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British Bikes / Re: She's hot
« Last post by Billington on May 22, 2022, 12:06:32 AM »
Thank you Leon for all the things to think about, the bike was running okay when I stopped using it last autumn.
I checked the plug be for taking it for a ride and is was a light grey/brown.
I can kick the bike over okay and it has good compression, I need to use the lifter to get it over compression.
I run the bike with the air liver full closed it does not seem to make any difference open or closed, but I will try it open.
I run the bike with almost fully retarded, it seems to like it that way but I will try changing this again. I’ve heard that this can make the exhaust valve hot, is that correct?
No other part of the bike are hot.
I checked the contact breaker point gap before riding it was 0.008 inch however it should be 0.003, I will change this.
I also checked the inlet and exhaust tappet clearance are all fine.
The oil pressure was showing 6 psi which I believe is about right.
I did put a few drops of oil into the cylinder head before starting the bike to raise compression because I had not ridden the bike for 8 months.
The bike was not idling, if I closed the throttle the engine stopped.
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British Bikes / Re: She's hot
« Last post by cardan on May 21, 2022, 11:23:51 PM »
Boiling the fuel at 16C is a bit of a worry - better start figuring why the engine is running so hot.

Worth a quick check on the valve timing (roughly ex closing and inlet opening at TDC on the non-firing stroke), ignition timing (roughly points opening at TDC on the firing stroke on full retard), and compression (if you can't stand on the ks at compression it should be close - don't let anyone tell you old bikes don't need compression).

I guess you're familiar with riding the beast, so giving it as much advance as it wants. After it's warm and before it's hot, will it take full advance and (almost) full air?

When it gives up, is the engine tight? If you lift the exhaust does it swing over freely on the ks?

Is the lubrication system working correctly? Plenty of oil and the tell-tale plunger (does it have one in 1932?) fully out?

The move on to air leaks or jet blockage in the carb, making it run lean. The colour of the plug should give a hint here - hopefully it's not white.

Final suggestion is to check the bike over bike mechanically for anything tightening up - gearbox, chains, brakes or wheel.

Have fun,

Leon
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British Bikes / She's hot
« Last post by Billington on May 21, 2022, 10:34:36 PM »
Today I took my 1932 BSA 500cc sv, out for the first time this year. After checking it over and adding fresh fuel it started on the second kick. I then went for a ride, after just under 2 miles the engine stuttered and can to a halt. The carburettor was very hot, hence the petrol had become so hot it vapour locked the carburettor. I let it cool down for 10 minutes and it started up again so I rode home.
I had is problem in 2019 when the air temperature was about 20 °C. The kind advice from this forum indicated that I needed to fit a Tufnol flange spacer, which I did. After fitting the 5mm spacer the bike ran okay in temperatures up to 28 °C. However the temperature today was only 16 °C.
I know what the problem is, its vapour lock. My question is why is it now happening at a lower temperature and is the only solution a thicker carburettor flange spacer?

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British Bikes / Re: Timing cover leak
« Last post by Oggers on May 21, 2022, 08:46:19 PM »
Well I now have a new band seal to fit around the chaincase. I'll also give some thought to pouring in some warm tallow to help seal the base of the joint - as one handbook advises - or some modern equivalent perhaps? I really do loathe the things! Never seen a truly oil-tight banded seal yet.....   
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British Bikes / Re: Timing cover leak
« Last post by iansoady on May 20, 2022, 03:12:01 PM »
There's a lot of debate about doing this for Nortons which have a slightly better oilbath chaincase. Some people who've tried it report reduced chain life, and of course the oil lubricates other things like the clutch bearing.

I had an odd hybrid for a while - Norton ES2 engine / box in an Enfield frame - and because of the close coupling of the engine and box only an outer cover over the primary chain. Despite frequent oil can applications the chain wore very quickly.
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British Bikes / Re: Timing cover leak
« Last post by Oggers on May 20, 2022, 12:20:40 PM »
Ian

Well quite.. why Velocette and others could not emulate Ariel and heaven forfend - Triumph - in providing a proper cover goodness only knows. Penny wise and pound foolish springs to mind....I wonder if such an arrangement put folk off buying them back in the day? As an aside, there is a school of thought which suggests that not putting in any oil in the chaincase at all and simply spraying the primary chain with lube every now and then may suffice. After all, that is what is done with the drive chain.....
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British Bikes / Re: Timing cover leak
« Last post by iansoady on May 20, 2022, 10:18:39 AM »
My Venom had the cover with tiny screws all around it which was better than the band but still not good. The fact that the inner cover is already liberally supplied with holes doesn't help....
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British Bikes / Re: Timing cover leak
« Last post by Oggers on May 19, 2022, 12:23:00 PM »
Ian

I agree that Velo clutch adjustment is not straighforward. However, I find that if it is done right, changing gear can be just sublime. My MSS is near perfect. The Viper has yet to attain this peak of peeling perfection as I have the leak on the kickstarter housing to address first!

I would have thought that a flanged cover at least instead of the useless banded cover would not have been that more expensive to produce. Certainly the Velo club recommends these as being a great improvement, and I am tempted myself. Pricey though....     
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British Bikes / Re: Timing cover leak
« Last post by iansoady on May 19, 2022, 11:40:34 AM »
I think one problem is that Velocette were always on the margin of viability and like Norton spent a huge amount on the racing machines. Although this meant that much good stuff did percolate down to the bread and butter bikes it also had the result of limiting investment. The Velo clutch, for example is just a refined / bodged (take your pick) of the original which was fitted to a lowly 2 stroke.

The persistence in running the final drive outside the primary, although having some racing advantage in giving a narrow stiff crankcase and ease in changing final drive ratios, was not that useful to the road rider and indeed given the number of people unable to read and understand the manual led to incessant problems with clutch adjustment. You only have to join the Velo "forum" to see a lot of new owners struggling..... https://velocette.groups.io/g/main/topics
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British Bikes / Re: Timing cover leak
« Last post by Oggers on May 19, 2022, 11:34:07 AM »
I am not convinced that poor design such as a pressed steel chaincase can be forgiven on the altar of misty eyed nostalgia. The Ariel has cast covers, proper gaskets and adequate fixing screws around the peripheries, and most Ariels are pretty basic workmanlike machines and priced accordingly.  As far as I know it has never leaked oil - despite me removing/replacing them several times.

I agree that other traits of old classics are about the experience and the delight in riding and maintaining such venerable machinery, but for me, the pressed steel chaincase is a poor design rather than a mere characteristic or foible, and one is left with incessantly trying to make a silk purse from a sow's ear.     
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