Author Topic: Engine failure troubleshooting  (Read 897 times)

Online Greybeard

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Re: Engine failure troubleshooting
« Reply #15 on: 18.09. 2019 16:25 »
Not too sure that B&Q sell ethanol proof fuel line though! If that starts to disintegrate then you will have blocked jets etc.
Maybe for mowers?

Offline owain

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Re: Engine failure troubleshooting
« Reply #16 on: 18.09. 2019 16:47 »
Update: fitted some clear plastic tubing for the fuel lines to the carb. So I bought some from the local hardware store in N.Wales (Stermat). No idea if it is ethanol proof or not. So I've just reserved some 6mm fuel tubing from Halfords.

I cleaned all the carb components and blew through the jets with some hose to make sure they were clear and reattached the carb.

I also checked tappet clearance, all of them were very tight. Opened them all up some that a 0.015" feeler gauge could slide between them smoothly.

Kicked the bike and started the engine ticked over nicely. I'll take it for a test ride once I've refitted the fuel hose with hose that is definitely fuel proof. I can see straight away however that the left fuel tap (which doesn't have a filter attached to it) allows bits of debris to pass to the carb i.e. this debris can be seen in the clear tubing. The fuel tap on the right has a filter and the fuel looks nice and clean. Just so happens that I usually ride with just the right fuel tape open and the left (non-filtered) tap closed....except when the TV crew were filming, then I had both taps open and the bike conked out after an hour or so of riding.

PS: I'll also fit an extra filter in the lines.
Sweden & North Wales
'50 BSA A10
'69 BSA A75R

Online Greybeard

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Re: Engine failure troubleshooting
« Reply #17 on: 18.09. 2019 16:51 »
Update: fitted some clear plastic tubing for the fuel lines to the carb. So I bought some from the local hardware store in N.Wales (Stermat). No idea if it is ethanol proof or not. So I've just reserved some 6mm fuel tubing from Halfords.

I cleaned all the carb components and blew through the jets with some hose to make sure they were clear and reattached the carb.

I also checked tappet clearance, all of them were very tight. Opened them all up some that a 0.015" feeler gauge could slide between them smoothly.

Kicked the bike and started the engine ticked over nicely. I'll take it for a test ride once I've refitted the fuel hose with hose that is definitely fuel proof. I can see straight away however that the left fuel tap (which doesn't have a filter attached to it) allows bits of debris to pass to the carb i.e. this debris can be seen in the clear tubing. The fuel tap on the right has a filter and the fuel looks nice and clean. Just so happens that I usually ride with just the right fuel tape open and the left (non-filtered) tap closed....except when the TV crew were filming, then I had both taps open and the bike conked out after an hour or so of riding.

PS: I'll also fit an extra filter in the lines.

Offline Swarfcut

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Re: Engine failure troubleshooting
« Reply #18 on: 18.09. 2019 19:30 »
Maybe I feared the worst ,but get that slip ring clean 'cos catching fire is not an optional extra.

Swarfy.

Online Peter in Aus

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Re: Engine failure troubleshooting
« Reply #19 on: 19.09. 2019 01:57 »
Righto, I just tried starting the bike before reading all these comments and the damn thing caught fire! Looked like it started at the carburettor. Fortunately it was a very small fire and I had a fire extinguisher within arms length of me, so it was out within a few seconds.
Just how I like start to the morning *lol*

I've cleaned it up now and I've just removed the carb. I'll drain the tank and remove the petrol taps. I also noticed that air is escaping from the timing side cover via one of the screws when I kick it over...not sure if it is note worthy how the bike is? I'll check back on the forum regularly throughout the day to keep you updated and see how things progress!

Also to answer Greybeard, Yep the magneto has been serviced by APL magnetos a few months ago. I'd be hugely disappointed if the mag is playing up already.

Image is from post-fire extinguisher antics:

I noticed in your photo that you don't have a carby drip  tray 67-0120 fitted, without that it is a potentially a fire hazed.   

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58 A10  SA

Online ironhead

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Re: Engine failure troubleshooting
« Reply #20 on: 19.09. 2019 03:52 »
Righto, I just tried starting the bike before reading all these comments and the damn thing caught fire! Looked like it started at the carburettor. Fortunately it was a very small fire and I had a fire extinguisher within arms length of me, so it was out within a few seconds.
Just how I like start to the morning *lol*

I've cleaned it up now and I've just removed the carb. I'll drain the tank and remove the petrol taps. I also noticed that air is escaping from the timing side cover via one of the screws when I kick it over...not sure if it is note worthy how the bike is? I'll check back on the forum regularly throughout the day to keep you updated and see how things progress!

Also to answer Greybeard, Yep the magneto has been serviced by APL magnetos a few months ago. I'd be hugely disappointed if the mag is playing up already.

Image is from post-fire extinguisher antics:

I noticed in your photo that you don't have a carby drip  tray 67-0120 fitted, without that it is a potentially a fire hazed.   

Yep, the cause of many flaming A10's
SA

Offline owain

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Re: Engine failure troubleshooting
« Reply #21 on: 19.09. 2019 07:44 »
Slipring is all cleaned up now Swarfy. Don't want repeats on the road, even if the fire extinguisher lives inside the sidecar!

