Author Topic: C15S 1959 Oil Pump total oil loss from oil tank  (Read 886 times)

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JulianS

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #15 on: 03 April, 2018, 22:35:31 »
The tube in the oil tank has a horizontal hole in the side just below the top.


You can see it on this service sheet.

AWJDThumper

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #16 on: 04 April, 2018, 08:35:01 »
Hello thanks for the help again. i stripped the oil pump which looks ok. i think the NRV bearing may have been stuck. Its free now. Can you tell me which hole leads to the inner NRV?

Sorry but another question. Before stripping the bike I checked to see if oil was going back into the tank. The pipe that i thought would let oil back into the tank appears to be a sealed tube that sweeps upwards and ends up inside the filler cap opening. I checked inside with a mirror but couldn't fathom out how the oil would return. No doubt I'm missing something obvious!
It's likely to be the hole closest to the inside of the crankcase. To check, simply blow down the other two holes and they should be connected to the inlet and output pipes to the oil tank. As indicated in Julian's diagram, the return into the oil tank is via a small hole in the pipe at the top of the tank. Just blow through the rubber return pipe to the tank and make sure it's unblocked.

TDub62

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #17 on: 04 April, 2018, 21:19:40 »
Thanks again, I haven't had chance to get out after work tonight but will hopefully have a look tomorrow and let you know how things progress

TDub62

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #18 on: 08 April, 2018, 22:00:33 »
Oil pump checked and all seems ok in theory , i blew down the NRV hole but no idea if it did any good or not. Anyway all back together and and it turned over ok as previous. Checked valve clearances and the I put the plug in and turned it over gently to check compression. A hissing sound could be heard on compression which after much squirting and soaping around the head gasket joint I thought must be coming from behind the push rod tube. off with the head and sure enough a small fault and repair between the tube and the chamber with a small rectangular impression in the face. I;m going to see if i can get a better repair done and guess I will need it skimming as well. The bike has had a new high compression piston fitted and I'm slightly worried about adding a skim to this. I've read that you can get slightly thicker gaskets possibly from BSA singles in the USA. Anybody know of a UK supplier.

AWJDThumper

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #19 on: 08 April, 2018, 23:15:55 »
That looks like an odd bit of damage. Have you got a higher resolution pic of it and how do you think the damage was caused?

TDub62

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #20 on: 09 April, 2018, 12:41:08 »
I have better pics but struggle to upload them onto the forum. It looks like it may have been repaired previously as the pushrod tube opening has a slightly flattened surface near the damaged bit. The damage is like an impression of something but probably too deep for that. Sadly it came to me like that. Think I may take it to park engineering at Malton near where I am to see if they can repair it.

AWJDThumper

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #21 on: 09 April, 2018, 14:31:34 »
Just needs a bit of TIG Al welding followed by the milling machine.

GUY HUTCHINSON

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #22 on: 24 April, 2018, 13:38:16 »
I've picked the head up, its been repaired with 'liquid metal' and a fine skim at our local classic machinery engineers. There was concern about heat distortion with a weld repair so close to the push rod tube area.
Next problem I can see is the gap between head and barrel being too great for the head gasket. To get around this I'm going to try a double gasket with copper spray to help seal it. Anyone else gone down this route or got views?
The oil pump seems to work pumping back to the tank (on kickover) but wont pump to the rocker union unless I put my finger over the tank return, might this resolve at normal engine speed?

AWJDThumper

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #23 on: 24 April, 2018, 17:26:16 »
I don't think a double gasket is a good idea - the better solution is either to get one of the correct thickness or to skim the top of the cylinder to enable the gasket you've got to fit correctly with 4 thou or so compression.

GUY HUTCHINSON

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #24 on: 25 April, 2018, 13:20:54 »
I'm wary of skimming the top off the barrel lip as I don't want to increase the compression, having said that presumably a thicker base gasket would counter that.
The new head gasket that I bought does feel a little thicker than the old one which may be enough with the copper spray that I also bought. I'll have a play this weekend.

AWJDThumper

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #25 on: 25 April, 2018, 14:01:47 »
According to my calculations, if you skimmed off 5 thou, you would increase the compression ratio by 0.5 which is nothing to worry about and could probably be viewed as a positive advantage. The best thing is to measure the head/barrel clearance using a feeler gauge with the head fitted without the gasket. This will tell you how much would need to be skimmed to leave you with 4 thou compression of the head gasket.

TDub62

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #26 on: 14 May, 2018, 21:21:18 »
Ok so head repaired, camshaft outer bush changed and reamed and all back together.
I fed some petrol into the carb and tried to kick some life into the bike, nothing at all. I tried to choke the carb a bit (rag over the intake) which produced an engine ignition but also a massive kickback through the crank (ouch). Checked the timing (with a disc) which was spot on as per electrexworld 35.5 degrees. I retarded it very marginally. After the kickback I removed the footrests which get in the way with the U shaped lever and tried again. Same result, nothing until I choked it then bang a kickback (which I was more prepared for this time but still not good).
Any ideas what next? The fuel is from last summer which maybe doesnt help but how would that explain the kick back? I've checked the timing again and it looks spot on.

PS I seem to have created a second log on in the past with a different name on my work computer. TDub62 is me (Guy).

AWJDThumper

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #27 on: 15 May, 2018, 07:08:54 »
It's probably kicking back because the ignition is far too advanced. Standard C15 advanced ignition is 33.5 deg BTDC but with modern fuels it's best to reduced this by a couple of degrees. I would check that the ignition has been set with the auto advance mechanism rotated fully to the advanced position. Also, if the fuel mixture is too rich it can produce the same effect as a more advanced ignition timing.

GUY HUTCHINSON

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #28 on: 15 May, 2018, 12:41:59 »
Thanks I'll try retarding it to 33.5. I went by the figure given in the Electrexworld instructions which was 35.5 for a C15. Carb set up standard for the bike but I haven't got the air filter connected at the moment which I guess would make it more lean.

AWJDThumper

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Re: C15S 1959 Oil Pump total oil loss from oil tank
« Reply #29 on: 16 May, 2018, 08:46:31 »
It takes a lot of effort to make a C15 kick back and it won't be the odd couple of degrees of advance that is causing this. I would double check the way you have set up the Electrexworld - are you sure the engine was accurately positioned at TDC before you tightened up the rotor? In terms of the missing air filter, it won't make much difference to starting the engine but it would be sensible to increase the main jet by 10 to compensate.