Monday, 26 March 2018

BSA Beaver


After reading the article on the Beaver in a previous UMG, my appetite was severely whetted. The tidy little machine was just the thing to satisfy my upwardly mobile lifestyle at the age of sixteen. I immediately began my quest to smoke out and trap a Beaver of my very own. My search was long and hard for the elusive creature, but I finally tracked one down through an advert in the UMG.

On first sight the bike looked like a complete whale ejaculation, the frame was badly corroded (not unusual for British bikes in my experience) but had only clocked 6000 miles. The front forks were too short and had obviously been transplanted from a C50 and bodged on to the BSA. The owner explained that the original forks were violently distorted after a sudden seizure of the front drum brake resulting in a head on collision with a stationary Wanklux (Toyota Hilux). After some heated haggling we agreed on forty quid, which some would say was a lot to pay for a pile of cat chod but I was determined to claim my prize.

Once the Beaver was safely caged in my bike shed, l began a thorough inspection. I had bought the bike as a non runner and therefore expected to encounter mechanical failure. Surprisingly, after just resetting the points to the specified gap and re-routing the tangled web of electrics, the bike gave birth to a large cloud of blue smoke and chortled into life.

My attention was then focused on finding some replacement forks. Originals are hard to come by since few bikes were made, therefore alternatives had to be found. These came in the form of TY50 forks and yokes from a previous motorcycle. Unfortunately. the TY's steering column was an inch too long so a spacer was cunningly fashioned from a piece of brass boiler tube. Now that the new front end was attached the bike sat parallel to the ground.

The bike ran but I was sure that in its present condition it was too tatty to pass an MOT, so I decided on a complete strip down. The little beast was of simple construction, consisting of a loop frame and mono-shock suspension, so with only minimal help from a reluctant brother few hours were needed to dismantle the bike.

Surprisingly, the engine was in remarkably good condition with hardly any bore wear. Obviously, the bike had never been seriously thrashed. I decided to leave the bottom end alone as the four speed gearbox had seemed fine when I rode the bike around before.

The frame needed rubbing down, followed by a coat of Rusty and then Smoothrite. The bike was then reassembled with TY50 handlebars and front wheel. The tank and seat were left alone as they were in reasonable condition. Another interesting point about the BSA was that it used a rear stop light for the main beam and dip - obviously an ltalian job!

The bike passed the MOT second time around after a loose swinging arm failed it the first. Screwing its arse off in top gave an indicated speed of 30mph but in actual fact I was clocked by a fellow biker doing at least forty. This aroused my earlier suspicions that the replacement Kawasaki clock did not have the same gear ratio as the original.

The Wop two stroke single cylinder motor felt fairly crude, but produced enough in the way of power to compensate for the large gap between the ultra low first gear and the more reasonable choice of second gear ratio. First was apparently chosen to let the bike climb up the side of a house.

The bike handled well around corners but was a bit light under hand, especially when using the rear brake. The bike was also a touch on the small side for me, as l was 6' 3" and 12 stone - heavier than the bike itself. Equipped with a larger engine sprocket, the top end was increased by a further 5mph.

This gave a more even spread of grunt along the flat, preventing arse rattling engine revs in top gear. One annoying factor is that at high revs the petrol tank resonates violently, which over long periods gave rise to a bad case of diesel willy.

150 miles to Hull would be a real test for the little Beaver, not only to find out if the engine would stand the pace but if the bike was comfortable enough for me to stay seated for nearly six gruelling hours. I set off early one summer morning from Windermere and everything ran well for two hours until half a mile outside of Long Preston the little bugger began to misfire and lose power.

I pulled over to inspect the damage. The down pipe was smoking copiously. I removed the spark plug to find that the electrodes had fused together. l had forgotten to bring a spare, but had a Swiss army knife with which I was able to separate the electrodes. As a precautionary measure l re-tightened the cylinder head bolts.

I then mounted the bike once again and proceeded to have an uneventful 90 mile ride into Hull. Tightening down the head bolts must have cured the problem because the engine has no cylinder head gasket and I suspect it was allowing extra air to rush in, thus weakening the mixture. It was lucky that the spark plug went instead of the piston!

The seating position was quite adequate, even for me, although extra seat padding would have given a softer ride to my buttocks. My stay in Hull was pleasant, only marred when a jealous friend saw my tidy motor and decided to blemish the tank by painting KNOBCHEESE across it...

So, as an overall summary, I would say that the Beaver has good fuel economy (100mpg) and a top speed of 45mph. Although the bike is small, it will cope with anyone from a 5 stone weakling to a 12 stone gorilla.

Adam Rawcliffe
 

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