www.b50.org

kommando

Until someone can explain how a detergent oil can negate centrifugal forces that are used by the sludge traps the detergent vs non detergent argument is not applicable to sludge trap equipped engines.

kommando

Non Detergent oil use not necessary, per the American Petroleum Institute We have all heard the well meaning but flawed advice to use non-detergent oil in old engines. So I asked the folks who should know: the American Petroleum Institute. You might be surprised at the response. Especially the part ...

kommando

Thanks

kommando

I was planning to add one of those tanks to a C15 frame, who was the eBay seller Baz ?

kommando

Citric acid is lemon juice, will not affect paint, neither will vinegar.

kommando

You buy citric acid as a powder, boil the water in a kettle and mix with a few tablespoons of citric acid powder, vinegar will work too but as its already mixed heating it causes eye watering fumes. The heat just accelerates the action, cold or lukewarm will work but slowly.

kommando

Fill with a hot citric acid solution, leave for a day and then drain, repeat until it comes up clean and then protect using diesel or oil mixed with white spirits.

kommando

Chain comparison

https://www.youtube.com/watch?v=1dgO7oI8enE

kommando

It will not tick over cold when the carb is tuned properly for hot running, you need to get an extended throttle stop screw to allow on the go adjustment with gloves hands. For starting you will turn the throttle stop screw in 1 turn or so, start the bike which should then idle after a few blips of ...

kommando

Just checked 3 900 carbs, the depth of the pilot bush down the mixture screw aperture is 20 to 21mm, the pilot bush is only 3 or 4mm long. So at 25mm you should be through the jet and into the chamber behind with plenty of space before you come to the next obstruction.

kommando

You are drilling by twisting the tube between 2 fingers so it's by feel, no way you will drill through the other side. You can mark the correct depth for future reference. Never had to use much pressure, you will be able to see the pilot Bush by peering down the hole once the mixture screw is out.

kommando

The info is in the link from post 2 http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html This photo shows the horizontal pilot air screw adjuster on the right, if you follow that to the left then you get to the pilot jet bush which is marked in red. http://www.jba.bc.ca/JBCycle/Resources/pilot%20circ....

kommando

My next challenge might be oil leaking from the slider into the brake drum, the shoes were contaminated with oil, I guess from the allen screw holding the damper “cartridge” in place. Under the head of the allen bolt should be an aluminium washer, when you use these and unscrew the allen bolt the w...

kommando

They took the carb apart and washed it in one of those high power washing machine type things... then put it back together. I would think it would be totally cleared out?? That would clean the majority of the carb but not the pilot, the small size of the pilot means nothing but a physical probe or ...

kommando

Your pilot jet bush needs clearing out with a #78 drill which is a 16 thou drill. Glue it into a surplus WD40 red tube or similar. It will only get worse until the bike won't start at all.

kommando

Yep, too high.

kommando

360 = 1 Turn

kommando

Those chainguards are for 69/70, the shallow one is for the Shooting Star, the deeper one with the ribs is for the Victor Special. They do work better than the 68 and earlier against the vibration as they are further from the front mount but your swingarm will be missing 2 threaded holes just in fro...

kommando

Strictly yes, you get the engine up to normal temp and then screw the horizontal mixture screw in and out say 1/4 turn to get the highest revs with a shut off throttle. Stop adjusting when you get the highest revs then use the angled throttle stop to drop the now probably higher revs to your preferr...

kommando

The angled screw is the throttle stop screw, unscrew for a lower tickover.

For more detailed info.

http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html

kommando

Nothing to worry about except you need to stop starting and just idlling, it needs to run under load to get the rings bedded in.

kommando

BSA had a machine tool business that had overseas sales, that included sales to Eastern Europe before the fall of the Iron Curtain. They insisted of being paid in £ or goods to the same value, so you will find a lot of Eastern European bearings in your BSA.

kommando

Bantam John got the last bits of OTJ's stock.

kommando

The Vandervell shells are fine if they are VP2 which is a leaded bronze on steel overlay plated with lead/Indium. If they are Whitemetal throw them in the bin. VP2 is a dull silver, Whitemetal has a shiny bearing surface. Roller bearings are pretty standard nowadays, the differentiation is the quali...

kommando

Remove the follower, fit the camshaft and then fit the outer cover, is there any camshaft end float or does the inner cover stay proud of the crankcase (if so measure the gap between inner cover and crankcase, this is negative end float).

kommando

Just hope the DVLA do not ask for the frame number, a legitimate question if the bike is at your address, not sure its too faint to read will do you much good. The frame stamps are faint but 50 years later the DVLA will not be interested.

kommando

Until you tune the pilot circuit on a fully warmed engine you can expect issues. The 1 1/2 turns out on the pilot mixture screw is a starting point. Premier's are also known to be cold blooded and a lot of people end up fitting a 19 pilot jet instead of the 17 pilot.

kommando

All that matters is the feedside in the short term, open the OPRV and there should be oil there after 50 kicks. I think I counted 100 kicks before I saw a physical oil return to the tank, Long before that I felt the engine turning over easier due to oil getting to the rings.

kommando

The shaft is .015" smaller in diameter on the crankcase side than the side that enters the kicker shaft I can't remember the sizes but the C15/B40 F type engines prior to the change to the C15/B40G and B25/B44 engines had a bush in the crankcase for the layshaft which later became on the G onwards ...

kommando

Have your B25 crank welded and ground to take the A65 rod, that takes a 3/4" pin. You can also get a bit more stroke during the welding. Spacer under the barrel or ask Thunder Engineering for a custom length A65 rod.

kommando

Rebuild the original, should be much the same as the Norton one, the pattern ones are naff and your key should come out in the parking position.

https://web.archive.org/web/20190301033 ... terthannew

kommando

Push the old liner out, bore near what you think is safe, weld a 6061 crankcase spigot section on and have it Nikasil coated. Bob's your uncle. Gotta go to 92 mm like a big bore B50 with a stud repitch. I'm doing an old XL250 at the moment. Gone from 76 to 88 mm. You cannot push the old liner out o...

kommando

For a Trials bike I would go to Surrey Cycles first and see if they have an Aluminium alloy bodied premier first, lighter and better looking with all the advantages of the premier. They also have the option of brass slides which are even better than the anodised premier ones.

kommando

Ref the max bore on a B44 when you can make your own piston then I remember Mark Cook saying it was 82mm, but I think that was with a Nikasil plated alloy liner not the original cast in liner. You can get a full B44 alloy barrel bored out to the B50 bore of 84mm but blowby is an issue next to the 4 ...

kommando

Only difference left to right is the tickler, 120 mains is way too low, 200 would be a better start.

kommando

You paid £3600 on an auction site so it's worth £3600, your £2K misses out all the Labour you will do for free but would otherwise cast £50 an hour.

kommando

The angle is to give some directional stability to the follower, if Twinshockers measure close to 2 degrees then 2 degrees will do the job.

kommando

And when your throttle sticks open ?

kommando

The plate is a piece of stellite, an extremely hard material. It should be ground flat to the correct angle.

kommando

No oil seal, the engine breathes out through the main bearing and some other holes with gauze. The sprocket should be a living fit, find where it's binding and use a file. The engine oil is shared with the primary so whatever oil you pick for the engine must not contain friction modifiers or the clu...

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