If so - I'd be interested to know your jet, needle and slide cutaway please.
I've mine in bits at the moment and getting some contradictory info regarding main jet size. Also whether or not you have an air filter.
Thanks

Anyone know where I might source a B31 plunger oil tank (I know about eBay etc)? I'm doing some repairs on mine but would like to replace it with a less corroded one.

I have a 1953 plunger B31. I needed to repair the pinholed oil tank. I found a good match for the original colour (now heavily patinated). The bottom 1/3 of the tank has been repainted and rubbed back a bit to try and match the old. Thought it worth sharing in case it's of use to anyone.
Please don't suggest I paint the whole tank - thank you 🙂

I'd like to prepare my C15T (currently in bits) and myself (horribly out of shape) for this years Tamar Trial which is on my birthday in October. It would be great to get any tips on doing this trial on a C15T. I read that someone once cleaned every section on one!
I did this trial about 15 years ago on a KTM 300 and haven't done it since.
I'm intending to get the bike back together over the next month or so, do a bit of greenlaning, head to our local trials practice place regularly and go to the gym.
Bike set up info would be very welcome.
Thanks.

I'm using monograde oils in my two BSAs. This is my first year of ownership so I've not been through this process before.
When do you change from winter oil to summer oil? I'm thinking it's better to hold off until we're into full summer temps.
I have SAE30 in the bikes now and will be changing to 40 for one and 50 in the other.
Please do not suggest I use multigrade oil.
Thanks

Anyone in mid cornwall (st austell, Newquay, Truro, Bodmin etc) fancy meeting up for a ride?

I have a 1953 B31. I tend to stick to back roads but often see 60 -65 mph out of it. It's not been restored but is in good mechanical order with good oil. It so far doesn't seem to complain. It's on standard gearing but 3.5 rear tyre. What do others ride theirs at? This is more about a comfortable limit with regards to mechanical sympathy than what the bike can do. I've not had a long stroke single before and think I was initially guilty of lugging it at low revs too much (as it's fun).

Anyone put a Gandini piston in a C15? If so what clearance did you use? They won't give me a number. I have an aluminium barrel on mine so I guess that will have some effect. Tempted to just buy it and chuck it in the oven with the barrel and see how the dimensions change.

I have a vokes half round air filter that came with my C15T. The previous owner took it off and put a ramair pod filter on it. I'm not keen on this as one blob of mud and it'll be half blocked. I'd like to refit the vokes filter but don't know anything about the filter media. I know sheets are available from the usual classic bike outlets but I've no idea what would be the best bet. I would also want to oil the filter -another reason why the pod filter is a bad idea. My leg will get stuck to it haha.
Anyone know about this who can advise?

Any Cornwall based trail riders here? Nearly got my C15T lane ready so looking for people to ride with. Not into high speed enduro style. I prefer to stop at the top of a lane, take in the view and have a swig of coffee 

Doing a strip down of the front forks of my C15T. The bike seems to be a bitsa with C15T frame, road bike subframe and mysterious forks. I think they are the C15T forks (heavyweight) but with the bottom nut from the Bantam Bushman. It also looks like someone has fitted some additional damping held in place by the bar secured to the top nuts.
Anyone able to identify/confirm what these fork parts are and if they work ok together? I need to replace the bushes and seals. Quite tempted to get another pair of forks if these remain a mystery.

Hi,
My 1960 C15T has one of those straight through perforated tube silencers. It's really very loud. I've just been refused entry to our local trials practice ground due to the noise.
Can anyone recommend a quiet trials silencer for my bike? Are the Terry Weedy ones (Avery) quiet/any good?
Thanks

Im considering fitting some lights to my road registered 1960 C15T. It has none at present and the only electrics on the bike are in the battery less ignition circuit-

Modified Lucas alternator to give 12v
Lucas rectifier
Zener diode
Lucas capacitor
Points
Coil
Plug

I'm currently re-wiring this lot as it was a corroded mess. I'm considering adding head and tail lights. Is this doable with a battery less system like this? I don't want to fit a battery and I don't want to fit electronic ignition. I have a much better chance of understanding and fault finding the current system. I don't want a box of tricks so please don't suggest it! Would LED bulbs work?
Thanks

Hi,
What do those with C15 trials bikes use for a rear tyre? I was pleased to see that mine had an MT43 4.00 x 18 when I bought it but having just taken the rear wheel out I can see that it's really too big for the frame. The tyre has rubbed a hole through the exhaust!

Hi,
Would some one be able to explain how the rear brake pedal pivot pin should be removed please. I need to change the pedal and the pivot pin isn't playing ball. I'm assuming once the nuts off it should tap out of the frame bracket but would like to check in case I'm doing damage.

Here's my C15 trials bitsa. Seems to be trials frame, modified subframe (maybe from road version), ss80 bottom end, alloy barrel, C15t head with valve lifter, bantam wheels (I think). I think the tank may be a genuine bsa trials but not sure. Bought as a runner but lots of issues coming out of the woodwork. Lovely little bike though- I've always wanted a bsa trials. When I'm not fixing it I'll be pottering about on greenlanes.
If anyone knows this bike I'd love to hear from you.

Can anyone confirm the threads top and bottom of the C15 rocker box studs in the 40-121 head please?
Rupert ratio has them as 1/4" BSF whereas Draganfly have them as CEI. The thread for the stud above the exhaust port has gone thanks to an old repair that eliminated the dowel. I need to drill deeper into the material around the exhaust port and retap. I'll probably replace most of the studs too.

The clutch sprocket on my C15 is quite wobbly - around 2-3mm if I grab the outside of the clutch and move it around. I've read that some wobble is normal but is mine excessive? I've only taken the cover off to get to the crank nut so I can get to TDC.

Does anyone know whether published gear ratios include either the primary or final drive? Getting some odd results from my calcs. Makes it look like my c15 revs to 22000 rpm 

Anyone have any idea what the barrel is that's on my C15 with FSS80 motor? I'm assuming the head is standard and the barrel isn't but happy to be told otherwise. The barrel is alloy.