E: Engine Comet Oil Resrictor Disc

[brian gains]

have posted on this before but don't seem to have had response.

150 miles today fast road work and some ton riding oil consumption approx' 1 pint / 6ooml , motor has breather with BB restrictor from mag' cover, no extreme leaks or breather issues, chain oiler turned off, no signs of billowing smoke which doesn't mean there may not be a slight haze behind me, people I ride with do not get old machines , a kick start baffles them so no useful feed back there. So, I'm considering putting in a restrictor disc, any justified reason not to given the above?.

 

[ClassicBiker]

Richarson's book gives the engine number where discs began being fitted. Their purpose was to prevent over oiling and excessive oil consumption. If you're not fogging for mosquitos as you go along (unlike myself currently) and not pumping it out elsewhere I can't see the point of fitting one if one isn't already fitted. If the opposite is true then I would consider it remedial to curing the problem.
Steven

 

[brian gains]

OK, so as I say the oil consumption is excessive, I'm not making appreciable smoke but that does not mean a fine haze is being generated. As there isn't a disc fitted it would seem that I could do so at my peril or at least the cams.

 

[passenger0_0]

Over 17 years of ownership, I've found the oil consumption in my twin to vary from nothing for 500 miles to 1 pint for 200 miles. It's done a high mileage and keeps going so I'm choosing to let sleeping dogs lay. I don't believe we should be measuring these engines against modern technology so my advice is - if it's not fouling plugs or leaving oil spots of following riders then keep it together and enjoy it for what it is.

 

[Martyn Goodwin]

OK, so as I say the oil consumption is excessive, I'm not making appreciable smoke but that does not mean a fine haze is being generated. As there isn't a disc fitted it would seem that I could do so at my peril or at least the cams.

The factory spec on oil consumption is 2000 miles per galllon! That a pint every 250 miles - and your consumption is sort of in line with that.

Our Vincents use a LOW pressure oil system and if you start talking to folks and also going back over old MPH mags and the resources available on the club web site you should come to the conclusion that instead of restricting oil flow you should be trying to increase it. I', in the midst of a rebuild at present and I am doing all I can to increase oil delivery inside the motor - Its nothing to do with oil consumption - its all about keeping the motor healthy.

If the spark plug is not fouled with oil and in the inside of the exhaust pipe (at the rear) is not coated with a tar like substance that would suggest things are OK with the valve guides and the piston rings. Remember the biggest other cause of excessive oil consumption is poor engine breathing. Correctly set up you cannot get much better than the original timed breather. If you have any other type of breather it is ESSENTIAL that it is not open all the time, else you will never get the slight negative crankcase pressure essential for an oil tight, low oil consumption, motor. If there is NO timed breather then alternative breathers MUST have some form of PCV valve fitted.

As a test, why not fit a catch tank to the breather outlet (use an old plastic drink bottle) and you will soon know if any oil is being lost via the breather.

 

[greg brillus]

If you are really unsure, rather than a restrictor disc, blank it off altogether and try it for a while, just make up a small solid disc out of some shim steel/brass and refit the timing cover. My guess is if the barrel is original then the drilling through it is too high and feeding oil between the rings (very common) and this will cause oil consumption no matter what you do. If the problem goes away, then you know then what you need to do (if you want to fix it properly that is).............Cheers..............Greg.

 

[Bill Thomas]

have posted on this before but don't seem to have had response.

150 miles today fast road work and some ton riding oil consumption approx' 1 pint / 6ooml , motor has breather with BB restrictor from mag' cover, no extreme leaks or breather issues, chain oiler turned off, no signs of billowing smoke which doesn't mean there may not be a slight haze behind me, people I ride with do not get old machines , a kick start baffles them so no useful feed back there. So, I'm considering putting in a restrictor disc, any justified reason not to given the above?.

What type of oil do you use Brian, I like mono grade 40 for summer, Or are you on thin stuff ?. Cheers Bill.

 

[Martyn Goodwin]

PEI was known to say that more Vincent engines were destroyed by using heavy oil in preference to thin stuff.

 

[Bill Thomas]

PEI was known to say that more Vincent engines were destroyed by using heavy oil in preference to thin stuff.

My Badly abused Road Comet is now on Coarse 50 Oil now, Has been Road Raced, Sprinted etc, Never had the cases apart since 1977, When I built it. Cheers Bill.