Pre-65 Bikes

Query for you knowlegable people. Is there meant to be a slipper pad on the B40 duplex chain tensioner. Mine seems to run on the metal adjuster bracket !! It is also badly grooved, where the chain has been running. Is their supposed to be a pad of sorts ?

hi there can anyone help me has the b40 top yoke got any mounting brks on it for the clocks and such like as i have just got one with no brks on and i woundered if it was a compertition one can anyone help

Help required please for a wd engine & gearbox Is there a alloy clutch basket available for this engine Mine has teeth broken and slots are worn like a zig zag Who supplies gear selector forks for a wd gearbox & replacement gearbox spares. mine are ground and worn on faces, no thrust washers etc Can i convert 5/8" kickstart to 3/4" splined unit with a wd engine & box ? Again teeth broken on kickstart gear. Kickstart gear pinions worn need replacements. What do you lot use for cleaning crankases for removal of old gasket goo. sorry for all questions but saves time

hello! just thought i would share a picture of my bsa b40. been in my family for 20 years and i know 2 of the previous owners. just got it back from having some essential modifications. see if you can spot the obvious ones! I would love to start doing some 'miller' rounds or perhaps traditional trials rounds, but need to register it........... any pointers will be very much appreciated. cheers

Can anyone help with an issue relating to B40 / B44 engine specifications? I have bought a B40 to convert for Trials. The B40 Engine has a B44 round Aluminium barrel with std bore. Found so far;- B44 Al. round Barrel marked 41-42 with a gasket face to face of 82.4mm B44 piston 41-571 (std bore) B44 con. rod marked 41-550 Problem When turning the Engine without the Head the piston at TDC is above the Barrel by approx. 3mm Same problem with a std B40 piston 41-075. I believe the Barrel has been reduced in length but suspect machined too far. really would like to use this Aluminium Barrel, The B44 con rod results in a stroke of 90mm (not 70mm as B40). Questions;…

Can anyone reccommend alloy tank supplier for these bikes. Or doea anyone have any secondhand ones for sale. ?. At a reasonable price of course Any alternative tanks that may fit perhaps ?.

Hello all I'm after some advice please. I have a bsa b40 with a wd engine. She's been sitting for a while and the carb has all disintegrated. Could anyone tell me what AMAL carb it has fitted please so I can try and source another. From what I can see it's a 626 L but all the one's on the net seem to be L and three numbers. Many thanks

Morning all could anyone please tell me how to set up the 4 clutch springs? I know on some you tighten them all the way then back them off 4 turns but not sure about the bsa. Also should they be wired once set up? Many thanks

Good evening wonder if anyone can give me some advice. I have inherited a b40 off my father he took the clutch apart a few years back now. Could anyone please tell me the way the clutch plates go back in ie friction plate, steel plate, friction plate ect? And what oil and capacity should I use in the clutch/primary chain. Many thanks

Help required. After stripping down my B40 i noticed the following. The engine has a high compression piston. Should there be a compression plate fitted ?, as the piston has touched the valves. Any advice on thichness of plate. The bike was always difficult to kick over, which maty explain this. Any advice appreciated.

Hi Have started the rebuild of a 1964 BSA B40 and have 2 questions 1st the bike has a high level front pipe from s/miller but needs a new rear part of the exhaust, has anyone had the silverback exhaust of e bay http://www.ebay.co.u...=item27cdc599c6 or do you have any other surggestions. Having spent a small fortune on the engine up to now and still not running would like some help with engine oil, what is the best full sinthetic you can use in the old thumper, eg 20/50 full or part sinthetic. thanks simon

Here we go again! Im trying to fit a PES outrigger bearing plate to my b40 but the chain sprocket seems too wide to get a full nut and also no clearance between the outrigger bearing and sprocket nut. Has anyone fitted one of these and had the same trouble? Seems like you have to make the sprocket a little narrower? Please help one step forward and one step back at the moment!!!

Hi All, I'm building a B40 trials bike and wonder if you could help with primary and secondary sprocket selections? i don't have a crank primary sprocket or gearbox output sprocket yet or a rear wheel sprocket. any help would be much appreciated and save me some money and a lot of time getting it right! cheers Michael

Hello all again I'm after some advice. My B40 is running 13t gearbox sprocket and 60t rear but I feel I need a but more speed on the hills. What combination are people running for trials? Many thanks

Hello, my bsa jumps out of 1st gear, it has been running for 5 trials since opening the engine without problems. now suddenly it jumps out of first gear what could be wrong? 2nd gear seems to be fine 3th and 4th too. when i run around in low revs it seems to be fine but when i go uphill and give it some throttle it jumps in neutral it doesnt make scary noises just clik and out of gear. anyone can give me some hints where to start? i need the bike next weekend for a trial so i have to work fast. anny help apreciated! best regards bob

Hello all wonder if you can help. I have just got round to getting my Dad's old B40 out after been sat for 15 years. It doesn't seem to have any spark and I've been told they have electronic ignition is that true? So I'm a bit stumped.

Hey, i want to build a pre 65 trials bike, the bike has to be competitive on Europeen pre 65 trials. not sure wat to choose i was thinking B40 or Ariel 500 as that is wat the pre 65 experts ride in europe, i don't want a 2stroke (i can't ride one i'm to used to 4stroke power) but i'm not sure what's the easiest to build. I found more info on building ariels but a B40 is probebly cheaper and easier to find parts? most people say the B40 is the easiest bike to ride and a bit lighter than an ariel (over here the pre 65 bikes are no semi modern specials like in the UK) no one rides ajs or matchless on the expert route, are these bikes harder to ride than an ariel? i have…

Hey i have a Bsa B40 GD now but i would like my bike to be a bit more nervous and powerfull. the bike has a standard piston for now but i would like to know if there if a piston available that gives higher compression (from a road version of the b40?) and can i just change my piston ( it has a flat surface) for a high compression piston or do i have to balance the flywheel and do other stuff to my engine? best regards bob

Hi Guys My first post & I hope it's in the right Forum Can anyone recommend a supplier near to Solihull West Midlands able to rebore my B40 barrel & supply a new piston, ideally at a sensible price. Thank's in advance Cheers - Frank

Good evening all. Would anyone know if a C15 rocker covers the same as a B40? Also does anyone know where I have get new rocker cover nuts from. Many thanks