41 replies to this topic

[Shamrock]

Hi All,

I thought it was time now to fix the oil problem. Been searching the forum a bit but seems
it's just a matter of pulling everything apart and see how it looks and act accordingly.
The idea was to put all my findings in this topic for future help.
My TDM is from '98 and taking about 1dl every 250 km and smells bad, I've been told

Started today by checking the compression. Drained cooling fluid and removed radiator first for better access.
Cylinder 1 checked out to give about 1 bar and after the oil squirt about 2 bar.
Cylinder 2 gave about 7.4 bar and after oil squirt about 7.7 bar.
So no doubt something is wrong here and it will be interesting to see what happened to cylinder #1.

My TDM was still going strong before the winter started so I'm quite confused with the result from cyl #1.

To be continued .....

[wicklamulla]

Hi All,

I thought it was time now to fix the oil problem. Been searching the forum a bit but seems
it's just a matter of pulling everything apart and see how it looks and act accordingly.
The idea was to put all my findings in this topic for future help.
My TDM is from '98 and taking about 1dl every 250 km and smells bad, I've been told

Started today by checking the compression. Drained cooling fluid and removed radiator first for better access.
Cylinder 1 checked out to give about 1 bar and after the oil squirt about 2 bar.
Cylinder 2 gave about 7.4 bar and after oil squirt about 7.7 bar.
So no doubt something is wrong here and it will be interesting to see what happened to cylinder #1.

My TDM was still going strong before the winter started so I'm quite confused with the result from cyl #1.

To be continued .....

do u mean 1 litre every 250 km's ???

[tdm850rider]

do u mean 1 litre every 250 km's ???

I think he meant deca-litre.

A litre every 250km would be like having a hole in the sump. We don't use deca-litres here but I think that would be a litre for every 2,500km.... (I didn't get a calc out) is that reasonable?

[wicklamulla]

hey i just realised we have more than 1 member from Uppsala on here now !! welcome Shamrock.

[Shamrock]

It's called deci-liter, 0.1 liter. I think a deca-liter equals 10 liters.

I was thinking to pressurise the cylinder and check where it's leaking.
But on the other hand, I will have to take everything apart anyway.

[wicklamulla]

It's called deci-liter, 0.1 liter. I think a deca-liter equals 10 liters.

I was thinking to pressurise the cylinder and check where it's leaking.
But on the other hand, I will have to take everything apart anyway.

f

ya may aswell fit TDM 900 barrels and pistons while ya have it apart.

[Shamrock]

It sound like a good solution.
I saw you had yours fitted last year. Did it all work out?
I contacted a dealer here in Sweden and mentioned the 900 barrels
when asking for a quote on parts but there was no reply on that so I assumed it was not
possible.
How much did all your replacemend parts cost?

[wicklamulla]

It sound like a good solution.
I saw you had yours fitted last year. Did it all work out?
I contacted a dealer here in Sweden and mentioned the 900 barrels
when asking for a quote on parts but there was no reply on that so I assumed it was not
possible.
How much did all your replacemend parts cost?

i have yet to fit my 900 parts. Emmett has done it recently though.

[Stink-Foot]

Started today by checking the compression. Drained cooling fluid and removed radiator first for better access.
Cylinder 1 checked out to give about 1 bar and after the oil squirt about 2 bar.
Cylinder 2 gave about 7.4 bar and after oil squirt about 7.7 bar.
So no doubt something is wrong here and it will be interesting to see what happened to cylinder #1.

You propably have at least one valve not closing properly on cyl #1. I rebuilt my engine last winter becouse of high oil consumption. A few of the exhaust valves were leaking, which was sort of a suprise since they had never needed adjusting. Valve stem rubbers were shot which must have been one of the reasons for burning oil. I had all of the valve seats and valves recut and cylinders rehoned, and fitted new piston rings & pins. It used a little bit of oil for the first two oil changes (not enough to need a refill though). I've ridden about 20 000km since the rebuild and for the last 10k oil consumption was really negligible, it lost perhaps 2 mm on the dipstick over 5000km.

Machining of the head and barrels cost about 160€, parts including a new cam chain and all of the gaskets were perhaps 200€. I bought the cam chain and most of the gaskets from KEDO. Yamaha charges quite a lot more for them.

Fitting the 900 barrels might be a better long term solution but simple rebuild is cheaper.. I guess it all depends on how much time and money you're prepared to spend.

[Shamrock]

If possible I would like to skip the bore-up of the cylinders.
This saves me about 180£ just for the bore-up (70£) and two pistons (110£). The rings
I need anyway.
Stink-foot, did you check your cylinders for ovality?
So I guess if the valve is fu@¤ed, the whole head needs to be reworked.

