Oil overheating

Information relating to the Matchless G5 or AJS Model 8 350cc Lightweight
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Red Gauntlet
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Oil overheating

Post by Red Gauntlet »

I have noticed that after about 50 miles continuous riding on a warm day the oil overheats on my G5 making it seriously rattly, is this something others have found? Don't remember this happening on the old G2.
shifter
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Re: Oil overheating

Post by shifter »

Never happened with my Model 8 I use good quality branded sae 40

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jackstringer
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Re: Oil overheating

Post by jackstringer »

How hot is the oil getting? When was the last time you changed it? Is it the right grade?

I'm a G3 owner so I am used to having to adjust the thing to be ok when warm but just a little tight when cold.
Red Gauntlet
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Re: Oil overheating

Post by Red Gauntlet »

It's SAE 50 Castrol I have tried a Mobil multigrade 15W50 too but the same results, oil changed recently. Its fine for 40/50 miles or so then gets really rattly and the oil is way too hot, leave it 1/2 hour then ok again. Not hammering it, just cruising 40-50mph.
SPRIDDLER
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Re: Oil overheating

Post by SPRIDDLER »

Red Gauntlet wrote: Fri Jul 01, 2022 8:39 pm I have noticed that after about 50 miles continuous riding on a warm day the oil overheats on my G5 making it seriously rattly, is this something others have found? Don't remember this happening on the old G2.
I'm not being facetious but to state the obvious; if the oil is getting very hot it's because the engine is getting 'very' hot, perhaps due to wear or the current hot weather (if you are experiencing it).
It not easy from here to know what you mean by 'seriously rattly' but I would be inclined to ascertain the source of the 'seriously rattly' noise with a listening stick as even hot SAE 50 oil should still be doing its job.
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shifter
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Re: Oil overheating

Post by shifter »

My thoughts would be to check the timing is spot on & the carb i.e. jets as it may be running a bit lean causing the engine to get hot. I have done runs of over 100 miles in hot weather with a pillion on my model 8 and never had a problem overheating

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g80csp11
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Re: Oil overheating

Post by g80csp11 »

The Oil is supposed to get hot in the tank , that's one reason why there is a volume of oil and large surface area to loose heat
If you assume the engine gets to circ 80/90 deg C ( like a car engine) too hot to keep your hands on the crankcase then heat is transferred to the oil and away from the cylinder finning

The oil tank surface after a good run on a hot day will also be hot , certainly 50 -60 deg C ( hotter than the hot tap on domestic hot water system)

Assuming the engine still kicks over with out problem wen hot , and that the exhaust are not running blue then its probably Ok

As far as rattly engine goes , could be tappets need adjustment
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