Pre-65 Bikes

Never worked on one of these bikes before and I need to take out the kickstart shaft to see what is wrong with it. Are there any pit falls when stripping it or tips on how to go about it. Will I be able to get it out by just removing the casings or do I have to split the motor ! Thought it might be an idea to ask before getting the tools out. Any info would be great.

Does anyone know if there is a splined kickstart shaft available for the early distributor type C15 (Star?) engine? It's a 1963 engine. Really fed up having to drift out cotterpins every time I have to remove the kickstart. No matter which type I use they bend and really take some hammering to remove. The knuckle on my forefinger really hurting and being twice it's normal size thanks to the hammer was the last straw this tonight... Or I may have to investigate the possiblility of grafting a splined shaft from something else onto the C15 gear - or rather I will have to talk nicely and grovel to someone else... That sort of stuff is beyond my capabilities

Well, with only 2 unfinished bikes sat in the garage I though it about time I started work on another project !! In an attempt to piece together some 'spare parts' I am fitting a 250cc C15 Bsa engine into a Greeves frame. I have stripped the engine and the piston is already at +040 and need a rebore. I have heard of some C15's which have been overbored, what piston can be used and what CC does it take it out to? Any other tips / advice regarding the C15 would be appreciated. The engine is a SS model, I presume it has a racey cam which may need to be replaced.

Good morning folks, I spent a few days in Scotland at the beginning of the month watching the Pre 65 event and it's re-ignited my enthusiasm to get my 1960 C15 sorted and I'd be grateful of any advice. The rear frame loop where it attaches to the frame in front of the seat is welded which looking at the parts manual isn't standard as they appear to be normally bolted through a bracket between the tank and seat. I'm hoping that one day my entry for the Scottish pre 65 will make the ballot, would the frame as it stands make it through machine examination? I've fitted the smaller front primary drive gear and it has a 13 tooth front sprocket, the rear sprocket is 62 teeth …

Hi - I have just put my C15 engine back together after fixing a number of oil leaks (I hope!). It never ran very well before - it seemed to never idle properly. I've only owned it for a short while and managed to nurse it through for its first job which was just to deliver my daughter to her outdoor wedding (about 100 yards up a drive!) without getting oil on her dress! Now I have it all back together, it starts easily and I seem to be able to get a lovely, smooth, medium speed idle but as soon as I open the throttle it bogs and dies. I am out of my depth and need some help - maybe a sequence of things to eliminate/try? It is a fairly standard looking engin…

Is there a recommended process to make a C15 not a big oil leaker? When running, my C15 leaks oil on to the bash plate and then to the ground so it is unclear where it is leaking from. I don't see any obvious leaks from gasket areas. After parked for a couple of days, it starts to leak which I believe is wet sumping. All check balls and springs were replaced but during the rebuild most everthing was corroded so the condition of the ball seats is unknown. There is a tube fitting on the head which I connected to the oil tank so there is no real breather...is this correct? The frame has a right side kick stand that would seem to make the leaks worse with all of the ven…

BSA On ebay: BSA C15 It seems a very nice bike, but if Im not mistaken that seems to be a B25 with a B25 Frame (pre oil in frame) The B25 was made 1968 onwards What would happen if you tried to enter this bike in a Pre65 trial?

Hi just wondered if anyone knows if the original C15 fork bottoms (external springs) are suitable for machining and having more modern inernals fitted? bike currently has mz forks with machined seal holders that look the part but i really want to make this bike elliagble for major pre65. thanks

I finally got my C15 together. Thanks to those on the forum that provided input. So...what should it run like? I need to do some more tuning and I have never ridden a TL125 but it runs like a TL125 sounds. It is super smooth and pulls smoothly and strongly from very low rpms but does not respond quickly. It takes lot of effort to lift the wheel 1/2 foot. (Bultaco front end/ wheel with steel BSA tank) It has the standard cam, big valve/ small port head, Kehin 22 mm carb and an ignition with no advance...set at full (I believe). 18 tooth motor sprocket, 13 tooth trans sprocket and 54 on the rear. I was expecting some quicker response like a TLR200.

Planning to rebuild a C15 to trials spec. Is there any value in pushing the engine out over 250cc which I believe you can do with a Triumph piston or is it best to use normal oversize.

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

I'd be grateful if anyone could advise on rear shock absorber choice and length for a 1960 C15 trials bike, previously it had a strange rear subframe concoction but I've fitted a new rear subframe from Progressive Classic Products which is far more trials orientated and has also now allowed the exhaust to run inside the subframe without fouling the tyre. Any advice much appreciated, thanks. Pete.

Can someone tell me the size of the o rings on the rocker arm shafts? These fit in the rocker box when the shafts are pressed in. My gasket /seal kit does not include them. I have some 1/6" cross section, 3/8" ID, 1/2" OD o rings but they look too thick, like the shafts will never press into the rocker box..

Hi, I`ve recently bought a C15 head ( part no. 40-338) that according to the Rupert Ratio book is ` scrambles `59 `60 and big valve with 15/16 choke. The exhaust is standard C15 but the inlet measures 1" 7/16 ( no valves with head). I`ve read that SS80 is 1" 13/32, but does anyone know if mine is standard?. The inlet is ported but don`t know whether that is original or later. I need a new inlet valve and not sure where to get one? Thanks in advance, Dave

Hi, new to trials again and slightly out of the info loop as living in Ireland. Posted an intro which should explain most. Although there does not seem to be recognised pre 65 trials in Munster I do not see that as a reason to not try to prepare my recent purchase to it's potential. Last owner has done a fabulous job, but it is always difficult to know what is needed. My first instinct is to replace the items difficult to judge wear upon - needle and jets- replace plug and adjust tappets. Starts 5/6 kicks but would love to get it in 2. Info on expected compression reading would be invaluable as therein lies the wallet factor. My major concen at present is shocks. I have l…

Hello Just bough another C15 and the new side panel that covers the battery is missing. As far as we can tell from the reg the bike is pre 62 and the engine has the points on top not side, so this looks to be correct year wise. Are the side panels the same for all years?

The Rupert Ratio book mentions a steel/ bronze combination sleeve gear bush for the C15. It says it is a later model option but the distributor and side points parts books do not show such a thing. Where could I purchase? I'm in the US if that makes a difference.

My c15 slips out of 1st under a light load. So far at least, it has not done this under hard throttle. There are no sounds or jumps, it just sort of slips into neutral. I pulled it apart and the cam plate had a little defect where it catches the spring in first gear so I cleaned it up square with a carbide end mill. It seemed OK but after getting hot it started slipping out again. The cam plate has no BSA or part number markings. I have ordered a new one. The bike was dead when I got it and so I did a total disassembly with replacement of any suspect parts. If it was anything obvious I probably would have seen it. It does not slip out of other gears or have any o…

I have a distributor BSA C15 engine I intend to build for trials, I have a WD low ratio box, I want to keep it 250cc, also intend to keep the bush bearing having a new phosphor bronze one made to suit. Having removed the top end all looks good so far, not run for a while but sound. PVL or Electrex ignition will be used. Has anyone any more tips for a soft 250cc build?? Thanks in advance...

Any recommendations for best spark plug to use with a C15, PVL Ignition?