Head/cylinder sstud bolts

[2bhappy]

I am new to this forum. The first thing I did was to search the list for an answer to my question. I failed to find it. I just acquired a 1980 Midnight Specail Kit (basket case or boxes and boxes of parts. The PO did not include the stud bolts from the engine and the ones that are on (5) have been cut and bent.
My questions:
1. what is the easiest way to emove the existing stud bolts? They vary in lenght from 1 inch to about 4 inches. I wish I could perform the same operation on the PO.

2. And more importantly, where can I get replacement stud bolts. I have tried my local Yamaha stealer and he says they can not get them. Short of buying another engine case, any sugestions?

Thanks,
Marc

[andreashweiss]

If you are talking about threaded bolts that cylinder head slides onto I have some spare ones. e-mail to andreashweiss@yahoo.com

[TopCatGr58]

Hey there Marc,

Regrettably, they are discontinued parts, however, thanks to BikeBandit, they posted the part numbers with the metric sizes! They are all 10mm, I would think 1.5 thread pitch, but not sure, might be 1.25? There are 4 different part numbers, but only 3 different length sizes, so must be the length of the threaded portion that differentiates the 2 that are the same length!?

So aside from getting some used ones from Andreas, you may be able to find some metric threaded rod that matches these dimensions?

As for getting them out, I think thread lock was used, so you'll want to put some penetrating fluid like PB Blaster around them, possibly heat the crank up with a small torch, and use a pipe wrench to grasp them. Or if you have a welder,you could afix some nuts onto the ends to get a better hold to wrench them out!
T.C.

7 90116-10273-00 BOLT, STUD 6
8 2F3-11363-00-00 BOLT, CYLINDER HOLDING 3 2
9 90116-10275-00 BOLT, STUD 2
10 90116-10274-00 BOLT, STUD 2


7: DISCONTINUED
(M10-154L) [BOLT,STUD] 344274-001
$999.99
8: DISCONTINUED
(M10-154L) [BOLT,CYL HOLDING 3] 21354-001
$999.99
9: DISCONTINUED
(M10-184L) [BOLT,STUD] 344276-001
$999.99
10: DISCONTINUED
(M10-177L) [BOLT,STUD]

[chevy45412001]

hardened

wouldn't those studs be like grade 8 or some kind of hardened steel? they do hold the top of the motor together yes?and i might have a set if i can get the jugs off the block,rust you know,and don't ask...

[randy]

They are 1.25 thread pitch. And, they're only tourqued to 25 ft-lbs, so they're not under a lot of stress.

You can get metric threaded rod in stainless grade 8, but hard to find 1.25 pitch.

You can, however, do what I did, get longer than necessary bolts, cut off the head, and thread the free end yourself.

[2bhappy]

Thanks for all the good advise. If I can not get some used stud bolts I will try to get some long bolts, cut the head off and thread them. I would like to have the correct lengths and thread lengths of all the bolts.

Marc

[John]

The length of the new stud will be critical, because of the Acorn nut style of nuts used to attach the head. If the stud is too long, the top of the nut will contact the stud before it is properly torqued, and this will cause major headaches if not caught and corrected.