TOPIC:

What a day! So I bought my 83 KZ 750 H4 last October. Obviously used. Over the winter I've been doing different little things to the bike. I've never broke into the an engine before.

So I was looking at the exhaust last weekend and noticed something was up with the one stud. The rest were extremely rusted. So I went and bought new studs. Used penetrating oil and heat to remove the old nuts and studs. Of course two broke off. One was already broke off. And to top it all off, the one looks like at some point in its life someone broke off the part of the head that the stud threads into to. I believe I can get two of the broken studs out and might even be able to get the third one out. But it almost seems like I'm gonna have to replace the head because of the threads being broken. Any creative idea on how to fix this would be very helpful. If not, it's nice to vent my frustrations here anyway.

Ok. I took some pics. The one with the messed up threads looks like someone tried to JB Weld the stud in.

Yes you are right,this can be very frustrating, it´s like a worst case scenario but not hopeless.
6 mm studs snap off very easily.
Everything can be fix with some machining skills.
A good machine shop can weld up the broken part of the head.
The broken studs can be bore out with a header clamp guide exactly.



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Scirocco wrote: Yes you are right,this can be very frustrating, it´s like a worst case scenario but not hopeless.
6 mm studs snap off very easily.
Everything can be fix with some machining skills.
A good machine shop can weld up the broken part of the head.
The broken studs can be bore out with a header clamp guide exactly.



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Yea. The studs don't worry me as much as the head damage. Not to mention, who the hell JB welds a stud to head??? I'm letting them soak now. Tomorrow I'm going to get them out and see what can be done with the one with the broken threads. Don't really want to have to replace the head or even take it off with decent weather just around the corner. I guess I should have looked at this early in the winter.

I am about 90% sure you'll be removing the head to fix these problems.
I'd look for a replacement head myself and start looking today.
You should spend your good money on having the replacement one refurbed rather then dump a bunch of bad money into that one.... which probably needs way more then just a those broken studs and weld repairs, at this stage anyhow.
Just me ...but I've rebuilt a boatload of bikes in my lifetime.

missionkz wrote: I am about 90% sure you'll be removing the head to fix these problems.
I'd look for a replacement head myself and start looking today.
You should spend your good money on having the replacement one refurbed rather then dump a bunch of bad money into that one.... which probably needs way more then just a those broken studs and weld repairs, at this stage anyhow.
Just me ...but I've rebuilt a boatload of bikes in my lifetime.

Yea. That's what I figured would be recommended. Not what I wanted to hear but that's what I would tell a friend in my position. I found another LTD 750 on CL for 500. Says it's been sitting and no title. I'm thinking about throwing out a lowball offer just to pick it up as a parts bike and go check it out. The heads are around 100 on eBay.

missionkz wrote: I am about 90% sure you'll be removing the head to fix these problems.
I'd look for a replacement head myself and start looking today.
You should spend your good money on having the replacement one refurbed rather then dump a bunch of bad money into that one.... which probably needs way more then just a those broken studs and weld repairs, at this stage anyhow.
Just me ...but I've rebuilt a boatload of bikes in my lifetime.

Yea. That's what I figured would be recommended. Not what I wanted to hear but that's what I would tell a friend in my position. I found another LTD 750 on CL for 500. Says it's been sitting and no title. I'm thinking about throwing out a lowball offer just to pick it up as a parts bike and go check it out. The heads are around 100 on eBay.

How many miles are on the bike you want to keep vs the potential parts bike?
Have you ever pulled a head like this?
Have you ever RnR'd camshafts?
How about possibly swapping engines?
If I had a spare head that wasn't damaged, I'd spend a little money on it. You should freshen up the good head by lapping in the valve surfaces, install a new set of valve guide seals, new gaskets and just swap the heads out. That is the best bang for the buck.