Well I replaced the sleeve gear bearing oil seal and put it all back together .Went out on a run and oil still dribbling out all over the chain .Its supprising how a little oil can be sent everywhere .On closer examination the oil is not from the gearbox but seems to be engine oil this seems to be coming out of the breather pipe, the pipe seems a bit loose even when clip is tightened is this normal to have a fair bit of oil being sent up the breather pipe .Also the whole engine gearbox on a run seems to get very hot .
Hello there, If the bike h…
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Steve I agree with patrick…
Steve
I agree with patrick's comments re:- wet sumping amd overheating, but would like to add the following regarding the breather pipe (P/No. 23367). This runs (fairly closely) above the G/Box sprocket and into the back of the crankcase and should be tight, secured by a Union (P/No. 22314) on the early Nav/Jubs. [These two are currently listed in the NOC shop].The part manual also lists a grub screw for the breather P/No. E4590 - but I've never used or seen one.
If this union nut - a brass one - is not tightened into the rear of the Crankcase, then on starting up from standing - some oil is inevitably going to spew from the union.... the breather pipe should not wobble.... if it does (or the chain is loose) then the chain will cut into the breather over time - as happened in the early days of my Nav...
Overhot running - carb mixture too lean - are your plugs too white ? or timing incorrect ? - Nav's run 24 degrees BTDC (fully advanced) and 2 degrees BTDC (fully retarded). Compression ratio is 8.5/1 so at 1 atmosphere of 14.7 psi - this gives a theoretical 125 psi on a compression test - this may/will be less in reality. If rings or bores are worn - then bottom pressure will occur and thus oil will be forced out of the breather (but bear in mind - Nortons do wet sump on standing). So a check on the compression is relatively simple and easy.
Thats all for now
Cheers
Brian
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Hello there,
If the bike has been sitting for a week or two then some oil dribbling on first starting is usual as these engines wet sump like all Nortons but you shouldn't get noticeable oil dribbling out of the breather pipe once the engine has warmed up. Did you rebuild your engine as you could have worn rings or bores causing this excess pressure?. If you think your engine is getting very hot have you checked that timing and mixture is correct?
Patrick