Pretending it works on my P11

I have a modified 750 Norton engine that is a bit of work to get over TDC compression with the kick start. I'm not a 90lb weakling, but I'm not young anymore either. So I started telling myself I'll bet if I can get more air out of the crankcase on piston downstroke it should be easier to kick though TDC. Well dah. Hence I decided to take the plug cap off the hose barb fitting I installed in the drive side exhaust rocker cover during the last century and reconnect a hose to it. And Y that hose into the hose that vents to the oil tank from the cNw reed valve. Low and behold it does make kicking through TDC easier without stopping my kick entirely. I can still tell it has some compression, but it's a relief knowing I can kick right through it. What I don't know yet is if the reconnection of that hose will be detrimental to the power delivery at the top end since that hose out of the rocker cover does not have a reed valve on it to prevent it from sucking backward a little on upstroke. Hope to find out tomorrow.

I'm OK with butchering the rocker cover, because my '67 P11 is not a pristine high pipe restoration. If it was, I would have sold it 40 years ago and saved myself some dollars. ha

For those that don't already know there is quit a bit of air being pumped up through the pushrod tunnels on the pistons downstroke even when a reed valve is installed on the back of the timing case.

Anywho, ideally I would install one of the sump breathers to get air out of the crankcase. I think they probably work well, Unfortunately, my header pipes run right under the sump plug, and I like my funny looking exhaust. It both works and sounds impressive.

Schwany said:

For those that don't already know there is quit a bit of air being pumped up through the pushrod tunnels on the pistons downstroke even when a reed valve is installed on the back of the timing case.

Click to expand...

Not saying it ain't so, but how do you know that? It's not intuitive as the air has nowhere to go, other than increasing the pressure in the rocker chambers.