seems flat

[northeast400]

I went out riding today on the ice. Problem was it pulled strong until up top it seem to flatten out and won' t pull, not even to the stock rev limiter. is this a jetting issue, valve springs, or maybe a wiped out cam? I did a search and found nothing.

[northeast400]

any ideas

[sickmojave]

Has this been a problem before or did it just start?

[northeast400]

don't kow if was happening before because I was breakign it in and never got the rpm's up. first time I noticed it today

[sickmojave]

I would do a plug test to see where you stand with the jetting.

[Out_Sider]

main jet sounds to be maybe too rich, but im not totally sure on it

[K_Fulk]

Try going down on your main jet.

[WhiteBros400ex]

Originally posted by K_Fulk
Try going down on your main jet.

Like he said sounds to rich go down in the main jet what size jet is in there now.

[hondarider2006]

do a plug test.....more than likley that is your problem;)

[phebus]

Try a new plug before changing anything.

[northeast400]

plug is a little dark. after I installed the 426 I keep the jetting the same should I have changed it?

[northeast400]

I installed a new plug and did a proper plug test. It was very lean at wide open throttle. I used a borascope to see the piston and it was clean. I am riching it up and it seems to be running better.

[northeast400]

Ok plug color is now perfect and it still does it pulls hard to about upper mid range than falls on its face.:grr:

[MDE3]

When you did all this work, or had it done, were the valve springs changed? Seem slike a very large lift on the cam, and for that the springs would need changed and probably the valves shortened.

You could well be seeing a problem with the valves never fully closing at higher rpms.

[chrisp333]

did you say that you didn;t change the jetting after you did all of this work on the bike? of was that a type o? if you kept it the same you definately should have changed it...