Slower with shift kit

[Sidewinder Jerry]

It's like Ghost0 said its all about horse power and its efficient use. Just about any gear ratio can be made to propel your bike. What this then turns into is a legal question of how much power will your local area allow you to have.

 

[mew905]

Im hitting just over 40 mph on a good day with a shift kit but its taken a lot of tuning to get there and the closer to forty I got the harder it was to find gains. I am running the 9 tooth sprocket on the jack shaft output and have had the best results with that gearing on both climbing and top end speed. I have tried both the 10t and 11t with a few different setups but the 9t has always been best.

I see some people saying that 7th & 8th gears are more for downhill but my bike pulls 7th on flat ground pretty well sometimes even 8th but it wasnt until I made several motor changes such as Hi comp head and Jag ignition that it would pull 7th or 8th. but the 9t sprocket also helps to pull those gears. I dont have a tach yet so I have no idea about rpms thru all this.

I seem to have hit a speed barrier at 40 mph, I have tried a few things and I am running out of other things to try unless I do something drastic. I hit 44 mph a couple days ago but that was a tail wind of about 7-8 mph.

Reading your sig i see you have a sbp pipe, is it short or long? With gearing i would sacrifice launch speed for more high end (make the pipe shorter), unless its already where you feel the boost just before switching gears. Only other things i can suggest is porting (you probably already did), correct the transfers (jb weld, jags site has a tutorial) and/or reeds. With the puch head youve already increased compression to around 115psi, maybe a dellorto carb or better?

 

[Wild Bill]

I really need to get a tach. My header tube is shorter than most because of me wanting to run the pipe up instead of down because I ride in some dry weeds and I could just see some dry brush getting hung up down near the cranks and starting a fire.......I could do without that!

I have a total of about 15" to 16" header tube. I found I get best acceleration if I short shift (Shift at lower rpms) and let it wind out high rpms when Im in 7th or 8th. The engine has good bottom end and a fairly good top end.

I already have a Delorto knock off RT carb from Dax, I havent done any porting or internal motor work yet. I wanted to see what sort of gains could be had by bolt ons and tuning alone. I used to race Karts and I always did my own engine work (Piston port engines). I am ok with the horse power it has for now, Im building a second bike with a KTM clone and that will become my number one bike...... I hope.