Im gunna bore out and port and polish my blaster i kno i need a bigger carb and was wonderinv if a 30mm will be fine or do i need to go bigger?
Carb size
- Thread starter Jhabeeb
- Start date
If you don't need a rebuild, don't bore it. It won't help with power. Get yourself a good port job and the head redesigned. Look into getting a good pipe to.
Im def gunna get a full exhaust system and im boreing because im rebuilding my engine and my dads friend can bore it for free so i said why not
An agressive trail port, redesigned head , carb, exhaust, UNI air filter. You will have to jet your carb for each mod. You will have to modify the tube from the air filter to carb to fit the 30mm carb.
Port job + Pipe = massive power gains.
Get your mods down, find out (or roughly estimate) what RPMs your running, then get your carb after all that.
Your port job and pipe determine your RPM range. Buy a pipe then port it or have it ported to match the pipe. From there, you need to select your carb. Carbs flow x amount and x rpm. You get a carb to small, youll choke your engine at the higher rpm, if you get a carb to big, then you wont be able to flow enough to utilize the carb.
Heres is a chart i put together for stock bore and stroke(these work fine for large bores also). If it's a big bore or a stroker, carbs need to be bigger. We normally push are machines hard and 34mm is what we run. 30 is perfect for most people, most 125 dirt bikes just so happen to use 34mm carbs.
Get your mods down, find out (or roughly estimate) what RPMs your running, then get your carb after all that.
Your port job and pipe determine your RPM range. Buy a pipe then port it or have it ported to match the pipe. From there, you need to select your carb. Carbs flow x amount and x rpm. You get a carb to small, youll choke your engine at the higher rpm, if you get a carb to big, then you wont be able to flow enough to utilize the carb.
Heres is a chart i put together for stock bore and stroke(these work fine for large bores also). If it's a big bore or a stroker, carbs need to be bigger. We normally push are machines hard and 34mm is what we run. 30 is perfect for most people, most 125 dirt bikes just so happen to use 34mm carbs.
Have your dads friend mic the bore and piston to be sure they are witin spec. If it's out of round/tapered it will need a bore to NEXT size. Also mic piston to check piston/bore clearance, too much is bad. You sending it out for porting or DIY?
Get the port the Carb and exhaust... as stated have the Guy who was gonna bore check the piston clearance and make sure its in spec. If its not get a bore done of it is then get it honed and a new set of rings
