I have a trailblazer 250. It used to have ok power and when you jump on the throttle it would almost imediatly rev up and go. Its got an aftermarket pipe on it. Its been gradualy losing power over the last several rides and then finaly the top end went away. I re did the top end and put it all back together. Doesn't seem to have any more power than it used to before the top end blew. When you mash the throttle the power isn't there imediatly or just shortly there after. It seems to gradualy rev up to its peak power. Its got a K&N filter (clean). Any thoughts? TIA

 

check your jetting, that is more then likely it, when adding a pipe, you must go richer for results on a 2 stroke. also, did you change clutch springs or put a clutch kit in with the pipe? cause you should..

 

Don't know what they did. I bought the bike for the wife almost a year ago. It already had the pipe on it and ran well. Just recently before the top end went it started losing power. I figured it was the deteriorating topend that was causing the loss of power. I haven't got to take it out and ride it in the open yet but, riding it around the backyard I can tell the throttle response is not what it used to be. I'm gonna take the carb out and clean it tomorrow and see if that helps. Going to get a new plug also. Any other thoughts? TIA

 

Has the weather changed their much lately? That might have something to do with it. You might have to rejet. Also, check the head gasket and make sure it's not leaking.

 

Brand new top end. New gaskets etc. The old head gasket was leaking by however. Whats the stock jet size for a 250? With an after market pipe at sea level what would be a good jet size? TIA

Current mainjet. 130
Pilot 40 i believe. Thats the number on it anyway.
Air screw is 1 1/2 turns out.

 

No difference after cleaning the carb and new plug. Maybe I'm expecting to much. Seems to have had better power in the past. Of course I've been riding a raptor for a year so maybe I'm just trippen. [img]i/expressions/face-icon-small-wink.gif[/img]

Would crank shaft seals be a possible reason for power loss? Anyone have a website that shows the internal combustion sequence of this engine in a picture form? Such as a drawing or somthing. TIA