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#96217
Worth bearing in mind that when these engines were designed there was no such thing as 20W/50 oil, or any other multi grade.

My old BSAs from twenty years later were designed to run on straight 30 grade in the winter, 40 grade in summer, like most other engines. Mind you, I blew both of them up because Duckhams 20W/50 wasn’t all it was cracked up to be. 💔.

More like running out oil than running in oil. :o
#96229
windmill john wrote:
Sat Apr 10, 2021 10:22 am
I like FortNine’s videos. Take a look at Royal Enfield in this:

https://youtu.be/9GAUo8eUXeU

Oh, by the way wheaters, you blew them up because of the way you ride. I watched your motorway video :mrgreen:

John
All I did was open the throttle a bit.... 😎

The BSA C15 engine was built for me by Roy Pidcock, who founded Pidcock Motorcycles. He was the East Midlands grass track champion in the mid 1970s. He fitted a plus .060”, 12:1 piston from a Triumph Trident making it a 272cc, a works scrambler bottom end and what was to have been a grass track Methanol cam. It would see off most British 500s but without a proper oil filter it was never going to last long; those engines only had a gauze strainer in the crankcase. I’m convinced Duckhams 20W/50 was partly to blame - looking back I think it was more show than go. The bottom end wore out after about a year. I rebuilt it with a standard bottom end and traded it in against an A7SS. I was assured that the tapping noise it made was the rockers. It turned out to be a big end bearing and it seized on the M1 near Milton Keynes and a con-rod came through the crankcase. I repaired it all and by then needed a car and couldn’t afford to keep it.
#96235
41 years ago, I got a CB250K4, second hand. I rode it home and by the time I got home it was whistling. Didn’t know what it was, but when I took the dipstick out.... there was no oil!

Anyway, I stripped it to find the arrows on the pistons were pointing backwards....

I corrected this and, for the first time, polished the inlet ports from the cast aluminium to smooth bores.

Once rebuilt, this bike would achieve an indicated 100mph. Not sure if this was a fluke, or the way it had initially bedded in with the pistons the wrong way round, plus the polished ports.

Anyway... ANOTHER...... Bike I should have kept.
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By Adrian
#96265
Another oil C15s don't like, at least not on the road bikes in the middle of a Kent Coast winter, is Castrol R40. Maybe it didn't get as cold as 'Oop North, but the chill Easterly wind must have turned the R40 to jelly-like consistency. The resulting seizure was quite a light one and the engine survived, but I wouldn't be doing that again. Could have got away with using R30 - possibly.

I might still get some R for chucking the odd egg-cup full into the petrol on Not A Fury, I'm getting used to releasing gummed-up Dell'Orto float valve needles now.

A.
#96268
Castor oil was originally used in total loss oil systems, either Pilgrim pump type four strokes, or two strokes. I don't think I'd use it as the main oil in a four stroke that was going to be used on the road but grass track racers liked the stuff because their engines were stripped and cleaned out a lot more frequently than most road bikes. As an impressionable teenager hanging around my local grass track club I really loved the smell and sound of those bikes! I think this is why I like my Bullet so much - it reminds me of those halcyon days.

Castor is useful in that it's a very "sticky" or tenacious lubricant on hot surfaces, more so than many more modern oils. AJS recommended it for my Stormer because it's supposed to lubricate the small end bearing better than mineral oils in the very hot conditions it sees.

I've still got a 5 litre can of vintage Silkolene R in the garage; bought it a while back on a whim. I only really wanted it for the can itself (my paternal grandmother worked at the Belper refinery for many years and I walked past there every day on my way to and from school), but it is nice to use a squirt of it in the petrol every now and again just for the smell of it.

However, I have a sneaking suspicion that my bike's recent stuck open exhaust valve episode was caused by me doing that; a small piece of carbon jammed under the valve was the cause. I've since drained the petrol and put it in my lawnmower! :oops:
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By Adrian
#96337
There was the whole issue a few years ago as to whether multigrade oils were any good for older classic bikes with roller big-ends, maybe some were better than others in this respect. I remember insisting in Silkolene 30 and 40 weight for my WD B40 engined BSA bitsa, I currently have Morris Oil Golden Film SAE 30 and 40 for Not A Fury's engine, though if it had had the floating bush big end instead of the needle roller one that's actually fitted, I'd probably have stuck with a good 20W50, which is what its builder would recommend!

A.

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