Still no joy trying to get water into the M91 radiator setup. I use a long needle on a syringe, but whether put into the hole in the knurled plug OR remove plug and push needle down into the radiator, it just bubbles back out. I have tried filling when engine is cold and tried filling when it is running....no progress either way. I do notice the cylinder getting hot and the radiator slightly warm, but I'd prefer the opposite.
Has anyone really managed to fill this radiator
Rog