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Sync'd my throttle bodies

7K views 17 replies 10 participants last post by  Ttrider 
#1 ·
OMG were they way out of sync at 11,322 miles. I suspect they've been out for a long long time. Vibration had become unbearable in the left footpeg, bars and the seat at anything above 5k rpms. The idle was hanging up and would not settle down for what seemed like a few minutes.

Anywho I did it with the paperclip mode and bike in dealer mode to lock the ISC in at the set 60 value. Don't attempt this without doing this. I do not have the SDS so I used the dealer mode method which is described in the service manual. IAP code C13 will flash due to the connector being unplugged but it won't affect any of the adjustment to TBs. You will need to remove the airbox but also remove the IAT sensor from airbox and plug it back into the plug to avoid a code on that. Everything else is pretty straight forward and very similar to a carb bike only your adjusting brass screws in each TB instead of a linkage that connects 4 carbs.Adjustment screws are located on the topside of the TBs, vacumn ports are located on the bottom.Also warm the bike to operating temp before disconnecting anything. Then put her in dealer mode and sync from that point on.

My sync tool is an old Motion Pro sync pro the latest one with no mercury in it. It is a basic and reliable tool for what it cost. Nothing super fancy. Well mine were way out of spec but are dead even now and it only took me about 2 hours, naked model is so easy to work on. I also discovered a small vacumn leak on a rubber plug cap I had added to the evap BS I removed a few years ago. All is well now and bike runs fantastic!
 
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#4 ·
The vacuum leak would not have shown the major imbalance that I saw once I setup to check the sync. Leak was very small just a dry rotten rubber cap.

TBs were way out with new cap plugged up and bike running before the sync. Engine sound being tuned to sync was music to my ears as I was performing the procedure. Loud M4 just fell into a nice rumble not the off balance surging mess it was before sync.

Well that didn’t go as planned on mobile I quoted my own post lol
 
#7 ·
So I am pretty certain mine has been out of balance since new. It is at 2k now so a TB sync is on my short list. I have an old homemade tubes with oil in them contraption, but it works quite well. So dealer mode will lock the ISC, good to know. Thanks for the info!
 
#13 ·
I have a question on TB sync, could not find good clarification via Google search, hence checking here : Do you guys sync at idle or cruise RPM(5000)?

When I checked at idle, had all cylinders way off. I sync'd them at idle and then checking at 5K rpm , they were way off. Sync'd them at 5k after a lot of trials and got it to a usable level - now idle is almost back to what it was(out-of-sync). Anything over idle - the cylinders slowly start getting back into sync upto 5k - and overshoot again >5K.

Just wanted to get a feel here before I put the everything back to where they belong and go for a test ride.
 
#14 ·
I have a question on TB sync, could not find good clarification via Google search, hence checking here : Do you guys sync at idle or cruise RPM(5000)?

When I checked at idle, had all cylinders way off. I sync'd them at idle and then checking at 5K rpm , they were way off. Sync'd them at 5k after a lot of trials and got it to a usable level - now idle is almost back to what it was(out-of-sync). Anything over idle - the cylinders slowly start getting back into sync upto 5k - and overshoot again >5K.

Just wanted to get a feel here before I put the everything back to where they belong and go for a test ride.
Sync at idle. Every now & then blip the throttle; then let them settle and continue with the sync. When complete, do a ISC learned value reset and clear any DTC's (if you get any).
 
#16 ·
I always sync at 1500 to 2000 RPM. 5000 is to high, so less effect from any difference and at idle is the closed butterfly, so I look for lowest stable throttle position that I expect all TBs are at least slightly cracked open. Worked for carbs and TBs on the bikes I've had.
 
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