Post by: yzkxf250 on June 26, 2013, 03:31:36 AM
I have just joined this forum for the purpose of trying to solve my yz250 issue.
Ok so i have a 2002 yz250 that suddenly lost power one day, it was running great then all of a sudden the engine refused to have any power in the higher gears, the bike runs great in 1st 2nd and then when im at high revs in 3rd it bogs down quite alot, it still accelerates but just not as it normally should, nor does it sound good at all,
1.The engine has a fresh top end, piston and rings, less than 1 hour on it.
2.fresh set of reeds less than 15mins on them
3.rebuild kit in carb including new float,
4.i believe its a 175 jet and on the 2nd clip for needle.
5.power valve was cleaned, i believe this is working fine.
6.carb has been cleaned many of times.
i have also noticed a grey oil that seems to gather round the carb, which is visable when the carb is removed.
could the crank seals have gone?
could it be the tpi?
I am pretty new to 2 stroke so any help from you guys would be appreciated
Post by: TMKIWI on June 26, 2013, 07:57:06 AM
Check your trans fluid.
Post by: Stusmoke on June 27, 2013, 08:42:04 AM
Post by: evo550 on June 27, 2013, 01:17:14 PM
Post by: yzkxf250 on June 27, 2013, 07:47:24 PM
The plug is a nice tan colour. It starts great runs nice on stand etc. Idles fine to.
The power valve got a good clean but it definitely doesnt run at all in the power band. That is where the bogging comes from.
Post by: _X_ on June 27, 2013, 11:07:00 PM
PV stopped working ?x2
Post by: Stusmoke on July 01, 2013, 07:53:24 AM
Im jet to drain the tranny fluid.
The plug is a nice tan colour. It starts great runs nice on stand etc. Idles fine to.
The power valve got a good clean but it definitely doesnt run at all in the power band. That is where the bogging comes from.
In that case its more than likely a powervalve issue. Pull it apart and make sure everything is in good nick.
Post by: eprovenzano on July 01, 2013, 12:59:00 PM
Post by: rlaj1004 on July 23, 2013, 12:42:47 PM
It ran fine, low, idled great
When he did the top end, he clocked the PV incorrectly. Everthing looked right, ran right but no power as it revved. He has a shop manual and looked at a friends bike to compare but once he saw the problem it was, No ****. I think he had it 180 out??
I remember reading something about making sure the piston is TDC when you hook it up, but don't hold me to that. I will try and find it.
Post by: cnrcpla on March 04, 2013, 04:30:38 PM
Post by: Stusmoke on March 04, 2013, 08:43:14 PM
Post by: _X_ on March 04, 2013, 09:03:30 PM
Post by: Stusmoke on March 04, 2013, 10:11:58 PM