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View Full Version : 1985 atc 250r 36mm carb or 38mm?



william16339
09-20-2012, 10:40 PM
helo i have an 85 atc 250r. i am sick of the crappy 34mm carb...i like my bottomend. i like topend...wich carb would i loose more lowend? also wich would wake up the motor? its a 250 2 stroke not a big bore so you tell me what you think...36vs38. my guess is the 38 will give me more top less lowend, but how much tourque will i loose?

KASEY
09-20-2012, 10:46 PM
without pipe and porting or compression mods a carb is really not going to make that much difference! i have a 310 that will pull your arms out and it only has a 34 mm on it,,

200xranger
09-20-2012, 10:46 PM
an 86 flat side style is a 36mm i think and will be an upgrade from your round slide factory carb. i have a duncan racing 36mm on my R and with reeds exhaust and air filter it does good. if im not mistaking smaller carb=more torque and less top end and vice versa

william16339
09-20-2012, 10:50 PM
yeah i thought so....i want to do some porting to my 250r but its so much money

bkm
09-20-2012, 11:26 PM
an 86 flat side style is a 36mm i think and will be an upgrade from your round slide factory carb. i have a duncan racing 36mm on my R and with reeds exhaust and air filter it does good. if im not mistaking smaller carb=more torque and less top end and vice versaThe '86 carb is a 34mm PJ flat slide.

RIDE-RED 250r
09-23-2012, 07:26 PM
Whatever you decide to do, you need to run the size carb best suited.

In other words, if you a porting, and piping your engine for low end, stick with the smaller bore carb and a reed spacer... Like Kasey's 310 he referred to, sounds like his build was more focused on low-mid.

If you are porting and piping for mid-top, go with the larger bore carb and don't run a reed spacer