Hitchcocks Forum

After about 75 miles of gently riding in my just rebuilt Electra X, the bike has decided to throw out masses of oil out the crankcase breather pipe (about 300ml in 50 miles). The rebuild included new barrel and piston. Can anyone please enlighten me as to why this problem has suddenly appeared?

It sounds like it`s developed more blow bye pressure than normal,a compression check should know.
I hope there isn`t too much oil in there to start with,on mine i`ve been told to check the oil level with engine barely warm after running or the day after but not after been stopped for a few days.Please note i`m new to these enfields.

Hey Robin. This is due to pressure in the crankcases. Is the oil clear or a mayonnaise type mixture of oil and water? If it's oil and water mixed it could be blow by past the piston. Having just rebuilt your engine you probably don't want to know this, but did you have the crank alignment checked out a la previous posts?

Robin,
I have no idea but my Electra did the same at one stage and it sounds as if you have drilled the under barrel breather stub out, good move but at some stage what I ended up doing was a plastic tube going back to the oil tank breather with a "T" and then running the tube out to the numberplate. This allowed the oil coming out of the under barrel breather to drain back into the tank. I also fitted a small plastic bottle to the end of the tube at the number plate to check just how much was being carried over. After a short time it settled down, after the rimgs bedded in. Hope it goes ok.

Hi guys - thanks for your replies. What is blow-by pressure exactly, Jaffa? I didn't check for crankcase alignment, Riggers, stupid excuse but no time as this is my everyday get to work machine. The bike never spat out this amount of oil before the rebuild though, so it must be caused by something I have done wrong. Ha, was hoping you'd reply, Norm. No, I haven't enlarged any of the breather holes in the crankcase. So you think it might be related to the rings not seating properly? Thanks again.

sounds like it could be an obstruction in the scavenge like a lump os snot (silicone sealant) blocking the crankcase drain drilling

Well, that's an interesting one to contemplate, Beeza. I wasn't too happy with the sealant I did use: '999 gasket maker'. The stuff is too thick, and it is possible that too much got pushed out on the inside. How could I do an easy check for the possibility of scavenge pump oilway blokkage?

My transport situation has been balanced on a knife edge for some time now. Crashed my little Chinese made deathtrap of a 125 a few days ago. I came off with a few bruises and sprains, but the bike is a write off, so will have to take the Electra X out in a mo to get to work despite possible oil way blokkage. Doesn't sound very wise does it? Will go slow though and keep my ears and eyes open for imminent engine failure!

http://www.whfolk.co.uk/REOCHUMBER/Arti ... eather.htm Is an interesting article about this.

Thanks for the mention Matt but the article only really covers Classic iron engines. I'm not sure if the Electra is the same. Also it doesn't really cover this sort of problem. It will, however, perhaps help to explain engine breathers in general.