I just picked up an 05 250EX. It is in great shape but the engine is knocking. After looking online, it looks like it uses a needle bearing main? It also looks like a typical honda in that you have to buy the entire crank. I have no problem tearing this thing down. Questions, where to get parts? before I do, any other ideas about what could make a rod type knock? If I have the thing tore down, any suggested mods?

 

About the mods, I've heard that the real best mods that are worth the money/time are: Exhaust, Airfilter/Airbox Mods, and jetting. I have all three done to mine and there is a major increase in power, and while you have the carb separate now is the time to do rejetting, otherwise it is a b*tch to do. About all the rest, I really can't help you, just wait for some pro like HondaMechanic/Gimpster or any of the guys who've helped me in the past to help you out.

 

im goin to bore mine out 1mm more and make it a 270cc.. it will have alot more power.. i have a 02 250ex that is knokin too... how u know it the needle bearing main?? and not the piston or valves?

 

I say if its knocking replace the berrings .....if you get it apart there should be no play in the connecting rod ...if theres even a small amount of play replace the berring while its apart....wich youll have to have done most likley by the looks of this 250x crank im looking at...

 

yep.. or valves

 

Thanks, I have it all apart. The crank went. I have a new rod kit coming this week and already have the crank split waiting for a new rod kit. Thamks.

 

how hard was it to split crank and put back together im in same boat