[Stink-Foot]

Stink-foot, did you check your cylinders for ovality?
So I guess if the valve is fu@¤ed, the whole head needs to be reworked.

Cylinders were measured at the machining shop. They were slightly oval, 0.01 - 0.02 mm if I remember correctly. Still below service limit according to Haynes so I just had them rehoned. Old honing marks were clearly visible back then at 65 000 km and there weren't any deep scratches. The cylinders were in a lot better condition than I expected. Pistons seemed to be fine too, and rehone + new rings cured the oil consumption.

Head rework isn't as big of a job as it sounds. Very basic for a shop with proper tools and experience. Just don't take it to a bike shop, they'll rip you off! Oh and don't bother to try lap them yourself.

Once you have the head off, pour petrol or something similar in the combustion chamber and see if it leaks past the valves. It should be easy to see which, if any, valves are leaking. Of course you could have just the leaking valves done, but personally I would have them all reworked. No point in saving pennies if you then have to do it again next year.

[dandywarhol]

Cylinders were measured at the machining shop. They were slightly oval, 0.01 - 0.02 mm if I remember correctly. Still below service limit according to Haynes so I just had them rehoned. Old honing marks were clearly visible back then at 65 000 km and there weren't any deep scratches. The cylinders were in a lot better condition than I expected. Pistons seemed to be fine too, and rehone + new rings cured the oil consumption.

Head rework isn't as big of a job as it sounds. Very basic for a shop with proper tools and experience. Just don't take it to a bike shop, they'll rip you off! Oh and don't bother to try lap them yourself.

Once you have the head off, pour petrol or something similar in the combustion chamber and see if it leaks past the valves. It should be easy to see which, if any, valves are leaking. Of course you could have just the leaking valves done, but personally I would have them all reworked. No point in saving pennies if you then have to do it again next year.

An easier method is to pour petrol/paraffin down the ports - and watch for it coming into the combustion chamber - easier to see that way

[Shamrock]

Had another question .........
What's the general opinion regarding non-original parts eg. a gasket set.
I got one offered for about 70£, including valve seals and that's where i get a bit
worried as well. I don't want to replace valve seals again next year due to bad quality parts.
But on the other hand, original is no guarantee either.

[Stink-Foot]

Had another question .........
What's the general opinion regarding non-original parts eg. a gasket set.
I got one offered for about 70£, including valve seals and that's where i get a bit
worried as well. I don't want to replace valve seals again next year due to bad quality parts.
But on the other hand, original is no guarantee either.

Again I recommend KEDO, many of the gaskets they sell are actually genuine Yam ones but cheaper. Valve stem seals weren't terribly overpriced from Yamaha if memory serves, but for example the valve cover gasket cost me 40€ ! (finally had to change it after re-using several times)

I have no experience with gasket sets although I've heard bad things about Athena quality from thumper riding friends. You don't need a complete set for just top-end rebuild, but I think buying all of the necessary gaskets original would cost more.

[ChrisG]

You propably have at least one valve not closing properly on cyl #1.

Sounds like rings as well as the valves though to get the increased compression with the oil.

I fitted new rings in mine some last winter, and did a bit of a writeup here if it's any use. The head was coked up but none of the valves were leaking. Unfortunatly I could't find a local place that would hone the cylinders so had to send them off via a local bike shop. Rather embarrasingly I dind't really get a chance to use the bike much last year so have managed less than 100 miles since the rebuild, but it's not smoking on acceleration and after the initial couple of hundred miles I've not needed to top it up.

Edited by ChrisG, 07 February 2007 - 10:35 pm.

[Shamrock]

Interesting story Chris!
I took the head and cylinder off today.
The pistons look pretty ok I´d say, especially compared to yours.
The head is coked up. I´ll pour in some fuel into the ports tomorrow
and see if it comes out anywhere.
I´ll send them away next week to have the head fixed and barrels measured.

[Shamrock]

All the valves on cylinder #1 appeared to be leaking (explaining the 1 bar compression) and cylinder # 2 appeared ok.
Found one of the supports for the inlet cam-shaft damaged due to propably lack of lubrication (short period). It's like
it got scraped and there's also a scratch which can be felt with a fingernail.
I'm unsure what to do with it since it's impossible to replace anything besides the complete head?
Any ideas?

[jht]

All the valves on cylinder #1 appeared to be leaking (explaining the 1 bar compression) and cylinder # 2 appeared ok.
Found one of the supports for the inlet cam-shaft damaged due to propably lack of lubrication (short period). It's like
it got scraped and there's also a scratch which can be felt with a fingernail.
I'm unsure what to do with it since it's impossible to replace anything besides the complete head?
Any ideas?

Can you post up photo of said scratch?