• Welcome to the website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Hon. Editor and Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this website.

    If you have previously registered to use this forum, you should log in now. CLICK HERE.

    If you have never registered to use this website before, please CLICK HERE.

ET: Engine (Twin) Persistent oil leak

Chris Launders

Well Known and Active Website User
VOC Member
I have a terrible dilemma, my black painted Rapide leaks just about everywhere and I haven't really wanted to dismantle it as it's running ok. Now I have plenty of no-riding time I'm still reluctant to do anything as it will need totally stripping, the old flaking paint stripping off, blasting and repainting which I won't be able to get done and if I need to take stuff anywhere for work I can't do that either so I would end up with a pile parts just when I will be able to ride it again.
 

Albervin

Well Known and Active Website User
VOC Member
Repainting is an option. The paint is window dressing. Over here we are more concerned with oil tightness and tune. Bite the bullet and seal it. It can be done in a week. I was horrified at the leaks at the last International. Beautiful paint and alloy and a couple of cups of oil on the ground. Sort of says a lot about the owners really.
 

BigEd

Well Known and Active Website User
VOC Member
VOC Forum Moderator
Repainting is an option. The paint is window dressing. Over here we are more concerned with oil tightness and tune. Bite the bullet and seal it. It can be done in a week. I was horrified at the leaks at the last International. Beautiful paint and alloy and a couple of cups of oil on the ground. Sort of says a lot about the owners really.
I think you may have offended quite a few people who actually ride the Vincent machines. :oops:
 

Bill Thomas

Well Known and Active Website User
VOC Member
I was talking to a Bloke on the Coast
I said I had better go before it Pees All Oil
All over the tarmac.He said I dont think so.
He would be wrong.
 

greg brillus

Well Known and Active Website User
VOC Member
Striping and re-painting a Vincent engine is definitely not for the faint hearted........Best off to fix all the external leaks and leave the heavy duty ones alone. The absolute best way to find leaks is to thoroughly clean down the area, and I mean really clean.......then take the bike for a short ride, do not go for a 20 mile blast down the nearest highway, just a mile or so at most. Then return to base quickly shut the engine down and get onto your old and worn out knees with a good torch and find that leak. They will show quite easily, but not on some grubby oil soaked engine ........ ;)
 

Chris Launders

Well Known and Active Website User
VOC Member
I'm not afraid of stripping and rebuilding my engine, just the time and potential cost and the amount of space I would need to free up to do it, I've no idea when it was last apart, certainly not by the previous owner so it has done at least 25,000 miles without any work other than an engine sprocket and ESA springs and as it starts first kick and is utterly reliable with just a leaky engine I'm reluctant to do it.
Greg you must have fabulous eyesight, you can obviously see my engine from 1/2 way round the world.
 

Albervin

Well Known and Active Website User
VOC Member
I think you may have offended quite a few people who actually ride the Vincent machines. :oops:
Really? I ride mine and so do many I know. Two of the big mile riders here rack up over 5,000 miles a year easily. No leaks. I tend to do two or three longish rides a year, 1,000-1,500 miles. No leaks. Well, I do have a chronic problem with carbs. One day fine and next day not. I am pretty sure it is a sticky float needle but being intermittent it is difficult to prove. Original type 276. I never saw leaks under Ernie or Gill's bikes either.
 

Albervin

Well Known and Active Website User
VOC Member
There is no doubt that breathing is a big key. A lot of people now are cutting a larger slot into the timed breather. However it will not cure poor sealing. Older type sealants go off, lose flexibility and break. That is what happened to my Rapide. The joint between the engine and the gearbox broke and allowed oil to transfer between engine and gearbox. No leaks on the ground but gearbox oil was black and level was low. The only option was to pull the lump down and re-seal.
 

Cyborg

Well Known and Active Website User
VOC Member
I would have thought , If the liner fitted right , It would not matter ?.
No doesn’t matter. This one was ok and I ended up using it on my Mongrel Comet project. I popped the liner out to see what sort of crap was built up in there ( check fit) and also deal with the oil feed hole in the liner which like every other one I’ve measured was too high. The muff seems to be darker since I installed it, so suspect it is still oozing slightly. Would be nice if it waited until it at least until it go some engine heat! Originally the plan was to paint that engine black, but the cylinder muff kind of put me off that track.

I’m a little concerned Robert hasn’t responded to my wisecrack about baby powder. He’s about twice my size, which is what I would normally worry about, but with social distancing rules he’s likely loading a projectile.

DB315F6D-3E97-4D44-B619-7DA51A6724A0.jpeg
 

998cc

Website User
VOC Member
Check your rocker oil feed bolts. I have a leak from the front exhaust rocker oil feed that ends up in the places you describe. The new Neal Videan washers have an undersize ID causing a light burr on the washer. This leads to a slight weep which becomes ugly after the oil gets hot.
Albervin.
Good thoughts there. I used to have problems in these locations. For this build, I bored the VOCS copper sealing washers oversize to accept a small O-ring which is also snug on the bolt shank. It is essentially a home made Dowty washer that seals the underside of the bolt head to the top face of the banjo.. So far, no leaks there.

