Power / Revs Problem

[aln_gs500]

Hi,

I got my GS500 fixed a while back and since then I have never been able to get it into the 'red line' area on my revs clock -it gets too about 7/800 and then it seems to jerk a bit (jerks is too strong a word for it).  Before I got it fixed this never happened, apparenty there was a problem with the jets and it had to re-shimmed. (See http://gstwins.com/gsboard/index.php?topic=21879.0 ).

What could the issue be here, my dealer is a dead loss so I will have to figure this out for myself

Thanks,
Alan

[Egaeus]

Reshimming has nothing to do with jets.  If there's a problem with your jets, then it's a carb problem.  Valves are reshimmed. 

Also, I read your other post.  If they called it a rocker cover, then they're stuck on pushrod motorcycle engines (aka Harleys), and shouldn't be trusted with any engine that can go over 5500 RPM without shaking itself apart.  There are no rocker arms in the GS, or other overhead cam engines. 

It sounds like it might be starving for fuel.  If it's limiting revs, then you might need to clean the carburetor, paying special attention to the main jets.  Rejetting it to 40 pilots and 125 mains (if it's pre-2001) wouldn't hurt.  I can't think of anything else that would be causing that specific problem.  Maybe someone else would have a better idea.

[scratch]

Is hesitation the word you're looking for?  That is an indication that it is lean.  Now, you have a 2002 and you're in Ireland, so you're jetting is going to be different, but that is most likely what is going to fix it (if the dealer did the valve adjustment right (who'd they send it too?  A Suzuki dealership?  If so, try dealing with them directly)).

Another thing is that your bike may have a restrictor in it, restricting it to 33hp.  I think UK has some kind of law that restricts it, if it is a learner's bike.  Maybe find out where the bike came from, or what it's history is.

[aln_gs500]

Hi, 

That's a better word alright scratch, whenever it starts doing that I ease off as I'm afraid to push it - maybe it would do it (could I damage it doing this?). It's not restricted, the last rider had his full licence > 2yrs so that avoids that in Ireland.

The funny thing is; it ran so really after I got it back, so I figured that the reason it was happening was that they had tuned it so well (I've no mechanical savvy!), and that the revs clock and enigne were out of sync or something.

They told me they did all of it, bar the shimming themselves - I have started to lose faith in these people (garages in general) - so who knows what they did. 

I'll try to see if it will push on further, and maybe see about the jetting as well -it's well out of peak condition at the moment so it won't be any harm.

thanks Egaeus  / scratch.

[Egaeus]

Running too lean is a good way to damage an engine, especially an air-cooled one.  It causes the engine to run hotter.  It sounds like you might have clogged jets, which could be fixed with a cleaning.  However, since the bikes are jetted lean anyway, you should consider rejetting the carburetor.  I don't know the recommended rejetting for your year model offhand, but I know that I've read it here.  It's probably in the FAQ's.  If not, then a search should bring it up.  The result is a better-running engine at the expense of slightly fincreased emissions and slightly lower fuel efficiency.