2 Stroke oil in Exhausts

[Wilf]

OK, bless me for I have sinned, I bought this particular 2 MA in 2019, where does the time go? briefly, it was ride-able but lacked a lot of performance and required replacement Pipes as the YEC race pipes were crap on the road and a major carb rebuild. I ordered the carb kit and stripped the carbs down then got way laid with other bikes, life and work so that is how it sat......for 5 years
My conscience got the better of me and just before Christmas got in on the bench to finally get it sorted once and for all, and have done quite a bit of work to it. Today I felt I was at a point to give it an engine start, as I said it was was running sort of OK 5 years ago so it was only going to be carb rebuild issues I thought, after quite a few kicks it did actually fire but for the few revolutions it did not sound good. I notices dripping from the engine and further investigation revealed it was coming from the exhaust near the seal. I removed both exhausts and tipped about half a cup of two stroke oil from each side (and they were new exhausts) so my questions are.
Do you think that in the 5 years it has doing not a lot allowed  two stroke oil to slowly siphon into the crank case? if so I am surprised it managed to go through the oil pump but I cannot think of other way oil has made it way there.
I am going to have to take off the head and barrels now as I am sure the crank case is full of oil, but then what? would I be able to get the oil out of with the engine in situ and flush it with petrol or would it be better to take a backward step, remove the engine and have a better chance of flushing out the crank case?
The last worry is that the brief firing has caused some hydraulic compression to the engine, something that can happen to four strokes when you get water in the engine, the difference being it was oil in mine.
Has anyone else had this issue with their bike?

[tzr-v4]

All Yamaha oil pump will leak oil when not used.
The one way valve (spring + ball) is not 100% working (even new ones).

Here is a link to 3XV oil problem.
https://pure2strokespirit.net/forums/index.php?topic=8666.msg82963#msg82963

[Wilf]

Merci.

[biggz]

I had a problem with oil in a crankcase - perhaps not as much as yours - but pulled the reed out and went in with this, several times, until there was only a smear visible. Friendly farmers' co-op supplied the syringe body without enquiring as to why an obvious non-farmer might want such a thing...

Best of luck

Laurie

[Old fella]

Hi Wilf, my experience was the same as yours. I'm not sure how long it had been since my TZR250 had run when I bought it but mine had been converted to run on premix. The fuel tap was faulty (leaking) and I presume the fuel had gone down into the carbs and then into the crancase. I first noticed that the crank had red oil over the lobes when I removed the reeds for inspection and could see inside. I wiped as much of the oil off as possible but the thing smoked like fury when I started it up for the first time. I decided to remove the engine for all sorts of reasons and when I turned it upside down more red oil came dripping out of the intakes. Since then I've converted it back to run with the autolube pump.

[Wilf]

Thanks for the responses, I also posted it up on the facebook 1KT 2MA page and I think I have decided the way forward, I will let you know the outcome. One lesson is not to leave bikes sitting for years on end and I would not be surprised if I got some abuse for it, it would be deserved too.

[m in sc]

yup. they all do it, all the way back to my 67 when they sit for that long (to a degree).

when getting one that has sat forever, i always pull the plugs and kick it over by hand, usually will puke a lot out that way w out the risk of bending a rod. (if its leaked down).

[tzr-v4]

On the TZR250 1KT / 2MA and RD500, the fuel petcock can by modified to remove PRI (prime) position and have only :
 - ON
 - RES
 - OFF

No more need of vacuum hose and no more fuel leak

tzr250-fuel-tap-modified

tzr250-taps-left-standard

[Rasher]

Where can you get these modified fuel taps?

Had a nightmare with mine intermittently going on one cyclinder, took ages to discover it was intermittently letting fuel get into the vacuum hose.

Been trying to find an alternate tap as mine is shagged, even a rebuild kit has not stopped it leaking a bit externally and a new Yamaha one is £100!

[tzr-v4]

If the inside rubber parts are not gone then modification is easy :

Steps :
1- Unscrew the 2 small screws
2- Clean the inside
3- Check the o-ring seal on the brass cylinder
4- Bend the spring to give extra force to push the cylinder and o-ring in the hole
5- Turn the chrome plate upside-down (rotate 180°)
6- Screw the 2 small screws

Job done (back to OEM is possible)

Leakage can come from the O-ring not well inserted or the membrane.

Check the 2 positions => PRI should be OFF now.

Modified

[Wilf]

UPDATE

Took the plugs out, cranked it looking for oil and to my surprise not much if any at all, I think it all went into the exhausts first time round.
Replaced the pipes and plugs and went for another restart, a bit slow to get going which is not surprising as it was flooded with oil previously but now running and even ticking over quite happily. OK it smokes like a steam train but time and heat will sort that out I am sure. At least I know the carb and petcock rebuild was a success, next job, seal the pipes properly and get the front brakes rebuilt and then possibly a run up the road....if we ever get a dry day!
Thanks for the reassurances form everyone, you can over think some things

[Arrow]

Hi, I offer a full restoration service on the oil pumps. Pm me for details.

[teezer250]

I can recommend Arrow for oil pump rebuilds as he did 2 of mine around 6 years ago.