Idles Too Fast

[Keith Meatyard]

70 Steeltanker 125 that runs well, but it idles too fast even with stop screw not touching slide, plenty of slack in cable.  Got any suggestions on what to look for?

Thanks

Keith Meatyard

[Paul Danik]

Keith,  

Are you sure the slide is coming down all the way even without the idle screw being involved? Sometimes from hitting the idle screw over time a slide will get a bit of a burr or bumped out area on it, causing it to not slide down all the way properly. You should be able to hear the slide hitting bottom with a metal to metal sound.

   Is the engine running properly except for the high idle? If not you may have a leaky crank seal on the ignition side, it has to get the air from somewhere. I would check over the side very carefully first.I wonder if the choke could play a part in letting it idle fast, maybe one of the others has a few thoughts on this.

Hope this helps.

Paul

[Keith Meatyard]

Paul, the slide definitely bottoms soundly when you snap the throttle.  I do want to take the carb back off and see if the insulating washer and bushing all look proper as shown in the parts manual.  This motor and carb was all put together by someone else, and I want to be sure everything is there that is supposed to be.  The crank seal could be the issue, as when the motor revs, it will slowly return to it's lowest rpm like it has an air leak.  Can that seal be changed after taking off the ignition plate somewhat like a KTM motor?

Keith Meatyard

[Rocket]

With the bike running, mag cover off, spray carb cleaner around the back side of the ignition and also around the cylinder side of the carb. If RPM changes you found the area that needs attention.

[Paul Danik]

If you determine thru Rod's method that the seal is the problem, yes, it can be changed from the outside, but it is a much different procedure than with the KTM engine.

It involves removing the ignition and any mounting plates to get clean access of the seal, and then using some creative methods to pull the seal out towards you without doing any damage to the case, crank, or causing you to lose red fluid from your body:)

Details and suggestions can follow if you determine the seal is the issue. I am sure that others have some great thoughts on this procedure as well.

Paul

[Keith Meatyard]

I will pick up some carb cleaner and check per Rocket's method.  I assume from Paul's description, the seal is pressed into the case from the outside by sliding it down the crank journal and tapping it in using a piece of tubing.

Keith Meatyard