high idling

[OnTheEdge]

As soon as this '86 250R is fired up it revs completely out. I cleaned the carb and adjusted the throttle freeplay. The slide sits all the way down in the carb. It seems as though it is barely getting gas causing it to rev wayyy out. Any ideas? Thanks much!

Nic

[deathman53]

I'm suspecting a air leak of some type, crank seals, sucked in base gaskets, or intake leak.

[norcalduner]

Originally posted by deathman53
I'm suspecting a air leak of some type, crank seals, sucked in base gaskets, or intake leak.

I agree. You will need to perform a leakdown test. Now if you are unfamiliar with this procedure, go to the Duncan Racing website and read the 2 stroke FAQ's section. Keep us updated.

[1promodfan]

This is crazy, I was going to post the same problem. When I first start my bike it revs hard for about 5 to 10 seconds, then it will idle down to normal. Could I be having the same problem as the other guy. When I pull the choke to start, do I need pump the gas 4 or 5 times before I kick it...........or not? Or should I just pull the choke and kick it without giving it any gas?

[norcalduner]

Originally posted by 1promodfan
This is crazy, I was going to post the same problem. When I first start my bike it revs hard for about 5 to 10 seconds, then it will idle down to normal. Could I be having the same problem as the other guy. When I pull the choke to start, do I need pump the gas 4 or 5 times before I kick it...........or not? Or should I just pull the choke and kick it without giving it any gas?

Mine will initially rev hard too for about 5 to 10 seconds BUT it always goes down to normal speed. As I understand this, if you are jetted correctly, you should not need to open the throttle on a cold start since this defeats the purpose of using the choke.

[trx310R#24]

Originally posted by norcalduner
Mine will initially rev hard too for about 5 to 10 seconds BUT it always goes down to normal speed. As I understand this, if you are jetted correctly, you should not need to open the throttle on a cold start since this defeats the purpose of using the choke.

yeah mine to maybe a lil longer idk i never set there an counted lol

[OnTheEdge]

Mine doesn't just rev hard, it revs ALL THE WAY OUT and stays that way too. I thought air leak too but dang I cant find any.

[Aceman]

Make sure your pilot jet and air screw are dialed in also. Duncan has a tuning guide you can follow.

Here's another one I keeped saved in my favorites:

http://justkdx.dirtrider.net/printcarbtuning.html

[dirtysouthmx]

I have an 86 ATC250R with the ESR 310 pv kit 38 mm mukuni v-force reeds MSD ignition system hot rod crank hinson clutches and much more. I have just done a fresh rebuild on the bike and after about 4 tanks of gas it started reving out and then it would start to die and id give it a little gas and it would do the same **** again I have checked everything I can think of and still havent found the prolem any suggestions?

[Jason Hall]

I would suggest you check the jug bolts to be sure it's not sucking air through the base gasket.

Another thing to check Is your right side crank seal. If the seal Is bad, the trans oil could have been partialy sealing It. It might be low on trans oil now, so It could be sucking air through the trans vent.

I had a 86 250r that had an air leak Inbetween the crank case and the transmision. It was the center case gasket. I had a hard time keeping the Idle consistent, for some reason I opened the trans filler cap with the bike running. The engine started screaming. The previous owner didn't Install the case gasket correctly.

Nic, Do you know that on the stock R carb (PJ) the choke knob Is the Idle adjuster? Turning It to the left raises the Idle, turning It to the right lowers It.

[dirtysouthmx]

thanks i will check those areas