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Bikes, Pictures, Stories & more => All Other Bikes => Topic started by: A10 JWO on 09.07. 2019 17:30

Title: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO 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.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: JulianS on 09.07. 2019 18:06
Check the oil seal in the circular plate behind the clutch.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO 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. 
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: chaterlea25 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
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO 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.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Rex 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.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO 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.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO 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.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Greybeard on 11.07. 2019 17:44
Gear oil has a distinctive smell
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO on 11.07. 2019 18:08
Hi Greybeard. Never thought of the smell test, back in the cave tomorrow, thank you.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: RDfella 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.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Greybeard on 11.07. 2019 22:42
Yes, gear oil has a distinctive smell, but who puts gear oil in their gearbox?
Me
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: ironhead on 11.07. 2019 23:01
me too
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: trevinoz on 11.07. 2019 23:13
And me.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Brian on 12.07. 2019 04:25
And me also.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Angus on 12.07. 2019 08:23
plus one :)
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Rex on 12.07. 2019 16:26
So do I, where the engine and gearbox oil are separated.
I doesn't seem too matter too much where the engine and gearbox oils are mixed though... ;)
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO on 12.07. 2019 17:22
Am I right in thinking that the gearbox oil seal is fitted from the outside behind the clutch or inside prior to assembly of the gearbox. Thank you.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: chaterlea25 on 12.07. 2019 20:55
Hi A10JWO,
I think the seal can be changed without splitting the gearbox
Oil can and will leak out if the sprocket nut comes loose or even along the sprocket splines
later Triumphs have an O ring on the assembly to help stem the flow
Some sealant helps too
If the sleeve gear bush is worn where it goes through the sprocket inspection plate it will chew up the seal there

John


Title: Re: Triumph 500 Unit strange oil leak ?
Post by: RDfella on 12.07. 2019 20:59
Those who use gear oil in their 'boxes, what grade do you use? EP90?
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Rex on 12.07. 2019 21:35
Am I right in thinking that the gearbox oil seal is fitted from the outside behind the clutch or inside prior to assembly of the gearbox. Thank you.

Outside prior to the clutch assembly. If you strip out the clutch assembly and remove the primary chaincase circular door and the gearbox sprocket it's usually possible to remove and replace this oil seal. Don't forget there's another smaller oil seal in the removable chaincase door.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO on 12.07. 2019 22:45
Thanks lads, now a midweek job. Appreciate all replies.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: Greybeard on 12.07. 2019 23:00
Those who use gear oil in their 'boxes, what grade do you use? EP90?
Yup
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: ironhead on 13.07. 2019 00:29
penrite 80w90
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO on 13.07. 2019 15:49
To conclude ( I think ) I drained the gearbox which was full when I went out last time. Today I got an egg cup full out of the drain plug. New seal ordered. Will have to get some Gunk as well to remove the EP90 from the rear of the bike. Thanks for all replies.
Title: Re: Triumph 500 Unit strange oil leak ?
Post by: A10 JWO on 24.07. 2019 16:03
Stripped the gear box completely, the leak was out of the blind bearing that pushes into back of the gearbox. Removed and refitted with sealer. I now have a happy gearbox. A few hours work for the sake of some sealant. Thread complete, I hope.