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Model 18 starts. Owner astounded.

Submitted by john_carter on Fri, 30/03/2018
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Singles

Postings seem a bit sparse of late so I thought Iâd indulge myself and contribute a story on my 1936 Model 18. I bought this last August after selling my last Norton (Commando 750 Roadster) in about 1974. This one had not run for, I think, at least five years although was complete and quite original. I was going to spend the winter recomissioning it but what with one thing or another didnât do much. I cleaned it up, put back the parts that came with it but were unconnected, fitted new tyres, checked the magneto worked, gave the carb a good old clean, filled it with oil, greased all that is required to be greased and then left it for 3 months.

I came back to it and found that it had shed a lot of its liquids onto the garage floor. Iâd heard the chaincases are problematic if youâre a traditionalist and prefer the oil on the inside but my machine seems to leak it from everywhere. Anyway, in a âI wonder ifâ moment I kicked it over and to my surprise it started! I was told the engine had been rebuilt and I hadnât yet checked the valve and ignition timing but I guess it must be near enough.. I stopped it pretty quickly as it belched out clouds of noxious smelling smoke from the exhaust. So, a few questions which I'd appreciate any views on:

  1. Is it realistic to get a Model 18 leak free? I assume this should be my aspiration?
  2. Are recommended torque settings for the machine available?
  3. The smoke on startingâ? What might this be due toâ?. wet sumping maybe? Oil accumulating in the barrels? Any ideas. There was a lot of it and it smelt acrid. Way more than it running rich or something like that.
  4. Any âtop tipsâ with regards to the engine, clutch and gearbox that one should really think of doing before getting a bike this old back on the road after a long lay up?

Thanks..

Submitted by richard_payne on Fri, 30/03/2018

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It's not possible to make a pre-war Norton oil-tight without using catch tanks or bottles...there are several vents to atmosphere as well as a lack of proper oil seals.

The good news is that it shouldn't be too bad - the odd drip, not puddles. Your problems are almost certainly due to the oil tank contents having drained down into the sump. There is a point where the sump simply overflows while standing - and most comes out of the breather behind the primary chaincase - it runs down the back and can make it seem as if the oil is coming from the case.

The gearbox will probably drip a little - both from kickstart shaft and from the sleeve gear (a shielded bearing here helps).

If it were mine, I would drain the sump, top up the oil and take it for a good run.

If the inlet cam bush is OK, you shouldn't see much from the mag chaincase drain, but there can be a drop or two and on the '36 engine you have exposed valves so they will be a bit oily, but not spraying everywhere if it's been properly put together.

Don't expect to find torque settings listed - even aspects such as valve to guide clearance don't seem to be mentioned anywhere.

Do you have a copy of the Edgar Franks book ? Well worth finding.

Submitted by michael_crehan on Fri, 30/03/2018

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It has went to a new home 10 years ago but my 1928 was pretty much leak free. If it had been on a long run it used to get a wipe over when it got home but it could then be left on its stand in thx garage for weeks without any oil dripping onto the floor. At the point I sold it it was at least a 25 year old restoration.

Submitted by robert_tuck on Fri, 30/03/2018

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I have a 1936 bike that leaks from about 6 places, I have spent a fair bit of time and money to no avail(yet!) . I leave it with a tray under. Look at it this way, the dirt/sludge settles to the bottom, it leaks from the bottom, fresh oil goes in the top. It's like a continual service !!.

Submitted by john_carter on Sat, 31/03/2018

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That's very helpful and encouraging, thanks... The oil that collects in the sump is presumably leaking through the oil pump. Is that due to wear or merely a product 'feature'?

I think I read that earlier models had a tap on the feed from the oil tank to prevent wet sumping. I'm pretty forgetful so I'm not sure it's a price worth paying but does anyone recommend reinstating one?

Is the Edgar Franks book predominately about the OHC models? That's the only one I could find on the interweb. I'll keep searching.

I'll do as Richard recommends, drain the sump and take it for a long ride if it ever stops raining.

Thanks again..

Submitted by george_phillips on Sat, 31/03/2018

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Hi John - if you search for "wet sumping" on this website you'll have a fun weekend of reading! It would appear that they all do it to a greater or lesser degree. Similarly the fitting of a a tap/valve on the oil feed attracts a myriad of views/comments. With the bank holiday coming up you've got plenty of time to gen up on it. Happy reading!

Submitted by richard_payne on Sat, 31/03/2018

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Edgar Franks was responsible for the 1932 re-design of the Norton OHV and SV range and can be credited with creating the engine silhouette that survived right up to the end. Perhaps the greatest unsung designer in the industry. I believe that he also did quite a lot of work on the OHC machines but of course there were others at Norton who took credit for those.

The book covers the whole range, with year by year changes and actually goes on to include the early post-war twins. As far as I can tell, no info on the singles was dropped but the earlier an edition you can find, the better.

Gear pumps will always leak down to a degree but the Norton line was that a pump in good condition didn't do it excessively...although in 1975 they gave up saying that and fitted a valve to the last Commandos. Wear obviously makes things worse.

Andover Norton now make steel bodied replacement pumps for the singles and they provide a significant improvement. That said, any Norton left standing for six months is likely to have more than the proverbial 'tea-cupful' in the sump :)

 


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