TS 250 Oil Leak

[Puffs]

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[Kruh]

I see. Makes sense.
In my case the smoke is clearly visible at idle. But the idle doens't behave always.
So its surely carb related.

But now with fresh parts ig can only be better still...


Maybe the overheating would explain the first seal going bad.
But now that they wore a bit and only a short ride after with new seal, still leaks a lot. So they wouldn't explan it

[Kruh]

Update.
I've done close to 1000 kilometer with the bike now. The crank seal is bone dry.
No leaks. I guess that modification (hole in oil guide plate) made all the difference.


I've also been chasing a gearbox leak for a long while now. Replaced the seal and seal carrier gasket multiple times and coated many parts with sealant, yet a few drops of oil would always appear below the bike. Coming from the side cover.

I finally figuered it out. The shifter drum plug came loose.
A litlle bit of widening, thread locker, and hamering it in place, its all good.

Something to check when you fail to find the leak.

[Blurredman]

Hi,

Thank you for getting back to us after all this time.

It is interesting how your unorthodox method has worked, despite the theory...



As to your shifter seal.. Yes.. In the last year I have encountered a lot of people having the issues with the seal you have pictured.. The main reason: They have all split open the cases... This seems to disturb the seal somehow.


Anyway.. I rebuilt both my bike's engines some time back, and both were leaking from that same seal... For the one bike just recenter-ing the core plug with some taps on a drift seems to have done the trick there..

The other bike it's core plug is mashed up by a previous owner- so the next time I do an oil change on that bike I will be replacing it with a new core plug that I have already and all ready to install when that time comes.

[Puffs]

Good you found it, and I'm happy I've sofar escaped this particular valley of muck.

[Kruh]

Small update.
Its been 2 years and about 4000 km, the seal is still godd and dry. Now I'm even more confident in saying that my unorthodox method did work.

Unfortunately, due to a separate issue I was forced to dissassemble the engine. But, it gave me a chance to take a good look at everything.
Everything was in great condition, except the main issue, which is the connecting rod developing quite a bit of play. The needle bearing was not damaged, but there was a bit of pitting in the conrod bearing surface. The crank is the original 42 year part, its done almost 30 000 km (acording to the odometer). However, the bike sat in a shed for more than 15 years, so even though on the initial dissasembly of the engine there was no play, corrosion seems to be the main culprit. Which helped to accelarate the wear once the bike got back in use.




Here's the picture of that oil guide plate and the aforementioned hole:

[Puffs]

Removed

[Blurredman]

Ah yes, this is one reason I decided to rebuild my ES250/2 straight off the bat (not used in 40 years, plus guaranteed water ingress- and indeed, I have the original big end bearing back and it was pitted and probably wouldn't have lasted long). As Puffs says, at first everything seems within spec but the use after slight rust, creates pitting and then the tolerances become too big.. A bit like grinding your teeth together, the non smooth surfaces contact and influence.


I think I was lucky with my ETZ251. Although I did later re-build that engine, I did some 12,000 miles on that engine which hadn't been used in 13 years, I do wonder actually how long it might have lasted otherwise..


I notice you put RTV over the core plug. After replying last to this topic, I did replace the one on my ETZ250 and I do believe I also had to use extra sealant (I don't honestly remember, i'll have to check) - I don't seem to have any leaks, but still have problems even after replacing the one on my 251 (previously mentioned it has been messed up by a previous owner somewhere down the line). I'll be using some epoxy there I think when I get around to it...