift for that matter) so much smoother? But it did. Significantly.
Finally, vibrations. I did not realize how my subconscious had either learned to tune out or ignore the vibrations that migrated from the engine through my hands and up my arms. But now that those vibrations are all but gone, and I am now aware that they were once there - in droves. Now, it's like resting my hands on a glass table.
Truly a different bike.I had no idea the improvements would be so pronounced. Don't what aspect of the entire procedure contributed to what improvement but thanks to all here -particularly Fred -that contributed to the cause which ultimately lead me to go ahead with it. Thanks
Incidentally, the Motion sync pro is calibrated in 1 cm increments and when I first synced at idle cylinders were within 1 cm of the 10th notch. I recall the the max difference was between one and three cylinders which was about 2cm. Once synced at idle, #1 and #4 were 2.5 cms higher than #2 and #3 at 4k. It took a lot of fumbling but I had them to within 1 mm of each other at 4k. Then I tried syncing them at idle again, but now I had all the bleed screws turned in and the idle screw turned all the way in. The idle sync was now WAY off. Again, after much fumbling I got them all synced but they were now about 1 cm higher than they were when I took the bike apart. I do not know the actual numerical value of the pressure (but I am going to go purchase a pressure gauge for the next sync). The other observation was that the bleed screws (or sync screws or whatever they're called) were in completely different positions than when I started, even relative to each other. So was the idle screw. At the start the screw that was out the most was 2 1/4 full turn and the least was only a 1/4 turn. Now they are all withing a half turn of each other. Finally, I also changed the plugs and ran some Sea Foam through the airbox during the tune. Again, don't know if they contributed to the improvement or how much.
I ordered a Motion Sync Pro recently (as a side note, I wouldn't buy another. This unit does work but it doesn't show specific vacuums/pressure, it shows relative pressures. That is, you cannot tell when you're pulling say 10 mm Hg or 200 mm, only that #1 is higher/lower than #2 etc.) so I could start doing my own sync. I just turned 50,000 miles on mine and the last sync was, well....pre-10,000 miles.
This thread was rather lengthy and hard to read what with all the updates,links and references too differences between Gen I and Gen II. I was just going to do a sync at idle but after pulling everything apart, I went ahead and did the entire thing. Well, halfway through the anxiety was peaking as I had wished I had just left well enough alone and did the sync at idle. I seemed to knock everything out of whack and couldn't get things back to what they were when I started. At this point, I'm pot-committed obviously.
After several back-and-forths - not to mention a dozen or so re-reads of this thread, I somehow managed get all four synced within a mm of each other at both 4k rpm and at idle, I wasn't sure if it was due to being meticulous or just plain lucky but I was happy with the results and anxious to get out for a test run. Thats when the sh*t hit the fan...as it always seems to do.
Since we were having a record breaking heat wave here on Vanc Is, I was anxious to close my garage door that I had open to vent the exhaust. Well, one of the bungee cords I had attached to the tank to hold it up was on the slide bar of the garage door opener and while my back was turned, the garage door was pulling on the tank as it tried to close. The only thing holding it back were the wires for the fuel pump and fuel gauge. I don't need to tell you who won that battle.
I got the wires reattached and everything back together and didn't have the time for a ride, so...tomorrow.
Well, sorry to tell you, ABQFJR, but the results were truly unbelievable for me as well! And, it wasn't some expected or placebo observation either. This bike truly felt like a different bike and I would have noticed this in 100 feet of riding if had someone else had done the same thing to it without me knowing. Aside from it being long overdue the main reason I was motivated to perform this maintenance because I noticed a subtle/distinct unevenness at idle. This was remedied immediately and I observed the change as I was performing the sync itself. But the next thing I noticed was the surge was eliminated. My FJ always seemed to lurch forward or back whenever I rolled on the fuel or came off it. I just assumed it was the nature of the beast over the years and was accustomed to it. That was gone! Completely smooth transitions during power on or power off. *Smile on my face*
Next came shifting. How did this procedure make shifting from 5th to 4th at highway speeds approaching a stop(or ANY other shift for that matter) so much smoother? But it did. Significantly.
