Dominator 88

johnm said:

Yes LOL

And this is why despite the fact I have owned a Commando over 40 years and raced my Dommie for 15 years I generally do not comment in "what do I have threads".

Its a nightmare.

For example I tried to get a 500 SS head for years. Now I have two SS heads. But i certainly would not put my hand on heart and say they were original 500 SS's. They fit 500 barrels and have the full SS shape. That's all I know.

I had guys send me heads that they were honestly certain were SS but were not. Always take a 500 head gasket with you for a start.

Click to expand...

Hi John
Once you are armed with a bit of information along with a few proper bits of terminology this easily falls into place by ignoring the DD baby talk.
1. All the small barrel head DO NOT have desaxe (squish bands).
A dealer selling parts called me for a consultation. A guy thought his gasket set was not fitting his engine. The pix was of a small barrel head-gasket BUT sitting on a desaxe squish band head (750 atlas) We didn't even know fact-certain the head would fit on the barrels!!!
2. A 88SS/136 is 1.625 verticle stud 25mm head. I'd suggest completely ignoring the early/late 22707 as infantile baby talk. Considered to be first year 122ss and all 14ss head.



3. The S650/136 is the famous downdraft head used officially on 62+ 88SS/122 engines and all manxman and 650SS/18 engines. Don't let the "late 22707 DD" head name drag you down to their infantile Goo-Goo talk. It is a small bolt pattern head- end of story. NO DESAXE squish band.

As considered to be stock 1.5" seats use 1.4 intakes. spigot or not otherwise the same head. And late heads used some 06-0380 casting but still machined as small bolt pattern and when no squish band of course had a different Norton PN 25358. The 1.5 seats would allow not stock hotrod 1.5 atlas valves in a small barrel head. Same valve seats in an atlas head.

FWIW even the real early heads used 1.5" seats but with 1.3" intake (and exhaust) valves.
I rest my case....

dynodave said:

Hi John
Once you are armed with a bit of information along with a few proper bits of terminology this easily falls into place by ignoring the DD baby talk.
1. All the small barrel head DO NOT have desaxe (squish bands).
A dealer selling parts called me for a consultation. A guy thought his gasket set was not fitting his engine. The pix was of a small barrel head-gasket BUT sitting on a desaxe squish band head (750 atlas) We didn't even know fact-certain the head would fit on the barrels!!!
2. A 88SS/136 is 1.625 verticle stud 25mm head. I'd suggest completely ignoring the early/late 22707 as infantile baby talk. Considered to be first year 122ss and all 14ss head.

3. The S650/136 is the famous downdraft head used officially on 62+ 88SS/122 engines and all manxman and 650SS/18 engines. Don't let the "late 22707 DD" head name drag you down to their infantile Goo-Goo talk. It is a small bolt pattern head- end of story. NO DESAXE squish band.

As considered to be stock 1.5" seats use 1.4 intakes. spigot or not otherwise the same head. And late heads used some 06-0380 casting but still machined as small bolt pattern and when no squish band of course had a different Norton PN 25358. The 1.5 seats would allow not stock hotrod 1.5 atlas valves in a small barrel head. Same valve seats in an atlas head.

FWIW even the real early heads used 1.5" seats but with 1.3" intake (and exhaust) valves.
I rest my case....

Click to expand...

Hi Dave,

Thanks for this. Just to let you know I have returned to NZ now and basically retired. Moved house and built a 50 m^2 shed which was finished last month. When I get settled I plan to get back to the bikes so maybe in a few months I will pull out my heads and have a good look. The 06 0380 casting rings a bell. My 500 bike came as a race bike from the UK and I have no knowledge of its history. The previous owner passed away and I never met him. It had an SS head but with 1956 crankcases so a bitsa.

The other head came from the USA so again no history.

Both have the 90 270 stud pattern and are as per your second photo. It would not surprise me at all to learn they are 650 heads. Both machined for the barrel flange. Nothing to be learnt from the port diameter because both have been modified.

Regards John

Well guys tonight I will be doing a talk at our local VMC club about the Norton - for those on Facebook, here's the link to the Album I kept of the progress - this weekend I took it for a nice long ride and I'm happy to report no major issues! It's no rocketship that's for sure but it's wonderfully smooth and handles so well - I think the Honda NSR yokes have quite a big offset so it's got a longer wheelbase I suspect but it's a real pleasure! I'm not quite sure what to do with it yet - I've thrown quite a lot of cash at it for what is really not an original Norton so I'm wary now to take it further. There's not much big money to be spent, but lots of little details which detract from the overall appearance. Anyway, luckily that is a future problem!

Thanks again for all the valuable advice given on this thread - I would have no doubt battled a lot more without it!