Hitchcocks Forum

My Bullet started leaking oil where the distributor is bolted to the engine (three bolts). I replaced the gasket, but it still leaks when I am driving at more than 45-50 mph (on the highway). I recently installed the high-output oil pumps by Hitchcocks. Could this be related ?
Any suggestions on how to improve the oiltightness ?

Two possabilities spring to mind. One is that the timing chest is pressurising, the other is that the oil is being pumped in faster than it can return to the oil tank.



In the case of the former, I'd expect a leak round the tappet cover first/as well. However a blocked crankcase breather could cause pressurisation.



The oil returns to the oil tank from the timing chest through a hole or holes in the crankcase. This will also determine the level of oil sitting in the timing chest which ought to be well below the level of the dizzy. The picture below is taken from the inside of the oil tank. The two holes are the return from the timing chest. If this was obstructed, the timing chest could overfill. I suppose if the pump was pumping more than can run back through the hole in the same time, a similar thing could happen but I presume it was working ok with the high flow pumps before?







The holes are between the two idler gear shafts when viewed from inside the timing chest. As you can see on the picture below, the oil level should sit a long way below the dizzy.







To be leaking past the gasket, either the gasket is a very bad fit or it's being pressurised as well as the oil level being excessive, it should only really be getting splash lubed at that height.



So if it were me, I'd check the breather isn't obstructed firsrt. Next I'd order a new timing chest and dizzy gasket then open the timing chest to check those holes aren't blocked. I'd replace the dizzy gasket while I was in there although this is a bit of a pain because you'll need to pull the distributor drive gear and re-time (ignition timing) the bike afterwards.

Might just be worth checking that the oil tank is venting properly while you're at it, as you can see from stinkwheel's helpful photos, that's where anything exiting the timing chest will end up. Does your Bullet have the older type bayonet fitting oil filler cap with the vent hole or the later un-vented screw-in version?



A.

Stinkwheel and Adrian,
thanks very much for the reply.
My Bullet recently got the improved oil breather system from our host. And that right after I had installed the higher output oil pumps.
I recently had to open the timing chest for putting a new gasket on the distributor (the round gasket with the 3 holes for the bolts). I even used
WellSeal.
The timing in of the ignition (Boyer) was a bit of a job, but it didn't take a long time. Boyer's procedure described in the manual plus checking with stroboscopic
lamp didn't take a long time.
I will first uncouple the new oil breather system, and reuse the old breather system. See if there still is a leak.
Then I will check both holes that connect the timing chest to the oil tank.

@Stinkwheel:
Not sure about the following: the dizzy gasket, is that the gasket around the timing chest, or the circular gasket (with 3 holes) for the distributor ?

@Adrian: I have the later unvented screw-in version of the oil filler cap. The cap being the oil temperature meter.

The "dizzy" gasket is the round gasket with the three holes that fits between the "distributor" (it's NOT a distributor, the Bullet is a **single cylinder** machine so it's only a CONTACT BREAKER - rant over) and the crankcase.



OK, so you have the later un-vented filler cap version of the breather kit, (part number 90061?) which means that the breather OUT of the oil tank really needs a good clear run for all the breather gases to get out of engine as easily as possible, and stinkwheel's warning about blocked crankcase breathers needs to be considered.



If you have a long pipe from the breather tower to the back of the bike, I would use the short duck bill pipe that came with the kit instead. Having successfully used a long pipe with my Electra-X (there's another post about this) I naturally fitted one to the breather tower on my AVL hybrid bike, which is based on a set of classic crankcases. This however resulted in quite a heavy oil leak where the breather tower screwed into the crankcase, o-ring or no o-ring. Despite the long pipe being clear when I checked it, I still disconnected the long section and ran the short section over the rear sprocket. After a good run, no leak!



Is there any way of making an extra pinhole breather in the filler neck just under your temperature gauge?



A.

That model had a small hose connection under the Dizzy,you sure you sealed that off properly?That
could be the leak source.It's an oil return from the oil separator.
colin

Yesterday I reinstalled the old filler cap, and the old breather system. Today I drove the bullet from Hurdal to Oslo, 94 km, with varying speeds, 75 kmph to 90 kmph. No leakage. That proves that ventilation was the cause of the problem.
Thanks to everyone who replied to my question.

All the parts to do with the "distributor" are referred to as such by royal enfield, so it helps to give parts the same name as the manufacturer uses, so there is a "distributor shaft", a "distributor body" and yes, a "gasket, distributor flange".



The contact breaker is the bit on the end of the distributor shaft comprising the points and componants associated with the stator plate.



I always understood the main thing that defined a distributor is that it is a rotating shaft for the purposes of ignition timing which is seperate to but driven by the crank or camshaft, usually by gears. Something quite possibly unique to the royal enfield motorcycle?

I know what you mean stinkwheel. I have heard the same "mistake" with calling the early Triumph Cub points housing a distributor. It's because they look a bit like one I suppose.