70cc bbk

[skuttadawg]

Yeah 7mm does not sound like much but it was a huge improvement for my 2T when I put on a BBK and pipe . Actually take was less since the new pipe is unrestricted but midrange I can ride a wheelie while going down the rode with 13 wheels instead of 10s like many have and top end goes beyond the 50MPH mark on the speedo and I dont have a GPS to verify . There was a radar that displayed speed and at 20 , 30 and 40 it said my speedo was 4MPH higher than what the radar said all three tests . The BBK also has a larger exhaust port that is fully bored where the 49cc is shaped like a D instead of an O . Stock engine and pipe it would max at 8,000 RPMs and fizzle if I went past that going downhill . With BBK and PM Racing pipe it can hit 10,500 and even 9k while going up a large and steep hill with a running start .

I would try a larger main jet and maybe lighter or heavier rollers and enjoy the stock engine and get a BBK later . Stock I could hit 45 to 50 all day long . With the BBK I have outran two 150s and walk off and leave all other 50 to 80 4T scooters I raced .

Most use 4g or 5g rollers . Mine came with 6g . I tried 4g and they were too light as it sounded like it over revved on takeoff and had a top end loss . Put on a blue finned CDI from PFS and had the same top end but a hair more pep on the bottom and midrange . I mixed up 3 6g and 3 4g to equal 5g and I liked how it ran . I now have 8g sliders to try and cut down the RPMs while on the highway as it drinks way more gas than when it was stock . Takeoff is slower but I love to see the looks on peoples faces when I pass then on my lil screamer .

I would get an iron cylinder since they are cheaper and more forgiving in a soft seize . I have this BBK http://shop.jupiterscooters.net/Cyli...CC-10mmpin.htm it only had a 75MJ which I used on the 50 but it did have a 45 idle jet that was an improvement over the 40IJ with a BBK . I had bought one and it did not have the jets and dang it a wristpin came out and ate up the engine . The second kit had the jets and I tugged on the wristpins before sliding the cylinder down on the 2nd one . You need to measure your wristpins as some use 10mm and others 12mm