big bore kx250

[bansheedave]

300 big bore. best mod ever. awsome woods machine. now i need a 500 and a 125 to complete my collection.

[KXDINO]

Can you please tell us more,what brand ,what model engine,does it vibrate more etc.

[bansheedave]

it is an LaSleeve 300 big bore. bored .020 over. it is a 94 kx250 with a complete wiseco top and bottom. as for vibration, it doesn't vibrate any more than normal. i'm running 14/50 gearing which seems to be perfect for woods. i've had to play with the jetting a bit. when it was stock bore it was spot on. for some reason i have had to drop both pilot and main. it is at 35 pilot and 158 main, needle clip 2nd from the top, air/fuel screw 2 turns out and an NGK br8es plug. i did a compression test cause this thing is a bear to kick over. i read 238 psi. she has a routine in order to start, kinda like a 500. piston needs to be top dead center and kick all the way threw the stroke to start. i like her. oh, and the frame and plastic is 99, the motor and suspension is all 94. running ebay aluminum radiators as well. they fit well, constructed nicely and the motor never over heated with them. very impressed

[bansheedave]

and it scared my neighbor. lol he has a modded crf250r and my bike pulls and hits harder.

[DoldGuy]

A little confused (it's normal).....you say .020" over? What size (mm) piston do you have?

Glad to see you are happy with it & keeping the smokers alive.

DoldGuy

[bansheedave]

A little confused (it's normal).....you say .020" over? What size (mm) piston do you have?

Glad to see you are happy with it & keeping the smokers alive.

DoldGuy

its a 73.45 mm piston

[Spac]

Having to lean off jetting is normal. The larger motor creates a higher vacuum through the carb, making it run richer. This is why a KTM125 will run much larger jets than a KTM380 with the same size carb.

A fresh motor is also more efficient at drawing air in, which has the same effect.