Pre-65 Bikes

My old man is finally going to ditch the horrible standard ignition system on his C15S. What options do we have on a electronic version? I think we would like to go down the crankshaft mounted route to avoid the backlash in the distributor system. Do any of them have lighting coils fitted as standard/option. Thanks

My C15 project is at the point where I need to mount an "inside the frame" exhaust to get leg clearance. This is a 1960 goose neck type frame. The oil tank has been moved in and slightly forward. See the pictures. (The oil line is not as close as it appears.) There is a section where the pipe sort of steps up and out. It looks like it may be possible to cut and rotate that section so it goes in an down. Has anyone tried that? Or...is it basically easier to build from scratch? Any advice on either option?

Anyone know if and where you can purchase longer than standard Stantions with springs ?

Asking for someone else who doesn't do a lot on the web... Is a BSA C15 frame possible to get into shape for trials? (I know the sub frame wants altering) but other than that can they be made good or best to get after mkt frame?? It's a 63 bike dizzy engine?/ Thanks in advance....

I'm looking at a bare C15 frame. Should the swingarm pivot be parallel to the short frame piece across the back at the bottom of the frame? Mine does not look so. The little frame piece just holds the pegs but I would expect them to line up.

Hi while assembling the gearbox components I fitted a new camplate spring, second hand camplate (identical) because point at 3rd gear postion on trackway was not worn on the spare I found in a box. Spring was set at correct height, when depressed, in relation to cam pivot and all seemed well. Assembled the cases to check and found that the camplate makes a definate clunk against the bottom of the housing when selecting 4th. Viewing with a bright light spring is engaged in camplate correctly. Looked at the old camplate and there was no wear mark at the spring/camplate location to indicate that the cam was being held out of place by the lowest point of the camplate meetin…

My gearbox is worn out on my C15, can I replace all the g/box components with B25 items or are they different?

I have a c15 which has standard road gearbox, I’ve lowered gearing including primary drive to make first ideal for sections but obviously it makes fourth rather slow and the rear sprocket is large, chain has jumped off couple of times. I’m not very up on gearbox internals so hoping someone can help. If I replace 1st and 2nd with these 29 tooth 40-3176, + layshaft 2nd gear 26 tooth 40-3132 and mainshaft or 2nd, 24 tooth 40-3130 will it make significant difference. Does it lower first gear internally so I could reduce size of rear sprocket. Thanks in advance for any help

Riding round the garden today on the C15 and had to reverse the bike in gear with the clutch pulled in and it wouldn't go backwards unless it was in neutral.The clutch is fine and clears all the gears,is this normal????.I have never noticed this before (recently changed gearbox camplate with upgraded part,gear change is fine),could it be something to do with the kickstart/pawl as it's action now seems further forward than it used to be. cheers the noo Brian

Hi all, my mate has pulled his c15's gearbox out of the centre casing without removing the clutch so all the bits kind of fell out. The camplate has been inverted to give an other-way-round gearchange. He's stripping the clutch off the shaft to reassemble it but was wondering if the selector forks still go back in the normal way that they would with the camplate the right way up. The reason he's opened it up is that it's jumping out of first gear, any ideas?? Thanks for any help / info, Craig

Does anyone have a sprocket recommendation on a C15 for Trials? I would prefer to stay away from a huge back sprocket and am really only concerned about getting first low enough. This bike has the 33/17 first gear....listed as wide ratio in the RR book. (Oddly the other gears match the close ratio numbers in the book.) From what I can tell, the smallest transmission sprocket is 13 tooth and the smallest motor sprocket is 18. With the existing 56 rear sprocket, I calculate an overall 1st gear about 24:1. The same calculation for my Reflex with 9/44 final drive gives me 45:1. Am I missing something?

Hi, I am looking for 2 x C15 gears to put in my Distributer type engine. Well actually I would like a complete wide ratio box for the bike but hens teeth are easier (and cheaper) to find!! I am looking for a 20T part No 40-3101 & 30T Part No 40-3100 These were fitted as 2nd gear in the wide ratio box. I have tried all the shops who advertise in Classic bike and Old bike mart hoping to find some NOS but no luck. Can anyone help? stephen.bird1@ntlworld.com

I have a C15 with Alpina forks and 13 1/2" shocks. The frame is a 1960 C15S, gooseneck type and I struggle with the lack of ground clearance. It is 2 or 3 inches shorter than a TLR200. I also have a spare, later model, C15C frame. Do these later model competition frames have more ground clearance? How do others deal with this lack of clearance? Probably due to the offset Bultaco forks, it turns pretty well so I'm reluctant to just jack up the back end. Plus, I don't have that much ground clearance myself.

Evening folks, I'd be grateful of any advice for two problems, the first is in relation to a Triumph piston which I've bought from Burton Bike Bits as an upgrade for my 1960 C15 I've had the barrel rebored to 69mm but on fitting the recommended Triumph piston the gudgeon pin is too tight in the little end, it'll fit but far too tight. Do I need a different little end bush or is the con-rod just incompatible? The other problem concerns the clutch actuator arm, where the clutch pushrod seats into the barrel in the arm, the barrel has a pin through it but the pin carrier has sheared and no body has a replacement part, I could fabricate something solid but it looks like …

Is it worth converting to Taper Roller or is cup and cone sufficient?..If taper roller is worth the hassle, where can i get them?

Hi all, is there much of a difference between the pvl and electric world ignitions, is one better at plonking down to nothing without stalling etc. many thanks

I'm thinking of moving into the 21st century and getting electronic ignition on my C15. I've looked at the various options and I'm thinking that the crank driven type is what I'll be going for. I don't need a battery or lights so it seems the easiest and best option. I've identified three that look suitable, the PVL from SM, Electrex World and Rex Caunt. The PVL is at least one that I've heard of and looks and seems decent quality, I can only seem to find them at SM though. The Electrex World is a good deal cheaper but seems less trials oriented. The Rex Caunt also sounds ok and has the advantage of parts of the kit being available separately but it's more expensive. Al…

Does anyone know if a C15 engine will fit into a bantam frame? I’ve built a rolling chassis for my bantam, no engine but I do have 3/4 of a c15 engine!

Anyone point me to an extended inlet manifold to fit a C15?

Could someone tell me what thread size the studs are that screw into the inlet port on a C15 head. I want to fit longer studs to move the carb backwards but I'm useless with British thread sizes. Secondly, does anyone know if they can be bought in longer sizes? If not I'll buy bolts and make studs out of them.