CN250 type engine the Honda CH250

Posts: 5

Hello buggy fanatics!!!

I am from the Scooter side but we share the same CN250 type engine in our machines (or at least for some of us).

I wanted to find out what gains the DrPulley variator gives? Scooters have the option of a Malossi Variator, and I was wondering which had the better performance...?

The other thing I would love info about is those strange rollers that are not round they sell for buggies, what is the advantage of these?

Sorry to barge in with the scooter aspect u can always kik me out if I am a pain Laughing

Hope to here from you soon Very Happy

Posts: 1387

The CVT system consists of a variator and clutch assembly.

In the variator there are either rollers or sliders that move to the outer edge as variator RPMs increase. This pushes the wedged pulleys closer together and makes the belt ride higher creating an upshift in ratios. The weight of these rollers or sliders determines how fast your CVT "upshifts". Sliders have the advantage of not wearing as fast as roller but have more drag so an equivalent slider is 2g heavier than a roller. There are some variators that have a larger face - This translates into taller final ratio. Some variators will also change the ramp angle - This will slightly affect the ratio rate of change.

The clutch assembly has a torque spring that helps determine how fast the CVT will "downshift" when torque is removed. On the clutch are three small springs. Each holds back the clutch pad arm until centrifugal force overpowers the spring. This would be your clutch engagement RPM.

The buggies are much heavier than scooter and typically climb hills, so we tune the CVT to stay in low ratios longer before getting into the top ratio. With your scooter, you could retune your CVT but you need it to transition to higher gears faster than our buggies.

Posts: 5

Thanx pghruby for your answer Very Happy

I get what you mean you guys are looking at different ratios for off road work Wink

But I guess that all the engine upgrades would be valid for a scooter? I was thinking that a upgraded rev limiter might have some advantage... Is there a way of finding out the max rpm of my rev limiter? can I use a multimeter or something to measure this?

Great forum must say with loads of info Wink

Posts: 1387

To improve your scooter performance get the following:

1. Replace airbox with a low restriction intake and filter
2. Rejet caburetor to take advantage of above
3. Replace CDI and coil with performance unit
4. Replace spark plug with a NGK Iridium

Posts: 5

Hi I have just recieved all my parts, and would need your advice on how to use the adjustable CDI unit that came for the CN250. Is it pre-adjusted to a given rpm? There is one little adjuster on my unit what is the best procedure to adjust the CDI? I also am not used to the mono-cylinder setup as I am normally into cars... how might I setup a tacho to check my max RPM?

Sorry about all the newbie questions Embarassed