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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Mysterious oil leak at front of engine!
Post Info TOPIC: Mysterious oil leak at front of engine!
TTRfan


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Mysterious oil leak at front of engine!
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I refurbished a TTR for my brother-in-law Keith a few years ago. 

Great bike and he has been enjoying riding it, when he can't get out on his Duke that is!

However, from early on there was an oil leak which we put down to one of the banjos on the external oil line. However, Keith replaced all the washers with Dowty ones but the gentle oil weep continued.

The usual suspect is the decompressor plug but his engine was completely dry and oil free in that area.

The oil seemed to be around the front base of the cylinder.

Oil leak 1.jpg

Oil leak 2.jpg

 

We reluctantly came to the conclusion that the culprit was the cylinder base gasket and today was chosen for the strip and replacement.

Keith is quite a competent mechanic so I let him do most of the work and just handed him the tools he needed along with advice whether needed or not - oh yes, and play tea boy wink

Keith at work.jpg

 

He soon had the engine stripped and all was looking good "inside".

Engine stripped.jpg

 

We were hoping to find something obvious such as damage to the base gasket but, frustratingly there wasn't no

However having got this far we had no choice but to clean off the old gasket and fit a new one - this time with a bead of sealant on either side!

Keith got a bit carried away cleaning up the barrel and carefully scraped off the tensioner gasket not realising I didn't have a spare. Time to dig out a sheet of gasket paper I bought yonks ago and revive the long-lost art of making a gasket!

This involves using a ball pein hammer and tapping around the sharp edges of the casting to cut the gasket the correct shape. Sadly my small ball pein hammer seems to have disappeared and the bigger one I had wasn't ideal.

Making tensioner gasket 1.jpg

 

However, Keith made the best of a difficult job - photo below of the nearly finished gasket.

Making tensioner gasket 2.jpg

 

Keith finished bolting everything back together and, after turning the engine over a while without the petrol on to get the oil circulating, the TTR started and sounded fine.

I am waiting to hear if (a) the tensioner gasket worked and, more importantly, (b) if we fixed the leak!

A nice way to spend a day with good company and getting hands dirty on a TTR's internals biggrinbiggrinbiggrin 

Brian



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TTRHead


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I hate oil leaks.

Mine went at the base gasket. Cleaned the engine off and started the bike. I could see it weeping out. As you no the worst bit is getting the old gasket off!

I would say deffo the base gasket.

Nothing else it can be really. Although I have seen hairline cracks in the heads on XR400's but never TTR's

Gasket I bet ya

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TTRfan


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I think I am going to ask Keith to clean off my base gaskets in the future - he did a brilliant job in less than 20 minutes whereas it takes me at least an hour!



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ttr steve


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He can do mine as well!!

Nice Job, no pasties???



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MikeBarnacle


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My Bikes exactly the same at the minute! Can you rent him out for a day 😃

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Moo


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My bike is also exactly the same currently!

Does the rubber o ring also need replacing? I'm also in two minds whether to put new rings in while im in there...

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ttr steve


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Moo wrote:

My bike is also exactly the same currently!

Does the rubber o ring also need replacing? I'm also in two minds whether to put new rings in while im in there...

Worth doing and check your cam chain at the same time. 



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