Finally, vibrations. I did not realize how my subconscious had either learned to tune out or ignore the vibrations that migrated from the engine through my hands and up my arms. But now that those vibrations are all but gone, and I am now aware that they were once there - in droves. Now, it's like resting my hands on a glass table.
Truly a different bike.I had no idea the improvements would be so pronounced. Don't what aspect of the entire procedure contributed to what improvement but thanks to all here -particularly Fred -that contributed to the cause which ultimately lead me to go ahead with it. Thanks
Incidentally, the Motion sync pro is calibrated in 1 cm increments and when I first synced at idle cylinders were within 1 cm of the 10th notch. I recall the the max difference was between one and three cylinders which was about 2cm. Once synced at idle, #1 and #4 were 2.5 cms higher than #2 and #3 at 4k. It took a lot of fumbling but I had them to within 1 mm of each other at 4k. Then I tried syncing them at idle again, but now I had all the bleed screws turned in and the idle screw turned all the way in. The idle sync was now WAY off. Again, after much fumbling I got them all synced but they were now about 1 cm higher than they were when I took the bike apart. I do not know the actual numerical value of the pressure (but I am going to go purchase a pressure gauge for the next sync). The other observation was that the bleed screws (or sync screws or whatever they're called) were in completely different positions than when I started, even relative to each other. So was the idle screw. At the start the screw that was out the most was 2 1/4 full turn and the least was only a 1/4 turn. Now they are all withing a half turn of each other. Finally, I also changed the plugs and ran some Sea Foam through the airbox during the tune. Again, don't know if they contributed to the improvement or how much.
@MajBach -
First off, glad to hear the sync was so successful, even with the little garage door SNAFU. So far I have had a few people that said there was not much of adifference, but most have noticed a lot of improvement like you did. I guess it all just depends on how far out of sync they are when you start.
Second, the fact that your gauge doesn't measure absolute values is insignificant. The Morgan Carbtune that many other folks use and love (including me) also does not measure inches of mercury, since it is just four metal rods sucked up into glass tubes. The entire point of a synchronization is just to balance the vacuums between cylinders under various conditions. You have no ability to change the absolute value of the vacuum. It will be whatever it will be at a particular rpm.
Third, I appreciate your feedback about the thread being confusing. Although I originally posted this as a "procedure", it was also under some significant amount of discussion with other people as to how well it would work, and the procedure did get changed slightly. I think that all one needs to read is the first post in the thread, as I have gone back and edited that first post to reflect the most recent information / theories / procedures.
I will now go back and post some sort of warning to that effect at the beginning of first post so maybe someone who comes along later won't be distracted by all the subsequent chatter.
FWIW - I also keep and host copy of the procedure on my FJR-NERD's Repository Web Site, (along with a few other useful procedures) which can also be accessed by clicking the little nerdy icon in my signature line,
First off, glad to hear the sync was so successful, even with the little garage door SNAFU. So far I have had a few people that said there was not much of adifference, but most have noticed a lot of improvement like you did. I guess it all just depends on how far out of sync they are when you start.
Second, the fact that your gauge doesn't measure absolute values is insignificant. The Morgan Carbtune that many other folks use and love (including me) also does not measure inches of mercury, since it is just four metal rods sucked up into glass tubes. The entire point of a synchronization is just to balance the vacuums between cylinders under various conditions. You have no ability to change the absolute value of the vacuum. It will be whatever it will be at a particular rpm.
Third, I appreciate your feedback about the thread being confusing. Although I originally posted this as a "procedure", it was also under some significant amount of discussion with other people as to how well it would work, and the procedure did get changed slightly. I think that all one needs to read is the first post in the thread, as I have gone back and edited that first post to reflect the most recent information / theories / procedures.
I will now go back and post some sort of warning to that effect at the beginning of first post so maybe someone who comes along later won't be distracted by all the subsequent chatter.
