Norton 750 Commando Cylinder Head

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Just can't believe it. Took my head over to the local machine shop to have the two forward mounting bosses cleaned up as they were a bit dodgy. They looked like someone had torqued the head down without washers at some time. I instructed the shop to just touch off and remove .005 from the surface. The shop claimed that the wrong button was pushed on the CNC and it plunged down .250. In addition, the spindle hit the head gouging it and broke one of the fins. I don't think it can be fixed.
I am just sick. I've got a ton of money and time in the restoration and now the search for a good replacement.
I have an ad in the wanted section and would appreciate any help.
Chuck Poe

750 Commando
750 Triton
750 CB Café
Bultaco Pursangs
 
That's awful, are they going to try and make it up to you, compensation etc... I don't see how can they just say oops, sorry we goofed up, and then hand it back.
 
Sounds like a job for a good welder followed by some machining and charge them for the lot. Not sure I would let them do the machining.
 
Unless it was a back door job they had better pay up. Figure out what it is worth (not what you had in it)
and get that from them in cash or in machine work. Andover sells heads as does Fullauto.
Don't let them weasel you.
 
What kind of troglodites run the machineshops these days ?
Seen the posting of a messed up crankshaft posted yesterday on this forum, and now this.
These guys just do not seem to care. Sorry for your loss..
 
The shop needs to pay for trashing your head by providing a Fullauto replacement.
 
Step 1. Complain in writing to the firm for restoration/resolution.
Step 2. Brush up on your local consumer protection laws (if any) and follow their processes if step 1 fails.
Good luck.
 
That's really bad news.
What spec is your engine?
Info on inlet port size, valves, exhaust threads, compression ratio, etc might help in finding a suitable replacement.

Where are you located?

Good luck.
 
Onder said:
Unless it was a back door job they had better pay up. Figure out what it is worth (not what you had in it)
and get that from them in cash or in machine work. Andover sells heads as does Fullauto.
Don't let them weasel you.

Since when do Andover supply new cylinder heads?
 
kommando said:
Sounds like a job for a good welder followed by some machining and charge them for the lot. Not sure I would let them do the machining.
You might try sending it to "the norton motorcycle machine shop" in colorado --aka comnoz from this forum. I think that if anyone could fix it he could, check out his website. You can't go wrong with a brand new Fullauto either, I think we're lucky to have both of these options. I have one from a project motor that I'm toying around with and it needs a ton of work too- stripped exhaust threads, pulled studs & stripped spark hole threads etc... when I get my "spare cash" set aside for it, I'm sending it to comnoz, but if he says it's -toast- I'll save up some more money and get a fullauto.
 
two forward mounting bosses cleaned up as they were a bit dodgy.
:?: :?: :?:
5/!6 front studs? Which vintage/year 750 head...just curious....why cut .005" ??? what's the point?
 
Thank you all for the reply's. Un fortunately, the shop I was dealing with was a good shop but the owner died two weeks ago and his wife is trying to keep the shop running.
They have two machinists. One experienced ( the one the screwed up the head) and the other spends a bit more time consuming tee many martunies.
I was trying to keep the shop going as I use them for my business and good machine shops are hard to find. Anyway, I am paying the price.
My head was already restored with new guides, valves. The exhaust threads were perfect and the engine ran great. I was only working on a nagging oil seep from the two studs before this happened.
I have checked on Ebay and there are many Atlas heads to be had. Will these work? What is the difference?
I hate to spend the money but a CNW new head may be the best choice at this time.
Man, My days have been ruined by this.
By the way, the tool shop called today and I spoke with the machinist. He claimed he ran into an inclusion in the casting and had to bore down to get to clean metal.
I asked.. Why in the hell did you not call me and let me know rather that drill to China!!!!!! I don't believe him. .005 would not have found a hole and even if it did, how big was the inclusion?????
 
" In addition, the spindle hit the head gouging it and broke one of the fins. "

That part doesnt fit with his arguement about needing to go deeper !

Unfortunately people are human and they screw up. You just wish they would screw up on their own time !! The machine guys I go to would front up to fix it at their cost. But then I have known them for 30 years.

Another friend has so much screwed up by others that these days he pretty much has his own machine shop and send out almost nothing.

You have my sympathy !
 
topolino1 said:
Thank you all for the reply's. Un fortunately, the shop I was dealing with was a good shop but the owner died two weeks ago and his wife is trying to keep the shop running.
They have two machinists. One experienced ( the one the screwed up the head) and the other spends a bit more time consuming tee many martunies.
I was trying to keep the shop going as I use them for my business and good machine shops are hard to find. Anyway, I am paying the price.
My head was already restored with new guides, valves. The exhaust threads were perfect and the engine ran great. I was only working on a nagging oil seep from the two studs before this happened.
I have checked on Ebay and there are many Atlas heads to be had. Will these work? What is the difference?
I hate to spend the money but a CNW new head may be the best choice at this time.
Man, My days have been ruined by this.
By the way, the tool shop called today and I spoke with the machinist. He claimed he ran into an inclusion in the casting and had to bore down to get to clean metal.
I asked.. Why in the hell did you not call me and let me know rather that drill to China!!!!!! I don't believe him. .005 would not have found a hole and even if it did, how big was the inclusion?????


HUGE difference between PRODUCTION machinists and REBUILD machinists. Sadly, many of the former confidently beleive they can do the latter. This type of failure happens ALL THE TIME. Others be warned..... :idea:
 
Ugh definitely another significant example of Commando manhood tester. Just to ease taking fate so personally one fella a decades ago had a finished boxed head delivered unknown and left in plain site in front of garage door so wife entered car inside, remote opened door and backed over it crashed ruined. Maybe get agreement to cover the repair somewhere else or replacement. Hurry up and wait some mores tests me all the time.
 
concours said:
...........HUGE difference between PRODUCTION machinists and REBUILD machinists. Sadly, many of the former confidently beleive they can do the latter. This type of failure happens ALL THE TIME. Others be warned..... :idea:
That must be it, when I read the part about "he said that he pushed the wrong button" it sounded like they were just a rookie operator to me. I hope it works out for you topolino.
 
Likely weld fill in the augured out hole and re-cut would not weaken any vital stress areas to fly again. I'd think the Muzzy propane alu repair rod would work with less thermal distortion issues. Fin would be remade too but may have paint to conceal the alloy color tint difference.
 
Well, the trashed cylinder head has been replaced with a good unit. It required a full rebuild including new guides, black diamond valves and inlet seals.
I started this project trying to solve the seeping oil leaks from the two front mounting studs. I am happy to report that is has been corrected. The modifications I made
was to open up the two holes in the copper head gasket to accept Viton O rings. I made sure it was just large enough to avoid interfering with the head sealing to the bores.
I had sealed up the studs with high temperature thread sealant but it still leaked. This time I wrapped a couple of turns of Teflon thread sealant around the studs before installing. The final solution was to install Parker thread sealing washers under the thick washer under the top nuts. These washers are designed to drive into the threads and, according to Parker, are capable to withstanding pressures of 5,000 psi. So far, there has not been one drop of oil from this area. The nice thing about this modification is that the only part modified was the copper head gasket so it is completely reversible.
If anyone out there is experiencing similar issues, I do have a few left over O rings and Parker sealing washers left.
 
Hi , your solution are interesting, could you post any picture , or reference number for those parts, it could be helpfull for some people (may be me , I had found a cylinder head RH10 which is supposed to leak ............)
 
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