kawasaki kv75 engine mods
- Thread starter johnson281
- Start date
- Tags engine kawasaki kv75 mods
Since it's a two stroke it is relatively easy and cheap to get a little more power.
Mill the head .020 to .030 and re cut the squish band to match bore. Don't exceed 150 psi cranking pressure or you will inhibit flow through the transfers.
Raise the exhaust port .030 and widen slightly. Don't get radical here. Raising the port too much will kill all low end. With such a small displacement you don't have much to begin with.
Those two mods should give you about a thousand more rpm and 10% more hp. If you want more, try to find an expansion chamber made for your bike. If you can't find a good chamber you can modify the baffle in the stock muffler but I would have to see a picture of the baffle to suggest how to modify. Don't recall ever seeing the baffle from a 75cc. Just removing the baffle usually does more harm than good; it makes the stinger diameter too large.
You will likely need to raise the needle (lower the clip) in the carb and go up one or two sizes on the main jet. A good flow through air filter will help also.
Mill the head .020 to .030 and re cut the squish band to match bore. Don't exceed 150 psi cranking pressure or you will inhibit flow through the transfers.
Raise the exhaust port .030 and widen slightly. Don't get radical here. Raising the port too much will kill all low end. With such a small displacement you don't have much to begin with.
Those two mods should give you about a thousand more rpm and 10% more hp. If you want more, try to find an expansion chamber made for your bike. If you can't find a good chamber you can modify the baffle in the stock muffler but I would have to see a picture of the baffle to suggest how to modify. Don't recall ever seeing the baffle from a 75cc. Just removing the baffle usually does more harm than good; it makes the stinger diameter too large.
You will likely need to raise the needle (lower the clip) in the carb and go up one or two sizes on the main jet. A good flow through air filter will help also.
This has the port timing specs, as a reference, starting point.
Looks like it could use more compression and port duration.
Transfers are pretty small. Adding a reed block would allow a boost port on intake side, helping a lot.
http://sundry.tech.purdue.edu/mleasure/Personal/KV75-Service-Manual.pdf
I was eying a Yamaha Chappy 80 jug, similar but with a big reed area. Possible swap. Same source for aftermarket pipe options.
Looks like it could use more compression and port duration.
Transfers are pretty small. Adding a reed block would allow a boost port on intake side, helping a lot.
http://sundry.tech.purdue.edu/mleasure/Personal/KV75-Service-Manual.pdf
I was eying a Yamaha Chappy 80 jug, similar but with a big reed area. Possible swap. Same source for aftermarket pipe options.
