Nut Sizes on Cylinder Head

madwheels37

madwheels37

New Member
Could someone tell me what size the nuts are on a cylinder head for a 2stroke 49 and 66cc? What type of socket will I need? Cause I can't seem to find one that will fit between the fins. Thanks.
 
i have two shyhawk motors.. and they both have different size nuts on the head bolts.. either way i never have a hard time getting a socket wrench between the fins???

on my one motor, the size is 13mm.. and the other one has 10mm. and both are easy to get at with a socket wrench.
 
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DON'T FORGET if acorn nuts bottom out you run a chance stripping the studs out of the motor case!
 
dmb said:
DON'T FORGET if acorn nuts bottom out you run a chance stripping the studs out of the motor case!
Click to expand...

most are sizes right, but good point. one of my kits came with two washers and a lock nut washer under all my head bolts.. and im thinking its because the acorn nuts bottomed out.
 
Acorn nuts can and will bottom out. I replace them with shouldered hex nuts for that reason. In fact I would say that most of the factory installed acorn nuts are too shallow for the purpose. What happens is the nut bottoms out then there isn't enough thread on lower end of the stud to properly tighten down the cylinder head. I've found too many to discount this as just a rare occurance. The acorns are pretty and make for a nice look but they are unreliable as a proper cylinder head fastener.
Here's an old thread that talks about this subject> http://motorbicycling.com/f3/acorn-vs-hex-nuts-6846.html
Tom
 
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I have been using lock washers like this with fair success.
 
i use flange nuts cause i got lots of metric stuff yrs ago, dont use nyloc to torque but you guys know that. dennis
 
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