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Thursday 8 January 2015

Aspen - Because they're worth it




I don't know about you, but the thought of crappy petrol and ethanol gives me nightmares over the winter months when my bikes are laid up. I've tried or considered a few options since this became a problem.

Drain the tanks? Then you have a bare metal tank which to me isn't that good an idea. Also not kind on cork washers in fuel taps as I found out to my cost when they shrunk beyond repair and needed replacement.

Stabiliser? I find it hard to believe that a 1-2% mix of anything will fix all of the ills of modern fuel and prevent corrosion due to water content.

Fill the tank to the top? Hmmm. Even more fuel and more water hygroscopically absorbed by the ethanol.

Luckily I have discovered a better answer. Aspen is a pure petrol sold in 5 litre containers designed primarily for use in garden machinery. Putting aside the fact that it is way more environmentally friendly, it has NO ethanol and is so pure and stable that it lasts for five years before loosing any potency. The downside is cost, but at around £18 for a once yearly five litre slosh, its a damn sight cheaper than a new tank or an ultrasonic carb clean. Aspen is available in straight petrol or 50:1 premix. Get the blue can and if you need to put 2 stroke in it, you can mix your own ratio.

I've just drained all the rubbish out of my tanks and installed a can of Aspen in each bike and flushed it through to the carbs. No more sleepless nights, and as a bonus, you end up with a very nice re-useable container to store pump petrol for the car or mower.


Here is a link to the Aspen website:
http://www.aspenfuel.co.uk







Wednesday 7 January 2015

B50SS - The Bike That Dare Not Speak Its Name



When I was 14, I had a poster on my bedroom wall which featured an OIF BSA A65 Lightning and a B50SS. I've never really paid much attention or registered any emotion for these bikes since then, but these things must have a profound psychological impact because when I stumbled across this bike for sale in December I just had to get my hands on it.

Unbelievably skinny and very light at 140kg, the B50 was the very last in the line of British 500 singles, and as such deserves a place in motorcycling history. With a punchy 34bhp engine and 'trail' styling, its looks were somewhat ahead of its time.

Controversially, BSA decided to add the 'Gold Star' name to the SS, which deeply offended DBD owners. To be fair, as well as setting a TT lap record and winning its class in both the Thruxton 500 and the Barcelona 24 hours, the B50 (with assistance from CCM) went on to have an illustrious off road competition career so maybe in hindsight it has earned the right to use that sacred title.

I think I'll to refer to it as a 'Goldie' just to annoy people.

My example is an American import (as most are), with only 11,000 miles on the clock and is in very original condition. I'm not going to restore it, I think that would be a shame. Just a thorough re-commission and a good clean and polish should result in a nice, useable bike with some patina.





Tuesday 6 January 2015

Amal Carbs - The Proper Way To Restore A Distorted Flange

I'm in the process of bringing another bike back to life, and as usual the Amal Concentric carb has been over tightened. As a consequence, the flange is warped. It's a low mileage bike and the carb is surprisingly good, so it's worth fixing.

Now the obvious thing to do would be to get a sheet of glass, some 400 grade wet and dry, and rub away to flatten the flange. Obvious, but not really the best way. A more effective solution is to use an accurately made tool to apply the opposite pressure to push it back into shape. Not only will this bring the flange back to true, it will restore the shape of the rest of the body which has been distorted.

I made the tool a few years ago and it has rescued quite a few carbs from the scrap bin. The base is a flat alloy block with a threaded rod fastened securely into the centre. The 'slide' is turned from solid alloy and is machined to fit the carb bore accurately.

You simply pop the 'slide' into the carb, feed the threaded bar through a hole which is drilled to be central to the inlet and then as you tighten the nut, it pushes the whole thing back into shape. A pair of of 5 or 10 thou feeler gauges (one placed below the mounting hole on each side), allow you to bend the flange past straight so that when the nut is loosened the natural spring in the metal will leave the joining surface and the body absolutely true.

With the aid of this simple device, it takes about two or three minutes to fix a carb properly. If you work on old bikes regularly, it's well worth knocking one up.










See this link for information on how to install an Amal carb: