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| Motorized Bicycle General Discussion Topics on bicycle engine kits, help articles, repair and modifications for your motorized bicycles |
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06-07-2009, 08:54 PM
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Motorized Bicycle Elite Member
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Join Date: Oct 2008
Location: alabama
Posts: 384
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N A S A We have a problem!!!!!!!!!!!
ok, i over tightened my head bolts and have stripped out my threads down in the crank. What size should i tapp out the threads? PABLO???????????????? lol.
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06-07-2009, 09:14 PM
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Motorized Bicycle Elite Member
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Join Date: May 2009
Location: usa
Posts: 420
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Re: N A S A We have a problem!!!!!!!!!!!
go to an american size that is comparable to the current metric size.. american will be just slightly larger. just tap it out and be careful... done stuff like that many times..
you'll want 16 thread
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06-07-2009, 09:58 PM
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Master Bike Builder & Forum Sponsor
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Join Date: Dec 2007
Location: Duvall, WA PNW
Posts: 3,291
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Re: N A S A We have a problem!!!!!!!!!!!
Quote:
Originally Posted by toker_ace
ok, i over tightened my head bolts and have stripped out my threads down in the crank. What size should i tapp out the threads? PABLO???????????????? lol.
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What size are you starting with? (is it 6mm or 8mm?)
Did the threads pull out?
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06-07-2009, 10:52 PM
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Motorized Bicycle Elite Member
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Join Date: Oct 2008
Location: Urbandale Ia
Posts: 634
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Re: N A S A We have a problem!!!!!!!!!!!
Quote:
Originally Posted by toker_ace
ok, i over tightened my head bolts and have stripped out my threads down in the crank. What size should i tapp out the threads? PABLO???????????????? lol.
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Jeff, I thought you said you had a torque wrench. LOL If you get into big problems give me a call, might have to heli coil it or I can make you some special studs.
Maybe the book was right when it said head bolt torque 10 Ft. Pounds?
John
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06-08-2009, 04:05 AM
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Motorized Bicycle Elite Member
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Join Date: Oct 2008
Location: alabama
Posts: 384
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Re: N A S A We have a problem!!!!!!!!!!!
i,m not sure which size pablo. i'll find out. i figure i can just tapp them out into a standard size. i just hope i can find some bolts. are head bolts special like grade 8?
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06-08-2009, 05:54 AM
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Motorized Bicycle Elite Member
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Join Date: Oct 2008
Location: alabama
Posts: 384
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Re: N A S A We have a problem!!!!!!!!!!!
the bolts are 6mm.
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06-08-2009, 06:30 AM
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Motorized Bicycle Elite Member
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Join Date: Oct 2008
Location: Urbandale Ia
Posts: 634
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Re: N A S A We have a problem!!!!!!!!!!!
Quote:
Originally Posted by toker_ace
the bolts are 6mm.
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Jeff, You can either go to 8 MM or 5/16. The same size within about .003, just a different thread. I wouldn't worry about trying to find a grade 8 bolt.
John
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06-08-2009, 07:23 AM
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Motorized Bicycle Elite Member
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Join Date: Oct 2008
Location: alabama
Posts: 384
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Re: N A S A We have a problem!!!!!!!!!!!
hey john. i put my other head back on. i had an extra head bolt. now i have about half the power and will not idle. i sprayed the head with wd-40 with it running and no high revs. so that should tell me if i have a leak right? i put some gasket silicon underneath the jug and the crank case. i wonder if that is causing my problem? if i choke it while its running it wants to kill the motor, which is good. there isn't any certain way to put the jug back on the piston is there? i just slide it back over the piston. sever lose of power. no more raddle.....lol!
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06-08-2009, 08:06 AM
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Master Bike Builder & Forum Sponsor
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Join Date: Dec 2007
Location: Duvall, WA PNW
Posts: 3,291
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Re: N A S A We have a problem!!!!!!!!!!!
So the stud was stripped? Typical.
You probably have a head gasket leak. Research the aluminum paint trick and use a new gasket. Maybe get 4 new studs, so you can torque it up good. I went to 20 ft. #'s on mine, but they are 8mm. Sealed tight.
With 6mm......hmm......maybe 14 max.
LUBE and Compress the rings as you slide the cylinder on carefully.
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06-08-2009, 09:22 AM
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Motorized Bicycle Elite Member
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Join Date: Aug 2008
Location: Tucson, AZ USA
Posts: 877
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Re: N A S A We have a problem!!!!!!!!!!!
A 1/4" is slightly larger than 6mm. I had one of the studs strip like that and I just used JB Weld to fasten it back in. That was about 500 miles ago and it is still holding. If it ever does pull loose you can still tap it out to a larger size. Good luck! There is always something with these kits!
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