Good point, I took the drip tray of because it was just so fiddley when trying to squeeze a concentric carb inside. I'll definitely be refitting it as soon as I'm back in my garage!
Sweden & North Wales
'50 BSA A10
'69 BSA A75R

Offline owain

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Re: Engine failure troubleshooting
« Reply #22 on: 19.09. 2019 19:59 »
Update: I took the bike for a test ride today after cleaning out the carb, cleaning the slip-ring and readjusting the tappet clearance. It was still fluttering and stalling after a minute of riding. Tickled the carb, engine started and I rode it again. This time the moment the engine stopped; I turned the petrol taps off and drained the float bowl to see how much petrol was in in the float bowl at the moment the engine stalls. There was hardly any.

Took the carb apart again and adjusted the float. Started it up and rode it a good coupe of miles without any problems.

Another question I do have however is about a mystery leak. I've finally sealed the chaincase and confident that it's pretty oil tight but there is a lot of oil travelling down the backside of the chaincase (i.e. behind the clutch) I'm not sure where it's coming from but it's a decent amount of oil dripping. No signs of a leak at the cylinder base gasket. I'm pretty sure I saw someone mention a breather hole somewhere at the rear of the crankcase?
Sweden & North Wales
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'69 BSA A75R

Online BigJim

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Re: Engine failure troubleshooting
« Reply #23 on: 19.09. 2019 21:20 »
I would suspect that the two main sources for that oil are the chaincase where the gearbox shaft enters or the engine breather. the engine breather is easily felt with a finger from above to see if that is the primary source. There will be photos somewhere here. lots of opinions re causes and am still working with mine whilst continuing to ride. The chaincase leak is common and lots of opinions on treatment are in those threads. The main thing is the volume and any obvious change from normal (?!).
Jamie,  Supporter of Distinguished Gentleman's Ride

Offline muskrat

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Re: Engine failure troubleshooting
« Reply #24 on: 19.09. 2019 21:32 »
G'day Owain.
You must have one of those new "stay up" floats, good. The correct fuel height in the bowl is crucial to tuning. The correct level is 0.090" to 0.120" below the bowl/body joint face. I have a bowl plug with a clear tube to hold up the side of the carb to check.
Yes the breather exits the c/case  back there. Or it could be the mainshaft seal (felt) behind the clutch.
Cheers
Jim types faster
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Online Greybeard

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Re: Engine failure troubleshooting
« Reply #25 on: 19.09. 2019 22:19 »
Owain,
Can you tell if the leak is gearbox or primary case type oil? In my bike the primary has red ATF fluid, that turns brown after a few miles. The gearbox has EP90, which has a distinctive smell and is, of course thicker than ATF.

Online berger

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Re: Engine failure troubleshooting
« Reply #26 on: 19.09. 2019 23:36 »
I have not been to the pub. greybeard have you got any glitter in your box *eek* *whistle* as I understand things EP90 can attack the bushes . I found glitter in my box *eek* when I used to use EP 90.

Offline Swarfcut

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Re: Engine failure troubleshooting
« Reply #27 on: 20.09. 2019 08:31 »
Owain, The good news is that it's a runner again, but as always another obscure facet of the design appears, to keep you on your toes. On your plunger design, the original primary case seal behind the clutch is little more than a compressed fabric ring, and is a prime source of leakage. The later S/A set up has the felt ring (and sliding plate). The original type seal swaps easily with a modern seal of the same size...shaft, housing, width.

 On the plunger design this seal can only be changed with the gearbox removed from the engine unit, and as you know this ain't a 5 minute job.

The breather exits the engine just under the chainguard extension on the back of the primary case. It may have an extension pipe, if still original, leading down and clamped adjacent to the sump plate.  The gearbox oilseal on the sprocket is another common source of leak, also the mainshaft/drive sleeve bushes.

 So its time to get out the big mirror and the rags, clean off as much muck as you can and observe where fresh oil appears. In the short term, if it turns out to be that pesky seal, try reducing the amount of oil in the primary case. My trick is to drain the case, start the engine, the add oil until a reasonable amount of oil can be seen flicking past the filler hole, rather than a cascade. This shows the chain is just dipping in the oil, rather than deeply immersed. This level helps keep oil off the clutch.

Plenty on the Forum recently about the seal, and how folks have solved the problems of holding it in place. Worth checking gearbox oil, in case that is overfilled and working its way out.

 Looks as if you have a concentric carb fitted, if I have followed your posts correctly.

 Bergs...I can't make up my mind about EP90 and phosphor bronze bushes. Anyone know for sure if this is true or an urban myth? Glitter is more likely to be particles worn from gear teeth in use rather than stuff eroded by some chemical reaction between bronze and oil additives, to my simple mind.

 Swarfy.

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Re: Engine failure troubleshooting
« Reply #28 on: 20.09. 2019 09:01 »
I have not been to the pub. greybeard have you got any glitter in your box *eek* *whistle* as I understand things EP90 can attack the bushes . I found glitter in my box *eek* when I used to use EP 90.
I am not aware of particles in the gearbox oil. When I had the gearbox rebuilt by an expert last year he said nothing about oils, so I guess he didn't find evidence of bushes being damaged by EP90.

Online berger

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Re: Engine failure troubleshooting
« Reply #29 on: 20.09. 2019 11:34 »
ok chaps we will not  *fight* but as I understand these things EP/ extreme pressure oils attack bronze materials because of their additives.