Advice plz - rough running Aircooled

[Cakewalk]

1982 Aircooled Automatic. Stock 2.0 litre CU engine. Stock Solex carbs

Had van bout 3 years and it is and was well serviced

Did Ulswater a few weeks ago and it was purring like a kitten

Took it for a run out yesterday and it is running awful. Really awful.

No power

Popping and hesitating all over, went straight home.

Been in engine bay tonight and it will start and idle. Give it any gas whatsoever tho and it runs rough as.
Sounds like machine gun from right hand cylinders. Left side sounds ok.
I can see fuel air mixture coming back up the carb venturi.

My medium-ish mechanical knowledge thinks, in order of crossed fingers:
1- Expired cam follower(s) on RHS
2- Burnt out valve seat on RHS
3 -Dropped a valve an it is dancing about on top of the piston

Would love some advice in case I'm missing summat stupidly simple.

Next step = compression test. Can I do this with a cold engine? If so how? Dont want to run it if I dont have to.

Cheers all in advance

Ben

[dazzzer1]

have you checked it isnt just drawing air in from somewhere

[Cakewalk]

have you checked it isnt just drawing air in from somewhere

I haven't to be honest. I'll get the WD40 out tommoz. Gut feeling says its worse than that tho

[BOXY]

If you take the basket off the fan you can turn the engine over with a socket & extension through the number plate flap. Turning the engine by hand might let you feel if there are any metal to metal contacts. Check the pipe that runs from the inlet manifold via a rubber elbow to the servo pipe, and make sure the two nuts holding the carb to the manifold haven't come loose.

[dazzzer1]

Gut feeling says its worse than that tho

know what you mean, it'd be a pain if you went in head first to find it was a simple fix though