Breathers, can anyone help.

[John Jones]

I have a lovely Norvin with a standard spec Rapide engine finished in black.
After a particularly hard ride over the mountain on the IOM with Glen English on my tail, on a Commando, (with his wife on pillion),the poor 66 year old motor started to weep.
Nothing from the top end, just from a few secret places hidden under the engine. Very difficult to source as the motors painted black but I have a strong suspicion it could be from the vertical crankcase joint.
I have only 1 breather on the rear inlet valve cap and the standard timed engine breather.
After all the years of research and prototyping of breather solutions for this kind of problem there must be an agreed "industry standard" remedy but for the life of me I can't find it on the web.
There seems to be multiple solutions suggested ranging from moving the breather pinion 2 teeth to fitting elephant trunks to the points cover.

Does anyone have a tried and tested solution or should I just rebuild the engine in standard trim and hope for the best?

John.

 

[timetraveller]

At least one mistake is having one breather plus the timed breather. The one on the rear cap is sucking in air when the pistons are going up and the timed one should be shut trying to make a slight vacuum. One or the other but not both. I would remove the rear one, make sure that the timed one is open when the pistons are going down and closed when they are going up (checked by blowing down the timed breather tube when you know where the pistons are). If that does not do it then check these pages for details about some small plastic breather valve that some people have found useful.

 

[usefulidiot]

elephant trunk worked for me, its ugly but it works

 

[mercurycrest]

Use one breather and put a rubber "Duckbill" breather from an older Indian Enfield (My '87 350 has one) at the end. It'll blow, but it won't suck...

 

[Jim Richardson]

Fitted the duck bill breather to the standard breather on my Rap, it is cheap, discrete and seems to work.
Any of the older Enfield dealers would know what you meant, Think I got mine from Hitchcocks for about £7 each.

 

[vibrac]

subject found earlier this year with lots found with search term "pcv valve" and the best one I think is thread
"more on breathers"

 

[Chris Launders]

Leave the extra breather just fit a one way valve to it so it can only blow out.
If it's leaking from the crankcase joint the only solution is to strip the engine.

Chris.

 

[Jim Richardson]

And if you split the cases we can get the Silk Thread thread going again.

 

[clevtrev]

And if you split the cases we can get the Silk Thread thread going again.

I`ve been down that road.

 

[John Jones]

Giving it the berries.



Glen and Co.