Clutch slipping when trying to kickstart

My recently rebored C15 with new clutch plates is still being a complete pain to start from cold.

You get it to the point of compression on the kickstart, take it just past, then go for it and on one kick out of eight it will turn over but the rest of the time the kickstart lever goes straight to the bottom without any sensation of it turning the engine over.

Mark came round today and offered to help push start it. He ran up the road once and nearly got it going so I offered to take over the handlebars duty so that he could concentrate on pushing.

"That's it Mark, head down, keep pushing, we're nearly there!", I shouted encouragingly.

"Blimey, Dad, this bike is a pig to push and sounds like the engine is turning over too!", he replied between gasps.

"Er, yes, son - it'll help - keep pushing!"

"Aargh, my lungs, my legs, come on - start you pig!", he shouted, on the verge of losing his rag.

And then it fired up! Went round the block on it a couple of times to warm it up and then tried kickstarting it a few times. It had improved to maybe one kick in four that was gripping, so I'm not sure if it that the engine had warmed up, reducing resistance which was allowing the clutch to grip or whether it was because the engine was lubricated by running it in gear. I'll take the primary chain-case off tomorrow and tighten up the clutch springs a turn to see if that helps.

I only told him after we'd put the bike away and had a brew that I'd been sitting side-saddle on the bike while he was pushing it. It'll do him good.

Rebuilt engine back in!

As usual, click any image to zoom in.


It was a lovely, sunny day yesterday. Mark and I started work at 11am and by 8pm all the tools were away.

It wasn't too bad a job really - removed the seat, petrol tank, rear mudguard, chainguard, chain, carb, exhaust, engine and then put it all back together.






Once the new engine was in we filled up the oil tank and gearbox and Mark ran the bike up and down the road with the spark plug out and in gear to get the oil round the engine until we could see the oil return pumping oil.

The bike fired up first kick, which was nice!

We had a bit of trouble starting the bike a while later because the clutch needed adjusting (adjustment bolt was too tight).

I was sitting on the bike ready to ride home when it cut out and we couldn't get it started again.

I left it at Mark's overnight and we had another go this morning, adjusting the timing, and were fast running out of ideas when Mark suggested changing the spark plug. At that point he noticed that the rebuilt engine had a Champion N4C plug and not the recommended N5C. It started first time with the N5C plug in...

RTS engine quote

The bill for my engine rebuild will be £850-900 ish. That includes new alpha big end, main bearings, rebore, new piston and rings, valves and springs etc, plus cams and larger inlet valve.  I'd hoped it would be around £750:00 but I suppose the cam and inlet valve modification are worth the extra.  I see no point in doing so much work on the engine, knowing that the head needed sorting out, and not completing the job properly for the sake of £150:00. 

At least the bike will be up to spec apart from the front forks and indicators. We can then fit the indicators and put some oil in the forks and see if any oil leaks and, depending on how fast any leak might be, that will help me decide whether to just keep topping the forks up, or consider having the forks repaired!