97 rm 250 wont rev out

jowek70
Posts
109
Joined
2/9/2023
Location
austin, TX US

Morning forum,

Recently purchased and built a 97 rm250 for the mrs, brand new engine from the bottom up; lots of new parts, etc.  Starts easy, revs nicely, but wont hold an idle and wont rev out clean, sounds like its loading up a bit.  I tinkered with the jets, the ignition timing, swapped pipes (wasn't sure if the stocker was clogged up) and was thinking of playing with the power valve setting.  

I haven't had a chance to ride it yet as we're waiting on suspension yet, but on the stand it doesnt seem to want to rev out, from a sound and feel standpoint, compared to my 98 kx250.

I was thinking maybe i installed the right hand crankshaft seal backwards and its drinking oil?  Haven't had a chance to pull that side apart yet, but i put the seal lips to the outside, away from the crankshaft.  Any advice?  

1
1
|
jowek70
Posts
109
Joined
2/9/2023
Location
austin, TX US
6/8/2026 5:15am
pic 1 1pic 2 1.jpg?VersionId=CZj
1
1
jowek70
Posts
109
Joined
2/9/2023
Location
austin, TX US
6/9/2026 4:07am

oh i forget to mention, could the reeds be causing this? I reused them cause they looked alright, but a new set isn't very expensive so i was gonna pick up one.

6/9/2026 5:44am

Won't idle and won't rev out, could be a number of things...

image 3172.png?VersionId=7Pya99sPXyba7lzS1
1

Post a reply to: 97 rm 250 wont rev out

The Latest