TBS question on 08

[GPRIDER]

I noticed this at the first sync around the 600 mile mark. Didn't think much of it till now. What got all this started this time was my 08 not idling up like it is supposed to at cold start up. It idles up to about 1,400 rpm when cold and makes a clunking noise occasionally till the first bar shows on the temp gauge. I thought I'd run the idle up a little from the current 1,100 rpm on the engine to see if that would help. I turned the idle adjuster, between the engine and fairing, as far as it would go and it didn't bring it up any. To make sure I was turning it the right way, I backed it off the other direction and the idle started to go down. So when I turned it the other way again till it stopped, the idle just went back up to 1,000 rpm. I read a thread on the forum about opening the air screws on the TB's a full turn and then the idle should go up so you can adjust the idle knob accordingly. Well, I tried that and re synced the TB's and it didn't seem to help. I also noticed that the vacuum pressure at idle is right at 220mm Hg. instead of the recommended 250mm Hg. It was lower than that before I changed the air screws. Never had any problems like this with my 04 FJR. A little insight from the more knowledgable crowd here would be appreciated.

GP

 

[RaYzerman19]

I can't offer FJR experience, but it looks like idle is controlled by the bypass air valve. On the Honda ST1300, e.g., fast idle is controlled by a device with wax in it, which melts after warmup to drop the idle back down. Not sure how the FJR bypass air valve works, or whether it is a wax concept. In any case, just turn the throttle a bit before you start up, in case it has to "position" itself.

The cold idle on my '07 isn't all that high either, but it doesn't bother me much. I am getting the impression one would have to reprogram the ECU to fix all the "lean" issues on this bike. I discovered a fix for many of these.... 89 octane. Bike has never run better.

I had the hot idle up at 1100 or a touch more, didn't like it, so backed it off to somewhere around 1050. Since then I have installed the G2 throttle sleeve, and backed off the middle return spring, so I might dial it back down to 1000. I have not yet done a TB sync and was going to wait until it has some more mileage.

 

[RaYzerman19]

Found this after I posted.

https://www.fjrforum.com/forum//index.php?showtopic=119679

 

[GPRIDER]

Found this after I posted.https://www.fjrforum.com/forum//index.php?showtopic=119679

Thanks. Don't know if this is the complete fix for my problem, but it may be. Ill try it today. His sounds like the opposite of mine. His would adjust the idle up and not down. Could be the same problem though. As for the fast idle at startup, I saw a thread here a few weeks ago that talked about the wax thingie that controlls it. Fred W even posted a expoded isometric view of it on that thread. It does have a unit like that, but is underneath the throttle bodies and looks like you have to remove the TB's to get to it. Not sure I want to tackle that job. When you start your bike cold and it's idling, does it make the clunking noise I described? I don't mind the low idle at startup, but the cluncking doesn't sound like it would be good on the engine in the long run.

GP

 

[SCRider]

Found this after I posted.https://www.fjrforum.com/forum//index.php?showtopic=119679

..... When you start your bike cold and it's idling, does it make the clunking noise I described? I don't mind the low idle at startup, but the cluncking doesn't sound like it would be good on the engine in the long run.

GP

I think they all make the clunking noise shortly after startup, at least mine does on every cold start The engine miss-fires a few times for whatever reason when cold and the clunking noise is the gears in the transmission bouncing off one another due to the backlash in the gears and the sudden change in RPM from the miss-fire. Try pulling the clutch in before you start it and you'll notice that the clunking noise goes away, even when you can still hear the engine miss-fire.

 

[GPRIDER]

I'll try the clutch thing. Yzerman19, I tried the air bypass thing that HJHFJR tried in his post. I took it apart, cleaned and lubed it. Didn't help at all. If anything it's worse. Now it's idling at about 900rpms in nuetral after it's warmed up. That's with the idle adjustment knob screwed as far as it will go to increase rpms. I was hoping someone on the forum could help with this. Sure not looking foward to taking it to my dealership and have them work on it. Come on guys. Hows about a little help for a brutha.

GP

 

[Toynut]

I have that same odd clunking sound for a few seconds when my '08 is first started. I get an occasional hiccup during this period and an occasional stall if I try to blip the throttle (seems lean). Fast idle circuit does not seem to be up to speed either. This poor behavior is somewhat embarrassing. I never had that problem on my '05.

 

[GPRIDER]

Hmmmm..... I wonder if this is a problem with the 08 model year?

