Carb synch gone bad

[max]

So I met this guy on Craigslist riiiiiiight.... who here knows where this one is going? He works in a motorcycle shop and freelances for cheaper on the weekend. I tell him I need my valves adjusted, carbs synched. So he comes over and he seems pretty straight up, ex marine with the scars to prove it, has a ton of bikes, knows more or less what he's talking about. Anyways we get down to business, took apart the carbs together and sprayed them up and everything is looking good. I helped him re-assemble them, something I've done dozens of times.

Then he starts to check the valves, and finds that some of them are gapped too closely, some are too far apart. He tells me that I have new shims in my future, but for now what he did was swap out the close ones with the loose ones. I've never done this before but I can understand I guess what he was driving at. Unfortunately I had to go to work at this time so I left him there working on my bike.

I go tend bar all night and at 2AM I return and he is still there. He tells me he succesfully synched the carbs, and took it for a ride. However the bike is running really rough. At first it would fire up but it would return very slowly to idle, sometimes just staying at like 3000rpms. Wouldn't respond to the idle screw. Then I noticed the vacuum tube on the petcock wasn't hooked up, so we did that, primed it for 10 seconds and then the bike wouldn't start at all. We wore the battery down, then charged it up for a few mins while we had a beer. Finally we got it to fire up but it raced, we couldn't get the idle down, and #4 pipe was glowing red hot. He's pretty ****ed at himself for not being able to figure this out, and I sent him home on the condition that he comes back Monday to finish the job.

So here are my questions:
1. Swapping out the shims, standard practice and procedure? They looked spotless, no wear and real pretty, just some were a little close and some were gapped too much.
2. What's wrong with my bike? I really don't know much about valves and cams, but this does sound like carbs to me, something that I've been thru before. Is it possible that we buggered something up while in the carbs, what should I look for?
3. Would all this carb/valve tinkering void the carb synch? Did I waste $250 and a case of beer on some yahoo?
4. What's my next move?

Thanks guys,
Max

[robertbarr]

So here are my questions:
1. Swapping out the shims, standard practice and procedure? They looked spotless, no wear and real pretty, just some were a little close and some were gapped too much.
2. What's wrong with my bike? I really don't know much about valves and cams, but this does sound like carbs to me, something that I've been thru before. Is it possible that we buggered something up while in the carbs, what should I look for?
3. Would all this carb/valve tinkering void the carb synch? Did I waste $250 and a case of beer on some yahoo?
4. What's my next move?

Thanks guys,
Max

Probably the best overall suggestion: Do it yourself, and stay organized. Nobody is going to care more than you about the results. Perhaps this guy thought he was doing good work, but it's pretty obvious he's treading water here.

Swapping shims is SOP. You can look through previous posts on this topic -- I wrote up a reply that explains it pretty well. If it's done CORRECTLY, it's fine.

The sequence is fundamental. Get your valve clearances set first. Any ignition work goes next. THEN, after you've checked for / corrected any intake leaks, do you mess with the carb sync.

A bike that won't idle, or that idles down very gradually, generally is way out of sync. Whether you've wasted your $250 -- well, I guess that's subjective, but if the bike runs WORSE now...

[Jethro]

Oh man, $250 would buy a nice carb synch tool, a valve cover gasket, a brandy new factory shop manual and a pile of shims. Also a bucket of carb dip, new o-rings and float needles and seats.

Bummer man, sounds like he doesn't know much. Anyone who knows thier way wrenching around a bike can go through the valves, clean the carbs, synch them and have it buttoned back up in 4 hours. I'd quit while your behind with this guy... sorry...

[veda_sticks]

Interesting, i had the exact same problem with my gs550 when i got it, hard to start when cold, would not idle and would sometimes race, adjusting idle either made it race high or adjust down and it would slowly come down then die.

I tried cleaning the carbs up and no difference and now my bike wont even start.

I would maybe check the valve timing incase the chain has slipped a tooth, i've heard this happen before, this might make the valves be start to open before the compression cycle has finished.

1 pipe glowing red hot??? sounds like its increadibly lean somewhere stuck float maybe?

[max]

UPDATE:

I took apart number 4 carb and super cleaned it out, threw it all back together and there was a big improvement. I could get it to idle down altho it was still a little crazy, surging and dying a little bit. Took it around the block and the engine was a lot smoother, altho beneath 5000rpms was defiantely lacking in power, like im missing a lot of low end torque or something. Over that is all good, what does this mean?

Thanks

[t3rmin]

Checked your intake boots/intake o-rings yet? Messing with the carbs could have disturbed intake boots that were on their way out already...

[chef1366]

I bet he synced the carbs with the petcock vacuum line off.

[tconroy]

I agree with chef! he did not plug the vacumn line and probably didnt get the idle up to 1750 or whatever the book tells you to sync at.I would do it again and see what happens.The not pay him a dime.Working on you own bike will pay off and you only have yourself to blame if it doesnt act right.At least you will know what you did to make it worse.There is plenty of help right here with whatever you need to do anyway.I would trust the people on here before i would let anybody wrench on my bike.

[max]

I bet that's it. Such a simple thing...

You guys are awesome.