OzVMX Forum
Marque Remarks => Honda => Topic started by: Simo63 on October 11, 2012, 08:45:59 am
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This question is for the XR75/80 fanatics :)
I'm rebuilding an XR80 for my young fella and wanted to rebore it so figured a big bore would be the go.
Not interested in going 120cc as it will still have standard carb, ports and pipe, just wanted a bit more grunt.
What are the options?
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leave it stock or buy a 125.Its that simple.
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leave it stock or buy a 125.Its that simple.
Thanks but not what I was after.
Anyone got any helpful ideas/hints/tips?
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Wiseco & probably some others do a 2mm oversize piston that gives 83cc,I think thats as big as you can go with stock sleeve :)
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Simo you can use a CB400F piston in an XR80, it will take it out to around 98cc, you should be able to use the std carb as a TL125 uses the same size carb, I have a CB400F piston for my 78 XR75, it only works in the 5 speed XR75 if you use an XR80 crank and barrel, (you can't use a 5 sp XR75 crank and barrel as the crank stroke and barrel are to short) the CB400F piston is just over 50mm dia and has a 13mm piston pin, (does not work in a 4 speed XR75 motor) ;)
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Check these guys out
http://www.big50.com.au/items.php?section=parts&category=XR parts
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http://www.socalxrs.com/ http://www.powroll.com/ http://www.webcamshafts.com/ I have built a lot of very fast xr75 80 100 . Do not port the head , the ports are two big for the stock motor. A good reverse cone pipe, XR200 carb. web cam, XR50 ignition,
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Simo wouldnt have aspare head mate, just picked up project and it needs a head as the two I have has flogged out cam journals ???
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ozyditcher, I have a 77 xr75 [5 speed] bike laying around and a xr100 engine. Is there a good combo there I can mix to make a little rocket.
Cheers Troy
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The 100 donk will bolt straight into the 75 chassis ;)
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ozyditcher, I have a 77 xr75 [5 speed] bike laying around and a xr100 engine. Is there a good combo there I can mix to make a little rocket.
Cheers Troy
The xr 100 will bolt in the xr75. Put a 120cc kit in it and good reverse cone pipe on it this is a good cheep mod 10 hp. cam carb 12hp $$ . 130cc 14hp$$$, 148cc 18hp$$$$$$$$$.
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Just purchased a bbr 120cc kit with cam [$289 incl freight], what carb would be best. Might leave the 77 xr75 alone and convert the flogged out xr100 frame into twin shock and steel tanker. The ideas are flowing now for a fun bike to flog around with the kids.
PS. would the standard ignition be OK.
Cheers Troy
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Just purchased a bbr 120cc kit with cam [$289 incl freight], what carb would be best. Might leave the 77 xr75 alone and convert the flogged out xr100 frame into twin shock and steel tanker. The ideas are flowing now for a fun bike to flog around with the kids.
PS. would the standard ignition be OK.
Cheers Troy
honda XR 200
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Thanks for your help, much appreciated.
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BETRIC can you tell me which head gasket is used with the CB400F piston? Is it XR100? Or is there a different gasket made for the increased bore size?
Tony.