CA77 engine locked up while idling

[Geoff Hastings]

Hi there, I've recently got my 1966 CA77 on the road. It was bought as a basket case and needed lots of work but I slowly worked my way through it. When I stripped the engine I found the starter clutch was a complete mess and also when it had previously been stripped someone had not lined up the locating pegs in the cases with the holes in the main bearings. This resulted in one of them being pushed through the case. I examined the rest of the engine and gearbox and the rest seemed OK, I fitted a new cam chain and tensioner, ground in the valves, deglazed the bores, repaired the case and reassembled the unit. Anyway, after finding the inlet manifold insulator was also wrong and fitting the correct one the bike ran sweet. After about 60 miles I was sitting at the traffic light when a strange wirring sound came from the engine, it sounded like I had caught my leg on the kick start pedal but I hadn't. A couple of seconds later and the engine seized. The kick start wouldn't turn the engine over and rocking it back and forth in gear would not turn the engine. When I got it back to my garage I found that putting spanner on the crank nut I could move the crank slightly and I could also see the camshaft move a small amount so it looks like the gearbox has locked up. The gears and their bearings all looked fine when I had the unit apart, there was the correct amount of oil in it. I realise that I will have to pull the engine apart again but anybody got an idea what has locked up, I sort of suspect the kick starter mechanism due the the noise moments before it seized.

[G-Man]

Was the bike in neutral when it stopped?

Pull off the starter clutch/rotor first and take a look. Next pull off the primary cover, before you split the cases.

G

[Geoff Hastings]

Was the bike in neutral when it stopped?

Pull off the starter clutch/rotor first and take a look. Next pull off the primary cover, before you split the cases.

G

The bike was in neutral, and just idling. The noise sounded very like when you accidentally engage the kickstart when the bike is running. I'll pull the starter clutch off and have a good look. I sort of hope it's not that as I replaced all the rollers and springs but not the hub. When I got the bike the starter clutch was completely smashed and the crank slightly scuffed. On the other hand I don't want to drop the engine out again as my old back is not good at the moment so it might have to wait till that problem resolves itself. I'll keep you posted on what I find when I get the starter clutch off.

[Geoff Hastings]

Was the bike in neutral when it stopped?

Pull off the starter clutch/rotor first and take a look. Next pull off the primary cover, before you split the cases.

G

Pulled off the rotor and starter clutch and all was fine, I did notice two of the stator windings had a slight nick in them, in fact one of the wires was cut right through. Not sure if they were like that when I assembled it but would imagine a lot more damage if something had come loose and jammed the rotor. The clutch side also looked good but took the opportunity to investigate the rather life less clutch, it doesn't slip but has a rather soft take up. Found two of the steel plates have a slight bend in them so will replace them and the springs. I used an endoscope to have a look inside the gearbox but could not see anything that looked amiss. I'll sort the stator windings and clutch, start it up and see if it still makes the same wirring sound.

[G-Man]

Geoff

Can you rotate the kickstarter shaft in either direction?

G

Was the bike in neutral when it stopped?

Pull off the starter clutch/rotor first and take a look. Next pull off the primary cover, before you split the cases.

G

Pulled off the rotor and starter clutch and all was fine, I did notice two of the stator windings had a slight nick in them, in fact one of the wires was cut right through. Not sure if they were like that when I assembled it but would imagine a lot more damage if something had come loose and jammed the rotor. The clutch side also looked good but took the opportunity to investigate the rather life less clutch, it doesn't slip but has a rather soft take up. Found two of the steel plates have a slight bend in them so will replace them and the springs. I used an endoscope to have a look inside the gearbox but could not see anything that looked amiss. I'll sort the stator windings and clutch, start it up and see if it still makes the same wirring sound.

[Geoff Hastings]

Geoff

Can you rotate the kickstarter shaft in either direction?

G
Hi there, yes the kick start operates as normal. I've decided, to reassemble the clutch and stator, refill it with fresh oil and give it another go. I will drop the oil pump out first, even if the pump is ok I might be able to see if anything is amiss. If it still makes strange noises I'll shut it down immediately, Good thing Autumn is here!

Was the bike in neutral when it stopped?

Pull off the starter clutch/rotor first and take a look. Next pull off the primary cover, before you split the cases.

G

Pulled off the rotor and starter clutch and all was fine, I did notice two of the stator windings had a slight nick in them, in fact one of the wires was cut right through. Not sure if they were like that when I assembled it but would imagine a lot more damage if something had come loose and jammed the rotor. The clutch side also looked good but took the opportunity to investigate the rather life less clutch, it doesn't slip but has a rather soft take up. Found two of the steel plates have a slight bend in them so will replace them and the springs. I used an endoscope to have a look inside the gearbox but could not see anything that looked amiss. I'll sort the stator windings and clutch, start it up and see if it still makes the same wirring sound.

[G-Man]

Make sure you turn it fully clockwise before remounting the cover. That 'parks' the kickstarter pawl.

G

Geoff

Can you rotate the kickstarter shaft in either direction?

G
Hi there, yes the kick start operates as normal. I've decided, to reassemble the clutch and stator, refill it with fresh oil and give it another go. I will drop the oil pump out first, even if the pump is ok I might be able to see if anything is amiss. If it still makes strange noises I'll shut it down immediately, Good thing Autumn is here!

Was the bike in neutral when it stopped?

Pull off the starter clutch/rotor first and take a look. Next pull off the primary cover, before you split the cases.

G

Pulled off the rotor and starter clutch and all was fine, I did notice two of the stator windings had a slight nick in them, in fact one of the wires was cut right through. Not sure if they were like that when I assembled it but would imagine a lot more damage if something had come loose and jammed the rotor. The clutch side also looked good but took the opportunity to investigate the rather life less clutch, it doesn't slip but has a rather soft take up. Found two of the steel plates have a slight bend in them so will replace them and the springs. I used an endoscope to have a look inside the gearbox but could not see anything that looked amiss. I'll sort the stator windings and clutch, start it up and see if it still makes the same wirring sound.