I posted this question over at Y! last night - but Y! has been having issues and lots of people are out doing what they should be - RIDING!

As for synching the carbs, can the petcock be set to prime, or is it nescessary to have it set to run and vacuum applied? I'm not sure if there's actually a difference in fuel flow or vaccuum or whatnot.

Any quick tips on synching would be appreciated - I've looked at the clymers manual (can you beleive it wants me to remove the rear tire?:boxing: ) and have read plenty of posts here - but would appreciate any input.

Jon Landau (93VN750) was able to get a t-fitting to run between the manometer and the vacuum line/s, and so could run the bike as needed, turn it off, turn the sync screw, run it, etc. I couldn't find the right size t-fitting, and so have been running the bike for a couple minutes to ensure the bowls are full, then disconnecting the vacuum lines, hooking up the manometer, running the bike off the fuel in the carbs, syncing, running, syncing, til I run out of gas; then hook up the vacuum lines and run the bike again for a couple of minutes; then back to unhooking the vacuum lines and hooking up the manometer. This works ok, if only because it's readily apparent when there's a difference in vacuum, and so you only have to run the bike for a sec to see if one cyl wants to pull all the fluid its way.

Oh, and the petcock should be on "On" throughout the procedure.

I ended up "cheating".

I used the "on" setting, but had a syringe left over from a previous project (I think it was for putting oil in my forks on the GS550L - easy way to measure it)

The pre-existing vacuum line fit the syringe pretty well - I just pulled on it once in a while to make sure there was still vacuum.

I left the bike running the whole time - it took me a while since I couldn't find my 7mm wrench (my shed is a mess) - ended up sticking a screw driver head in a piece of vacuum hose - and that in a 8mm wrench - and adjusting as needed to turn the screw (required around 1 full turn - that was NOT fun).

I got it synced at idle, then turned idle to 3k (where it matters more than at idle) and fine tuned it.

Now I'm about 3 inches off from center at idle - perfectly balanced at 3k - hope to take it for a test drive later and see if it affected much - idle does sound somewhat better than it did (was around 8 inches off center - so 16 inches away from eachother).

The other weekend project was plugging up the reed valves with vacuum plugs, plugging the right hand vaccum port for the carb (that's supposed to go to emissions crap) and removing the related hoses.

Been such nice weather but I have too much to do (wife has a project and I've been playing "taxi".)

Off to take the wife lunch...

Rather than re-setting your idle (up to 3K), try syncing with your idle ~1100 rpm, and then see what happens when you open up your throttle to increase the rpm (3000 and up). Someone recently suggested to me syncing at WOT, which i've been afraid to try for reasons that I cannot explain - oh, yeah, maybe 'cause I'm gonna run the fuel outta my carbs and it's gonna be a long sync process. Anyway, you may be able to do that.

When you've got it in sync, you should be pretty darned close to even.

Sounds like you were creative with your carb screw sync "tool" too!!

yeah... that's more or less what I did - just turned the idle adjusting knob thingy instead of holding the throttle open...

Then I set the idle back to ~1100 and checked sync at 3k and up - it's a little off at idle but almost exact past 3k rpms.

Took the bike out for a spin and megads it sounds and pulls better! Methinks that if it had the extra 50cc's everyone else has (mine's a 700) it woulda lifted the front just a tad when I pulled out into traffic.

yeah... that's more or less what I did - just turned the idle adjusting knob thingy instead of holding the throttle open...

Then I set the idle back to ~1100 and checked sync at 3k and up - it's a little off at idle but almost exact past 3k rpms.

Took the bike out for a spin and megads it sounds and pulls better! Methinks that if it had the extra 50cc's everyone else has (mine's a 700) it woulda lifted the front just a tad when I pulled out into traffic.

Amazing how these bikes run when both carbs are working together, huh? Well done! :rockon:

Glad ya got it straightened out Curtis!

Just fyi, I sync'd mine by adding T's to the vacuum lines, didn't remove the tank or anything else. Easiest sync job I've done on a bike.

You're right - VERY easy sync job (well - could be easier if the sync screw was easier to get to).

I never did one on my Suzuki since it had 4 carbs (didn't want to actually buy the tool) and the screws were in such a place that you HAD to remove the tank AND buy a special tool to get the screws taken care of (screws w/in lock nuts if I remember correctly).

I might re-sync when it gets warmer (just to check my job) and I'll likely pick up a t fitting to do it.

Curtis

Been there, done that! My KZ1000 had the 4 CV carbs with the 3 sync screws with the lock nuts, had to use the special tool, and remove the gas tank to get to them. I used a high work stool with a platform on it to set the tank on and a long fuel hose to get fuel to the carbs while syncing. Never enjoyed syncing the KZ that much:D


Pick up two of those T fittings and you'll be set!;)

No reason to sync at WOT... plus not good for engine without load. I just suggest a good sync at idle... then turn up to 3k, to fine tune from there... then your set.... only time i have seen higher rpms used is on a race tuned cup replica

I was kindof wondering about the WOT thing. Seems like if you were using a mercury manometer you're liable to shoot mercury all over your garage! (not that I'd know from experience :) (I now use a vacuum gauge set)