Do I need a refresh?

[Pushrod Twin]

Super obliged for the education on metering wires. Its amazing what a giveaway the words themselves are!

Less familiar with Murphy's Vincent Law, Howard.

However, I am the originator of statute declaring that I am a seeker of mechanical soundness.

In all seriousness , I would like to be able to travel 1-200 miles in a day on the bike without any concerns and I would like to be able to do that next summer as I do enjoy the bike. I would hate to lose another summer not enjoying it through a breakdown with the engine out. Its full of character, makes lots of noise going nowhere fast and as long as I remember which side the gear shift is when I get on its all good. What is not so good is getting off the Comet after a few rides and hitting the rear brake on my MV thinking subconciously that I am changing gear!

The solution to the gearchange thing is get yourself a proper MV with the gearchange on the same side as the Comet. And they are a prettier looking bike as well!

 

[KennyNUT]

Hi,

I see you guys have got your sense of humour all revved up today!

Just a quick update from me and a few pictures of progress so far.

Got the comet engine supported on wooden blocks and the foot rest hanger lugs supported from the garage rafters with ratchet tie downs to minimise the chance of the bike toppling.

Dismantled everything in the following order:

1. Fuel lines disconnected from stop cock valves
2. Tank bolts removed fore and aft and tank removed - very tight at front of tank against top of girdraulic forks
3. Carburettor slide removed and exhaust valve lifer and clutch cables detached
4. Seat raised to remove rear spring boxes and all bolts to enable detachment of UFM to rear frame
5. Oil drained from main oil feed to base of crankcase
6. Wiring loom photographed and removed from headlamp and loom clip on UFM removed, horn button removed.
7. Entire front of bike and UFM removed from engine and rear frame mounts and supported in separate are of garage
8. Cylinder head bolts are now off
9. Inspection caps are off and valve oil lines
10. Exhaust nut is loosened (still to be removed after loosened at silencer
11. New copper washers looked out and refitted on oil banjo bolts, not tightened. Other nuts, washers etc fastened to their bolts or put into labelled takeaway boxes to be affixed upon reassembly.
12. Carburettor is now off

The garage was tidied up for the night and the rest of the work to remove the head, barrel and piston is planned for tomorrow.

That lot took me the best part of 4 1/2 hours and I haven't even seen inside the engine yet (beyond the valve inspection covers)! When Simon Linford spoke to me I am sure he said 2 to 3 hours to get the head off!

At least I have a short photographic library and I videoed bits along the way too.

Ready, steady, go!

Avoiding the inevitable tumble!

Comet's life blood all neatly in one place, for once!

For me, the easiest way to remove the loom was at the headlight. Not sure if this is conventional ?

Rear suspenders off, well nearly.

Access to the head. Oil lines and four main bolts all now off too.

Its a game of two halves! Comet just resting up for the night. Top oil lines also removed and carburettor.

I had better order some gaskets, sealant etc from the Spares company now before dinner!

Hopefully, an update tomorrow from me with everything off and ready to be boxed up for Simon Linford.

Hope you enjoyed that! Now where is that bottle of Glenfiddich!

Oh and before anybody has a chuckle, yes that is carpet in the garage.
Much cheaper in the long run and easier than paint on a floor.

Cheers, Kenny.

 

[clevtrev]

Hi Kenny, not sure if anyone's mentioned it, but at 10 miles the engine probably isn't up to temperature, and people will tell you it takes 12 miles to circulate all the oil once.

H

It`ll take you 25 minutes to circulate the oil once at 30 MPH.

 

[KennyNUT]

I am not surprised! It holds as much oil as my 1078cc MV Brutale and correct me if I am wrong but the oil in the Comet literally dribbles round the bike (and sometimes out of it) .

Is it not the case with the Vincent, that the bike's speed or rpm does not impact the oil circulation rate ie it dribbles round at the same rate whether at idle or 6,000 rpm?
If that is true, does the speed really matter?

Kenny.

 

[nkt267]

I am not surprised! It holds as much oil as my 1078cc MV Brutale and correct me if I am wrong but the oil in the Comet literally dribbles round the bike (and sometimes out of it) .

Mostly the riders dribble..John

 

[nkt267]

When you reassemble the bike fit bullet connectors to the rear wiring loom that way the loom stays on the UFM. Also a beer crate is the recommended support under the engine (after you've emptied it of course).John

 

[nkt267]

Dribble dribble,,,Before Matron arrives for lock up time---in theory you don't have to drain the oil to rmove the UFM. When you remove the top top of the feed pipe from the oil tank it SHOULD seal itself, but I always fit a blanking cap..John

 

[davidd]

I am not surprised! It holds as much oil as my 1078cc MV Brutale and correct me if I am wrong but the oil in the Comet literally dribbles round the bike (and sometimes out of it) .

Is it not the case with the Vincent, that the bike's speed or rpm does not impact the oil circulation rate ie it dribbles round at the same rate whether at idle or 6,000 rpm?
If that is true, does the speed really matter?