GP

 

[TahoeBound]

Hmmmm..... I wonder if this is a problem with the 08 model year?
GP

I have not experienced low idle on my '08, but I did have significant "clunking" problems on cold start. My problem was due to my AVCC install and one of the lines off the throttle body vacuum had worked its way off. Check all 4 caps & ensure they're on tight. Once I figured that out, the clunking noises went away except for every blue moon.

Tahoe

 

[Fred W]

A couple of ideas that may help.

1) It seems that, for whatever reason, the high idle on 2nd gens is never as high as it was on 1st gens. Yes, they seem to have the same wax motor high idle actuator, but something else is different.

2) If you have maxed out on one end or the other of the idle adjust knob when attempting to get to 1100 rpm with a warm engine, then all of the bypass air pots are either too far open or closed.

3) The absolute vacuum measured at idle is of no real consequence. Just get the idle set right and the 4 throttle bores synchronized.

4) Your original symptom of cold misfires (causing tranny clunkage) is probably due to the ECU's map being too lean at idle. It is too lean when the bike is warmed up too, that is what causes the lean stumble/surge symptoms when cruising at low rpm. Adding a PCIII is rather extreme, but it does fix the lean stumble. and if you add fuel in the 0 throttle 1000 rpm fuel cell it would probably makes it idle better when cold too. Maybe someone with a 2nd gen and PCII can pipe in.

 

[GPRIDER]

Hmmmm..... I wonder if this is a problem with the 08 model year?
GP

I have not experienced low idle on my '08, but I did have significant "clunking" problems on cold start. My problem was due to my AVCC install and one of the lines off the throttle body vacuum had worked its way off. Check all 4 caps & ensure they're on tight. Once I figured that out, the clunking noises went away except for every blue moon.

Tahoe

So what you're describing was a vacuum leak of sorts? I didn't notice anything off or loose in the way of the caps or hoses. I'll inspect it a little closer when I get home.

GP

 

[GPRIDER]

A couple of ideas that may help.
1) It seems that, for whatever reason, the high idle on 2nd gens is never as high as it was on 1st gens. Yes, they seem to have the same wax motor high idle actuator, but something else is different.

2) If you have maxed out on one end or the other of the idle adjust knob when attempting to get to 1100 rpm with a warm engine, then all of the bypass air pots are either too far open or closed.

3) The absolute vacuum measured at idle is of no real consequence. Just get the idle set right and the 4 throttle bores synchronized.

4) Your original symptom of cold misfires (causing tranny clunkage) is probably due to the ECU's map being too lean at idle. It is too lean when the bike is warmed up too, that is what causes the lean stumble/surge symptoms when cruising at low rpm. Adding a PCIII is rather extreme, but it does fix the lean stumble. and if you add fuel in the 0 throttle 1000 rpm fuel cell it would probably makes it idle better when cold too. Maybe someone with a 2nd gen and PCII can pipe in.

(1) I can just see the end of the sliding rail for the high idle actuator on one side below the throttle bodies. I can pull on it (or push, can't remember) and the rail will move and the rpms go up. It moves freely, but it feels like the spring is pretty stiff because it is hard to move.

(2) I guess I don't understand what the bypass air pots are. Is that the unit the idle aduster is hooked up to?

(3)I agree with setting the idle right and syncing the TB's, but now my idle will not go above 900 rpms. How critical is that? I believe the manual says to set the idle between 1000 and 1100 rpms and then sync the throttle bodies.

(4) Do you think resetting the CO levels higher will help the with the lean fuel problem. From what I've read so far, I'm not sure it will. I'd hate to think I have to install a PCIII just to get this thing right.

GP

 

[Fred W]

(1) I can just see the end of the sliding rail for the high idle actuator on one side below the throttle bodies. I can pull on it (or push, can't remember) and the rail will move and the rpms go up. It moves freely, but it feels like the spring is pretty stiff because it is hard to move.
(2) I guess I don't understand what the bypass air pots are. Is that the unit the idle aduster is hooked up to?

(3)I agree with setting the idle right and syncing the TB's, but now my idle will not go above 900 rpms. How critical is that? I believe the manual says to set the idle between 1000 and 1100 rpms and then sync the throttle bodies.

(4) Do you think resetting the CO levels higher will help the with the lean fuel problem. From what I've read so far, I'm not sure it will. I'd hate to think I have to install a PCIII just to get this thing right.

GP

1) Yes, some other 2nd gen guys say they could push that rail and get a higher high idle too. It's as if the wax motor doesn't push it far enough. Seems like yours is normal.

