1987 gs450l idle problems

[frozenfish66]

i have had this problem ever since i got the bike. it starts up fine and runs fine when cold. the problem starts when it gets warm. if you rev it over 3k then let it drop back down to idle it will come down to 3k normally then slowly make its way back down to idle (takes 5-10 sec) the carbs have been cleaned, the slides don't stick and operate properly. i have checked for air leaks with wd-40 and found none. the mixture screws are 2 turns out and a plug chop with new plugs shows a nice brown color on both cylinders.
the carburetor boots and gaskets are also new.

this really inst that big of an issue just an annoyance
when i slow down to a stop if i hold in the clutch it will display the above symptoms so what i normally do it let the clutch out just enough to grab and drop the rpm then pull it back in then it will idle just fine.

also when at speed if i let go of the throttle it acts like cruise control and the bike will slow down until rpms reach 3k then it will keep going at that speed it takes a very long time to drop down to normal

what i haven't done yet is check valves or sync carbs

anybody have an experience with this problem?

[Dave8338]

i have had this problem ever since i got the bike. it starts up fine and runs fine when cold. the problem starts when it gets warm. if you rev it over 3k then let it drop back down to idle it will come down to 3k normally then slowly make its way back down to idle (takes 5-10 sec) the carbs have been cleaned, the slides don't stick and operate properly. i have checked for air leaks with wd-40 and found none. the mixture screws are 2 turns out and a plug chop with new plugs shows a nice brown color on both cylinders.
the carburetor boots and gaskets are also new.

this really inst that big of an issue just an annoyance
when i slow down to a stop if i hold in the clutch it will display the above symptoms so what i normally do it let the clutch out just enough to grab and drop the rpm then pull it back in then it will idle just fine.

also when at speed if i let go of the throttle it acts like cruise control and the bike will slow down until rpms reach 3k then it will keep going at that speed it takes a very long time to drop down to normal

what i haven't done yet is check valves or sync carbs

anybody have an experience with this problem?

You sir...need new throttle cable. A slow and hanging idle that can be manipulated by clutch movement can only (in my small mind) be friction related. You could try to lube the cable, but I would rather KNOW that the cable is not the problem. I have had more than one toy, leave home without my say so, having only a throttle cable that was binding a bit.

The only other issue I can think of that would do the same thing is a slide diaphragm(s) with a pinhole or two.

[Nessism]

Started to write about the intake boots and O-rings then noticed you have changed them.

I'd try 3.5 turns out on the pilot screws, and sync the carbs. Needless to say the valves need to be adjusted as well since they are at the core of the engine and one of the most important things you can do other than changing your oil to make the engine live a long life.

[hillsy]

Started to write about the intake boots and O-rings then noticed you have changed them.

I'd try 3.5 turns out on the pilot screws, and sync the carbs. Needless to say the valves need to be adjusted as well since they are at the core of the engine and one of the most important things you can do other than changing your oil to make the engine live a long life.

Ditto on the pilot screws.

[tom203]

also when at speed if i let go of the throttle it acts like cruise control and the bike will slow down until rpms reach 3k then it will keep going at that speed it takes a very long time to drop down to normal

This part sounds like sticking throttle cable,as Dave8338 said. Maybe the cable is routed poorly or throttle grip itself is sticking.

[frozenfish66]

i don't think its the cable when the motorcycle is off everything operates smoothly and doesn't bind, i will try turning out the screws 3.5 and report back.

*update* turning screws out didn't help. ill take a look at the diaphragms and see if i can spot anything.
also does anybody know of a place in ct that can do valves and sync carbs on a bike this age w/o charging an arm and a leg?

[12Bravo]

I had the same problem with my 83 450E and found that the idle jets were clogged. I cleaned the jets, reset float height and sync'd the carbs and now it works fine.

[frozenfish66]

well it looks like the problem is the valves, today i did a complete tare down of the carbs. dipped, blown out, sprayed and blown again. put it all back together and slightly better but not much. is there anybody in ct that can help me with setting the valves or if anybody has a pdf of the manual for this bike it would be great.