Topic: Source for HD cylinder head nut

[johnyvilla]

Hey guys.

I'm fixing a top end leak on my CB750k last rebuilt 9 years ago. The head nuts I used back then looked great and were all tightened within spec, but I can't seem to find them online. They were flanged grade 8 like Cycle X or Dynoman's offerings, but they didn't cost $80.

A quick search online netted many grade 8 M8x1.25 nuts but I have no idea if any of these nuts are reliable. I just spent a paycheck on parts from Cycle X among other places and I'd like to save a little if possible.

Has anyone used another source for head nuts?

I have APE studs.

Thanks

[madmtnmotors]

You can get a package of 100 of the M8x1.25 Class 10 (10.9) JIS for nine dollars:

 https://www.mcmaster.com/#95108a102/=1dwyej9

How many do you need?

[johnyvilla]

You can get a package of 100 of the M8x1.25 Class 10 (10.9) JIS for nine dollars:

Man, those are cheap. Has anyone used them?

They look good on paper.

The ARP nuts are pretty expensive..

[slikwilli420]

You can get a package of 100 of the M8x1.25 Class 10 (10.9) JIS for nine dollars:

Man, those are cheap. Has anyone used them?

They look good on paper.

The ARP nuts are pretty expensive..

You get what you pay for. ARP make some of the finest fasteners at any price.

[scottly]

Why are you replacing the HD nuts you already have??

[johnyvilla]

You get what you pay for. ARP make some of the finest fasteners at any price.

Absolutely.

I'll buy a $80 set of nuts if that's all I can find that's reputable. There were different suggestions on this forum 9 years ago and the $25 nut-set I bought back then was still torqued to spec, (minus the 6 middle bolts) when I took things apart the other day. Money is tight after tires, gaskets, RT valve emulators, springs and such. You know how it goes.   

I might have bought them from Mike Rieck when he sent back my head at the time. dunno. 

[johnyvilla]

Why are you replacing the HD nuts you already have??

I'm changing a head gasket and replacing some leaking valve seals. Would you trust a nut twice?

[scottly]

Yes, especially one that is better than OEM.

[johnyvilla]

Hmm.

I was under the impression that head nut threads stretch enough to warrant replacement every rebuild.

Am I worrying to much about nuts? I'd be thrilled to throw my grade 8 nuts back in there if possible.

[scottly]

Hmm.


Am I worrying to much about nuts?

Yes.

[PeWe]

I tightened stock nuts 20 ft lbs with APE studs in my ongoing K2 build. Back in the 80’s 20.6 ft lbs with stock studs and stock nuts.
I use standard forged nuts with kibblewhite hd studs in my K6. Flange is thicker, thin washer used under. It might be needed to grind the flange some to get longer thread lenght. A machine to make it real flat and 90 degrees rel threads.

I have mentioned the type of nuts several times, DIN 6331
Like this
https://www.elesa-ganter.com/products/machine-elements/series/din-6331

Note! You need 13 mm socket to tighten. Stock is 12mm
Some heads have really tight holes for the 4 short studs. My K1 head need a thin 1/4” 13mm socket.

Cheap sockets are often thick, good brands have thinner walls since they are better made and use  better steel. Bacho, Gedore, Kamasa and maybe Hazet have thin  walled sockets as I know

[slikwilli420]

Hmm.

I was under the impression that head nut threads stretch enough to warrant replacement every rebuild.

Am I worrying to much about nuts? I'd be thrilled to throw my grade 8 nuts back in there if possible.

Fortunately for you and everyone else here, totally wrong. Use them again.

[madmtnmotors]

You can get a package of 100 of the M8x1.25 Class 10 (10.9) JIS for nine dollars:

Man, those are cheap. Has anyone used them?

Class 10.9. I would use them without hesitation if I needed them.

[DaveBarbier]

You can get a package of 100 of the M8x1.25 Class 10 (10.9) JIS for nine dollars:

Man, those are cheap. Has anyone used them?

Class 10.9. I would use them without hesitation if I needed them.

Same here. No need to spend all that money on ARP 12pt nuts. But they do sure look pretty.

AvE did a test and found the Chinese fasteners he had to be stronger than the US made. Only a small sample, but it was a surprise.