Anyone ever use long head bolts

a.graham52

a.graham52

New Member
I have very little clearence between the head and the frame. I feel long bolts would make assembly and disassembly in the bike much easier then studs. Anyone have any luck?
 
I am considering the same thing. my motor is tight in the frame. I cannot pull head off studs. I must pull studs from block for all top end disassembly due to engine being too tight in frame. Bolts are the answer, you must measure precisely. Hardened Allen Heads would look tough as ****. Maybe have them made/lucky if off the shelf. I'll be doing this soon. Tell ya what I find.
 
was considering making long studs so I could anchor their tops (above the head nuts) to brackets attached to the frame, but they started making balanced cranks a couple years ago & head steadies didn't seem needed then
 
It was my experience that I was unable to find bolts long enough with the proper thread. In spite of what I've read here from others, every engine I've used has had fine threads in the engine case, 8mm X 1 and course threads, 1.25 on the top end where the head nuts go.

Local fastener suppliers were unable to provide a bolt long enough with a fine thread. It seems that once you go above about 5", or 1200 cm, they go to a course thread which will be 1.25.

If you're fortunate enough to have course threads in the case you should be able to find either hex head or Allen head capscrews the proper length. Just make sure that your case threads are course, or 1.25.

Tom
 
Another choice is to helicoil your cases for whatever thread you can find correct bolts in.
This would be my choice due to Helicoils being significantly stronger than raw chinese aluminum.
The stock cases are borderline for holding power anyway, so this is a good mod for improved strength even with the stock studs and nuts,
 
seen some with matching 8x1.0 at both ends
seen some with matching 8x1.25 at both ends
seen some mixed & seem some with proper interference threads at the top

they're getting a lot like gump's chocolates
 
I was going to recommend helicoils too, only problem is most helicoils are a little short to do the length of the case thread, one option is to put two helicoils in each hole in which case sometimes it can cause the thread to bind. However one helicoil in each hole should be ample, as long as the rest of the hole has correct clearance for the thread.
But strongly recommend helicoils if using bolts, as these threads will stuff up with multiple use and head retentioning.
 
crassius said:
seen some with matching 8x1.0 at both ends
seen some with matching 8x1.25 at both ends
seen some mixed & seem some with proper interference threads at the top

they're getting a lot like gump's chocolates
Click to expand...

Guess I'm just a lucky sob that got 1.25 on both ends of the stick .
 
Just came in:




All my head studs stuck out of the nuts a couple threads when tight plus a couple washers. I have room for shorter bolts which is why I went with 100mm long boltd
 
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i've used nothing but grubee motors and they all have the same pitch thread, case and nuts.

and i run the older starfire motors and the GT5-A's with the 6mm studs.

i've done a few motors with allen head bolts purchased from my local McFadden-Dale fastener warehouse for about 50¢ each. also picked up stainless lock washers and larger diameter flat washers for a few cents more.

correct length is extremely important. too short and you'll pull the threads out of the case, and too long you'll get head gasket leaks, but an extra washer or two can fix that.

sorry, can't help with the larger thread bolts. never used them...

another important thing is to check ALL 4 case holes. some can be threaded deeper than others.
 
iv put quite a few miles on the motor since installing the head bolts (without heli coiling the block) and have had zero trouble. no leaks, no lostening of the bolts, no signs of threads coming out.
 
Every engine I use has had the same pitch on both sides, type a or type b motors. I just swap them out with a hardened version use loctite on the bottom and use nylon nuts up top. No issues to date...
 
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