Recomissioning My 1959 BSA Star - C15
After many years of riding my 1959 and allowing her to be ridden in all weathers, I decided late in 2025 to rebuild her. From getting a new rod on her Crank, to getting her cases welded up.
My BSA C15 Star has for a long time being called "drippy" I can't recall who named her that. My very good friend Laura, or myself but her name was appropiate. It stuck. So, she had a bad oil leak from her inner gearbox case and overtime this became really really bad.
In 2025 I'd had a really stable period with my 750s and decided to throw untold effort and money at sorting once and for all my 59 BSA. For me, I enjoyed riding this small 250 as much as my 750 classics. She proved herself on many local journeys and I loved her dearly.
November 2025.
Engine build starts
11th March 2025
I started to strip her engine out of the frame and take the engine appart. My friend Peter recommended Cambridge rebores, so the Engine cases and her crank barrel all were sent to Cambridge. They had the engine nearly six months, and during this period I started to investigate and catalogue her parts and ordering bushes and parts. Many were sent direct to cambridge rebores.
April
majority of the engine strip
Crank comes out.
insert photo here.
May
Engine strip complete
October 25
Cambridge rebore finish my engine ( ish)
21st November 2025 - I collect my parts.
4th December 2025
Engine cases connected to the engine jig and I start to dry assemble a lot of the engine and gearbox parts.
29th December 2025
Disaster - cases explode.
31st December 2025 photo session of the rolling chassis and prep to strip. Piston is fitted to the crank. She starts to look like an engine.
5th Jan 2026
parts go to powder coaters - KDS Whittlesea.
17th Jan 2026
tank and tinware taken to painter. John Sillet Chatteris. Wheels come up lovely after cleaning.
18th Jan 2026
I start to strip the forks.
23rd Jan 2026
Barrel goes on the engine.
31st Jan 2026
ignition and clutch ( new plates ) go onto the engine.
engine is mated to the frame ( in my living room !!!)
4th Feb 2026
lots of replacement parts arriving daily, i find an original throttle.
9th Feb 2025
I start to clean many of the small parts in preperation for paint and assembly.
10th Feb 2025
I manage to get a rolling restoration
Monday 16th Feb 2026
Dry fitted the armour exhaust.
Tuesday 17th Feb 2026
Small niggly jobs. Centre stand fitted. had to get the powdercoating off to get the pins in. Then final drive chain, but made a mistake when i tried to fit the chainguard. I couldnt so the chain has to come off. I am dissapointed to report that the armours exhaust may not actually fit as predicted. I will spend more time on Friday trying. I will obviously not let that lye. If it is the case. I fiited the old rocker box cover, had to remove two studs to get her under the main spare. But will fit the final one this weekend. slow progress. clutch cable seems to be far too long.
Friday 20th Feb 2026
started to layout the cdi and coil, and the front brake cable. Then i decided to cut down the new exhaust header pipe. I had to shave off several inches at both ends. Not a great thing to do when paying so much.
28th Feb 2026
Slow progress. Had a problem with a pushrod tube that took an hour to sort that I’d not planned for. Another new exhaust fitted, outer case dry fitted. She now stands upright and is slowly starting to look like a motorcycle. Many of the parts that appear to be fitted are simply placed and being checked for fit. Tomorrow afternoon I’ll take better pictures.
Monday 2nd March 2026
Rolled her out for a photoshoot. A lot of parts are not properly fitted. But hoping that the photos help me nudge slowly forward.
Wednesday 4th March 2026
Painted the rear brake arm, need to get the arm fiited. So i can fit the brake switch.
Thursday 5th March 2026
Had to touch up the brake arm as I missed a bit. Used spray paint.
Saturday 21st March 2026
Wired up the brake switch wiring up. Fitted the offside outer case and the FEKED downpipe.
Sunday 22nd March 2026
I started to sort the wiring on her. Converting her from 12v+ to neg, and using wago connectors to mock the wiring up.
Monday 23rd March 2026
Had an hour refamiliarising myself with superseal connectors. I created one for the CDI to loom unit. I intend to use in several areas. I have ordered more heat shrink, as I intend to try and work my way through the loom. It is somewhat confusing converting from pos earth to neg. I need to wire up a temporary solution. I have ordered a small fuse box. I intend to isolate the loom by fuse. Namely the following circuits.
1. From the main battery.
2. From the rear brake light circuit.
3. From the horn circuit.
4. Maybe a spare fuse.
I will calculate the amps based on load. to dertermine the correct fusing.
Wednesday 25th March 2026
New front mudguard arrived, along with rocker cover and front brake adjuster.
Thursday 26th March 2026
Tried the front brake cable adjuster, it did not fit. I got it wrong. Adjusted the cable at the lever end, and I have a front brake on the C15. I am still head scratching re the wiring. I will keep trying.