Help needed: Rotor bolts for spider and hub

[QWERTYMage]

I need to find a replacement for a single missing rotor bolt (small bolt, attached the rotor to the spider) and 3 bolts for the spider (large, attaches the spider to the hub)...

What sizes are the two types of bolts (thread, pitch, length)? I will be buying a complete set of each size to ensure they are balanced.

It's for a '75.

Thanks.

 

[TwoManyXS1Bs]

I have no idea, but you may be able to decode the bolt part numbers from parts manuals.

More info in these:

http://www.xs650.com/forum/showthread.php?t=33606
https://thexscafedotcom.wordpress.com/2011/03/15/xs650-nuts-and-bolts-from-1975

 

[QWERTYMage]

Wow. That's great stuff. Thanks!

 

[QWERTYMage]

The Smaller "spider bolt" is M6 18mm length. Part number 90109-06018-00. Ordered from Boats.net

The bigger "Hub bolt" is M8. Unknown length. Part number 90109-08367-00. Not in Boats.net inventory.

This helped a lot, TooMany XS1Bs. Thanks again.

 

[TwoManyXS1Bs]

The Smaller "spider bolt" is M6 18mm length. Part number 90109-06018-00. Ordered from Boats.net .

Good. That '06018' is easily decoded.

The bigger "Hub bolt" is M8. Unknown length. Part number 90109-08367-00. Not in Boats.net inventory. .

Bit more of a challenge. That '08367' *might* be decipherable, research that 2nd link.
The middle '3' may mean a special head or treatment, with possible length of 67mm.

... This helped a lot, TooMany XS1Bs. Thanks again.

You're welcome. Often not sure if helping, or making it worse...

 

[fredintoon]

Bit more of a challenge. That '08367' *might* be decipherable, research that 2nd link.
The middle '3' may mean a special head or treatment, with possible length of 67mm.

Hi 2Many,
FWIW, I just swapped my front disks from one wheel to another so I still vaguely remember the disk attachment bolt sizes.
8 has to be the M8 thread size.
The final 67 translates to 2-5/8" which seems a bit too long for the bolts I took out but admittedly I didn't measure them.
The 3 might indicate a reduced head size because the stock bolts on one side have smaller heads than the Bolt Supply House sourced Gr 8.8 bolts on the other.

 

[5twins]

Why not just measure one of the three remaining bolts you have?

The disc mounting bolts are M8 and have the standard thread pitch (1.25) but if your hub has blind mounting holes, you must be sure what you use isn't too long. If it is, it could break the back out of the hub.

On the later hubs, starting around '76 or '77, the holes were open on the back and the bolt part number changed. That may indicate a longer bolt. The later bolts are 30mm long but like I said, that may be too long for an early blind hole hub. If you have one, best you measure the hole depths, add 7mm for the disc thickness, then knock a couple MM off for clearance and just to be safe. On a blind hole hub I have, I'm using 22mm long bolts. That just happened to be what I had on hand in stainless. I'm thinking the originals may have been 25s, but don't hold me to that.

 

[5twins]

My blind hole hub. It's from a '73 or '74 TX750 .....

 

[QWERTYMage]

I was gonna measure as a last resort. I want to make sure I get as close to factory spec as possible, since my life rests on the brakes working properly.

Thanks for the help, guys!