Yamaha TRX850 Enthusiasts Forum

Ive got a yamaha trx850 (same as tdm850 engine). I've recently had it apart due to a few problems and having reassembled it im still having the same problem i had prior.

Basically, the window in the sump wont indicate any oil even though ive filled with the specified amount and circulated throughout the bike.

The return pump is certainly pumping oil having disconnected the return hose whilst running the bike but its just not coming up in the window apart from when i initially filled the bike with oil.

I have replaced the oil pump, bled the engine as presribed in mr haynes, but still, no oil seems to be coming through to the window.

Any ideas? im stumped!

G'day Thom!

It's a dry sump engine, so you need to run the bike for 10 mins, then shut if off & check the oil, is this the method you used?

Thom wrote:bled the engine as presribed in mr haynes,

Not sure what you mean this, can you elaborate?

Thom wrote:Basically, the window in the sump wont indicate any oil

I assume you mean the window in the holding tank? or maybe there is a window in the sump, mine maybe a special. (I hope not, as I have never seen it.)
Not helping?

Do a search cause there are the odd one or two threads on this very subject.

When I do an oil change I put in 3.8 litres of oil,run the bike for a couple of minutes, then recheck the oil window which is usually got nothing in it. I then top it up with the extra .2 of a litre which brings it up to the mark.

G'day Thom,
The bike needs to be vertical, on level ground, put a chock under the side stand to get it near vertical, front wheel in line with back wheel, crouch down on the right side of bike, you need to be able to see the oil level window, hold right bar and apply F/brake, left hand to a frame rail, then gently pull bike toward you, you will feel when the bike is vertical.

sorry lads, ive been calling the oil tank the sump by mistake, i do know the difference but id had a drink by the point of posting

and when i say bled, to avoid air locks there is the m8 bolt you unscrew on the cylinder head to ensure oil is circulating fully.

Oh and thanks, i didnt realise you had to run it for 10mins to get a decent reading. ill try that but i didnt want to make the bike go pop in trying

Thom wrote:sorry lads, ive been calling the oil tank the sump by mistake, i do know the difference but id had a drink by the point of posting

and when i say bled, to avoid air locks there is the m8 bolt you unscrew on the cylinder head to ensure oil is circulating fully.

Oh and thanks, i didnt realise you had to run it for 10mins to get a decent reading. ill try that but i didnt want to make the bike go pop in trying

It's a good idea to get into the habit of checking the oil right after a ride, that way the engine is good and hot. I used to stop the engine, get off the bike and check it straight away- all you have to do is ease it up off the sidestand and use your body to stop it falling over

Bit of a misunderstanding about the GALLERY bolt on the left hand side of the head. It does not 'bleed the engine' to ensure oil flow but as the name GALLERY bolt suggests gives a visual check that oil is getting there. Just a point.

Cheers, Andy.

Cheers guys,

i cant very well ride the bike yet incase there is an oil problem, and its running a bit rough so i need to sort that first but oil is getting to the head as the gallery bolt is allowing oil passed when backed out. i'm unsure how to check its getting into the sump to ensure complete circulation, should i simply check oil flows from the sump bolt?

Otherwise if this is okay i may just get running the bike, ride it a short while to get it hot and then try checking from there, maybe this is all it needS?

Thom wrote:Cheers guys,

i cant very well ride the bike yet incase there is an oil problem, and its running a bit rough so i need to sort that first but oil is getting to the head as the gallery bolt is allowing oil passed when backed out. i'm unsure how to check its getting into the sump to ensure complete circulation, should i simply check oil flows from the sump bolt?

Otherwise if this is okay i may just get running the bike, ride it a short while to get it hot and then try checking from there, maybe this is all it needS?

You do need to run the engine to check the oil, you can't do it from cold. If it's getting to the head, and there are no leaks and it's not being burnt, then it must be circulating surely?

Yep, has to be, especially as it`s been established that it`s returning to the oil tank (after the oil return hose was disconnected).
What I find weird is that no oil shows in the oil tank window when the engine`s running, can`t be enough oil in it.

4litres in there mincehead mate!

which is more than should be anyway and i darent go any further.

It has been suggested on another forum that a one way valve may be missing/damaged - does such an item exist as this would explain my problem surely as then any oil would simply flow back to the sump?

The oil pressure relief valve? See from page 36 on, although I`ll admit some of those Yamaha diagrams are shite:

http://www.motomaniac.net/trx850/hosted ... manual.pdf

I`ve been wondering if it`s `sumping`, the only way you`ll know is if you can nip the oil hose closed (the one from the rear of the oil tank along the flexible section) with some mole grips lined with a strip of rubber. That`ll stop oil getting to the motor, then take off the oil filter housing and the drain plug on the left side of the motor and see how much oil is in the motor only as opposed to the motor and tank combined.
If virtually all your 4 litres comes out of the motor and you`re certain you`ve stopped oil flowing from the oil tank you can suspect the pressure relief valve.

Mincehead, lead me double check before i do anything silly...

Nip the Oil tank-Oil pump hose closed to stop oil leaving tank.

Drain oil from oil filter housing as well as the drain plug on the LHS of engine

Check amount of oil

If about 4litres comes out then i suspect pressure relief valve is open and meaning oil is returning to sump.

How much should i expect to come out if the valve is shut? hardly any?

Complete oil change requires 4.2 Ltrs of oil - if you've done a complete oil change with 4 Ltrs you could be almost 1/4 Ltr short? I usually only put 4 Ltrs in on a change & it's fine but you never know?

Hold on, 4.2litres?!

haynes didnt tell me that :/