Motion Pro Carb Sync Tool

[RzrBak]

I recently purchased the MotionPro SyncPro Carburetor Tuner and did the TBS. I wanted to do the "unofficial" TBS using the throttle plate method rather than the air bypass method. After reading the posts on the unofficial TBS method, the question I find myself asking is, "how do I know exactly how much kPa (mm Hg, 9.8" Hg) each line on the MotionPro represents. I've searched Google to see if any information is out there and nothing!

Does (or has) anyone have this tool and if so, can you shed some light on the number each line represents? Yamaha manual specs say that the vacuum pressure at engine idling speed should be 33.3 kPa (250mm Hg, 9.8" Hg).

 

[ionbeam]

Don't sweat the exact mm reading value, it'll vary with rpm, altitude and ambient air pressure so there is no one "right" value, all you need to do is get the readings equal. During balancing you will probably find that the cylinders will dictate to you where the level the will actually end up.

 

[Intech]

What Alan said is very true. I have done the TBS both ways. To put it a different way; once equalized with the throttle plates the screws should be close to 1.5 turns open. After adjusting to balance it is not a problem if a little more or less. You just don't want them too close to closed or wide open.

 

[ionbeam]

And, another thing... As you sync the TBs, the idle speed will change and IMO, you should adjust the idle speed as often as necessary to keep it around 1,100 rpm. This almost always prevents the issue where after the TB sync the idle screw won't adjust idle speed up far enough or it won't adjust down far enough.

A fun fact that isn't important and doesn't need adjusting, as you adjust the idle speed on a Gen I and Gen II it moves the TPS range up and down so you may not have 100% at full throttle or you may be over 100% by a few percent when you look at the TPS setting at full throttle.

 

[Intech]

A fun fact that isn't important and doesn't need adjusting, as you adjust the idle speed on a Gen I and Gen II it moves the TPS range up and down so you may not have 100% at full throttle or you may be over 100% by a few percent when you look at the TPS setting at full throttle.

I didn't know that. I am done for the day!

 

[RzrBak]

Thanks for the responses, guys.

What I did...before posting here:

I calibrated the tool, then attached the vacuum hoses to each cylinder. Found #2 was really high (compared to baseline on #3), #1 was a little below #2 and #4 was a tad bit higher than #3. As Alan stated, I used the air bypass screws and got #1, 2 and 4 in line with #3 but then noticed the idle speed was between 1500 to 1800 and sounded/ran like crap!. I had to adjust the idle speed screw to get the RPM back down and it finally settled in around 1000 or a just a tic above.

Had to go back and adjust the cylinders again to get everything lined up. I added 8 oz of Seafoam right after the sync and rode to work the next day. On day 2 at fill up, I added another 8 oz. I did this after reading an article/forum post about deposits on the TB plates and it potential effects. When I bought the bike it had 10,080 miles. I've put over 33,000 in just under 2 years so I figured it was time to clean out the gunk.

I've now ridden about 700 miles since the TBS and the "old girl" is smoother but still feeling the "buzz". Reading further into the syncing process documentation, it sounds as if doing the TBS at idle is not exactly the best way to reduce the buzz in the handlebars that occurs between 4000 and 4500 (where most of my riding occurs). I also believe that my air bypass screws are not 1 - 1 1/2 turns out as Bob stated. I wanted to go back and do process again using the TB plate method which should help reduce the vibrations while at highway speeds...hence the reason for my original question about the cm/Hg reading on the sync tool.

 

[Intech]

I didn't notice until just now that you are in Fredericksburg! I am in King George. I am hosting my fourth tech day May 7th. Come on over and introduce yourself. If there is any other maintenance you want to perform just bring the consumables. I have all the needed tools.

 

[RzrBak]

It's been a while, huh Bob? No need for "introductions". You helped me with the first TBS not too long after I bought the bike. I was a "newbie greenhorn" when it came to motorcycle mechanic-ing. I think I had just missed your tech day and never got an invite to another one. You seemed to be a pretty busy guy so I didn't want to keep reaching out to you so I threw in the towel and jumped head first into learnin'.

Since then, I've done all my own maintenance and add-ons from installing HID headlights, LED brake/turn lights in my Shad top case, FZ1 mirror swap to brake/clutch/radiator flushes, front and rear brake overhauls, all pivot point maintenance, drive shaft service etc. Instead of OEM exhaust I now have a Delkevic system with removable baffles (sound is AWESOME). I can now add the TBS to the list...yeah Me! I need to tackle the valve adjustment and TCC but haven't read up enough on it yet to feel confident to get it done. I'll have to put your tech day on my calendar so I won't miss out.

 

[LittleJon]

An important thing I've learned on this forum: Don't wait for an invite. Check the events posted and if you want, throw your hat in the ring. I've been here for less than a year, and I've already made some friends by keeping an eye on posted events and reaching out to the host to join the fun. We may be dysfunctional, but generally friendly, welcoming folk.

