98Yamaha YZF600 throttle situation

chris1998 · 06-11-2007, 12:32 PM

I am having some throttle sticking issues when I stop at stop lights. It always sticks between 2500 and 3500 rpm. IF I rev it up the throttle will stick for a few seconds then drop back down slowly. Also after I come to a stop, and its sticking, after about 5 seconds it will slowly come back down as well. It seemed like if I put some force on the throttle grip and tried to twist itfurther than the stop, that it would also drop in rpms a little bit. But I am not sure if thats just a coincidense or not. The throttle feels nice and smooth and its not hanging up anywhere. Any ideas?

Noltz · 06-11-2007, 01:24 PM

Sounds like you have a vacuum leak! It would explain all the problems you're having. I'd check on that, and if no fault found, pull the airbox and make sure the plates are closing all the way. Turn your bars left-right and see if the RPMs jump or drop, indicating a hanging cable somewhere.

Good luck!

Lady Sprocket · 06-11-2007, 02:01 PM

I can't remember if the 98 is carbed or not...but if it is I would suspect the carbs are getting "hung up" & need cleaning.

Otherwise I would try lubing the throttle cable if it hasn't been done for a long time.

zzr-jason · 06-12-2007, 09:28 AM

Give us a little more info. Does the bike have a jet kit ?, was there any service work just performed ?, does the bike sit outside ?, did it just happen or has it been getting worse over time?

chris1998 · 06-14-2007, 01:14 AM

I just got the bike about 2 months ago. I turned the idle down to about 1000 rpms and its not doing it anymore. As for the jet kit I have no idea, and the bike sits inside.

Another thing I noticed though was when you get on the throttle and rev it up, it bogs down a little bit. I wonder if the the air/fuel mixture needs adjusted, or if the carbs are out of sync a little bit.

Lady Sprocket · 06-14-2007, 12:50 PM

Quote:

Originally Posted by chris1998

I just got the bike about 2 months ago. I turned the idle down to about 1000 rpms and its not doing it anymore. As for the jet kit I have no idea, and the bike sits inside.

Another thing I noticed though was when you get on the throttle and rev it up, it bogs down a little bit. I wonder if the the air/fuel mixture needs adjusted, or if the carbs are out of sync a little bit.

I should have thought about the idle...as odd as it sounds I got defensive a few days ago when my RPM's were hanging a bit, but then I turned my idle down a tad & it hasn't done it since, LOL!

I know when I'm running low on fuel and I go for a wheelie (lots of sudden throttle) mine will bog out instead of getting the power, I call it "falling on it's face"...so it may be your mixtures like I mentioned earlier being a bit off if you have eough fuel in your tank.