Very bad blow by - Help!

[Albervin]

Why do you want to fit a one way valve (slick or otherwise)? While I am borderline in my understanding of mechanical devices it appears a one way valve will lead to -ve crankcase pressure on the upward stroke of the piston? What am I missing? You could fit a small air filter or catch bottle at the end of the breather.

 

[Ducdude]

Why do you want to fit a one way valve (slick or otherwise)? While I am borderline in my understanding of mechanical devices it appears a one way valve will lead to -ve crankcase pressure on the upward stroke of the piston? What am I missing? You could fit a small air filter or catch bottle at the end of the breather.

At this point I am trying to maintain neg pressure (below atmosphere) in the crank case and the valve should only let the small positive pressure pulses out and should seal in the small negative pressure pulses. The net effect hopefully should be less oil leaking out all over that’s the theory any way...I doubt this will have an detrimental effect on the upward stroke holding the piston down as the pressures are just not that large or that that long in duration. I just would like to keep the seals in place and oil free-ish..

Eric

 

[stumpy lord]

At this point I am trying to maintain neg pressure (below atmosphere) in the crank case and the valve should only let the small positive pressure pulses out and should seal in the small negative pressure pulses. The net effect hopefully should be less oil leaking out all over that’s the theory any way...I doubt this will have an detrimental effect on the upward stroke holding the piston down as the pressures are just not that large or that that long in duration. I just would like to keep the seals in place and oil free-ish..

Eric

Can I sugest that rather than force the old seal back into its housing, that you cut it off, degrease the housing and carefully fill the seal housing with black silastic , if done carefully you can hardly tell the diferance and it will be oil tight.
One dis advantage of fitting a one way valve in the breather system is that it can effect the scavenge side of the oil pump, on my twin I found that at slow speed it would fill the cranck case up with oil and not untill I removed the valve did it start to scavenge properly again. Yes I know that on a lot of machines Flap valves work perfectly well, but on my machine it did not. I now use one of russels elephant trunks with no problems.
stumpy lord

 

[Ducdude]

Well 32 ft/lb done up in stages from hand tight to 32ft/lb in 3lb
increments in a chris cross manor did the trick and the rear head no longer
leaks air...
The old girl had a renewed vigor when on the gas... Which is
good...Except I guess some of that old oil got on the rear brakes which left
me with just the fronts and some coaster brakes...OH well live and learn

The exhaust valve did need to be adjusted just as Max said...after the head
torque..

I fitted the D breather and did my best to seal the push rod seals into
their recesses..
I sealed up the stock breather though I will need to do a better job of
that...it looks pretty bad..Is it true that a ET24/3 plug will seal up the
stock breather hole in the case?

I gave the bike a good bath and then we went for a brief shake down ride...

She does pull better and seems to run soother at idle...

There are still a host of leaks now seemingly from the front as I have drips
on the mag cover but that could just be my lousy stock breather seal
job...I'll work on it...

The D breather does spit oil and I was thinking if a fine mesh screen in
the tappet cover would help keep the oil out of the pipe? What do ye say?

Thanks all for you input...We are getting there..

Eric

 

[timetraveller]

If it turns out that the leaks at the front are not from the sealed off standard breather then have a look at the oil feed to the rockers. The copper washers can be annealed if they have gone hard and often the seals below the 'banjos' have squashed or split. However, if you do replace those then check the thickness of the new ones. There has been some thin rubbish supplied for these that means that the banjo bottoms out on the top of the oil feed before it clamps down on the lower seal. Good luck.

 

[Albervin]

Better still, buy a set of leakproof washers from Neal Videan. Of course when you fix all of the leaks a new issue will arise, but that is what Vincents do.

 

[Ducdude]

Better still, buy a set of leakproof washers from Neal Videan. Of course when you fix all of the leaks a new issue will arise, but that is what Vincents do.

Sorry I was away for so long.....The Site was down and then I got wrapped up in the garage working on the Shadow...

I do have Neal Videan seals on all but one of the oil feeds to the rockers and they seem to be staying dry...The oil was not coming from the stock breather port. It looks now to be comming from the upper exhust push rod gland nut on the foward cylinder.. So this week end I will try to seal that up with some new seals as long as I can get the tube to slide down far enough..

Cheers,
Eric

 

[nkt267]

So this week end I will try to seal that up with some new seals as long as I can get the tube to slide down far enough..

Don't forget the trick of splitting a top pushrod tube washer and easing it around the tube between nut and lip to give a double seal.John

 

[timetraveller]

Or even using a suitably dimensioned 'o ring and stretching it over the top of the push rod tube.

 

[Ducdude]

Or even using a suitably dimensioned 'o ring and stretching it over the top of the push rod tube.

Say now! That is a mighty fine idea!

Thanks all!

Eric