Crank oil seal. Nitrile or Vitron ?

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As title really, need to replace the right crank seal but the local bearing company have asked me if i need a nitrile or vitron.
They also want to know if it's a single or double lip?

Nitrile seems to be for use in fork seals e.t.c., but because (i'm assuming) the crank seal will have to deal with quite a bit of heat?? they say i might need the vitron...

Any advise on this ?

Thanks
Dave
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DRZ-400sm

[Blau Zedong]

[Robby]

I think, although I can't be totally sure, that viton is better at resisting petrol over time. Good in a 2-stroke. Carb needle valves are viton tipped.

If the shop recommend it, I would go with the viton.

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Cheers robby,

The reason i'm asking is because someone on the dt125 forum (which is what this seal is for btw) linked to the nitrile one. He has used that in his and i'm assuming it's been fine but i don't want to take a chance on what he's fitted as in his guide he has the wrong sized bearings and oil seal wrote down
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DRZ-400sm

[Ariel Badger]

Viton will not cost very much more than Nitrile and compared to the time it will take if you need to strip the bike again if it fails it is a wise investment.
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Bikers make great organ donors, get 115 on your licence today.

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Ahh well, viton it is then ; Which the fookers don't have in stock
I am curious wether yamaha have used the viton though...

The next question is if it is actually the crank seal. Is there anyway of knowing for sure it is that without stripping it?

At the moment it's losing the oil within about 10mins of running (it goes from half to just visable on the sight glass) but there is no leaks anywhere else.
Theres no visable smoke outta the exhaust though, and no oil in the water... and other than getting spluttery above 8k rpm there are no other symptoms.
(Head & barrel has been skimmed with new genuine gaskets and piston/rings are within service limits)

cheers for the reply's anyway
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DRZ-400sm

[rodeobob]

You cant just buy any seal.


The seal you talk of is a double opposed seal, Not just a twin lip seal like the other side.. Dont let a bearing shop talk you into fitting two smaller seals back to back.



Go to a bike shop and order a new set of Pro-X viton tipped seals for it. Shouldnt be much more than 20 quid. This is the only source i have been able to find for these seals, they must get them specially made.
New O ring under the spacer is a good idea too. (yamaha part)


Now the reason it might need them. Has it been left sitting for a long time?? If it hasnt, the bearings on the crank are probably stuffed and the new seals will only patch it up for not very long. If theres slop in the crank seals wont save it.

If you are going to do one seal, pull the flywheel and do the other.

Check the play in the crank with the seals out of both sides.


Bob.
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DT200R '91
DT175 '91
Various IT/DT175 engines for 'projects'

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Cheers for the reply bob,

I'll just get onto yamaha and order them from there i think...
As far as i'm aware, you need to split the cases to replace the magneto side crank bearing ? which i don't really fancy doing but if there's any play in the crank i'll replace the whole lot anyway.

Just phoned yamaha and they want £17 just for the RHS seal but he say's if that was broke the bike wouldn't be idling properly aswell as being really smokey yet it's neither! (just passed it's mot aswell )
The coolant looks a little bit dark and there is a tiny bit of white creamyness in the oil, but certainly not enough to explain .75 litre of oil going missing within 5 miles!

https://i187.photobucket.com/albums/x13/fronterapics/DT125/Image1049.jpg

https://i187.photobucket.com/albums/x13/fronterapics/DT125/Image1048.jpg

https://i187.photobucket.com/albums/x13/fronterapics/DT125/Image1047.jpg

https://i187.photobucket.com/albums/x13/fronterapics/DT125/Image1046.jpg

https://i187.photobucket.com/albums/x13/fronterapics/DT125/Image1045.jpg
No, that's not jizz in the oil

There's definately no external leaks anywhere (cleaned and checked sprocket shaft e.t.c.) so where the hell is my oil going ?
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DRZ-400sm

[rodeobob]

Is the breather blocked or something similar, behind the tacho drive under the carb.
That could do funny things with oil level.

You should never get oil in the water. The oil is not pressurised so it can not get in there. The water is in a pressurised system so you could get water in the oil.
If you do get an oily film in the water it could be from the head or base gasket and the oil/fuel from the intake pressure. If water was getting into the crankcase the motor would probably stop due to a wet plug.


Is that bowl graduated?? How much oil came out??

Id pay little, no make the zero, attention to what the sight glass says. Its tucked away in there in that stupid spot with that spring hook on the back of the lever just begging to poke a bloomin hole in it. What a dumbarse idea.

Go buy a 4L bottle of Dextron II Automatic Transmission fluid and use that. (you know not to ue regualr car oil right?? ATF or propper 2T gearbox oil only) Measure it out and tip it in the bike. Ride the bike for say a day or a week. Drain into a container and measure. I thought my 200 was doing the same so i did that, it was all good. Got out what i put in, did it twice to be sure.


Doesnt sound like the problem anymore but still could be. Dont buy genuine Yamaha. get the Pro-X seals. Im sure they fit the blaster and they have the Viton tips on the seals because they got hot in the air cooled quad.



Yes you will need to split the cases to do the bearings, both of them.


It would probably idle bad if the crank seals were leaking. Thats right, but if its had the jetting altered to suit then it would not be so noticable. The seal could also be leaking only one way, sucking into the crankcase. Might be due to the wrong seal, or blocked breather.

You say about smoke, if your bike is jetted rich it might not smoke real bad, just dump all the oil into the exhaust. The temps are not high enough for things to be hot enough to make the oil smoke.




Go buy yourself a big plastic tub with a lid. Something big enough to put a spare air filter, filter oil etc, a couple of 4L oil containers and a few bits and bobs in. That will keep all your stuff together. The tub is mainly for the next bit, go buy a graduated measuring jug and a small funnel. (or pinch one from the kitchen, could get you in strife) Use it. Keep it in the tub and dust will not be alble to stick to the oil film. I usually wipe mine with a rag then stuff the rag in it then into the tub. Measure your 750ml in the jug, then with a funnel into the motor. Best thing is, all your stuff for you bike is in that tub and you know where it is all the time. If your running low on something you wil know.

Bob.
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DT200R '91
DT175 '91
Various IT/DT175 engines for 'projects'

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Cheers bob

When i first filled it up it took about 500mls but i then topped it up after a ride round the block and it took another 200mls. Then after another ride it took another 100mls (give or take X mls that i dropped on the floor through not catching it in time)
When i emptied it into the above bowl i then filled it back into the empty oil bottle (75/90 i think 2t box oil) it showed around 700mls.

It's still showing nothing in the sight glass but emptying it back into the bottle shows it at roughly 700mls, which is exactly how much the owners manual say's it needs...
So maybe it's not burning it at all! Something is not right though...

I'll run it for a little while and see how it goes. Will also go check the breather...

Thanks for the info...
Dave
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DRZ-400sm

[rodeobob]

Yep, pay no heed to the sight glass.


Change the oil regular, measure it out to check, and measure the new stuff back in.



Bob.
____________________
DT200R '91
DT175 '91
Various IT/DT175 engines for 'projects'