FWIW - I also keep and host copy of the procedure on my FJR-NERD's Repository Web Site, (along with a few other useful procedures) which can also be accessed by clicking the little nerdy icon in my signature line,
sapest
Well-known member
As this thread has re-awakened -
Yes - its a different bike. In my case, a little less vibration, but the top of the rev range is transformed. 5,000 rpm and up has gone from 'thats a nice pull' to 'who lit the afterburners'. Eager to rev and happy to do so.
This procedure is a must do. Put it right up there with change the oil.
Thanks Fred.
-Steve
Yes - its a different bike. In my case, a little less vibration, but the top of the rev range is transformed. 5,000 rpm and up has gone from 'thats a nice pull' to 'who lit the afterburners'. Eager to rev and happy to do so.
This procedure is a must do. Put it right up there with change the oil.
Thanks Fred.
-Steve
MajBach
Well-known member
Unfortunately, I need to make a bit of an update regarding my observations with my recent sync.
The other day I went for another drive, significantly longer and higher speed one than the one I had done when I posted my previous observations. I noticed the bike didn't seem quite as smooth as the stark difference I had seen immediately after the sync. But what really grabbed my attention was the apparent lag at highway speeds when I opened it up. At first it seemed like I had some power loss, especially when I noticed I had trouble passing an F-150. After that, I experimented downshifting to third and applying WOT from speeds upwards to 100 mph. It just seemed 'slower', smooth but slower. I wondered if I was imagining things and indeed I thought perhaps I had just OD'ed on buffalo wings at Dee's the night before and the extra baggage was starting to show. When I reached the city and made a few hard accels from a stop, the bike seemed normal. Then, I was climbing a mountain - smooth steady paved ascent about 2 miles long; I kept the bike in 2nd most of the way, revving it around 5-7000. Whenever I opened her, there was a definite lag. At first, it almost seemed like the clutch was slipping - that's the type of lag I am talking about - but there was no associated increase in rpm as you would expect in clutch slippage. Rather, I could hear the engine 'groan' and try to develop power but with without really grabbing,(not unlike the groan when you open up a normally aspirated engine too fast while it's still a little cold). After about a a second and a half, the rpms would pick up and she would run like normal. I stopped for a bite and let the bike cool and on the trip home the behavior was the same. Still, I wasn't convinced I wasn't imagining it all.
The two things that have keep me up at night wondering are: when I did the above sync, I adjusted the third cylinder screw even though that is the 'factory one' and you're supposed to leave it alone. Secondly, I had played around with the throttle body valves which is also something that isn't in the shop manual to adjust. Well, that was the entire point of this thread/procedure, right? And, it seemed worth it...at first. Now, I just want to put things back the way they were
Anyway, today I proceeded to do another sync but before I began I went and purchased a vacuum tester - one that I could determine if the third cylinder was drawing 25mm Hg as the Motion Pro carb sync tool just measures relative vacuums. Well, when I hooked it up to #3, it bounced around so erratically, that a specific reading couldn't even be guesstimated. The instructions state that it should hold steady and if it bounces around the 'carb' is out of whack. The other cylinders showed the same thing. Of course, I don't believe the bike is out of whack, Im probably using the wrong tool for the job or using it wrong. So, I proceeded to hook up the sync tool and was immediately surprised to see how the static positions were so different than when I left them. The Motion Pro has reference lines along the side that appear to be in 10mm increments. When I initially did this test, each cylinder was resting on the 7-8th notch and when I was done with the entire procedure, they were all steady on the 9th. Today, when I hooked it up, they were all on the 4th notch. That's more than can be attributed in a change to ambient air pressure I would think. Perhaps though, my idle was higher than when I finished as I think I can recall adjusting the idle screw to increase idle after I had done the sync. The #1 and #4 cylinders needed slight adjustment as they were high. Finally, all 4 were nicely synced when I revved right up to 6 rpm without load.
Tomorrow I leave for a week's drive down to Oregon and California. I'll see if there are improvements but in the meantime, I'd appreciate some input from the experts here.
