72 K1 gearing

[j1mmy]

Hi - Now that my K1 is on the road, I notice first gear is such a "granny" gear, i spend a short time in 2nd also, and top speed in 3rd is about 30. I have an 88 cc kit with a stock carb with a 64 main jet and it's a 3 speed automatic.

What changes can I make to get more speed out of first gear and maybe get it it up to 40 mph in 3rd gear? Do I switch out front or rear sprockets or both? More teeth or less teeth?

I don't care about low end grunt (since I'm not going to ride the trails) and I don't want to pop wheelies. I have street tires on it.

The sprockets on the bike are the stock ones as far as I know.

Thanks for your help!

 

[steampick]

Your 88cc should go much faster than 30. You can do a couple of things to get it up into the 40 range. First, you need to get the stock 16mm carb off of it and replace it with something in the 18-20mm range. You'll also need to get an intake manifold that allows the carb to angle out to the side a bit, that way you can put a better air filter on it, like a K&N or something. After that, the expense rises in relation to mph gained. A bigger ported head would increase top speed, and so would a different exhaust. As for your sprokets, if you want more top speed than go with less teeth on the back sprocket (I think stock was 35) and more on the front. That should keep you busy.

 

[j1mmy]

Thanks for the info. I forgot to mention I have a K&N air filter on it already.

I wanted to go with a kehien 18 mm but couldn't find one. I didn't want a 20 mm carb because I didn't want to change the throttle.

 

[MSZ]

Jimmy,

If you swap out the semi-automatic clutch and go with one of those Trailbikes manual clutches, get a 20mm carb for use with the stock head, and run 16/35 gearing, your bike will be capable of over 50mph and may hit 55. I'd ditch the stock exhaust and get a good flowing aftermarket one as well.

My 1993 with an 88cc kit went 55mph with the 3 speed no problem with 16/35 gearing. I ran a 20mm carb and aftermarket exhaust.

Dan