Forum

[Barry N]

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).

[Norm]

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

[Leon Novello]

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.

[Midge]

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

[Beezabryan]

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.

[Mickey]

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

[Phil Ashbrook]

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 .