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XR 70 trailbikes Race Head

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I just got a 97 Xr70 for $200 in non-running condition with only about 10 hrs of use on it. The intake valve was bent, so im either going to get the trailbikes 88cc kit and port the stock head, or buy the kit with the race head. Is the race head worth the extra $125 over a ported head? Most big bore xr50 kits with heads that i have seen use basically a ported xr70 head. Does the Trailbikes race head have bigger valves than the stock xr70? I gotta be able to beat my friends 50's with 88 kits and ported heads! Thanks for the replies

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Yes the TrailBikes head has pretty good sized larger valves than a 70 head. You should be able to whoop your friends with 88 ported heads, the only thing that may be a affect is that the 70 is a good bit heavier and bigger wheels makes it harder to get moving.

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I emailed the guys at hondatrailbike and he said the valves are 23 and 20 mm. I measured the ones from the stock head and they are the same. So i guess im going to stick with porting my stock head and install heavier springs. I havent been able to find any other companies that make big bore kits for the 70, everything is for the 50. Do any of the crf50 kits fit the 70?

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Hmm, I could have sworn the valves were bigger. But you shouldnt need any heavier valve springs, the stock 70 ones are stiff enough. Any of the 50 kits will fit the 70, as long as you have the right piston, because the 70 head uses a domed piston. So any 50 kit that has a head with it will work.

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I talked with Mike at trailbikes a few weeks ago and he indicated that the race head for a 50 was fairly comparable with the stock head on the 70 and he didn't think I'd notice any performance difference. That's why TrailBikes is so great - you get honest advice, not just a sales job.

Forgot to mention - I bought the Trailbikes 88cc kit for my 70. Went on easy and runs like a dream.

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Is that by chance the Dai Ichi kit? Is it anygood? Compared to a Takegawa? I am thinking of getting the kit w/ super head but am concermend that it is chinese junk

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Certainly not chinese junk. Quality is identical to Takegawa or Kitaco, I run the race head motor, have over 150 of hard running hours on my motor and still purs like a kitten.

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So basically porting my 70 head is the way to go. How do the trailbikes manual clutch kits hold up in the 70's. I have heard a lot of good reviews of the kits on 50's, but not 70's.

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Yea, porting it is definetly the way to go then. As for the clutch it should be fine, the 70's are no differnt than a 50.

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