Carb sync gone bad.

To start off with i have a 97 vfr750 and today I decided to try and sync my carbs since I was having some engine vibrations. Anyways I hooked up the carbtune and each carb was completely different from one another. Should have took a pic. So now I have been fing with it for a couple of hours and now it hardly runs u blip the throttle and it shuts off.
So my question is can you set them close and then use the gauge? Because honestly I didn’t know where to start since they were all so far off.
I appreciate any advise/ help

 

Left front is your carb you adjust the others to. Best to have it set up as the #1 tube and set the others in a manner you can easily remember which ones they are for quick adjustment. Small adjustments are best.

 

If things are too far out of adjustment (seems like yours are), you'd need to remove carbs and do a proppa bench synch before setting up gauges so you have a near baseline.

As TC sayeth, you'd need less than 1/2 turn on any screw after a bench synch, and each screw adjustment has some small effect on all cylinders.

Be sure to flick the throttle a few times after each screw is turned to allow the throttle butterflys and linkages to settle into their new position.

Read the service manual for the very important sequence of adjustments.

 

Carb synching seems like such an easy process but it never goes smoothly for me either.

The carbs never stay at a constant vacuum level. They seem to change as the bike idles and gets hotter. I have never gotten my carbs perfect. They're always slightly different then each other.

Josh, what process were you following when synching your carbs? usually the screw turns are very minimal.

 

That's a damn fine job of synchrolizing there squirrel--got them thangs dialed in on the money!

 

Small VFRWorld !! That carb and synch job was done on Slowbird's '86 700 when he brought his bike down here from the Toronto area about 2 years ago.

Briefly, i had 3 '86 VFRs in the garage at the same time.

 

FWIW, you should check your valve clearances before you bother syncing the carbs. Not that it won't make a difference, but if you have a few tight or loose valves and re-shim them, the carbs will no longer be in sync.

 

On a 97? Depending on the mileage there is a slim chances the valves clearances are off.

Everytime I hear of someone opening up a 4th gen motor to check the valves they are all fine, and when they're not they're usually off by such a small amount it's not worth adjusting.

Yeah, there's a chance the clearances could be off but I think it's a tiny chance. More of a last resort thing for these bikes

 

I had a feeling I should have kept my mouth shut, or my keyboard quiet... :smile: