Thumpstar 125 4spd swap to a auto engine.

[aflawinhumanity]

I know this may sound counter productive but I would like to swap out the 125cc engine that is 4spd with clutch for and engine that is automatic. I scored the bike basically for free and my 6 yr old son wants a dirt bike for Christmas. He has an Xtreme 90cc quad he has rode for 2 yrs. Its an auto. I don't think my son is ready for a clutch yet. I have taught my nephews and wife how to use a clutch but the aren't that little and it was on a quad.

So I was wondering if you quys had a good idea of an engine that would make an easy swap. I was reading posts and usually its all about better performance and not tuning the bike down. Maybe someone has swapped from a 110 auto to a 125 and can tell me what was involved or shoot me a link to their post seeing I was having a heck of a time finding anything.

Thanks

 

[Phil67]

I would think any auto engine would fit, 88cc?

 

[Westyftw]

what brand of engine is in it at the moment. Most likely you can just take it out and bolt in a new one. It might be better trying to teach him the clutch i found on a pit bike if i let the clutch go it won't stall like my MX bike it just depends. It shouldn't be a problem depending on what frame style it is. If your worried about power maybe put a limiter on it. Can you post a picture up of where the engine is bolted to the frame most likely its a crf50 style. If you know what brand it is that probably would be good.

Heres a link for a 110 engine it would fit most frames on the market these days. : Lifan 110cc SEMI AUTO RACING ENGINE 4 ST, 1P52FMH

 

[Rodney68]

I fitted a 110cc semi-auto Lifan engine into a bike that had a 125cc clutch engine in it. It fitted straight in the frame with no dramas everything lined up very easy. Just had to muck around with the wiring a bit changing the connections etc.

 

[zwebx]

Whole Clutch Kit(Front semi clutch) - Pit Bike Engine Parts - CLUTCH KITS - TRC-2425 - TBolt USA, LLC
if you are mechanically minded it should not be to hard
if your not so mechanicly minded
http://www.miniriders.com/mini-tutorials-how-tos/22107-how-replace-clutch-lifan-140-a.html

also look at alexmans videos on youtube

 

[Westyftw]

Whole Clutch Kit(Front semi clutch) - Pit Bike Engine Parts - CLUTCH KITS - TRC-2425 - TBolt USA, LLC
if you are mechanically minded it should not be to hard
if your not so mechanicly minded
http://www.miniriders.com/mini-tutorials-how-tos/22107-how-replace-clutch-lifan-140-a.html

also look at alexmans videos on youtube

Yeah i reckon that might be a better way actually.

 

[aflawinhumanity]

You guys are a lot of help. Thank you. I am mechanically inclined and think that the auto clutch would be great. That's a lot easier than a swap where I may have to modify wiring. And it will get him started on a shifter without the hassle of a clutch and stalling the bike.