Pre-65 Bikes

Jeezzzzzz it’s a steep learning curve with these things. Ok folks, current issue is what, is the gearing of choice for trials. This Cub is said to have a Serco gearbox in it according to paperwork history that came with the bike. That could be BS, but there is a receipt from Serco for other work done. How would you identify a gear selection of theirs.? The duplex Drive is a 16 tooth, the high gear a 27, it had believe it or not a 9 tooth front sprocket that had been welded on and a 46 rear. Now from the research I’ve done it appears that 13 or 14 is what’s used on the front. But would a Serco gearbox have completely different number of gear teeth to an orig…

I have just fitted a Honda TL125 Kehein carb to my Tiger Cub, it runs OK on tick over but as soon as I roll of the throttle, after giving it some throttle! it pops back through the exhaust, at the moment its 98 main and 35 pilot,with the needle raised one from the bottom,do I need to go bigger on the main or raise the needle to the max! I thought that the TL 125 carb just bolted on with the standard jets and that was it. My Cub is the 250cc Serco conversion.

Does anyone have a diagram or detail on disassembling the Lucas distributors for single cylinder British bikes? I have the long shaft/ cam/ advance mechanism out of the outer housing. It is rusty but looks salvageable. I would like to know how it comes apart so I don't just start trying to pull stuff off and end up breaking it. Thanks!!

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;…

Real simple one, should a C15 have a primary chain tensioner fitted?

All, i am hoping to fit a B25 Barrel onto C15 crankcases, also using the C15 head. many have already done this mod, my question is how do you get the oil back to the crankcases as the drain holes in the B25 barrel only one is the correct side as the C15 has them diagonal. can you drill down the side of the barrel and put a pipe in?? could you mill a track around the gasket face on top of the barrel from the where the drain hole from the c15 head meets the barrel? i have only seen one one and he had a very late B25 barrel and there was enough 'meat' to drill down the side? my B25 barrels are earlier and don't have enough room, hence my question about pipe?? as alwa…

What type of wheel spindle arrangement is best when using a Cub type hub in AJS, Matchless fork legs?