ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
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Post by ronnie2735 on Apr 8, 2024 8:33:05 GMT 1
Hello
A few day ago i wen on the highway and the enging heatet up very fast above 6000 7000 RPM at around 100 kmh
is this normal?
tanks for awnsers greetings ronnie
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Post by arrow on Apr 8, 2024 9:08:09 GMT 1
What bike?
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ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
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Post by ronnie2735 on Apr 8, 2024 9:32:37 GMT 1
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Post by arrow on Apr 8, 2024 9:33:56 GMT 1
Most likely head gasket. Is it loosing any coolant?
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Post by lcmarky on Apr 8, 2024 10:27:44 GMT 1
Could it be a blocked thermostat? Bin the thing and have another try.
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Post by arrow on Apr 8, 2024 10:51:23 GMT 1
No thermostat as standard in the 250LC.
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ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
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Post by ronnie2735 on Apr 8, 2024 11:09:58 GMT 1
No thermostat as standard in the 250LC. How does the heat sensor work? Is it just jes heat or no heat? Here is the video of thr needel just going up I was on the high way and stoped flic.kr/p/2pHWzmJ |
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Post by arrow on Apr 8, 2024 11:44:13 GMT 1
Wow! When that happens, does the engine feel that much hotter to the touch, or not?
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Post by steve63 on Apr 8, 2024 13:10:32 GMT 1
If you're off down the highway/motorway and the engine is up to temperature the air going over the radiator should balance the heat being produced by the engine. If it doesn't then you are in trouble.
If you stop then the cooling air stops. If you switch the engine off until the gauge drops to bottom the stop then turn it back on again then it's not unlikely that it will go higher than before you stopped.
6000/7000 - 100kmph is not to strenuous for a 250 so I wouldn't expect the cooling system to be tested to the limit. High ambient temp?
Something to bear in mind is that if the wire from the temp sensor is grounded then the temp gauge will go off the top of the scale. It's one way to check the wiring. It will go back to the low stop when the power is turned off.
The wrong sensor could have been fitted. Someone's fitted a thermostat and it's faulty?
Is there any/enough water in it? Don't laugh. I was asked to ride an LC from the owners garage to someone else's for temporary storage because I was insured and he wasn't. About 2/3 miles up the road I started to get the feeling something was wrong. It turned out he had forgotten that he'd drained the coolant out.
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ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
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Post by ronnie2735 on Apr 8, 2024 14:03:51 GMT 1
Wow! When that happens, does the engine feel that much hotter to the touch, or not? about the coolant and heat, im at work rn but i will test it today
tanks! greetings ronnie
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Post by shaunthe2nd on Apr 8, 2024 16:00:23 GMT 1
Sensor or wiring problem I reckon. When you put 12v across 2 of the temp gauge terminals that's what you see, and how I test usually.
It's easy enough to put a laser temp gun to the cylinders to check it's not over heating.
My experience with the 4L1 guage is that they either work, or don't. When they don't they usually sit at zero and don't move.
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Post by chrisg on Apr 8, 2024 16:22:32 GMT 1
After seeing that, my first though is that it may be a faulty gauge or sensor and the bike isn't actually overheating.
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ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
|
Post by ronnie2735 on Apr 8, 2024 18:45:16 GMT 1
After seeing that, my first though is that it may be a faulty gauge or sensor and the bike isn't actually overheating. Is there an alternative tep gauge you woud recomend Shirt video of nothing leaking and about normal heat Heat: i can feel some warmth while riding on my legs but i think thats normal Tanks for the help Greetings ronnie flic.kr/p/2pHWVjk |
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ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
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Post by ronnie2735 on Apr 8, 2024 18:48:27 GMT 1
If you're off down the highway/motorway and the engine is up to temperature the air going over the radiator should balance the heat being produced by the engine. If it doesn't then you are in trouble. If you stop then the cooling air stops. If you switch the engine off until the gauge drops to bottom the stop then turn it back on again then it's not unlikely that it will go higher than before you stopped. 6000/7000 - 100kmph is not to strenuous for a 250 so I wouldn't expect the cooling system to be tested to the limit. High ambient temp? Something to bear in mind is that if the wire from the temp sensor is grounded then the temp gauge will go off the top of the scale. It's one way to check the wiring. It will go back to the low stop when the power is turned off. The wrong sensor could have been fitted. Someone's fitted a thermostat and it's faulty? Is there any/enough water in it? Don't laugh. I was asked to ride an LC from the owners garage to someone else's for temporary storage because I was insured and he wasn't. About 2/3 miles up the road I started to get the feeling something was wrong. It turned out he had forgotten that he'd drained the coolant out. It was prety war outside yes If i turn the engine on an of it goes up and down again A service might fix it maby its old coolingwater |
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ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
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Post by ronnie2735 on Apr 8, 2024 18:49:22 GMT 1
Sensor or wiring problem I reckon. When you put 12v across 2 of the temp gauge terminals that's what you see, and how I test usually. It's easy enough to put a laser temp gun to the cylinders to check it's not over heating. My experience with the 4L1 guage is that they either work, or don't. When they don't they usually sit at zero and don't move. What is a good operating temarature and whats to hot? |
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Post by shaunthe2nd on Apr 8, 2024 19:53:58 GMT 1
I'm away at the moment so haven't got access to the service manual.
From memory, normal temp range is circa 50-80deg C and when it gets to 100deg plus that's when it's overheating.
Hopefully someone will confirm.
When you do get overheating it tends to be a slow process and you will see the gauge slowly creep up over a few mins, not instantaneous.
Its like boiling a kettle, takes a while!
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ronnie2735
L plate rider.
RD 250 LC 4L1 1981 Enjoyer
Posts: 44
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Post by ronnie2735 on Apr 10, 2024 15:29:39 GMT 1
After seeing that, my first though is that it may be a faulty gauge or sensor and the bike isn't actually overheating. Is there an alternative tep gauge you woud recomend Shirt video of nothing leaking and about normal heat Heat: i can feel some warmth while riding on my legs but i think thats normal Tanks for the help Greetings ronnie flic.kr/p/2pHWVjkHow does the temp gaue work and is there an alternative you woud recomend?
ronnie
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Post by chrisg on Apr 10, 2024 16:10:43 GMT 1
Is there an alternative tep gauge you woud recomend Shirt video of nothing leaking and about normal heat Heat: i can feel some warmth while riding on my legs but i think thats normal Tanks for the help Greetings ronnie flic.kr/p/2pHWVjkHow does the temp gaue work and is there an alternative you woud recomend?
ronnie
It measures resistance and depending on the sensor temp it gives a different readout calibrated temp. If you dab the wire that goes to the sensor to earth , the gauge should read maximum hot. You can get additional back up "in line" ones to give a second reading if you lack confidence in the original. |
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Post by crogthomas on Apr 11, 2024 13:34:12 GMT 1
To answer your question in the video, yes that is the sensor cable in the middle. A single wire going to the brass sensor in the cylinder head.
It looks to me like the sensor wire is shorting to earth, which would make the gauge rise to it's maximum temperature. I would be checking the loom very carefully for points where it might have worn through and be touching the frame. It might only touch the frame when you are moving or there is a lot of vibration (i.e. over 7000rpm).
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