[aeroden]

1998 Vulcan Classic E Here...

Just pulled off my fork and surprisingly found out that on bolt the right top clamp looks like this:

Weird, right? It looks like it was made from pressed powder or something like that. Its also for 7mm allen key and not 6.

I've used the left bolt to check what's up with the inner thread after it had such a torture and the thread was OK (thanks God).

I have a spare set of bolts 8x25mm that fit right in. However the left one bolt is 8x30mm.

So are these clamp bolts 25 or 30 mm long?

I've tried screwing by 25mm bolts into the head, and they go at least 10mm in.
Would that be enough?

 

[sunnybob]

1998 Vulcan Classic E Here...

Just pulled off my fork and surprisingly found out that on bolt the right top clamp looks like this:

Weird, right? It looks like it was made from pressed powder or something like that. Its also for 7mm allen key and not 6.

I've used the left bolt to check what's up with the inner thread after it had such a torture and the thread was OK (thanks God).

I have a spare set of bolts 8x25mm that fit right in. However the left one bolt is 8x30mm.

So are these clamp bolts 25 or 30 mm long?

I've tried screwing by 25mm bolts into the head, and they go at least 10mm in.
Would that be enough?

I've worked with motor vehicles for nearly 60 years and never seen a bolt in that condition before, It looks like it was left in an acid bath.
To find the bolt size on a blind hole just feed a thin screwdriver down into the bottom, mark the shaft, and measure it when you pull it back out. Dont forget to take off a couple mm for the compression of the tree clamp, and another 2 to allow the bolt to tighten without hitting the bottom if its uneven.

 

[sunnybob]

one thing just occurred to me, is this the remains of a helicoil? If the original thread was damged beyond repair, a threaded insert can be fitted. The thick top part of that bolt appears to have the remains of a helicoil on it.
Get a flashlight inside that hole to check the condition of the thread before refitting the forks. Thats a very important bolt.

 

[aeroden]

one thing just occurred to me, is this the remains of a helicoil? If the original thread was damged beyond repair, a threaded insert can be fitted. The thick top part of that bolt appears to have the remains of a helicoil on it.
Get a flashlight inside that hole to check the condition of the thread before refitting the forks. Thats a very important bolt.

There probably was some threading insert there. I've checked the flash light and did not come to concrete conclusion. Then I've took it to workshop, they passed that threading with a tap, I've put the bolt in and tightened it to required torque on the telescope and it holds firmly.

P.S. 30mm bolts go right in.