Starting a rebuild

[rhyatt]

Can you prove that oil is being fed to the engine?
Is there a place on the engine(pressure relief valve) that you can undo and see if oil is being fed to the motor from the pump.
Can you throw some oil into the rocker box area , this will run down into the sump and be scavenged back to the oil tank and obviously to the rockers.
Can you undo the pipe to the rockers and see if scavenged oil is getting there, even if it means briefly putting your finger over the return outlet in the mouth of the oil tank.
Are you able to run it without valve inspection caps and see if oil is getting up there?8
Sorry missed something you said, runs 5 secs , clunk and stops.
So this clunk physically stops/locks the motor?

[DAVE BRADY]

Hi,

I would undo the pressure relief valve and see if oil finds its way through to there.  If not then there could be an air lock in the pipe feeding the engine from the tank.  Slacken the feed pipe union and let the oil run out a bit.  Once you know oil is getting through to the PRV tighten it up again and turn the engine on the kick start but do not start it just yet.  Take the plugs out to make it easier. It could also be useful to remove the sump plate and allow any oil that is in there from rebuild to drain away.  After this, as you turn the engine and push oil through the crank, it will start to drip/run out of the sump.  This should indicate that oil is getting to the big ends so put the sump plate back on.  Now put about 1/3 pint oil down by the pushrods and allow it to get through to the sump.  Now as you turn the engine the pump will scavenge the oil and return it to the tank and up to the rockers.
Whilst turning the engine over you may get abetter idea of where the noise is coming from.

Dave.

[Gup holland]

Long time ago I had a cilinder rebore and head and guide valve job. New pistons in and had a same noise. It seemed that the valve touched the piston, they where GPM.
After investigation previous owners had the head skimmed off, several times. I noticed it when I saw a original head. It was much higher. The compression was also far to many. I made a thick koper gasket myself and this was de solution for me, 2,5 mm thick.
Happened 30 years ago.

Good luck, gr gup

[rhyatt]

Gear pumps are good at moving oil, but they don't suck very well.
So you need to force oil with an oil can into the gear pump supply side and scavenge side via the stubs, , then fill the supply pipe completely, pop it on the pump and then it will move this oil.

[Allan G]

A drop of oil on the valve stem during installation will help prevent premature wear and more oil consumption in the long run.

[LIONELSMITH]

 I'm not starting the Bike again until the oil priming is sorted, but turning it over I am getting two rattles from the top of the engine. I've been doing some reading. After finding one push rod had dropped out of the rocker cup a while ago I am wondering whether the cam followers are sticking.
Has anyone ad this? It is probably time for my umpteenth engine strip down only this time the block comes off.

[rhyatt]

Ultimately, the valve spring push the rocker arm UP,
And this pushes the other end down, keeping it snugly in the cup of the pushrod.
The pushrod then pushes downwards causing the tappet block/cam follower to follow the profile of the cam.

I can't work out what the noise is currently, but if you have set the valve clearances when the engine e is in the right point of rotation , then you can't do much more.
Are you able to get the plugs out and tank off and valve covers off (so you can see their actuation).
Get a pal to kick it over a few times whilst you look at things going up and down in sequence.
This surely will show you the rockers moving through their sweep.

[Pete Gill]

I'm not starting the Bike again until the oil priming is sorted, but turning it over I am getting two rattles from the top of the engine. I've been doing some reading. After finding one push rod had dropped out of the rocker cup a while ago I am wondering whether the cam followers are sticking.
Has anyone ad this? It is probably time for my umpteenth engine strip down only this time the block comes off.

I had an issue after i rebuilt my B31 a few years ago. It kept doing a similar thing and ended up with an unseated pushrod. It turned out that my friend who had replaced the valve guides for me hadn't done a great job at cutting new seats and also had not honed out the valve guides adequately to give sufficient clearance. The exhaust valve stem had galled in the guide and the valve stuck open intermittently.
I think you might need to get the head off and check the valve stems.

