Square Four MkI restoration complete - almost....

[Gui.dorey]

I could never get mine to turn using the nut on the crank. Neither the front nor the rear crank nut. Funny enough I could using the camshaft nut, but now I’d have to take the oil pump out, which I would like to avoid if possible. The kick starter moves fine if I depress the clutch and the rear wheel turns fine in neutral. Anything I can check to see if it’s the engine or the gear box?

[Gui.dorey]

Also, if I really put all my weight to it (to the kick starter), I can actually make the clutch slip and move the kick starter a bit. That's why it seems to me the engine is caught somewhere, but really scratching my head now. No idea what to check next...

[Mick D]

Hi

I'd check the push rods are all still located in the rockers and tappets and all of the valve collets are still in place before delving into the bottom end.

Regards Mick

[simon.holyfield]

Also, if I really put all my weight to it (to the kick starter), I can actually make the clutch slip and move the kick starter a bit. That's why it seems to me the engine is caught somewhere, but really scratching my head now. No idea what to check next...

Primary chain? Easy to check.

[Gui.dorey]

Opened up the inspection cover. Chain is there, tension correct. But without opening everything up can’t really see much. Thought also went through my mind if the nut for the engine shock absorber might have come loose. But can’t really see anything and If something like that had happened I would have expected some noise. The engine just stalled without any jerks or noises just before I was coming to a halt in front of the house...

[simon.holyfield]

You've had the timing cover off? Can you turn anything, even a tiny bit? You could slacken the timing chain if that helps.

[Mick D]

Hi

Can you turn the engine backwards from the rear wheel and in 4th?

Your description sounds like a piston could have nipped up.

Regards Mick

[Gui.dorey]

Hi Chaps,

Opened up the rocker covers and everything is as it should be up there. Tappets and valve collets are all in their places.

No, I can’t turn anything forwards or backwards. In any gear, either with the kick starter or trying to turn the rear wheel. I even tried pushing her back and forth in 4th and nothing. Mind you, she is a heavy beast and I’ll have to try with a mate. If I do get some movement it’s the clutch slipping. And that’s with the engine now completely cold, so if a piston had nipped up, it should have come free by now. I’m just very afraid something might have come loose deep inside and has caught somewhere.

I’m afraid I’ll have to start opening her up, if no one has any other ideas. A nightmare scenario after such a lovely start. I’m feeling very down just now...

[simon.holyfield]

I'd remove the timing and primary covers and see what moves & what doesn't. Then I'd take the timing chain off and try again, checking the camshaft, dynamo and both crankshafts. You could then remove the coupling gear cover.

I wouldn't touch the head until you absolutely have to. Don't get down hearted, it will be worth it in the end. These are great bikes but are not the easiest to get right!

Do the plugs look OK?

[Gui.dorey]

Thanks for the encouragement Simes.

The plugs look great. Perfect colour, everything perfect.

If I do remove the timing chain, I’ll lose my valve timing, right? That was another nightmare I wanted to avoid. It took me ages to get it right...