Author Topic: Triumph 500 Unit strange oil leak ?  (Read 447 times)

Offline A10 JWO

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Triumph 500 Unit strange oil leak ?
« on: 09.07. 2019 17:30 »
The engine was rebuilt in 2014 and not run very much at all. Previous keeper made me aware of a strange oil leak only when it is ridden. I took it out for a decent run for the first time and found that the bottom frame tubes by the side stand were slightly coated in oil. The primary looks oil tight as does the crank cases. I can't see a chain oiler and get the impression it's coming from the back of the motor clutch side. There was no leaks when it wet sumped sitting for 5 years. Any ideas please.

Online JulianS

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Re: Triumph 500 Unit strange oil leak ?
« Reply #1 on: 09.07. 2019 18:06 »
Check the oil seal in the circular plate behind the clutch.

Offline A10 JWO

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Re: Triumph 500 Unit strange oil leak ?
« Reply #2 on: 09.07. 2019 22:16 »
In theory, it would be red oil if that was the case, however it does get dirty quick. Will double check thanks. 

Online chaterlea25

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Re: Triumph 500 Unit strange oil leak ?
« Reply #3 on: 09.07. 2019 22:24 »
Hi A10 JWO,
Could it be the front fork leg leaking and blowing back ?
I had another strange one where oil travelled up the rev counter cable and leaked out a crack in the plastic and blew back onto  the engine *conf2* *conf2*

John
1961 Super Rocket
1963 RGS (ongoing)

Offline A10 JWO

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Re: Triumph 500 Unit strange oil leak ?
« Reply #4 on: 10.07. 2019 13:38 »
Thanks John, it is an odd one, more of a spray from somewhere. Everything around the barrels is dry as a bone. Your answer is appreciated.  Does anyone know if these engines had any sort of breather apart from the spring loaded one at the front of the engine. Thanks.

Offline Rex

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Re: Triumph 500 Unit strange oil leak ?
« Reply #5 on: 10.07. 2019 18:20 »
The breather on the older 500s is a timed disc on the end of the inlet cam and the pipe for that exits behind the primary case. The later units 68-69(?) had the crankcase venting into the primary and the pressure vented via a hose to the rear numberplate area.
Storing the bike on the side-stand causes oil pooling in the cam area and oil being vented out via the breather when you start it.

Offline A10 JWO

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Re: Triumph 500 Unit strange oil leak ?
« Reply #6 on: 10.07. 2019 22:22 »
Rex. you are a star, that seems to be a good start. I am not losing much oil at all it is just a bit messy. Is there a picture or drawing of the exit point I can look at to compare. Thanks again.

Offline A10 JWO

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Re: Triumph 500 Unit strange oil leak ?
« Reply #7 on: 11.07. 2019 16:25 »
Found the breather pipe and connected a rubber pipe to it. Started up and nothing came out. I got right under the bike and could see fresh oil near the drive sprocket and local casings, oil on the back rim and swinging arm. My oil level in the tank is good, I am wondering if the person that fitted this brand new wide ratio gearbox ( £600's worth ) never changed the £3.00 oil seal. As stated this leak is only when the bike is being ridden. Please keep replies coming, thank you.

Online Greybeard

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Re: Triumph 500 Unit strange oil leak ?
« Reply #8 on: 11.07. 2019 17:44 »
Gear oil has a distinctive smell

Offline A10 JWO

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Re: Triumph 500 Unit strange oil leak ?
« Reply #9 on: 11.07. 2019 18:08 »
Hi Greybeard. Never thought of the smell test, back in the cave tomorrow, thank you.

Online RDfella

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Re: Triumph 500 Unit strange oil leak ?
« Reply #10 on: 11.07. 2019 20:33 »
Yes, gear oil has a distinctive smell, but who puts gear oil in their gearbox? Our bikes use engine oil. My B31 hill-climber uses R40.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online Greybeard

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Re: Triumph 500 Unit strange oil leak ?
« Reply #11 on: 11.07. 2019 22:42 »
Yes, gear oil has a distinctive smell, but who puts gear oil in their gearbox?
Me

Online ironhead

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Re: Triumph 500 Unit strange oil leak ?
« Reply #12 on: 11.07. 2019 23:01 »
me too
SA

Offline trevinoz

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Re: Triumph 500 Unit strange oil leak ?
« Reply #13 on: 11.07. 2019 23:13 »
And me.

Online Brian

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Re: Triumph 500 Unit strange oil leak ?
« Reply #14 on: 12.07. 2019 04:25 »
And me also.