Thread: more rpm's out of motor

I was just wondering if there is any way to get more rpms out of a stock ct70?... well stock all except the carburator, air filter and valve springs. I installed the heavy duty valve springs when I put a race cam in. I have taken the race cam out and put the stock cam back in. I also have replaced the stock carb with a pz19 carb. I ground out the intake manifold about two millimeters in diameter on the carburator end so the inside diameter would be closer to that of the after market carb. Is there anything I can do to allow the the bike to rev higher? With the stiffer springs I don't think I have to worry about floating the valves or over reving it.

Also, this has nothing to do with rpms, but I did a compression test the other day and is was able to max out at 170-180 psi. How good of compression is this for that engine?

sprocket change maybe.
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put your race cam back in there, put a performance pipe on there, and rejet your carb and you'll get more power and more revs. Then regear to take advange of it.

Personally, my favorite combo on a stock motor is a mikuni vm20 carb, supertrapp exhaust, and a cl70 camshaft.

Why did you remove the race cam ?

Does anyone know how much more seat pressure the HD springs have than stock ?

I would think that the HD springs would actually rob power in a stock config.

I've heard some try the quad electrode spark plug but not sure if they help, haven't tried it yet.

always the nitrous, about 10hp shot.lol

More rpm's arent nessesary,more torque is the ticket. and the biggest bang for the buck is a stroker crank.of course you will need to modify around the the crank.exhaust,cam,headwork or pickup a race head,HD clutch etc. a pz19 works best with a 88cc setup.but with a stroker crank+88kit the vm22 mikuni works better on that set up.with my stroker setup,it pulls up hills in fourth gear,and will pull to 60mph real quick in that configuration.16-33 sprockets.

Originally Posted by P.C.

More rpm's arent nessesary,more torque is the ticket. and the biggest bang for the buck is a stroker crank.of course you will need to modify around the the crank.exhaust,cam,headwork or pickup a race head,HD clutch etc. a pz19 works best with a 88cc setup.but with a stroker crank+88kit the vm22 mikuni works better on that set up.with my stroker setup,it pulls up hills in fourth gear,and will pull to 60mph real quick in that configuration.16-33 sprockets.

...and plus it sounds awesome, forgot that.

Why did you remove the race cam ?

I took the race cam out because I had heard allot of bad reports on this cam... Such as it kills your low end torque and they are cheaply made and can mess up a stock head. Indeed, when I took it out, it was worn down at least 1mm on the lobes.