Sturmey Archer engine.

[smartfella]

Hi All.
Need some help. I have a 350cc Sturmey Archer engine in my New Henley and its very hard to turn over. It does turn over but it's too tight to kick.
What could be the problem. I have drained out the oil and refilled it but it's still the same. I can just about hand turned the engine sprocket but it's
very tight even with the spark plug out. All it seems to do is mess up my kick start ratchet teeth.
Any help is most welcome.
 

[iansoady]

Impossible to diagnose at a distance but first of all take the rocker box off (if it's OHV). Does this make it easier? Rocker spindles etc tight.

No difference?

Insufficient endfloat on the crankshaft or tight bearings? Slacken the mainshaft sprocket nut a bit and try.

Still no difference?

The head & barrel will have to come off. I would suspect a tight piston or insufficient end clearance of piston rings. If it's still tight with the barrel off then main bearings etc. Do check thet the con rod is free to rotate within the limits set by rge crankcase opening.

[R]

It might also be helpful to know a little history of this.
Has it done a million miles of faithful service for you (!),
or have you just obtained it like this ?

Whatever, this needs serious investigation, as Ian says.
Forcing it is rather likely to cause (further) damage.

[smartfella]

Thanks chaps.

I don't know the history of the SV engine. It's been sitting in a garage for years and yes, this is the way i got it.
I will try what R has suggested.
Thank you.