86 honda 70 fourtrax rebuild question's

4 posts in this topic

Newbee here and got a few questions for ya! I'm working on honda 70 and looking to find some aftermarket parts for it without going to local honda shop and spending a fortune. lol

I race karts here in NC and going to make a pit bike to ride around on and just wanting to hop it up a little.Just wandering if anyone knows where I could find a aftermarket cam with more grunt than a stock cam? My plans so far is to do some port'n and polishing on the head, boring out the cylinder and put'n in a little bigger piston. Can I get a piston and rings lets say .020 to .030 over? Also has anyone ever milled the head down for more cc's on these little motors? Would there be enough valve clearance if you did? Any help or advise would greatly appreciated! Thanks,,

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I moved this thread into the Honda forum, when you actually start the project, you can start a thread in the project room to document the process.

I always recommend Service Honda or Babbits online parts for good prices on O.E.M parts. As far as working on the machine, I know no one who has, nor have I. I do know that some parts may be hard to find. Although, most of these new knockoff m/c's and atvs use old Engines that are based almost entirely off of those old Honda motors, there may be some cross-compatability with parts, who knows.

Edited by DirtDemon

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Thanks for the reply. Right now I' waiting on parts to get here. I'm done with the port'n and polishing of the head and intake. I've milled the head down a few thousands to add a little more compression. Its funny you mentioned about parts interchanging. I was going to lap the valves in last night and noticed that the intake valve had all but pulled thru the seat. I got to looking around and found a GX 140 ohv engine in the corner. Pulled the valves out and wat u know they'll work! lol We use alot of parts off of the GX 140 -200 on our karts and can get parts dirt cheap. The oem valve for this 70 cost 20 bucks. The valve off of the gx, $5. lol

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Very nice, please keep in touch and let us know how everything goes. Feel free to post any pictures of the project as you go.

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