B40F/Sidepoints - some breathing/oiling queries

[hoogerbooger]

Have been trying to get my head round this using Rupert and parts catalogues.

1) I believe I'm correct that the chain-oiler acts as the breather for the otherwise enclosed primary chaincase and that as my oiler is bolted off, then using a baffled breather inspection cap is sensible...although not essential ( I haven't seen any comments about effects of having no breather)

I am a bit confused on the kickstart section of the outer timing case......and gear box.

2) Seems to be that the gearbox was enclosed before sidepoints were introduced and had a breather in the cap. On sidepoints it seems a breather was introduced....but where to ? ,  the kickstart area? if not where ?. 
(doesn't sound like anyone is worrying about a different gearbox oil travelling else where though)


3) I can see that there is an oil seal where the kickstart arm exits the case, but how does oil enter and leave the kickstart area,  & does it have any other breather if so where to?

[Rupert]

The plain chaincase cap originally came in two versions, either with a tiny drilling for breathing or not. Drilling a 1mm hole through a plain undrilled cap is a simple solution if the oiler is blanket off. Fitting the breather type chaincase cap with the baffle plate over the clutch centre is not a good idea as the clutch centre screw will foul the baffle plate.

On all sidepoints engines there is a hole through the inner timing cover below the kickstart to allow gearbox oil to flow to the kickstart area.

Gearbox venting to atmosphere doesn't seem to be too much of an issue. The metal filler cap was vented but replace from 1967 on most models by an unvented plastic cap/distinct. I think I've seen plastic dipsticks with a groove up the thread for breathing? But sealing that cap completely doesn't seem to cause any issues.

The breather through the sidepoints inner cover next to the clutch cable vents the engine compartment, not the gearbox.

[hoogerbooger]

Many thanks.

1) I have indeed discovered that the baffled cap will run into the clutch centre screw. I had thought the reason it wouldn't screw home was because I didn't have the fibre washer/gasket in place...which the Feked site indicates as 1.6mm deep. So I made/put in an extra thick cardboard gasket and thought this cleared the screw....but not so. so have done 10km with it scraping the baffle plate, with possibly/probably some swarf ending up into the clutch case, so I guess I need to drain that oil out and refill. Any advice? (apart from stop being such a wally).

clutch centre screw looks almost un scathed, but not the cap baffle plate. I will refit the old cap and look for a suitably small drill bit.

(so on what bikes did the baffled caps fit. I found the advice on this site in answer to a query on the same bike. That'll teach me to be too trusting !!)

2)/3)  A small amount of oil is showing at the kickstart. So the seal at the kickstart is not perfect.
If it is just a simple hole below the kickstart level, then I presume the fill level in the gearbox determines the height of oil in the kickstart outer timing case,when standing, but the action of the gears may push more in during use.....but it will drain back to matching levels when stood up ?? So if I notice oil drips forming after use, but this stops after an hour or  so ? then the connecting hole is working as it should ??

Is that right ?? can oil levels reach the kickstart on a sidepoints.....but not stay there at rest? If it drips at rest is there a circulation problem?

[Rupert]

Cap with baffle plate was fitted from 1967 onward on chaincases which have a second cap positioned higher up.
The gearbox/kickstart oil level shouldnt be affected by whether the engine is running or not. But it will be slightly affected by whether the bike is on its sidestand or is upright when being ridden. That could cause the intermittent leak you describe. Either way, change the seal.

[hoogerbooger]

So removing the outer timing cover to renew the kick- start seal requires draining the gearbox?

( as if oil is dripping from the kick start at rest, the gearbox level must be higher than that level)

( whilst I'm asking novice questions, should there not be oil on the points side of the outer timing case, as ( as long as not heavily wet sumped) it drains to the sump at a lower level? )
 

[Rupert]

Yep, removing the outer over needs ghe gearbox draining unless you lean the bike far enough over to get the oil away from the outer cover.
It is possible to remove the seal without disturbing the cover, if you can find something suitable to push between the shaft and the seal and prise behind it. The new seal can be drifted into place using a suitably sized length of tube.

There is usually about 1/4" of oil (up to the drain hole) in the engine compartment under the outer cover.