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Post by payneib on Apr 8, 2013 2:50:28 GMT -5
Sorry if this has been explained before, but it's given me a bit of a head scratcher this morning.
Historically, the breather tube from my rocker/Vv cover has collected half a length of frothy oil and water, with a hint of petrol in it maybe also. I've drained this off once a week as part of my cleaning routine.
Two days ago, my exhaust down tube gave up. I've been running it held together with jubilee clips and wire mesh from work. It sounds like a Harley, and I get extra power, but the parts are on order, and I had to get to work for my last two shifts of rotation, so I pushed out another 180 miles with it like that.
This morning, coming off my last night shift, she wouldn't start. Barely turning over on the starter motor, only a burble out of the kicker, until the kicker didn't spring back. "Seized motor" I thought. As I began to panic, I happened to glance at the breather drain. It was wedged full of water and frothy oil, so I drained it, and the scoot started first time on the button.
About half way home, I got some drastic bogging, so I pulled over, and the engine died (just like with Vv clearance issues). I checked the drain again, completely full. So I drained it, and put the cap in my pocket. No further issues, and slightly more power all the way home.
I've not ridden through any puddles. It's not rained. The weather is just warming up slightly. The bike is always either in the garage, or under cover at work. There's nothing changed, other than the impromptu "free flow" exhaust. What could be generating this much water in the Vv space, to the point where it locks the engine?
Thanks for your help, sorry for rambling,
Ian
EDIT: it's a 125cc Pulse Lightspeed 2, if that's useful.
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Post by xylon on Apr 8, 2013 5:47:47 GMT -5
Um without the plug won't air get sucked in though the tube, negating the air filter?
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Post by wilds on Apr 8, 2013 7:33:29 GMT -5
It shouldn't fill up that fast...
Have you changed the oil, if so you might have overfilled it and check the oil level.
The oil in the tube gets sucked into the carb when it's overfilled and that is probably the reason why the engine stops...
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Post by ridecheap on Apr 8, 2013 10:05:48 GMT -5
The fact the air filter is saturated with oil is not a good thing at all. Someone posted this when they tracked down the cause of that:
I took it outside and started it up and wow did I ever see a problem. As I mentioned above the valve cover vents down to a small reservoir which then is vented up to the airbox and it also has a large clear drain tube and plug. I stared it up with airbox connected to the carb and right away that tube filled with oil. I removed the connection from carb to airbox so there is no air intake and it still filled. I then removed the plug and drained the oil out of the tube and left the plug off. I started the engine and oil was blowing out of the tube like spray paint
Turns out the bike needed new valves.
There it was, the top ring was somewhat functional but the second was totally stuck and there were scorch marks and smearing on one side of the piston
When it seizes up that is telling you somehing
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Post by payneib on Apr 8, 2013 10:10:00 GMT -5
It shouldn't fill up that fast... Have you changed the oil, if so you might have overfilled it and check the oil level. The oil in the tube gets sucked into the carb when it's overfilled and that is probably the reason why the engine stops... Facepalm. Yes, yes I have. Although its at the usual level. I'll double check it, and maybe drain a little off. Thanks mate. Ian |
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Post by payneib on Apr 8, 2013 10:29:35 GMT -5
I stared it up with airbox connected to the carb and right away that tube filled with oil. I removed the connection from carb to airbox so there is no air intake and it still filled. I then removed the plug and drained the oil out of the tube and left the plug off. I started the engine and oil was blowing out of the tube like spray paint It's not as bad as that, but I'll check my oil level tomorrow, and then test with/without the air box on just to be thorough. I've got a maintenance day tomorrow anyway, once Mr FedEx arrives with my exhaust parts. Ian |
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Post by rockynv on Apr 8, 2013 21:18:26 GMT -5
Valves too loose will cause excessive blow by and filling of the purge tube as will a heavy hand on the throttle with a cold engine which may also show a lot of water vapor in the purge tube. A one time overfill with oil can snap the bottom oil ring and make this worse especially when the engine is first started.
Your symptoms on an air cooled 125 lends to water vapor blow by from too much throttle on a cold engine with the possibility of valves set too far open and maybe rings that are marginal. Taking the cap off will probably mask the problem and run you a bit lean. You need to find the source of the excessive crankcase pressure/blow by. You could even be looking at water vapor in the gas tank getting recirculated into the crankcase.
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Post by payneib on Apr 8, 2013 21:53:46 GMT -5
Your symptoms on an air cooled 125 lends to water vapor blow by from too much throttle on a cold engine with the possibility of valves set too far open and maybe rings that are marginal. Taking the cap off will probably mask the problem and run you a bit lean. You need to find the source of the excessive crankcase pressure/blow by. You could even be looking at water vapor in the gas tank getting recirculated into the crankcase. That sounds plausible. Since the exhaust went, I've avoided warming it up properly due to the embarrassing nature of the noise. I don't think it's the fuel tank: I do a 90mile round trip on a 1 gallon tank, so it's fresh petrol every day. WRT the valves, where's the TDC mark on these? I can't seem to find a way of getting the fan cover off, but it does have a view port at about the 10-11 o'clock position. All I can see in there is an electrical striker plate just behind the fan, which I assume is for timing. I hope it's not the rings. That would require expenditure and time I can't afford at the moment. Things to do tomorrow: Check oil level, drain if necessary. Check Vv clearance, adjust as necessary. Replace exhaust down tube and gaskets. Warm engine and test run, looking at breather drain tube specifically. Anything else that won't require a full strip down and re-build? Thanks for your help guys, Ian |
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Post by xylon on Apr 9, 2013 5:39:52 GMT -5
Mine was 2/3 full after 400 miles. Is that bad?
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Post by payneib on Apr 10, 2013 10:14:48 GMT -5
Turns out it was the Vvs. The intake was bent slightly, I didn't detect anything on the exhaust. I tried straightening the bent one, it ran for a while then died.
The intake is now very bent, timing chain has snapped and the intake tappet has snapped off and disappeared.
It's going back to the dealer on warranty. Will still cost me £180 on transport costs though.
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