hello , my bike used to have a 17.5 carb on with 70cc engine but i have upgraded to a 21 carb. it used to wheelie off the mark and now doesnt and bogs bak sometimes , also its not as fast up hills. my 17.5 had a 80 main jet in it and this one only has a main jet size 60. the guy said the other 2 jets were bigger than normal so 60 is enough because its the sum of the jets that counts . wat do you think the problem could be :/ it goes about 3 km/h faster but accell is a lot slower any suggestions? ohh and when i throttle if i fully open it bogs loads so i only open bowt 3/4 of the way to get to top speed. thanks
i dont know you have to try it to see you should read the guides to get an idea of jetting as the only way really is trial and error you will have to buy a jet box also the jet out of the 17.5 will not fit your 21mm as your 21 needs 5mm jets not 6mm
Not all 21's use 5mm y'know ? Measure the jet. 60 is far too small though. i'd start at 80 and work your way down. What are your bike setup?
just fixed it , the manifold had a slit in it got a new one and its all ok now. and sorry its a 72 jet got mixed up with my mates carb jet size. thanks for helping
