want to add a 38mm carb to my 01 cr125

[2-strokes-4-life]

i want to add the bigger carb in hopes of gaining more top end power.i know what i gain on top i will lose off the bottom but thats fine with me since i will keep the stock 36 and if at any point i want some of the low end back,just switch them out.my question is will i need to mod anything to bolt up the bigger carb such as the intake boot or air box boot?any baseline jetting suggestions?eric suggested i try an sst pipe and silencer which i will be ordering very soon since all the searches i have done on it seem to yield good reviews.as of now the bike had a v-force reed cage procircuit pipe and the stock silencer.any input will be much appreciated

 

[marcusgunby]

I fitted a 38mm carb from the 2001 cr250 to the 125-it does give more top, i cant remember jetting specs but it was in a earlier thread, try a search, i remember it was a pain to get jetted right, and it had zero bottom end with the 38mm.

 

[Masterphil]

... and it had zero bottom end with the 38mm.

Kinda makes you wonder how the 125sx has such good bottom end power using a 39mm carb.

 

[MXP1MP]

err I don't think any of the current 125's have good bottom end (here ride my '06 yz 250) in fact just yesterday I was talking with my friend what would happen if I put a 36 mm carb on my 125 shouldn't I get some better bottom at the exspense of topend overrev but we was ridding indoor so it's not like that would matter. sometimes these 125's seem to be over carburated. Langston's 125 sx had a 35 mm carb on it at one point.

 

[Rich Rohrich]

Kinda makes you wonder how the 125sx has such good bottom end power using a 39mm carb.

The design of the intake, reed area, crankcase, and transfers is significantly different. Apples and oranges comparison, so to speak.;)