Starter won't turn engine

In no 4 video you were turning the engine over by hand on the kickstart lever. That tells me that the engine still has std compression. If the head had been skimmed to raise the compression a,La, like the combat engines you should be near able to stand on the lever and it not move against compression. For the compression to be raised by a significant amount the head face will be level with the fins. If there is still the raised surface of the gasket face on the underside of the head that means the the head has not been machined to intentionally raise the compression. Machining 40 thou (approx 1mm) off the head face will, raise the compression by about 1. Did it have a head gasket fitted?

As baz says the (de)compression plate goes under the barrels,
Does it have a base gasket as the earlier 850 models only had a sealant joint.
The early composite head gaskets were 0.75mm thick but the latest type sold by AN are 1.00mm thick as they are more reliable or was it a copper gasket, should also be 1.00mm? However I'm not sure a 0.75mm head gasket or no base gasket or both would be enough compression to stop the engine turning over.

L.A.B. said:

As baz says the (de)compression plate goes under the barrels,

Andover Norton - COMPRESSION PLATE .028

COMPRESSION PLATE .028

andover-norton.co.uk

Does it have a base gasket as the earlier 850 models only had a sealant joint.
The early composite head gaskets were 0.75mm thick but the latest type sold by AN are 1.00mm thick as they are more reliable or was it a copper gasket, should also be 1.00mm? However I'm not sure a 0.75mm head gasket or no base gasket or both would be enough compression to stop the engine turning over.

Andover Norton - GASKET for CYLINDER HEAD 850 (EYELET) 1mm thick - 06.5051

GASKET for CYLINDER HEAD 850 (EYELET) 1mm thick

andover-norton.co.uk

Andover Norton - GASKET - CYLINDER HEAD 850 (1mm thick COPPER) Re-usable <span class=

GASKET - CYLINDER HEAD 850 (1mm thick COPPER) Re-usable <span class=

andover-norton.co.uk

Click to expand...

Ieaving the headgasket out and no base gasket would probably raise the comp ratio by approx 1.5
It would not stop the engine turning over.
The electrical system needs installing properly (no jumper leads and croc clips)

YellowPeril said:

Thanks! That's a very thoughtful response, I also believe it has to do with the compression. I took the head off today and am thinking the previous owner skimmed it to bump the compression up. Add to that the large amount of carbon on the pistons...extra high compression. I needed to check for cracks and porosity anyway, and will measure to see how much has been taken off. I'll probably try a spacer plate between the head and barrel when I put it back together.

Click to expand...

YP,
My bike came with.035 skimmed off the head(RH10) and is now.042 after Jim Comstock cleaned it up when he rebuilt my head. Myself I don’t think you need any kind of spacer you mentioned.
Mike