New Float Needles/Seats in - Questions about Re-Sync

[Gold]

So, I've got everything back together, carbs are good as new. Its time to take her in and get sync'ed.

I fired it up, and it actually held the idle when I finally disengaged the choke (even though the idle was sort of all over the place.)

Is this normal for a non-sync'ed bike?

Also, once in a while you hear a little bit of a putt (almost like a small backfire) out of the exhaust as it idles.

Just want to make sure everything is good, and that she'll be ok once I get her sync'ed.

[cintidude04]

What do you mean by idles all over the place? And an afterfire is through the exhaust, backfire is through the intake.

[Gold]

Well, its not a smooth idle (goes to different RPMs)

And I guess yeah, a bit of an afterfire while idling (very quiet though)

[cintidude04]

Idle should smooth out with a sync. Unless you have a hanging idle.

[Kreylyn]

Check for vacuum/air leaks.

You can do a "partial sync" without a sync tool to see if that will help.

Set the idle at around 1800 rpms or close as you can, then turn the sync screw on carbs 3-4 no more than 1 full turn. Check either direction, if the rpms pick up... your probably closer to sync. Adjust the idle back to 1800 with the idle adjust cable, and then Switch to carbs 1-2, do the same... no more than 1 full turn either direction. When the idle pics up a bit (if no change, put it back to the starting point)... adjust the idle again and switch to between 2-3...

If you started out with a close bench sync, it would be very possible to get much close to proper sync with this method by simply listening to how the engine responds.

Never go more than 1 full turn this way. Always keep track of what you have changed so you can "go back" or "reset" to the bench sync position.

If you do that, then you cant' really mess it up too bad as you can always reset to what you had.

If you get it closer to the right sync, you should see an improvement to the bike's idle and running performace. The throttle should be responsive and quickly go up and down in rpms when you "blip" the throttle.

You DO still need to have them actualy fully synced with a tool! Don't skimp out on that.

Krey

[Gold]

Also, could the A/F mix screws affect anything? I think I have them all at 2.5 turns out, but its hard to tell if they're all even.

[Gold]

Does anyone know if you have to re-sync after adjusting A/F screws? like is there a way to do it without re-syncing the carbs?

(I just got mine sync'ed today, but I might have to adjust the A/F screws later)

[cintidude04]

I believe it is preferred, thats why I invested in a sync tool, lotta tuning on my bike.

[Wild-Bill]

If you touch the AF screws then you want to re-sync. There's absolutely no way you'll adjust every one of them exactly the same amount so you'll want to compensate for that with a sync.

[Gold]

Ok, well its sync'ed, but it seems to die pretty easily and the idle is really low.

I screwed it up last time by playing with the idle adjustment screw so much, so what do you guys suggest?

If I put it up higher, the throttle will probably hang & not come down.

Question #2 (Do I have to re-sync if I replace the spark plugs?)

[jetmerritt]

I bench synced my old GS850L and it purred like a kitten. I used the smallest drill bit I could find, adjusted all the throttle plates to drag slightly on the drill bit and never touched it again.

It probably could have been better, but I had a good idle and no hang so I didn't bother to spend any more time on it.

I synced the Kat myself and it turned out good. It ran "fine" before but after the sync I noticed an improvement where it seems smoother and can idle smoother at lower rpms without stalling. I still idle it at 1100, but you get my point.

[ep87]

I would think not you would need a sync with plug swap unless you have a real bad plugs (Miss-fire). I bought a sync tool and consider it part of my regular maintence. In your case I'd start by checking for vacuum leaks like other have said, it could be the root of all your idle problems.
Good luck Richard

[TheCheetorProject]

i need to sync mine but i dont have a tool but ill invest in one