Building a 4 Stroke that competes with KTM 50s?

Hey guys,

I am looking into upgrading my son's '04 CRF50 to try and compete with the KTM 50s in the PW4-6 classes. I know that it might be easier to just buy him a new KTM Senior but I don't want to spend 3K on a bike that I have to fiddle with all the time (i.e., clutches, new parts, etc.).

The CRF is lagging behind the KTMs in 3 main areas: power, suspension, and weight.

I figure since the big 4s get to run twice the CCs then, I should be able to run at least a 100 cc 4 (maybe a 110) against the 2 stroke 50s.

My question is would an 88 big bore kit or a 110 kit make as much HP as the KTM 50s? If so, are there any shocks and forks that can be adjusted for a kid weighing 60-70lbs? Lastly, are the aftermarket frames and swingarms significantly lighter than the stock components?

I was thinking that I could also throw a 3-speed manual transmission on it too. I just think that it would be really cool to have a little thumper out there on the track banging bars with the 2-strokers. What do you guys think? :naughty:

Do you care to elaborate Huracane?

Check your other post.

Throw a TB 88kit with race head on it.

Are you racing AMA or outlaw? I don't think AMA will allow you to run it. I know around here they run the Honda 50's with the oil injected bikes and they make us put it in 2nd gear and take the shifter off. Got sick of getting beat so we bought an LEM R2. What a POS but it is fast when it runs. Looking forward to 65's.

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