On the big bore issue, I think something isn't optimum with the 250 displacement on this engine. Yes, I know it started life as a 250 before a 300, but the engine just seems ill suited to good power output at 250. Even when you inspect the 250 piston, you see the valve reliefs are way down the sides of the piston toward the top ring. I don't think this is optimum for good intake flow or flame front for combustion. Just going to the 300 jug, which is really 292cc, it seems to wake this engine up way more than the percentage increase of 43cc. When you do any displacement increase from the 300 jug on up, this engine just comes to life. Don't get me wrong, however, when it comes to adding a pipe, opening the intake, and proper jetting. The stock 250 engine definitely picks up more mid-range and top end with those mods. I think the engine is absolutely horrible in stock trim.

 

second that, stock its more like a 125cc bike. I would get the big bore even before the muffler (just drill out the stock one) for the cost diff ,jet it and snorkle and you will have some torque to play with even in this form.

 

Does anybody have Bill Blue contact information?

 

Wow, first post after being a member for 5 months.

bandbcyclerestoration.com

 

Pipes, filters and jet kets would still add to the thrust of a bigbore kit so which ever way you go your not throwing money away.

 

Careful with the drill out on stock. It was very popular early on, but others have confirmed there is little if any benefit, and it ruins the spark arrester, which you probably need for riding on any public off road trails.

 

THIS ^^^


Don't bother drilling out the stocker, it does nothing. If you want more flow out of the stock exhaust you need to cut out the crappy "straw" of an exhaust outlet and put an end-cap with a larger opening on there.

 

Theres NO replacement for displacement. I was extremely let down once I got my 2010. I dumped a few more hundred in it... and Im still not impressed. The carb on that bike sucks too.

This fall... carb & big bore... with all the listed mods.. then she will kick *** for woods bike. I bought mine for the woods because I need it to be registered and street legal! Great size for the price....

 

Wildcard,
What happens to the spark arrester? Is it damaged in the process?

 

If i hadn't already drilled the pipe my mods would have kept the spark arrester intact. Its actually pretty far down in there behind 2 baffles that the "straw" exhaust outlet is attached to. If you simply cut out the straw and not go anyfurther down into the pipe the spark arrester remains untouched.