Hitchcocks Forum

I remember an article that describes how the Redditch factory recommended cutting the flat end of the duckbill back so as to leave only about three-sixteenths of an inch (or therabouts) of flat portion, to improve its effectiveness. Has anyone tried this and if so, was there a noticeable improvement in either the amount of oil that escaped or the engine breathing itself? I ask this because my 612, with the Acralite piston and alloy barrel loses about 100ml of oil every 100 miles from the (unmodified) duckbill, which is not much of a problem, as it drains into a plastic pot in the toolbox, but if trimming the duckbill might reduce this, I'll give it a try. (The motor isn't clapped by the way, it's been nicely run-in and done nearly 2000 miles - I put it down to a characteristic of the tuned engine, with more generous piston clearance, etc).

Barry, 1mm per kilometer is quite acceptable for this type of motor. 2 612's we have here are using 3ml per k but they have the Ace piston in them which has a 3 piece oil ring which should prevent usage but it is not working. We are going to have to find a better oil ring for them. Compression rings are fine. Even though they are chewing through oil they don't foul the plug ( one is a twin plug) and they perform very well apart from that

My Bullet used to gulp oil to the extent that I had to carry a 500ml sauce bottle of oil with me as no oil would be showing on the dipstick after as little 100 kilometers; after using Castrol Edge 25/60, I can do 250/300kms in a day and oil is still on the dipstick halfway down. Or, maybe the rings are run-in now.

Time for MR H's breather mod perhaps. I have it and never 'loses' any oil, burns it maybe but that's anaother story.

I junked the breather mod & went back to the duckbill, I am more than happy with the miniscule amount of oil lost in chain lubrication and having unadulterated oil running round my engine.

Hi Barry. Carried out this simple mod to my 535 some time ago but can't say it has made any difference to breathing/oil consumption. What it has done however is get rid of that dreadful 'quacking' noise from the breather pipe at idle speeds which many Bullets seem prone to. REgards, Mick

I did 200 miles after a rebore and pulled the cylinder and changed the rings and my oil level only dropped half an inch in 1,000 miles , breaking in an engine the expensive way works .