"Idle" threats...

[vtlion]

Hey all.  I just bought my first bike.  A 97 GS500E.  It's in great condition, but I'm having one problem... As the bike heats up, the engine races to about 4000rpm.  the throttle play seems fine and despite my best efforts to adjust the idle using the screw for this purpose, the engine still attempts to idle at or about 4000rpm from time to time.  When this phenomenon occurs, If i have the bike in gear and release the clutch just until I feel the trany engage, the idle returns to normal (even after i squeeze the clutch back to disengage the transmission) only to gun again at some apparently random time.

It has come to my attention that the person who previously owned this bike ran it with the choke open.  Could this be the cause of my problem, or is it more likely my inexperience with the idle adjustment?

Any advice would be appreciated.

[glenn9171]

"As the bike heats up, the engine races to about 4000rpm."  Is this with the choke on?  The revs will climb as the bike warms up with the choke on.  Just lower the choke to keep it about 2500-3000 RPM.  Use the idle adjustment screw to get the warm temperature idle to 1200 RPM.  This takes about 10 minutes or so to get it hot enough for a consistent idle at this speed.

[vtlion]

Nope... this is happening with the choke fully closed.  I guess the question I'm hitting at here is "can running the bike for 8000 miles with the choke opened cause any problems or damage?"  I'm really just not sure whether the kid who owned it before having run it with the choke opened for 8000 miles has something to do with my woes, or if its just my own inexperience with adjusting the idle  (I'm not the most mechanically gifted individual).  Either way, this may be a job for my local dealer, spontaneously revving engines and novices don't mix  :lol:  I'll keep trying to get it adjusted.  Thanks for the response.

[The Buddha]

Lean at the low revs....40 pilots to fix this or you may hvae a vacuum leak. Make sure its not a leak, make sure all the carb o-rings and air box hoses are intact and then put in 40 pilots. You may be able to adjust your air screw to help the issue as well. So if the brass plugs are out try that first. If not...well the carbs are going to have to come off anyway and you might as well put in 40's.
Cool.
Srinath.

[pantablo]

what srinath is trying to say (partially) is that the bike comes lean from the factory. This causes the condition you have in addition to cold starting problems (its cold blooded to start and takes a while to warm up in colder weather). This is solved by jetting the carbs-40 pilots, etc per srinath. Or check my site on rejetting carbs pages where I describe it all (again qouting mostly srinath on my page).

What I've done is set the idle speed when it was doing that to about 2000 so that most time it idles where it should.

Running with choke all the time would run really rich and probably wouldnt run very well but other than foul the plugs probably not harm anything.

[Rema1000]

I noticed something similar:  my '92 idles at about 1200 once it has warmed-up (run long-enough to run smoothly without choke).  Then I take it for a spin on city streets, and after 5 or 10 minutes, I notice that at stoplights (first gear, clutch pulled), the idle is down to about 800, but it is still smooth and doesn't die.

Friday after work, I did some mixed freeway and highway driving in high heat for about 20 minutes, and when I returned to city streets, the idle at stoplights (first gear, clutch pulled) was about 2k.  It stayed that way until the end of the ride.  The next day, things were back to normal (1k idle).  I'm sure that the choke lever was not on Friday evening, but for some reason, my idle was stuck high for a ride.

[glenn9171]

The warmer the engine, the higher the revs will be at idle.  To get an "accurate" idle speed, you need to adjust it to 1200 rpm after it is fully warmed up. (At least 10-15 minutes of riding).

[vtlion]

Hey all.. thanks for the tips.  I decided to leave this problem to the pros, and here's what I was told:  

A bad spring in the carbs was preventing them from fully closing, causing the engine to race at apparently random times (usually when I gunned the engine) because they couldn't completely close and return to a proper idle.  The reason the previous owner ran the bike with the choke open was to compensate for the bike running rich by adding more air to the mixture.  Its all been corrected and I'm back on the road!!!

[The Buddha]

Yea... I dont buy it... way to many contradictions...
1. Choke makes it richer...not adding air... it replaces some of the air with gasoline.
2. Random nothing if you had a bad slide spring...besides it wont "allow it not to seat, it will prevent it from opening and wont race when the throttle is blipped...it will kill revs over 1/2 throttle...will feel like you'll never get past 5K or so.
Anything carb related will do it all the time when a specicic condition is encountered. Like for example...runs bad after warming up...will always do it if its warmed up. The issue was some else that they fixed accidentally...they just figured the'd sound smarter than saying well we had no idea so we started opening it and we put it back and its fine.
Hopefully the "bad spring" wasn't too expensive to replace and even more so...hope the problem is really fixed.
Cool.
Srinath.

[vtlion]

Don't trust my explanation of the diagnosis completely, I suck at anything mechanical.  I'm sure I rehashed it incorrectly in my post.

I'm just glad that the bike is running well, and even after the repair bill, I still come in under the book value... so I can still say it was a good purchase.

[pantablo]

Yeah, dont pay too much mind to Srinath...after all, you're happy, your bike runs and you're not out of pocket more than the bike is worth. Sounds like a good result to me.

Now you can enjoy the bike!

[The Buddha]

Pablo...your sig...damn I should shut up more often...It sounds stupid...

OK how's this, take out the mountains and the ocean part, and add in Meth labs and mexicans and I am living in fresno...
OK...that's about right...
Cool.
Srinath.