Kz900 Head

wrote:

I would run a mile from any shop that said they only needed two valves to do the job. If you get a spring compressor, you could take a look at the valves and seats yourself, measure them up etc, chances are a gentle lap with some fine past is all you will need. Most car workshops should be able to do the threaded inserts for you, they generally do it all the time and have the tooling. Its not too difficult to do yourself if you have the space and tools. Timecerts are far better than helicoils, but you may not have the option on the spark plug hole, a helicoil would be better probably due to close proximity of plughole to valve seat edge. 

Thanks, my problem is the spark plug hole. A previous owner attempted a repair and drilled about half way into the combustion chamber with a very large bit. The hole measures over 17mm. Deeper in the casting though the threads are still present so location and angle can be reproduced. I just don’t think I will find a timesert or bigsert to transition from 17mm + down to 14mm. I have a valve spring compressor and can investigate further.

When i do a valve job.
Assuming it's a simple maintenence service and guides etc are good, valves straight .
YOU WOULD GET -
New stem seals.
Valves re-faced if needed.
Seats recut on all 3 angles or where needed to give correct seating width and finish.
Stem height corrected / tipped etc to ensure plenty of shim range.
Depending on amount of height adjustment needed then spring seat shims to maintain correct spring pressure.
If cams supplied then will also bench shim if requested ( but they will need re-doing once the heads bolted back on and run ).

Beyond that i would only ask for parts after initial strip and inspection.
There's no way to know beforehand what will be needed regarding new components ( except for the guide seals) so no need to ask for other parts in advance.





 

DOHC, Ape looked at the photos I sent and said they couldn’t help. They did give me a referral but I’m hesitant to disclose that till I vet them. Schnitz also gave me a referral but I haven’t reached out to them yet. Stay tuned.

Big sert needs 16.77mm max so over 17mm is probably to big.
You need to get a machine shop to make a threaded insert with maybe an 18mm od thread or the minimum dia needed for the current hole .
There's limited space between the valve seats though so that may cause problems and a stepped arrangement in a partially threaded hole or a short insert in the drilled portion and then tap from the combustion chamber to pick up the threads from the remain in the head may work.
There is also the option of having the hole welded up and re cut or even blank the hole completely and fit a 10mm plug vertically like i do when twin plugging these heads.
 

As far as your pictures show, without involving a valve job, that is straight machine shop work.

You need a small machine shop with a knee mill and TIG welding capable. The small holes can be weld filled then drill/tapped. The spark plug hole needs to be enlarged slightly, a 6061 plug made on a lathe with the spark plug thread (or tap drilled hole) in it then pressed in and welded, then spot faced.

Any small machine shop should be able to fix what wrong with it, then you send it out for a valve job. There are lots of small machine shops that can do that work but can't do valve jobs, more of them around than can do valve jobs as well. There will be different shop rates involved.

I would look around for aircraft engine machinists.  Those guys are used to specialty stuff.

When I lived near Vancouver I knew a really good one, but since I moved to BC's interior I've lost contact.  

For all the work that head needs. And its just a stock cylinder head. I would start looking for a nice clean used head and use that one for a doorstop!!!!!
Fixing that plug hole if done correctly will set you back a pretty penny. Welding up the exhaust stud area and redrilling the stud hole is something that can be at a reasonable price.

After finding a nice used head all you would have to pay is the cost of replacing the valve guides and a valve job.
 

Rob,

   I like the stepped plug idea. The better ideas I can give the more likely I will find someone Willing to take the job on. 

thank you

Matt:  I usually don't recommend places much anymore to others just to keep myself out of trouble, but if it were me I would give Millenium Technologies in Plymouth, Wisconsin a call.  These guys did my cylinder work on my KZ-1000 and I was super happy with what they did.  They aren't cheap, but I wasn't looking for cheap when I went to them.  They were recommended to me by several motorcycle shops in my area.  I wish I could recall the name of the gentleman I dealt with, but I can't.  They are about an hour(ish) north of Milwaukee.  They have a very nice website that is informative and shows some of what they do.  If I had another KZ engine to rebuild they would definitely be the ones I would go to.  I wanted an exhaust stud crack in my cylinder head repaired when I sent it to APE for a valve job and they told me not to worry about it.  I think it was more of an issue that they didn't want to mess with it.  Millenium told me to bring it in if it gives me grief and they would take care of it.  So far it is okay, but nice to know someone will be able to repair it if needed.  If you need decide this place is worth investigating let me know.
Rick H.    

Ok. The more responses I read, I asked for what I wanted, a standard valve job. I have suspicions about this vendor. Thanks 

So last year I found a local guy that said he could do a valve, but said he was booked out a couple months. I gave him my number and was put on a list. He said when my name got to the top of the list he would call me. Turns out he never called. I called him, he said he had 11 other jobs still ahead of me and was swamped. So he turned me onto another local guy. Turns out the first guy would not have actually done the work he would have sent it to the second guy. After talking with the second guy I find out he is an old Z1 guy, him and his father run a small shop out of his house and said he could do any work I needed and his turn around time was fairly quick. Looks like I just cut out the middleman. I am going to drop off two heads to him the first of this next week for him to evaluate. One will be my Kz900 project head that I have repaired the fins, it only needs normal stuff, the second is the rough one (posted here) with the stripped out holes that I’m hoping to save. Let’s see how it turns out. I will ask him if he’s looking for additional work, if his quality is there, if he is accepting additional work, I will post his name and number for other members here to take advantage of his services. 

wrote:

I was gonna ask if anyone here has had work done at this place.     www.pitstopperformance.com/valve-jobs/

Yes, I have one experience with them (him), about two years ago. Please message me privately if you’d like me to describe my experience.