1958 BSA C12 Misfire Fixed

[@aeroearth]

No misfire there David! Bit of a gear whine and a knock which might just be piston slap. But could also be the big end bearing. My first motorbike was a BSA C10, rigid rear end. Bought on Saturday, went for a blast Sunday morning with my school mate Lionel (who insisted he be called Dave, his second name) and his C11 with the OHV engine, which would do 69 mph and my C10 would do 66 mph - and then it seized. Freed off when it cooled a bit but the seizure had pulled the gear box forward so LOTS of rattle from the primary chaincase. Sunday afternoon I worked out how to move the gearbox back to tension the primary chain and then the rear chain was too slack so worked out how to adjust that. School Monday and another mate Tony said the side valve engine's head was a simple lid so after school I took the head off to see the valves going up and down. When Dad came home he asked Mum where's Jon and his bike? No doubt fearing the worst. "Round the back, in bits" came Mum's reply. So Dad appeared and asked "why have you taken it apart?" So I said "to see the valves working" Dad never said anything, just walked away shaking his head in disbelief. I was just 16. I lusted after the C12 with its overhead valve engine and swinging arm rear suspension. but then passed my motorbike driving test so I went for BIGGER and FASTER bikes..... Subscribed

[@davidwallace5014]

Thank you for your comments Jon Interesting to hear others experience's. The early BSA's have straight cut gear's hence the whine when off throttle. Regards Dave

[@patchthesinclair5896]

Lovely, so like my first bike, a 1954 C11G. I bought it in December 1971 for £20. You deserve more subscribers so I have added myself.

[@jjj7665]

Glad you have sorted your problem out.

[@davidwallace5014]

Yes that one's done, looking forward to the next one !!

[@Mieke3133]

Well done! Nice to see an old motorcycle still running well. Reminds me of my first bike when I was 16 - a Triumph Tiger Terrier. 150 cc. 🙂

[@davidwallace5014]

Thank You The C12 makes for a good hobby bike and well set up capable of many reliable miles.

[@nicholasharvey]

I'll sleep better tonight knowing it is fixed. Phew!

[@grandadsfishingboat7455]

I love those little engines and that is very quiet. Ive had a few and done lots with them but Ive not had one so quiet well done.

[@davidwallace5014]

Thank you It's a hobby bike so have to keep fettling, but once set up keeps going well. Regards Dave.

[@stevemartin7660]

I had 3 C12s back in the 1960s they took me all over the country . Because they have bush big end bearings they were prone to wear quickly but even so if you used good quality engine oil and kept an eye on the oil tank level replacement bearings intervals were acceptable. Thinking of getting another one if I can find a decent one at a reasonable price.

[@davidwallace5014]

Hello Steve Thank you for watching the video The C12 is a great hobby bike and very easy to fix with basic tools as you already know, I'll keep refreshing the oil.

[@peter7624]

Hi David. I must've missed this post but just watched it eating my breakfast this morning, and noticed an elephant in the room in the form of a rather loud whine which you're obviously not aware of, as mentioned below. My guess would be an overly tight primary chain, or else the clutch cage or rotor which is rubbing at engine speed giving that whine. Of course you may have already fixed it by now, but just thought I'd mention it. Good work with the misfire!

[@davidwallace5014]

Hello Peter Pleased you watch my video. The whine is coming from the pri unit gearbox, and is caused by the straight cut gear's, I've tried EP90 gear oil but it makes gear shifting slow. "They all do that honestly officer" Regards Dave

[@nuskaha]

It sounds sweet mate 👍

[@davidwallace5014]

Yes Back to it's old self again.

[@hiscifi2986]

My bet is that it was the plug. I rev my C11 a bit more than that, as I am cautious of it stalling..! btw don't take it for granted that the points are in contact with the spring. I had a Greeves Challenger where the points were corroded, open circuit to the spring to which they are riveted.

[@davidwallace5014]

Hello Yes I was inspecting an old set of BSA point's and was thinking the same thing, after gripping the contact tip with pliers and twisting I found it to be good and strong. Only hope the fresh set of points are as good as the set in the bin !!

[@stevehughes7450]

Just the speedo to get sorted now then!

[@davidwallace5014]

Hi Steve Yes would be nice to see it working, the problem with it is the cable gear drive inside the gearbox. It's on the 'Must Do list' atm !