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A technical forum for all single cylinder Nortons

ES2 compression


Can someone tell me what the compression pressure should be for a newly rebuilt 1961 ES2 with rebore, new rings, etc.?

Mine is reading 90 psi (at 1000m asl).

Is it about right - the bike doesn't have much power?

Pre-gap in spark plugs...


I just learned something new!!!  Wondering how many of you fine fellows have heard of spark plug pre-gap?  Spark plugs from early eras did not have pre-gap which is something that modern plugs have.  The following is taken from the Harley-Davidson JD facebook group i belong to and i thought it might be of interest to you folks because it pertains to magneto ignition and it seems some of us experience (last sentence) oil fouling plugs.  (The author of the following is Steve Marks from JD facebook). 

i look forward to hearing your comments, experience, etc.

WD 16H Throttle Performance


I've been playing with a bitsa WD16H for a number of years. This arrived to me completley disassembled, parts missing and most of a spare, knackered, engine.  My objective has been to get a running machine, rather than any form of concurs appearance.  Engine number if 1982, with 79x100 on  cases.  I have fitted new bearings, honed the standard bore etc. Magneto has been rewound and the bike starts esily.

During my attempts to get the bike running well I have purchased a "new" 274 carburettor - configured for a WD 16H.

Seat for Pre featherbed swinging arm frame


Hi, I’m building up a bitsa from parts left over from my other projects using a 1953 ES2 frame, I have the right tank but am looking for a seat, ideally a flat one rather than the later one that is similar to a BSA seat. Does anyone have a seat/base they can photograph/measure for me or point me in the right direction for a similar one that could be modified? I’m not worried about it being concours, but I do want it to fit nicely. I have spoken to leightons and without a big order they cannot help at the moment. 



My `51 Model 30 is running. And a seat cover and tire question.


I finally got caught up enough on building a P11 for a friend to take a break and turn my attention to the Model 30 I bought in Las Vegas the end of April.  Happy to report after a good service and some critical checks she started right up using race rollers.  Actually rode it around town for 30 minutes or so and it's running way better than i hoped. I would post some videos here but I don't think it's allowed?  You can see some of the videos I posted on my Facebook page or the INOA and Norton single cylinder Facebook pages.

Prewar saddle tank sizes


Hoping that someone can advise on pre war post 1931 Norton petrol tank sizes. I have two tanks and one of them is a couple of inches shorter than the other. The mounting points on the short tank align well with the mounting points on my (assumed)1935 M50 frame but the front of the tank seems to be a bit too far from the headstock - certainly noticeably further back than the front of the longer tank on my ‘46 M18. Any info much appreciated.

16H outer primary drive cover


I am currently rebuilding a basket case 16h which was mostly complete. I have re-fitted the primary drive inner case clutch etc, but cannot get the outer cover to go on. The hole for the footrest in the outer cover, won't align over the footrest tube. Is there a trick to this?



Girder fork spring


I've not yet had the pleasure of removing the main spring from a girder fork. But can anyone answer a couple of questions please?

What is the free length, and how can I tell if it has a permanent set? I don't even know how compressed it is when on full rebound.

The WD manual looks like the entire fork must be removed and taken apart to change a spring. Is that so?

I have two girder fork Nortons.  When parked in the shed, the springs both measure close to 7 inches. I don't know if that tells me anything about the free length.



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