Excess oil to inlet rockers

Is the feed to the rockers before or after the aftermarket filter on the return line? It could be that any extra restriction to the return flow is sending more oil to the rockers. The other checks are make sure the rocker spindles are plain and not scrolled but I think the main suspect is a blocked return hole. It's not unknown for the head gasket to obscure the oil return especially if it is fitted upside down. Poke a wire down it and see.

Agree with Gordon. If you do find a problem, won't Norvil be able to fix it under warranty?

Oops correction! The rocker spindles should of course be scrolled assuming you have a normal 3 start gear to your oil pump. If you have a 6 start gear (and you shouldn't really), plain spindles might be in order, though not essential. It was a bit past my bed time when I posted last night... Also, check that the oil is returning to the tank. Any blockage here would send all the returning oil to the rockers. Gordon.

Not a situation I would like to be in. As long as you are positive the fault has not been caused by any of your work then I suggest you leave the engine as you received it from Norvil and contact them asap explaining the problem. As a consumer you have rights and as you have entered into a contract with Norvil they have an obligation to put things right or offer you a refund. I could think of better ways to start the new year. Good luck.

Best of luck! I doubt if Les will admit any responsibility. If you have scrolled rocker spindles, with a high output pump, far too much oil will be fed to the rocker-boxes. The scrolled spindles were designed to operate with lower oil pressure.

I do wonder why they fitted a 6 start gear to the pump. Quite unnecessary with a Domi engine. And as John says,you really need to fit plain rocker spindles with this modification.Hopefully Les will be helpful.

Lots of alarm bells going here...........Bill....you appear to have a pressure feed to the rockers from the back of the Timing Cover.

I have checked the oil tank return pipe, dia seems ok and there are no restrictions in the pipe. The feed for the rockers comes froma banjo just below the pressure relief valve, not sure if the shafts are scrolled or not. Bill

Previously william_howe wrote:

Hi all.I have just fired up my domi 99 - actually a 1957model 77 motor in a 58 featherbed frame, and i have a problem with too much oil going to the rockers so that the inlet is filling with oil. The motor has just been rebuilt by Norvil and I have run it up, tightened it all down and everything was fine until I took it out for the first shakedown run this afternoon andground to a halt after about 2 miles with oil dripping out of the inlet cover. I let it cool down, cleaned it up a bit and fired her up and limped home at low revs, with more oil discharge by the time i got home.

It seems to me that I have either got too much oil volume going to the rockers or a blockage in the oilway from the rockers? I have poured oil into the inlet and it seems to drain ok, albeit slowly, which would suggest too much oil supply? The motor has been fitted with a standard new oil pump and I have fitted a universal oil filter on the return line, both niorvil. The only other difference to standard is a central oil tank as the bike is cafe racer style. I am planning to do some static running tomorrow to check whats going on, (tank off, rocker covers removed and oil tank open), but any suggestions gratefully received.

Bill Howe

Well well how interesting you do know there are a two oil-ways at the in-let side drilling's at the side of the bottom steel cup washer that receives the valve springs this may of be covered up by some thing or something or wrongly fitted . this oil way then runs down at the back of the right hand cylinder head were in too the barrels and then to crankcases there is a L shape bend this another point were it get blocked and Good Engineer would know this one, there three places are a blockage can evolve a problem one it in the cylinder head were the springs are bottom shim cup wash , the head gasket area , and the crankcases were the barrel facings fit the case right side back of the cylinder there the receiving hole then there is this L shape drain hole that comes out into the timing case, so all you need is a tobacco pipe cleaner and a small drill of one eighth of a inch and very carefully clean these out, which may of been over looked by the engine builder. But then I do my own work and know these engine well by now, one more thing try fitting Bosch W7DTC spark plugs you find that these engines will run better.and start better, these engine were made for 3 point spark plugs , of the past now there here in the future too with more refinements too them, So there even better than before , and a six start oil pump is totally unnecessary on a 600cc twin . even my 650 runs very happily with a 3 start oil pump as long as its in good condition. and please do not worry about !/2 pint of oil or so in the sump area , its good thing its there . as it does more good than harm. as it splash feeds every thing on start up , And the restorer should of tested for these anomalies and seen that the machine had no problems before letting the owner or new owner take charge of the machine in the first place. this is the first rule of restoring motorcycles , yours Anna J happy riding

Would the over oiling of the rocker shafts and the flooding of the valve pockets have caused the engine to tighten up and gring to a halt as William says? I think not.

So what could have caused the engine to quit? Just generally too tight of a rebuild?

I've just had a look at a 99 engine lurking on the bench. My money is still on a blocked return oilway. Starting at the bottom. The oil drains to the timing side via the offside crankcase. Possibility for blockage there. Check by squirting oil into the drain hole in the timing crakncase and see if it appears next to the offside inlet valve. If it doesn't, the cylinder base gasket could be fitted upside down, obscuring the drain to the crankcase. Otherwise, there's not much to go wrong. You would have to lift the head to check further. Oh joy.

