It's (almost) alive!

[robsGS850]

Hi all, guess this one's more of a methodology question:

Over the winter i dove in way over my head and did a ton of work: new .05mm pistons, rebored barrels, rebuilt the carbs (aftermarket kits, still have the OEM parts), sealed my tank, new petcock, even brand new paintjob and correct stock exhaust system.

Finally finished assembling the whole thing bike night, fired it up on a whim (figuring it's going to take a lot of tweaks to get it right), and miraculously it started right up, no holed pistons or anything.

It revs to the ceiling on full choke, runs for a minute or two, then eventually dies out, no matter what i do with the throttle.

Set the petcock to prime to eliminate one variable, but now what?

Guess my question is, what to try next? I want to balance the carbs and set the airscrews correct etc, but right now I just want the bike to keep running long enough to actually tune it.

Right now I've ruled out the new paint job, but I'm open to any theories.

sorry for the long post, hope this makes some kinda sense.

rob

[reddirtrider]

Is your throttle cable stuck open? Make sure your butterflies are closed. There's no way it can 'rev to the ceiling' with them fully closed.

[lucabond]

Is the air box on ?

[robsGS850]

Yep the airbox is on, sealed up with the usual weatherstripping. Didn't service the air filter as it felt well-oiled, but now it's is on my list.

I checked the throttle cable, i had it a tiny bit too tight so I loosened it (pretty sure the butterflies were closed tho). THen unfortunately I had to stop and go vote in our provincial election! That darn democracy. Will take off the tank, rig up some kinda fuel line and start fiddling with the carbs tonight. Thanks for the suggestions.

[robsGS850]

Thanks for the help, finally got it to stay running (very very roughly ... my license plate has never made that much noise from vibration)

Do I need to adjust the valve shims because the +.05mm piston heart transplant?

bonus side question: anyone know the the recommended idle rpm? I've torn my manual apart looking for this, i thought it'd be a simple find. ah well.

thanks again,
rob

[Guest]

You didn't say how many miles have passed since the last valve adjust, but they should certainly not be overlooked.

The factory idle setting states: 1050 +/- 100 RPM.

Did you do a good bench sync before putting the carbs back on the bike??