88ss head and 650ss head

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Are the angle of domi 500 88SS exhaust ports the same as the 650SS?
The reason I want to know is there is a Norton Siamese Twin Exhaust System for an 88ss for sale and I have a 650ss cylinder head. I believe the 650ss ports are wider splayed than the 500?
 
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Bernhard,

As much as you seem to be interested in these bikes you should acquire some factory parts manuals to answer simple questions like this.

The parts books have different part numbers for 1961 88ss exhaust pipes than they do for 1962 88ss exhaust pipes, maybe because those two models also used different cylinder heads. The 1961 88ss did not have the 650ss style head, but the 1962 88ss did.

Interestingly the parts book lists three different sets of pipes for 1961-62 standard and Deluxe 88, 99, 650 bikes. Probably because although the 88 and 99 have the same head, the 99 has a taller cylinder, and though the 650 for all practical purposes has the same cylinder deck height, it has a different cylinder head than the 88 and 99 standard and deluxe.

At this point 60 years later unless someone with a set of pipes has actually tried fitting them onto a particular Norton Dominator model, I would have a lot of doubt that they would know exactly what they would fit and what they would not. Also the information in factory parts books would apply to original Norton pipes, but if a set of pipes are manufactured by some aftermarket company all bets are off.

I have a brand new set of original Dominator pipes hanging in the garage that would not go onto a 650 because they were too short vertically to drop below the timing-side of the engine cases. When I get the chance I will try them on a model 88ss with it's shorter 8-fin cylinder and see if that makes enough difference to let them fit, if that does not work then perhaps they are for one of the older style heads.
 
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Thanks for the advice. Therein lies my problem, the seller cannot verify which year they fit and if they are from the Far East, in addition, I have a 500 engine with the latter 650SS head, I don’t even have a frame to mount it in at the moment, so a parts book will tell me nothing.
Here goes good money on what might be a complete waste of energy.
 

johnm

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Yes the details of the 500 head from about 1959 until 1962 are different. (three different steps?) As Ben says 1961 SS and 1962 SS heads do have different exhaust angles but even that dating is not totally definitive because of different international markets, season changes for new models in the northern and southern hemisphere. I have been offered 500 SS heads by people who genuinely thought they were the latter model but they had a narrower exhaust angle. Whenever I go to part sales I take a template with me to check any heads because unless you work with them all the time it is easy to get it wrong.

I really doubt you will get a certain answer from someone on the other side of the world unless they are a real Norton twin featherbed expert.
 
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Thanks for all the detail.
Since it is a 650ss head, I have decided to obtain a 650ss/ Atlas pipes and see if I can shorten them to fit.
 

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