2) The "bypass air pots" are the brass screws that you adjust when you do a TBS. It controls an airway passage that bypasses the throttle butterfly plates when closed.

3) This is critical. If you can't get above 900rpm I would put one turn CCW on all 4 of the bypass air pots (which should raise the idle) and then adjust the idle to 1100. Then balance the 4 throttle bodies.

4) Yes, raising the CO via the Barbarian Jumper Mod would have a similar effect to using the PCIII the way I described. It is definitely worth a shot.

 

[TahoeBound]

So what you're describing was a vacuum leak of sorts? ...

Essentially, yes.

 

[GPRIDER]

(1) I can just see the end of the sliding rail for the high idle actuator on one side below the throttle bodies. I can pull on it (or push, can't remember) and the rail will move and the rpms go up. It moves freely, but it feels like the spring is pretty stiff because it is hard to move.
(2) I guess I don't understand what the bypass air pots are. Is that the unit the idle aduster is hooked up to?

(3)I agree with setting the idle right and syncing the TB's, but now my idle will not go above 900 rpms. How critical is that? I believe the manual says to set the idle between 1000 and 1100 rpms and then sync the throttle bodies.

(4) Do you think resetting the CO levels higher will help the with the lean fuel problem. From what I've read so far, I'm not sure it will. I'd hate to think I have to install a PCIII just to get this thing right.

GP

1) Yes, some other 2nd gen guys say they could push that rail and get a higher high idle too. It's as if the wax motor doesn't push it far enough. Seems like yours is normal.

2) The "bypass air pots" are the brass screws that you adjust when you do a TBS. It controls an airway passage that bypasses the throttle butterfly plates when closed.

3) This is critical. If you can't get above 900rpm I would put one turn CCW on all 4 of the bypass air pots (which should raise the idle) and then adjust the idle to 1100. Then balance the 4 throttle bodies.

4) Yes, raising the CO via the Barbarian Jumper Mod would have a similar effect to using the PCIII the way I described. It is definitely worth a shot.

(2) OK. I'm familiar with the brass screws for the TBS adustments. Done it quite a few times on the 04. This would be the second time for the 08.

(3) I tried turning the 4 screws CCW one turn like you suggested, but it did not raise the idle. Actually made it idle lower, so I turned them back to the original position and the idle came back up, but it was at least 100 rpm lower than before. This is wierd.

(4) I printed off the instructions on how to do the BJ mod, so I may have to try it.

Do you think this could be caused by some kind of a vacuum leak?

 

[HaulinAshe]

I might suggest setting all four(4) bypass screws to the same position, say 3/4 turn from fully clockwise. Be sure to first record where they are at now. Then use your sync gauge to see if there is a significant difference in vacuum between the cylinders. If so, there's a good chance you DO have an abnormal vacuum leak.

Just as FredW said, you should be able to give the bypass screws a full turn counterclockwise and effectively change the position of the idle trim screw. In my experience that setting changes most significantly in the first 20,000 miles of life, then everything settles down and requires very little tweaking.

 

[GPRIDER]

I might suggest setting all four(4) bypass screws to the same position, say 3/4 turn from fully clockwise. Be sure to first record where they are at now. Then use your sync gauge to see if there is a significant difference in vacuum between the cylinders. If so, there's a good chance you DO have an abnormal vacuum leak.
Just as FredW said, you should be able to give the bypass screws a full turn counterclockwise and effectively change the position of the idle trim screw. In my experience that setting changes most significantly in the first 20,000 miles of life, then everything settles down and requires very little tweaking.

I'll try to check the vacuum gauge after setting the bypass screws evenly. I've already tried to open them up more and it didn't change anything. Actually it lowered the rpm some. I started out at 1,100 rpm before the TBS. Now after doing all these adjustments, I'm down to 900. Frustrating. Thanks for all the replies.

GP

 

[TahoeBound]

PS. GP - I like your avatar...looks familiar Mine is somewhere outside Inyokern, Hwy 395 in Cali, heading to ahem, Lake Tahoe. How about yours?

 

[GPRIDER]

PS. GP - I like your avatar...looks familiar Mine is somewhere outside Inyokern, Hwy 395 in Cali, heading to ahem, Lake Tahoe. How about yours?

I believe it is 189 north in Wyoming just south of Jackson. Grand Teton Mountain Range in the background. We were on our way to Banff. Great trip.

GP