High Idle after riding for a bit

[motoDMD]

Hey guys,

So I thought I had worked out most of the kinks with the 89 that i bought but it is still being a little nancy.

Pretty much here's the deal.  After I got the bike, I took apart the carbs and rebuilt them/cleaned them making sure everything was according to the manual because the bike was idling incorrectly and wouldn't start.  Now I can get the bike to start no problem and the idle is fine.  However, after I ride for a few minutes (when the bike is technically warm according to most of the posts on this site), the idle goes up to about 2-3k rpm and stays up there.  Adjusting the idle does nothing, but when I shut the bike off and back on it readjusts back to 1-2 about and then when I start riding the next time I come to a light and let it idle it is back at 2-3.

I'm wondering what I should do.  Is it bad for the bike and I should I not ride it until i resolve it?

Otherwise the bike runs fine more or less.

any tips appreciated.

thanks



ps. can't wait for school to end so i can repaint that baby

i just read an FAQ about fuel screws, i assume that differs from adjustments made to the idle screw and the throttle cable, correct. thankee.

[Big Rich]

Is your choke operating correctly?

[Jared]

You have a vacuum leak. You say you rebuilt the carbs... did you  get  kits and replace the orings/seats/gaskets etc or just cleaned and reassembled with the old parts?

The intakes are often one of the culprits on older bikes. They dry rot and they will often look fine. If you haven't replaced them (25-30$ each ) it's a good idea.

[ben2go]

Sounds like a vacuum leak or a lean condition caused by a partially plugged pilot jet.Have you sprayed anything around the intake boots, while running the bike, without the tank on,to check for vacuum leaks?

[motoDMD]

@ Jared and ben2go:  Just cleaned and replaced the parts that were already on there, the rings and parts seemed clean and fairly new, i could see no issues in comparison with manual pictures or other descriptions.  I have not done the leak check.  I will try to do that since you mentioned that it's hard to catch with the naked eye.  If leaky, the rpms should jump if i use WD40 or something of that nature correct?

In the meantime, can the bike still be ridden or do I run risk of ruining anything since I'm really busy for the next 2 weeks and won't have access to this sorta stuff.

@Big Rich:  yes the choke is operating fine

[ben2go]

If you have a leak and spray the intake to carb boots with WD 40,then yes.The engine will increase in rpms.If the bike is running in a lean state you run the risk of overheating or burning a valve.Have you done a valve adjustment or carb balance/sync lately?When my carbs were out of sync it would cause idle issues.It's best to balance/sync the carbs after a valve adjustment.It's so easy, that I do it every time I adjust the valves just to be sure.

[motoDMD]

Ok I will check with the WD40 and see if I can find something to sync the carbs with... Still new to this game ;P

Either way, you suggest I avoid riding correct?  I can live with that...not happily though...

[Jared]

The O rings in the carb tops may also be a source of a leak. Carb Kits are  15$ each at Partsnmore.com  ( part #48-1947 )  should you want to  change those parts to be sure...

Yeah you want to fix it... 

[motoDMD]

Righto then.  To the truck with me it is! I'll keep you guys updated when I have time to take the poor baby apart again.  Dental school is currently kicking me in the rear so a few more weeks and I'm free for a little while. Thanks for the help and ill keep you posted.