Idle speed/Question

[Nazdorovie]

Hello reader, I'm new here at GStwin, had a question:
After I run my GS500EK for about 10-15 mins, the idle speed jumps from 1200 to 3000RPM. After a short while the RPMs keep incresing. What's wrong?
P.S.
I just got the bike 2 month ago, the guy who owned it had it for 8 years, but did not have a chance to ride in the past 4-5 years, so the bike has been sitting in his back yard unprotected in the weather. (Seattle - we live in a puddle 9 months out of the year) The bike got moss growing all over it, rust, fuel lines and hoses cracked. I replaced all of that. I do know that the carbs need to be synchronized, and timing needs to be checked. Anything else I need to check?
Thanks for your help.

[The Buddha]

You are lean ... start by opening air screws ... if that dont do much ... and possible that its useless ... dont open past 5 turns ... it will fall out and disappear on the road and I'll have to send you one ... fortunately I have them ... but dont open more than 5 ... anyway the next step is a 40 pilots and heck a rejet ... 125 mains and 1 #4 washer and 3 turns on mix screws ... AKA you are lean, its a "feature", and we offer a patch if you dont like the "feature" ...
Cool.
Srinath.

[Kerry]

You didn't mention whether the carbs have been cleaned since the bike came out of "storage".  Even if you drained out all the old fuel and put new stuff in, there could still be some varnish from the old gas clogging up the jets.  There are a few different ways to clean the carbs (more and less invasive) if it hasn't been done yet.

If they HAVE been cleaned, ignore this post so far.  But you may want to open up the carbs anyway to check the condition of the various O-rings and gaskets - especially the tiny O-ring just under the black cover on top of each carb.

Since the hoses were in such bad shape, I would also check the boots that attach the carbs to the engine.  If they LOOK fine you could try the suggestion in the picture below - while the bike is running.  If the RPMs change then there is a crack or leak of some kind that is allowing extra air in and leaning out the mixture.



Good luck, and let us know what you find.

[Nazdorovie]

[red_phil]

hi,
I think by 'air screws' srinath means the mixture screws on the bottom of the carb, which should be screwed in till they gently bottom out then backed out 3 turns. You can adjust them from there to tune things but about 3 is right apparently.


"40 pilots and heck a rejet" means replace the pilot jet with a size 40 one,
and while your at it you might as well replace the main jet too.
I believe 125 on the main jet and 1 washer to raise the needle is recommended with the standard air filter.

The jets are brass fittings inside the carb and the stock size varies depending on where your bike is from and what year it is.
have a look at this thread in the FAQ forum.
http://www.gstwins.com/forum/viewtopic.php?t=12929