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By windmill john
#85081
Hi, previous owner blanked off breather tube coming from back of timing cover across behind cylinder.
The other pipe from the crankcase goes to the back mudguard.

Bike runs okay:
Ignore?
Look at the Hitchcock breather adapter for filler cap? But I don’t have a breather on left of crankcase.

My bike registered in 2006 has 11*2002/24*0134*00 on frame (2002 model?)

Which brings up discrepancy in back of Made in India book. I have a screw in oil filler (book says 2003)
Yet my passenger pegs are not mounted on rear carrier bracket, therefore 2002; such fun.

Anyway, back to breather, any pointers or preferences?

Many thanks

John
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User avatar
By windmill john
#85082
Oh just noticed I have a 3.50 back tyre. Book says Bullet 500, mine’s a 350. I guess Royal Enfield like BMW Airheads used parts bins a bit.
User avatar
By Adrian
#85085
3.50" x 19" back tyres were standard on classic Bullets, 350 could just be your tyre manufacturer's designation. The book isn't perfect, but it's still a good reference item with some helpful pictures.

The later Indian Bullet breather systems pre-EFI/UCE got progressively worse as the factory messed about with the design, which has generated an awful lot of traffic on this and other RE forums.

From your photos your original breather system would indeed have had its exit pipe coming off the top of the oil tank rather than the left-hand side of the crankcase which was the traditional position. This pipe would have fed upwards into a catch-can with a small duck-bill type one-way valve, the blanked-off pipe at the back of your timing chest would have been the overflow pipe from the can to allow any built up oil back into circulation. Another pipe was supposed to pass the remaining fumes into the air filter housing.

What could and often did go wrong with this was that the main breather pipe from the oil tank would clog up with oily condensate goo (mayonnaise!) the resulting crankcase pressure would then seek another escape route via the smaller return pipe. In so doing it would pump the oil out of the timing chest, overfill the catch can and carry on pumping the engine oil into the air filter housing. Yuk. Result was, back end of bike a complete mess, and oil level in the tank perilously low.

Your bike's P.O. seems to have done what any sensible owner would do, leave his mods in place.

Or we start descending into this sort of madness...

A.
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User avatar
By windmill john
#85086
That looks like the flux capacitor!

The PO had removed the air box too when he fitted an Amal with a K&N filter.

Many thanks Adrian for your input. So what I can tell from what you have said, leave the big pipe to the back of the bike. The small capped off pipe running across the back of my cylinder, leave as is because if that got full of mayo too, additional oil still stays in the engine.
User avatar
By Adrian
#85089
Leaving the big hose pipe to the back of the bike and keeping the other hose sealed is precisely what you should do, just make sure it is a good run for the larger hose with no dips in it where the mayonnaise could form a plug. You could possibly stick a non-return valve in it somewhere near where it fits onto the hose-tail on top of the oil tank, if you wanted, but if what you already have works well enough, don't bother.

If you have the engine apart for any reason (hopefully not for some time) you can drill and tap the side of the crankcase for a 1/4" BSP x 10mm hose tail and run the breather from its original position.

The "flux capacitor" is actually a drip-feed lubricator, I thought it would be a good idea to see just how much oil was being chucked out of the breather, but it failed for various reasons. It might get reinstated.

A.

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