50cc hi comp head on 70cc kit?

So I've been searching for more information on this. All I have found is that it is *possible*, but I haven't found if its reliable. What would a 50cc head do to a 70cc kit? More compression and higher temp or will it be less effective since the squish band doesnt line up with the piston as well?

Re: 50cc hi comp head on 70cc kit?

Probably Fred /

The 70 cc head sucks unmodded so the 50cc

Is unusable

Re: 50cc hi comp head on 70cc kit?

If your piston is too close to the head, you'll get piston slap. Smaller heads can cause detonation because they leave trapped pockets of fuel.

If you plan on using a 50cc head on a 70cc kit, either have a buddy with a lathe turn your head so that you have the proper squish or get comfortable with a set of files and do your best to make it smooth.

If your head has a centered spark plug, you can chuck the spark plug in a drill, thread the head onto the plug, and use some sandpaper to turn down the squish. If you have an old 70cc piston, you can always glue some emery cloth to the top of the piston, and that will give you the correct shape.

You don't want any sharp edges in the combustion chamber.

Re: 50cc hi comp head on 70cc kit?

depends on the kit, if you have some crown to deck clearance you''ll probably be OK, other wise you may create too much compression and ping and/or overheat. If it does ping you could mill as per dirty dave

Re: 50cc hi comp head on 70cc kit?

Josh Koelker /

Great thanks. I have the stock 50cc and a hi comp 50cc. I think I'll try it out and do that spark plug bench press idea before ordering a 70cc head.

Re: 50cc hi comp head on 70cc kit?

Probably Fred /

Stock head needs modding too

Re: 50cc hi comp head on 70cc kit?

NO NO NO NO NO.

no. you are entering a world of pain.

your piston will hit the head unless you do stupid jacked up shit that will make it all way worse.

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