 

[RzrBak]

Thanks LittleJon, I'll keep that in mind...never been good at "crashing parties" and figured the posted events were for "members of the club".

 

[Intech]

It's been a while, huh Bob? No need for "introductions". You helped me with the first TBS not too long after I bought the bike. I was a "newbie greenhorn" when it came to motorcycle mechanic-ing. I think I had just missed your tech day and never got an invite to another one. You seemed to be a pretty busy guy so I didn't want to keep reaching out to you so I threw in the towel and jumped head first into learnin'.
Since then, I've done all my own maintenance and add-ons from installing HID headlights, LED brake/turn lights in my Shad top case, FZ1 mirror swap to brake/clutch/radiator flushes, front and rear brake overhauls, all pivot point maintenance, drive shaft service etc. Instead of OEM exhaust I now have a Delkevic system with removable baffles (sound is AWESOME). I can now add the TBS to the list...yeah Me! I need to tackle the valve adjustment and TCC but haven't read up enough on it yet to feel confident to get it done. I'll have to put your tech day on my calendar so I won't miss out.

Yeah, it has been WAY too long! I believe we will be doing at least one valve clearance check, forks, and various other tasks so come on down.

 

[RaYzerman19]

I've now ridden about 700 miles since the TBS and the "old girl" is smoother but still feeling the "buzz". Reading further into the syncing process documentation, it sounds as if doing the TBS at idle is not exactly the best way to reduce the buzz in the handlebars that occurs between 4000 and 4500 (where most of my riding occurs). I also believe that my air bypass screws are not 1 - 1 1/2 turns out as Bob stated. I wanted to go back and do process again using the TB plate method which should help reduce the vibrations while at highway speeds...hence the reason for my original question about the cm/Hg reading on the sync tool.

The FSM says to use #3 as a reference, but it doesn't matter as long as they are all in sync. Sometimes the screws from the factory are in too far, so initially turn them all in lightly to seat and back them out 3/4-1 turn (FSM says 3/4). Then if you use #3 as a reference, I don't think your screws will change much, mostly in a bit not likely more out (maybe). IMHO, 1 1/2 turns out is a bit too much. It is true the TBS might reduce the buzz in the handlebars, but not necessarily. Heavier bar end weights and Grip Buddies?

 

[RzrBak]

I've now ridden about 700 miles since the TBS and the "old girl" is smoother but still feeling the "buzz". Reading further into the syncing process documentation, it sounds as if doing the TBS at idle is not exactly the best way to reduce the buzz in the handlebars that occurs between 4000 and 4500 (where most of my riding occurs). I also believe that my air bypass screws are not 1 - 1 1/2 turns out as Bob stated. I wanted to go back and do process again using the TB plate method which should help reduce the vibrations while at highway speeds...hence the reason for my original question about the cm/Hg reading on the sync tool.

The FSM says to use #3 as a reference, but it doesn't matter as long as they are all in sync. Sometimes the screws from the factory are in too far, so initially turn them all in lightly to seat and back them out 3/4-1 turn (FSM says 3/4). Then if you use #3 as a reference, I don't think your screws will change much, mostly in a bit not likely more out (maybe). IMHO, 1 1/2 turns out is a bit too much. It is true the TBS might reduce the buzz in the handlebars, but not necessarily. Heavier bar end weights and Grip Buddies?

I actually did add HVMP (extra heavy) bar ends prior to doing the TBS and they made a noticeable difference over the stock ones. Getting the "authorized" TBS done didn't change the remaining buzz so I thought I'd give the "unauthorized" version a go and then see. If it doesn't change anything then no harm, no foul. I can live with the little bit of buzz. It will also give me another chance to see just how far out my air bypass screws are. I'm pretty sure they're further out than what's been suggested in the posts.

 

[RzrBak]

It's been a while, huh Bob? No need for "introductions". You helped me with the first TBS not too long after I bought the bike. I was a "newbie greenhorn" when it came to motorcycle mechanic-ing. I think I had just missed your tech day and never got an invite to another one. You seemed to be a pretty busy guy so I didn't want to keep reaching out to you so I threw in the towel and jumped head first into learnin'.
Since then, I've done all my own maintenance and add-ons from installing HID headlights, LED brake/turn lights in my Shad top case, FZ1 mirror swap to brake/clutch/radiator flushes, front and rear brake overhauls, all pivot point maintenance, drive shaft service etc. Instead of OEM exhaust I now have a Delkevic system with removable baffles (sound is AWESOME). I can now add the TBS to the list...yeah Me! I need to tackle the valve adjustment and TCC but haven't read up enough on it yet to feel confident to get it done. I'll have to put your tech day on my calendar so I won't miss out.

Yeah, it has been WAY too long! I believe we will be doing at least one valve clearance check, forks, and various other tasks so come on down.

I'll definitely try and make it. I didn't ask before but where do you post your tech day event?

 

[Intech]

It is in the Southeast Forum Linky