Kenny.

Kenny,

John is correct about the dribbling. The bikes pump quite a bit of oil as the RPM goes up. Egli owners who are able to observe the oil pumping through the lines know that it turns to a solid stream just over idle. Between 6000 and 8500 RPM it is impressive.

In general, the problem with the Vincent oil system is that it runs cool as Trevor mention, it does not deliver the oil quantity to all the areas where it is needed, and if you are running full throttle at consistently low RPMs you may need a twin start pump. It is a good system for the time and its designed purpose.

David

 

[KennyNUT]

Was I dribbling? Oh dear, that was 25 years ahead of schedule.

Thanks for the responses. I promised myself I would watch "Strictly" on the TV, tonight with the family, but this is much more fun.

Appreciate the bullet connectors idea for the loom. I will probably add an anti-sumping valve too though the Spares Co they are out of stock ATM. The head, barrel liner and piston will be away for 2-3 weeks, so probably time to get some of these other things attended to.

Thx, Kenny.

 

[Martyn Goodwin]

Just a few observations, most based on hard learnt lessons.

1. Oil – It is common practice with a tired and rattly motor to use a heavier grade of oil in an attempt to quieten everything down – and the belief that the thicker oil will provide better protection to the bearings. On many occasions Phil Irving addressed this subject and without directly quoting him the message was that the biggest mistake you can make is to use oil that is too thick. The information is that it is in the first few minutes of running that most wear happens – especially inside the timing chest. So Phil advocated a light oil to ensure quick and early lubrication resulting in long engine life. I am using a multigrade 10W30 oil so ensuring quick early circulation and protection of all things moving.
2. Loom – fitting connectors that allow the separation of the RFM from the rest of the bike is a very good idea. If you want to keep “the look” then use bullet connectors, else you can use modern automotive connectors, which generally are of a white colour – but can be painted black.
3. Anti-Sumping Valve. These are only required if the engine has excessive oil leakage into the sump when standing. It is my observation that between 1 and 2 cups of oil in the sump is normal – even if the bike has been standing, unused for weeks. What causes sumping is a worn or poorly fitted oil pump that allows oil to creep past/through it when its not operating. Fitting a Anti Sumping valve does not cure the problem – it just hides the symptom. The ultimate – and in my mind correct fix – is to fix the oil pump. Unfortunately to fix the oil pump requires a complete engine strip down – and you are almost at that point.
4. Oil leaks. Generally you will find that the engine does not simply leak oil all by itself. Remember the engine is an air pump and the combustion pressures inside the cylinder are replicated , all be it over a larger surface area, inside the crankcase – and it’s the engine breather that dissipates the crankcase pressure – if the breather is not working correctly then that pressure WILL force oil out of every weak spot to be found in gaskets and seals.
5. Breather: During the rebuild of my Comet I located the required parts and installed an ‘original’ timed breather; though I did follow the advice of Phil Irving in “Tuning for Speed”, which was:

“Better crankcase ventilation is obtained by filling straight across the breather valve sleeve until the slot is a full 3/8 inch wide, then rounding the outer edges of the flat so that the outgoing air has a clear passage; the edges of the slot should be left sharp to act as oil scrapers. Replacing the external banjo and pipe with a straight union and a large bore pipe running upwards and rearwards also helps ventilation.”

In my case I did not use a straight union, but rather a conventional hi-flow banjo. The other aspect I was careful about was breather positioning and timing. Combining information from Irving, Richardson and Stevens I learnt that the breather spindle needed to be installed in my Comet with the breather spindle slot pointing downwards. With the spindle correctly installed and with PEI’s mods made to the breather valve sleeve (in fact in my Comet I may have made the slot a whisker wider than Phils’ recommendation), I rounded and polished all of the faces of the breather valve sleeve and made sure that both the edges of the opening in it were knife sharp. I then timed the breather so that it was closing at or just before bottom dead centre; on my Comet this meant it was opening at around 20 degrees after top dead centre. I ran-in the rebuilt motor with considerable care and can report, now with over 10,000 miles on the rebuilt motor it remains oil tight and oil consumption is so low as to be almost impossible to measure.

As to the breather hose – I followed Phil’s’ advise about a large bore hose running from the breather outlet banjo upwards till it touched the bottom of the fuel tank, then it arches downwards, behind the battery where it exits into my home made catch tank (made from a small discarded plastic juice bottle). 1,000 miles of spirited running see’s around 2 teaspoons full of milky emulsion in the bottom of the catch tank. The only downside is I no longer have a constantly refreshed film of oil covering most of my bike, so I need to be a little more diligent about chain lubrication and drying the bike off after rain and washing. Basic lesson learnt: Poor breathing and oil leaks are not faults in themselves, they are symptoms of more fundamental problems relating to crank case pressurisation which MUST first be resolved before the oil leaks, if any remain, can be addressed.

All just my opinion.

Martyn