Thanks,
The other day I went for another drive, significantly longer and higher speed one than the one I had done when I posted my previous observations. I noticed the bike didn't seem quite as smooth as the stark difference I had seen immediately after the sync. But what really grabbed my attention was the apparent lag at highway speeds when I opened it up. At first it seemed like I had some power loss, especially when I noticed I had trouble passing an F-150. After that, I experimented downshifting to third and applying WOT from speeds upwards to 100 mph. It just seemed 'slower', smooth but slower. I wondered if I was imagining things and indeed I thought perhaps I had just OD'ed on buffalo wings at Dee's the night before and the extra baggage was starting to show. When I reached the city and made a few hard accels from a stop, the bike seemed normal. Then, I was climbing a mountain - smooth steady paved ascent about 2 miles long; I kept the bike in 2nd most of the way, revving it around 5-7000. Whenever I opened her, there was a definite lag. At first, it almost seemed like the clutch was slipping - that's the type of lag I am talking about - but there was no associated increase in rpm as you would expect in clutch slippage. Rather, I could hear the engine 'groan' and try to develop power but with without really grabbing,(not unlike the groan when you open up a normally aspirated engine too fast while it's still a little cold). After about a a second and a half, the rpms would pick up and she would run like normal. I stopped for a bite and let the bike cool and on the trip home the behavior was the same. Still, I wasn't convinced I wasn't imagining it all.
The two things that have keep me up at night wondering are: when I did the above sync, I adjusted the third cylinder screw even though that is the 'factory one' and you're supposed to leave it alone. Secondly, I had played around with the throttle body valves which is also something that isn't in the shop manual to adjust. Well, that was the entire point of this thread/procedure, right? And, it seemed worth it...at first. Now, I just want to put things back the way they were
Anyway, today I proceeded to do another sync but before I began I went and purchased a vacuum tester - one that I could determine if the third cylinder was drawing 25mm Hg as the Motion Pro carb sync tool just measures relative vacuums. Well, when I hooked it up to #3, it bounced around so erratically, that a specific reading couldn't even be guesstimated. The instructions state that it should hold steady and if it bounces around the 'carb' is out of whack. The other cylinders showed the same thing. Of course, I don't believe the bike is out of whack, Im probably using the wrong tool for the job or using it wrong. So, I proceeded to hook up the sync tool and was immediately surprised to see how the static positions were so different than when I left them. The Motion Pro has reference lines along the side that appear to be in 10mm increments. When I initially did this test, each cylinder was resting on the 7-8th notch and when I was done with the entire procedure, they were all steady on the 9th. Today, when I hooked it up, they were all on the 4th notch. That's more than can be attributed in a change to ambient air pressure I would think. Perhaps though, my idle was higher than when I finished as I think I can recall adjusting the idle screw to increase idle after I had done the sync. The #1 and #4 cylinders needed slight adjustment as they were high. Finally, all 4 were nicely synced when I revved right up to 6 rpm without load.
Tomorrow I leave for a week's drive down to Oregon and California. I'll see if there are improvements but in the meantime, I'd appreciate some input from the experts here.
Thanks,
Dude, you are over-thinking this thing way too much. And imagining things too, no doubt. Obsession is not a good thing.
Adjusting the 3rd cylinder screw is no different than adjusting the other three. It didn't cause your engine to sack out. What the absolute reading is on your vacuum gauge is not significant. You have no ability whatsoever to change that.
Take the ride and enjoy it and stop worrying yourself about nothing.
Adjusting the 3rd cylinder screw is no different than adjusting the other three. It didn't cause your engine to sack out. What the absolute reading is on your vacuum gauge is not significant. You have no ability whatsoever to change that.
Take the ride and enjoy it and stop worrying yourself about nothing.
MajBach
Well-known member
well, you're probably right. I re-sync'ed it and didn't have to make much of a change. Tonight I went for a long ride and the bike seemed fine. Still seems sluggish from when I first bought it but perhaps it's the 50,000 age or mt ever-increasing fat ass.
Thanks again.
Similar threads