One leak at a time. :)
 

Robert Watson

Well Known and Active Website User
VOC Member
I have dispensed my very little wisdom on chasing oil leaks so here are two things come to mind with the little "comments" in this thread.

No1 When John Andrews rode his Shadow from Nova Scotia to Toronto, he stopped at one point to fill with fuel. The young attendant (we used to have them in those days) inquired about the large quantity of oil that it had deposited on the ground underneath the engine and what he intended to do about it. "At the appropriate moment I shall put some more in the top!" was his reply.


No2 A not so unknown member of the Club resident at the US at the time, wondered which of his armament should be used to take out the large and noisy dog next door (at some distance mind you) to make it cease its incessant barking. I think at the next Section Christmas dinner he was presented with a mortar round to be used on the neighbour - not the dog. Cyborg beware!
 

998cc

Website User
VOC Member
All.
From the responses here, porosity or ducting of oil under paint or between metal surfaces are legitimate concerns. So let's assume the oil is oozing out through porosity of the muff. How does it get into the muff in the first place?

Though possible, it seems unlikely that oil from the head could migrate into the muff casting from above since the contact with the head is largely limited to the top of the liner spigot. Oil weeping from the head should therefore appear at the head joint.​
From the crankcase, oil migration seems to be more plausible due to oil under pressure being present at one head bolt (stud) for each cylinder. Also, crankcase pressure must have some influence on forcing oil up in between the muff and the liner unless the liner is a perfect fit in the muff.​
Assuming the oil comes up from the crankcase, I am thinking of cleaning and sealing the muff gasket face including along the line of contact with the liner with Three Bond sealer and letting it dry. Then assemble as usual. Next, pull the timing cover and block off the oil supply to the bores.

Your opinions (both pro and con) are invited.

Thanks.
Russ
 

Marcus Bowden

Well Known and Active Website User
VOC Member
No oil to my liners for last 200k plus miles, what I would like is an oil jet at the bottom of each liner to under the piston for cooling, if I was competitive but never really have been, and as everyone knows "Speedisexpencive" ! I believe Mr Vincent told Marty Dickenson that.
bananaman.
 

Glenliman

Well Known and Active Website User
VOC Member
All.
From the responses here, porosity or ducting of oil under paint or between metal surfaces are legitimate concerns. So let's assume the oil is oozing out through porosity of the muff. How does it get into the muff in the first place?

Though possible, it seems unlikely that oil from the head could migrate into the muff casting from above since the contact with the head is largely limited to the top of the liner spigot. Oil weeping from the head should therefore appear at the head joint.​
From the crankcase, oil migration seems to be more plausible due to oil under pressure being present at one head bolt (stud) for each cylinder. Also, crankcase pressure must have some influence on forcing oil up in between the muff and the liner unless the liner is a perfect fit in the muff.​
Assuming the oil comes up from the crankcase, I am thinking of cleaning and sealing the muff gasket face including along the line of contact with the liner with Three Bond sealer and letting it dry. Then assemble as usual. Next, pull the timing cover and block off the oil supply to the bores.

Your opinions (both pro and con) are invited.

Thanks.
Russ

Russ, is the bottom side of the oil tank wet with oil?
I ask that because I chased what I thought was a multitude of engine leaks only to find that the problem was one big leak up top.
The eyes see oil on a fin and the brain says it must be coming from around here somewhere.
Not necessarily!


Glen
 

Oldhaven

Well Known and Active Website User
VOC Member
Oops, meant to do a thumbnail image, but the picture above is what my muff porosity looks like, assuming it does not use a transporter beam.
 

kettlrj

Well Known and Active Website User
VOC Member
Hi 998,
Some time ago a section member had a similar problem with his Comet. Following all sorts of solutions put forward by other members such as piston ring broken, loose vale guide and all other weird ideas. I went to see the bike and when it was running there was a lot of oil dripping from around the exhaust port. I asked him what had he been doing to the bike lately and he It seemed that he had not fully tightened the pipe nut securing the return pipe to the cylinder head rocker feed pipe. The oil was then running down the head fins, totally unseen, and then running out next to the exhaust port. Therefore my advise would be to look at the link pipe between the two heads to see if it is leaking from where the flex pipe joins the rigid pipe.
Regards Richard.
 

kettlrj

Well Known and Active Website User
VOC Member
As a matter of interest, the joint between the rocker feed pipes and the cylinder head often leaks because after all these years the pipes do not always sit square and load up the fibre washers on one side which overloads the washer and squeezes the washer out from under the pipe fitting. I have started using 16mm Enots bonded washers under these pipes. The beauty of these seals is that they clamp down on the metal outer ring which pulls the pipe into line and lets the seal do what it should do. The other benefit is that you end up with what is classed as a hard joint instead of a soft joint which means that the clamp load from the screw is maintained, which is not the case with the soft joint determined by the fibre washer. I also use 1/4" BSP Enots washers on all the other oil pipe fittings. The long oil feed and return pipes can come loose with when fitted with the fibre washers due to vibration and being moved to enable the gearbox cover or timing cover to be removed. Making the joint to the oil pump a hard joint prevents this loosening action.
Regards Richard.
 

Latest Forum Threads

Can't Find What You Need?

Buyer Beware: Fake or Real?


Top