Broke a cam cap on a 78 kz1000... Now what?

wrote:

Hi jumping in on this cam cap.subject , what would people think to me changing from bolt to studs loctited into the head and shallow nyloc holding down the caps I only ask.bevause I have two failed  threads 
reSamantha

Th is perfectly doable. You need to insure that the studs do not stick up high enough to hit the cam cover. Some old racers did this, especially when using shim on bottom ( under bucket). This allowed for steel against steel threads when removing and reinstalling the cams, instead of steel against aluminum.

Apologies.  I had 1.25 on the brain because I was working with one today.  It is 1.00

Done these around 2006 and still going.

 Done these around 2006 and still going.

Did you use M6 exhaust studs?

I have never done this but I would use long cap head set screws. Depth (length) TBD. You could hold the stud rigid with Allen key while you torque the nut. 

 

Stepped studs, I made them myself, 8mm reduced down to 6mm, the ones for locating dowel holes have a shorter 8 mm section so they can sit below dowels, the nuts on top were reduced in thickness, and a little bit of material was machined out of the cover to accommodate them .

I belonged to a website that was owned by a professional motorcycle mechanic for the California police department who maintained their fleet of  KZP's. He said he saw a lot of stripped cap bolts and his quick and dirty solution was to use a hardened 1/4-20 hex bolt and just threaded it into the stripped hole without tapping and it would hold the proper torque. (He didn't mention grade so I assumed grade 8 or so). He said that the police department didn't want to spend the money to fix it properly, they just wanted the bike back in service ASAP. He also said that those bikes never came back for further service for that issue.

Please do not take offense Blipco,  but that repair method does not sound like a "professional motorcycle mechanic" repair to me. An effective hack job to make something work, but not professional.  Those bolts did not even need to be loosened for routine maintenance, so how in the world did they get stripped anyway?  The bikes may not have come back to him,  but I'm sure there were some WTF moments when those motors were disassembled down the road!

Again,  please don't take offense, my post is for entertainment value only!

Mike

Krazee1, I take no offense at all. It's a total hack and wouldn't sleep at night if I ever repaired it that way but I believed him. I never thought at the time to ask how they'd be stripped since you don't have to remove the cams to adjust the valves. He also worked on private citizens bikes in his own shop. 
It came up during a conversation about the wrong torque spec in the Kawasaki factory manual for the cam cap bolts which resulted in stripped threads. I believe Clymer copied the mistake as well.

wrote:

Krazee1, I take no offense at all. It's a total hack and wouldn't sleep at night if I ever repaired it that way but I believed him. I never thought at the time to ask how they'd be stripped since you don't have to remove the cams to adjust the valves. He also worked on private citizens bikes in his own shop. 
It came up during a conversation about the wrong torque spec in the Kawasaki factory manual for the cam cap bolts which resulted in stripped threads. I believe Clymer copied the mistake as well.

They would remove the cams on the later type, as I believe they had under bucket shims.
 

Samminorwich,
Replacing bolts into aluminium castings with studs is an excellent engineering solution; in the "olden days", it was common with iron castings to tap a coarse thread in an iron casting and fit a stud with a finer thread for the eventual nut. Much less chance of stripping the thread out of the casting, more controllable tension for a given applied torque. 
 

Krazze1, my KZP was a 2002 (my brother now owns it) and it has shim over bucket.