crankcase breather 750 atlas engine

hi all i am new to this forum stuff so go gentle. i am putting finishing touchs to a p 11 that i bought very nearly finished. the engine has been completely rebuilt and sounds really good. but. where the breather leaves the engine case (top left hand side) he has put a k/n filter. oil leaks and drips from hear. i have piped it longer and higher, finishing with the filter in the battery box. it stills drips oil even after turning off. should this hose go back to the oil tank as there are 2 connections on top of tank not in use. thanks. as i learn to use this i will put on photos of this bike as it is beutiful, and info on my other bikes inc mk3 850 commando. cheers

Yes, breather to tank vent return, then exit pipe from froth tower out to the back of the bike.

wow that was quick, thanks. is the froth tower the second pipe off of the oil tank, and should this be ran high or low out the back cheers.

There are many many threads on breathers and many ways to do it, the easiest and trickest way is Jim Comstock's valve which replaces the big crankcase drain plug new-product-t10721.html or you can pay to have the CNW breather mod done to your engine, but I think adding a valve of some sort to the timing chest will work very well if you modify your right hand crakncase to reduce the oil level as per Jim Comstock's way which implies drilling a new drain hole lower in the timing chest and having the big holes opened from the crankcase to the timing chest. That is what I did on my Commando build cafe-commando-build-thread-t8372-360.html and so far it seems to work well, it is not as good power wise and technicaly as what is sold by CNW, but it will keep oil leaks to a minimum.

Jean

Did you, or is the timed breather plate fitted on the end of the camshaft , near the outlet pipe?

i havent had the engine apart so dont know the answer, also not familiar with this area. will consult a manual and try and find out. thanks.

mudplugger said:

i havent had the engine apart so dont know the answer, also not familiar with this area. will consult a manual and try and find out. thanks.

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Just caught this thread - I've been away for some time and am catching up on past threads.

You should be able to unscrew the elbow from the crankcase and see the timed breather valve inside, if you are not sure if it was installed. The end of the camshaft should be a bit shiny, and the timed breather is dark. So if you see shiny, you'll need to split the case to fit a timed breather.

The breather pipe (hose) should go from the elbow up to the oil tank. The vent should go from the oil tank, under the mudguard (fender) and end just past the end of the mudguard under the license plate. The December, 2008 of 'Classic Bike' has a P11A on the cover, and one can clearly see the vent coming out from under the left side of the mudguard.

I used rubber-coated clamps to secure the vent, using the same bolts that hold the mudguard in place. There were a few different oil tanks, seats and mudguards, so routing of this vent may vary a little bit, but can be sorted with a bit of logic.

If you go here: http://archives.jampot.dk/Book/Spar...Norton_88SS_650SS_650-99_Atlas_G15P_G15CS.pdf and look at page 4, the timed breather assembly is shown - parts 82,83,and 84. (fixed plate, rotating plate, and spring)