Primary chaincase

[chris goldson]

Sorry to be asking so many questions but new to fettling AJ's.

My model 30 has the tin primary chaincase and suspected this was the source of oil stains on the nearside silencer after a recent run.

I removed the inspection/filler cap this afternoon and there looked to me to be a bit too much oil as it came over the top with the cap removed.

Does the crankcase breath into the primary chaincase as per other British bikes?

And is there an easy way of putting the inspection cap back as I struggled for hours trying to locate it and the gasket and try to tighten at the same time.

Again apologies for all the questions, as I said even at 69 (tomorrow) AJ's are still new to me after mainly Velo's and Triumphs..

[Rob Harknett]

Make sure the cap screw is not binding. It should turn easy with fingers. Perhaps the bar may bend a bit and make the threaded hole slightly oval.
Once the screw turns easy fit the cap, Line up the bar horizontal, pull on the screw to hold the bar in position and tighten the screw.
if the screw is tight, it will turn the bar out of position, even though you are pulling it onto the chain case to stop this happening.
Sumped oil could seep through the bearings into the chain case. Or you could be getting water in it, the oil will float on top of the water making the oil level higher.
If the chain case leaks a bit, I don't worry about that as any water will leak out first.

[chris goldson]

Many thanks Rob

Is it critical to have the bar horizontal as might need to take it off again which is a pain. Do you affix the gasket to the chaincase first or try to fiddle it all with the gasket on the cap?

Is the oil level too high when it is up to the inspection cover level?


Many thanks.


Best wishes


Chris

[dave16mct]

Yes, too high. The oil level should only just touch the very bottom of the chain. Also don't leave the bike on the side stand in the garage. No water will enter the chaincase if you don't ride through too many floods. The chaincase can be made oiltight easily by fitting the improved seal from club spares.
Dave.

[Rob Harknett]

Many thanks Rob

Is it critical to have the bar horizontal as might need to take it off again which is a pain. Do you affix the gasket to the chaincase first or try to fiddle it all with the gasket on the cap?

Is the oil level too high when it is up to the inspection cover level?


Many thanks.


Best wishes


Chris

If the bar is vertical the chain may hit it. Stick the gasket to the chain case with a bit of grease. I am sure my prewar bikes still have old cork gaskets with just a central hole for the screw so it stays where it should be. Not a cork ring. Oil should just reach cap hole with the bike upright on level ground. Oil is needed for chains AND clutch bearings

[chris goldson]

Thanks Dave

Yes I drained some of the oil off, just slightly worried that the oil is being topped up via the engine if it breathes into the chaincase, although loads of compression and bike runs lovely so can't think there is a lot wrong.

Thanks for your help.


Best wishes


Chris