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turbotodd34

best big bore kit for XR80 ?????

9 posts in this topic

Whats up, my name is Todd. Im a new memeber here at ThumperTalk. I wanted to know who makes the best big bore kit for an XR80? I have a Takigawa 88cc for my XR50 and it is amazing. So please let me know about the XR80 kits.

Thanks, Todd

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Powrol makes a 95cc kit for the XR80.

I have a Powroll 120cc kit in my XR100 and it very good kit.

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There are some Japanese kits out there which will big bore the 80. In Japan the 80 is sold as roady/trail bike with lights and in a couple of forms and go fast parts are limited. Im sure the 108cc kit for the XR50 which is NOT a XR50 Z50 motor but a small bore stroke XR100 style motor or CB50 motor in Europe (Yep Japan / Euro is a bit strange in their domestic range and Hi to out Japanese readers) will fit as CDI and cranks are listed as interchangable as a big bore but not as a "50". Finding out if this works is not easy but a couple of us on here found out about a lot of the Japanese stuff way before it all appeared in the States.

But after that a Powroll kit is a very good idea or if you can find on a CB350 4 piston (any O/S) will do nicely in a XR80. XR75's are a bit different depending on the year. TheXR95's rev very well and make good power and you have a better gearbox as the 80 is close ratio compared to the 100. :thumbsup:

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You could also get a KLX 134cc piston, then take it to a machine shop and have them chop the top a little. Then you end up with about 120cc or so with whatever compression you want. Or have them bore your rod 1mm and put in a Wiseco 120cc piston. I know one guy who did that.

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What about a stock KLX110 piston?

Would 2 base gaskets lower the compression enough?

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The stock KLX is probably the same size as a 95cc big bore kit. (although I'm not sure) I've look at the XR80 and KLX piston, and they're real close. The KLX piston is just a tad bit taller. (I didn't measure it) I'm no expert, but it looks like it could work.

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Beware with stacking base gaskets on XR80/100. The gaskets can compress enough to block the oil flow along the "transfer passage" that links the crankcase oil gallery to the barrel gallery. Stock Honda gaskets are the best to avoid the problem.

On the KLX piston the pin to crown height is a lot higher than the XR80. From memory its over 4 mm difference so it would be best to heavily mill the piston for height and valve pockets or add an appropriate spacer under the barrel. We studied it and decided that the 98cc piston was a lot easier in a XR80. KLX piston is good match for a XR75 motors though.

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thanks guys. but I am looking for something bad ass. I found this website that has a 120cc kit for the xr80, but I dont know how good this company is. anybody know? here is the link http://www.xr100.com/xrparts.htm , i would be getting the stage two (the third one down)

thanks, Todd

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Frank is well known but that kit is a XR100 kit. :thumbsup: The XR80 kit is lower down. The XR80 uses a different rod with a smaller pin and the barrel oil gallery is in a different location. The only real alternatives are those listed above.

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