[Steve.S]

Let me try and get this straight. You had no compression on the left cylinder and 50lbs on the right. (Must have been very easy to kick over?)
Did you oil the bores on assembly or were they dry? Likewise big end, little end etc? You seem reticent to oil the valve stems. Use lots of oil. Carbon will only build up after several thousands of miles. Less build up if you give it a damned good thrashing.
You did a water test. I would have used petrol, although this may evaporate and give a false impression, but it will find leaks better than water.
I cannot imagine a valve guide going in cockeyed, unless the guide bore in the head was badly worn. If it's an alloy head, the guide will probably come loose later on. Are you sure it's cockeyed? You would normally have to recut the seats, followed by lapping in with grinding paste. Your engineer recut the seats and presumably lapped them in, so I imagine he checked the guide to stem clearance......but I wonder? I fully agree with Pete.
Which pushrod came out? Surely, with correct tappet clearances, the only way this can happen is if the valve or rocker is stuck? Do others agree?
I see that the engine now stops when the clunk occurs, whereas before, it kept on running. I think the most likely cause of all this is an intermittent sticking valve, which is why the pushrod came out, and the clunk is the open valve hitting the piston. Hence, with an open valve the engine stops. As the engine cools for those few seconds, the valve closes, allowing you to start the engine. You probably now have a bent valve and maybe a bent pushrod?
Well, that's my theory. It's probably wrong, but it's the best I can come up with.
I also find it very odd that you had hardly any compression and it wouldn't start, but after cleaning the carburettor you must have had compression, because it started!
I can add nothing to all the advice you've been given regarding the oiling, except to ask if you have run the engine long enough for the crankcase to receive sufficient oil to allow the scavenge to start working and return oil to the oil tank and feed the rockers? It can take some time for the oil to return on a newly built engine. But do check what others have suggested.
Best of luck and keep at it.   

[LIONELSMITH]

I've now primed the Oil Pump and am getting oil through to the pressure relief valve hole and with the PRV refitted, into the sump. Here it collects and leaks out presumably under pressure. I spent several hours kicking the bike over to find this latest issue.I cannot find any information on the Scavenge pump. The pump had to have been fitted by SRM when they rebuilt the lower engine after regrinding the crank, fitting the timing side crank bearing conversion, cleaning the traps and fitting alloy Con Rods. I have tried poking a pin up the scavenge pipe and it hits metal, I assume something must rotate to pump out the oil and it is in the closed position. I have fitted an SRM high volume oil pump and have got to talk to them about a bearing and spring I never had.
Questions
Can a scavenge pump fail and how do I check it?
Is this the likely culprit or are blockages possible, should I drain down again and blow compressed air through?
Anything else
I just want to get it on the road before I am too old to ride it!!

[DAVE BRADY]

Hi,

The scavenge pipe in the sump has a ball bearing that sits to block the hole and partially prevent the oil in the scavenge side of the pump from draining in to the sump.  When you push a piece of wire up there all you are doing is lifting the ball and pushing it to its upper limit.  The ball should be very free to move up and own in the scavenge pipe and the ball should be just visible.
The oil pump has both feed and return/scavenge in the same body so both function together.
The bearing and spring I think you are referring to are fitted behind the pump and act to prevent oil from the tank getting through to the sump.  This known as 'wet sumping'.  It is highly unlikely that SRM would have assembled your bottom end without fitting the ball and spring.
The oil collecting in the sump is not under pressure but after being pumped through crank and (whilst the engine is running) getting splashed around the crankcase it drains to the sump to be scavenged by the pump and returned to the tank.
Oil will not return to the tank until there a minimum level of oil in the sump for the pump so it is advised that when an engine has been rebuilt or the oil system completely drained that about 1/3 to a 1/2 pint of oil is put in the sump to get the pump primed and oil returning to the tank.  The pump will soon scavenge this oil up the tank and this will also ensure a good initial supply of oil to the rocker shafts.
If you have the head and rocker box fitted then slowly pour the oil through the rocker covers and let all drain down to the sump.
Obviously the sump plate will need to be fitted otherwise there will be a mess on the floor.
You should get the oil to return to the tank and to the rocker box just by kicking the engine over.  Easier to do this with the plugs removed.  If you are concerned about dry rocker shafts remove the oil feed banjo and use an oil can to get some oil in there.  With the covers off you should see the oil oozing out past the rockers.  Whilst doing this squirt plenty of oil on the valve stems.  Excess will drain away and not affect the combustion chamber.
If you have purchased push rods from SRM then they are very unlikely to be wrong but check the adjusters and how they sit on the valve.  With the rocker covers off slowly turn the engine.  Is it possible that as the valve is opened the adjuster moves off one of the valve stems and the end of the rocker then contacts the valve?  This will make quite a noise.

Dave.