I heard that you had had to go for the larger 2" diameter items!!
Breather Check....
- Thread starter Ducdude
- Start date
Thanks Dan, Will do, as long as the vreather is operating correctly. I will either leave it be or at least re run it to keep the oil out of the tyre path.
Thanks,
Eric
Greeting gents,
I pulled the plugs put in the degree wheel and removed one of the tappet
covers and spun the rear wheel and blew into the breather hose at the
prescribed points yuck ...The determination....All is well
with the
breather timing....It was perfect, actually much to my surprise...The
immediate plan is to not worry about it and stop letting the bike sit at
idle for to long. As soon as the big stuff is done I will revisit
re-plumbing the breather line so that the path out goes out and up instead
of down..I am fairly confident that will limit the flow of oil out of the
pipe...
Tomorrow I am installing the front Thornton shock (damper) and spring, and
if I get lucky doing the wheel Barings, spacing and brakes...
Thanks All for your assistance and guidance as it is always appreciated...
Cheers,
Eric
I pulled the plugs put in the degree wheel and removed one of the tappet
covers and spun the rear wheel and blew into the breather hose at the
prescribed points yuck ...The determination....All is well
with the breather timing....It was perfect, actually much to my surprise...The
immediate plan is to not worry about it and stop letting the bike sit at
idle for to long. As soon as the big stuff is done I will revisit
re-plumbing the breather line so that the path out goes out and up instead
of down..I am fairly confident that will limit the flow of oil out of the
pipe...
Tomorrow I am installing the front Thornton shock (damper) and spring, and
if I get lucky doing the wheel Barings, spacing and brakes...
Thanks All for your assistance and guidance as it is always appreciated...
Cheers,
Eric
I made the mistake (hindsight: it may be bad, but it's always 20:20) of using a two start oil pump. It overwhelms the scavenge capacity. My advice with timed breather is to point the pipe straight up (to allow oil to drain) and to use a catch bottle, at least for a while. This way you can decide whether your motor is dumping oil, or burning it. The timed breather works fine, but you need a sense of history. In the 50's, using too much oil was a minor problem, seizure was major. You choose...
I use a D type breather on the front inlet rocker inspection cap, which is where Big Sid said (correctly, I established by ignoring his advice) it should be, and a non-return valve. If the catch bottle gets too full, which it does after 100 - 150 miles at 70 - 80 mph, I tip the contents back into the engine on a fuel stop.
The original breather terminated about 9" after it left the motor. The pipe was fed through a hole in the RH front engine plate, and stopped 2" later. Not much in the way of friction-induced back-pressure in 9" of pipe... It may have pissed oil, but in those days, no-one bothered. It was probably put down to poor oil consumption.
Thornton dampers, and soft (I met Laney in Italy, he reckons D fronts are softest) springs are what you need. Interesting guy. Knows his stuff. We (or at least I) owe him. Mine handles like a sweetie. Not like a Manx, but I don't race it, and it doesn't scare me shitless on roads I don't know and am travelling at, er, imprudent speeds on.
Keep us all posted.
I use a D type breather on the front inlet rocker inspection cap, which is where Big Sid said (correctly, I established by ignoring his advice) it should be, and a non-return valve. If the catch bottle gets too full, which it does after 100 - 150 miles at 70 - 80 mph, I tip the contents back into the engine on a fuel stop.
The original breather terminated about 9" after it left the motor. The pipe was fed through a hole in the RH front engine plate, and stopped 2" later. Not much in the way of friction-induced back-pressure in 9" of pipe... It may have pissed oil, but in those days, no-one bothered. It was probably put down to poor oil consumption.
Thornton dampers, and soft (I met Laney in Italy, he reckons D fronts are softest) springs are what you need. Interesting guy. Knows his stuff. We (or at least I) owe him. Mine handles like a sweetie. Not like a Manx, but I don't race it, and it doesn't scare me shitless on roads I don't know and am travelling at, er, imprudent speeds on.
Keep us all posted.
Eric,
Timetraveller is spot on. If you are interested in the numbers you can do it with a timing disc. With the rear cylinder set at TDC the dirty tube should be blocked. Bump the rear wheel and note where it opens. It should be 70 ATDC plus or minus a few. It will close back up a 30 ABDC. I found that my Rapide was one tooth off. On the single I use a Ducati breather to get a little more volume.
David
Timetraveller is spot on. If you are interested in the numbers you can do it with a timing disc. With the rear cylinder set at TDC the dirty tube should be blocked. Bump the rear wheel and note where it opens. It should be 70 ATDC plus or minus a few. It will close back up a 30 ABDC. I found that my Rapide was one tooth off. On the single I use a Ducati breather to get a little more volume.
David
Sorry to disagree with Tom on this but I have been using twin start pumps for about 45 years for both road use and a bit of racing and sprinting. If you look at the design of the Vincent pump then the scavenge/return side cannot be overwhelmed as it has a larger capacity than the feed side. If it was really being overwhelmed then the crank case would fill up with oil. A restricted return pipe could cause trouble with the return flow, as could either a damaged scraper in the crank case or reduced diameter flywheels with a standard dimensioned scraper. Whether the twin start pumps are thought to be necessary or not, there are enough of us using them to be sure that the design is not the cause of any over oiling.
What is the capacity of your catch tank Tom? To fill it up after a hundred and fifty miles does not sound right. I know one very hard and long distance rider who fitted close clearance pistons and sealed valve guides and does not need to put any oil in between oil changes. He has a ‘D’ with the standard breather and oil pump and clearly is not pumping any significant amount of oil out.
What is the capacity of your catch tank Tom? To fill it up after a hundred and fifty miles does not sound right. I know one very hard and long distance rider who fitted close clearance pistons and sealed valve guides and does not need to put any oil in between oil changes. He has a ‘D’ with the standard breather and oil pump and clearly is not pumping any significant amount of oil out.