Hi All

I think that this problem was mainly one of ignorance on my part, while I can work my way through a workshop manual, I am not an engineer and do not have experience of the variations that have occured with the Dominator over the years. When i plummed the rebuilt engine into the oil tank I should have blanked off the high pressure outlet below the pressure relief valve and fed the rockers from the return pipe at the tank. I have spoken to Les this morning and he has confirmed that the engine was rebuilt to accept low pressure return to the rockers as I had not specified otherwise. Having discussed the situation we decided to replace the scrolled rocker spindles with plain ones, which I have now done, and the problem is resolved. This retains the benefits of the high pressure system to maintain a good supply of cooling oil to the head, but makes sure that I get good lubrication volume and pressure to the big ends etc.

Hopefully the weather will improve over the next couple of days and I can give the bike a good run out to make sure all is ok.

Thanks for everyones help on this, I think I am a little wiser now?

Michael - on your point about why I ground to a halt, the motor did not seize, it sort of bogged - with hind sight I think that the head was pressurised and full of oil and possibly caused fouled plugs? All I did was leave the motor to cool for 20 mins, cleaned up the excess oil and rode home two miles in third at low revs. The motor did not feel tight.

Regards - Bill

Well we are Engineers and its all down to blocked oil ways at there is a eighth hole drain way back of the cylinder head right down to the crankcases and you do not need Six Start oil pump and plane rocker spindles , the six start was developed by Pumstead for the 750cc Atlas is it being a big CC was not coping with the 3 start pump so they doubled the speed of the oil with a six start gears so these wear out faster. you need the rocker feed from the oil tank return pipe. eighth copper brake pipe is ideal for this job yours Anna J

Previously phil_hannam wrote:

Lots of alarm bells going here...........Bill....you appear to have a pressure feed to the rockers from the back of the Timing Cover.

I have checked the oil tank return pipe, dia seems ok and there are no restrictions in the pipe. The feed for the rockers comes froma banjo just below the pressure relief valve, not sure if the shafts are scrolled or not. Bill

Unless Norvil has converted your cylinder head to plain spindles the pressurized rocker feed is going swamp it. The oil feed set-up for your engine is well over the top for a 600cc engine with 1.50" journals. The larger capacity pump is a good move but adding a 6 start gear/worm to this size of engine is not really necessary.Also, a mistake many owners, of pre-1966 bikes, make is converting their engines to pressurized rocker feed without doing the job properly. You generally have to change the scrolled spindles and the rockers unless the engine has had next to zero use. The reason being that the old 'return feed' scrolled spindles often worked in a minimal oil environment. This led to them acting like drill bit shafts and slowly grinding away the inside of the rockers. Consequently, fitting plain spindles into old worn rockers allows the oil to belt straight through into the head, This may have happened to your engine.Adding to the fun and games here.........please read the attachment regarding engines rebuilt by Norvil. Consumer rights, Warranty and Norvil always seem to make lots of NOC members fall about laughing when mentioned in this part of the world.

I like the way he says do not use 20/50 multigrade and use a SAE 50 all the time. this only makes thing worse not any better thin oil gets to the part in the engine quicker the thick SAE 50 this like try to ram a rag down a narrow pipe ! it put up Resistance just like SAE 50 modern synthetic oil are now even better . , But I have all way use a good 20/50 and even raced on it too. with no problems

Anna, whether, or not, you need a 6 start oil pump & plain rocker shafts, is not really relevant. Bill has no choice, as Norvil has already changed the pump (whether, or not, they fitted plain rocker-shafts to match the higher output is a different matter). However, I do totally agree with you regarding oil. In the English climate, a straight 50 grade oil is unlikely to reach working temperature in less than 50 miles.

Anna, whether, or not, you need a 6 start oil pump & plain rocker shafts, is not really relevant. Bill has no choice, as Norvil has already changed the pump (whether, or not, they fitted plain rocker-shafts to match the higher output is a different matter). However, I do totally agree with you regarding oil. In the English climate, a straight 50 grade oil is unlikely to reach working temperature in less than 50 miles.

well at lease we agree on something happy new year john !!

I have a similar problem with my 99, possibly ever since I had the oil pump overhauled. I had run out of ideas (having had the head and barrel off and checking the oilway) but now maybe I can progress. I suppose physically restricting the oil supply to the rockers is a really bad idea?

I have a similar problem with my 99, possibly ever since I had the oil pump overhauled. I had run out of ideas (having had the head and barrel off and checking the oilway) but now maybe I can progress. I suppose physically restricting the oil supply to the rockers is a really bad idea?

happy new year to all Now its a good idea when rebuilding your engine to give all the oil ways a good blow out with compressed air you can make a long pipe out of a length old copper brake pipe so you can get in the oil-ways in versus places around the engine if you find any crud then you can clean it out with a long 1/8 th drill bit and pipe cleaners, So have Fun , yours Anna J