Yamaha TRX850 Enthusiasts Forum

hi guys, whilst racing in the msv track day challenge at snetterton this bank holiday weekend we had to retire as were losing from the bike, gutted.
when i checked the bike over this weekend i noticed that there was lots of oil in the coolant bottle but not in the oil at all. Also i noticed that there was no oil in the oil tank so i suspect that the problem we had was oil starvation causing the engine to over heat. please can anyone tell me what damage might of occurred from this? as i am going to drop the engine this week and start pulling it apart. now i have oil in it it starts and ticks over fine with no rattling or smoke at all and doesn't overheat at all. also can anyone point me in the direction of where i can get parts from? called fowlers but parts were ridiculously expensive (£47 for a cam follower? x 10, yeah right). decent engines seem to be like rocking horse shit unless anyone has one for sale??.

Moving this to the "problems" area as that's the best place for it ... sorry I can't give advice though, but there are plenty here who will be able to help you

oil in your water sounds like a gasket problem

+1 on the gasket,
sounds like head gasket,
you wont really know what damage has been done till you strip it down, but the fact that its running is good! and fairly quiet is good too,
I would be looking for scoring on the crankshaft and bearing shells, if they are totally knackered then thats the main part that will condem the engine.
in saying that you might be lucky and have no damage at all, just depends on how much oil was left in it before it was shut down.
was the engine smoking badly before you stopped it? you might have burnt the oil and water in it and sent it out the exhaust

Left hand big end bearing is the first to go in my low oil experience.

YMMV, of course...

cal wrote:+1 on the gasket,
sounds like head gasket,
you wont really know what damage has been done till you strip it down, but the fact that its running is good! and fairly quiet is good too,
I would be looking for scoring on the crankshaft and bearing shells, if they are totally knackered then thats the main part that will condem the engine.
in saying that you might be lucky and have no damage at all, just depends on how much oil was left in it before it was shut down.
was the engine smoking badly before you stopped it? you might have burnt the oil and water in it and sent it out the exhaust

the engine doesnt smoke at all, it sounds nice whilst ticking over and revs up freely. it had no oil visible in the sight glass when we brought it in but did have at least 2.5 ltrs of oil left in the engine when i drained it down. i need to strip it down to replace any gaskets that could be mixing oil and water anyway and got a full gasket set inc valve stem seals delivered today so now i can get on with it. are there any signs that i should look out for if the main bearings have gone?

Its under load that you would notice the big end bearings knocking the most, but it is good if it runs and revs freely.
the fact that it still had 2,5 ltr of oil in it is pretty good also, and i would suspect that everything will probably be okay,
however you will only really know for certain if you strip the engine down completly so you can look at the big end bearing shells, if they are scored or damaged then you will need to get the crank reground with some oversize big end bearing shells to suit,
Given that it still had a fair bit of oil in it, and was probably still pumping that round the system, just that there was not enough oil in the engine to let it show in the sight glass i would be thinking that there was no damage done to the crank and it overheated due to lack of coolant.
IF it were mine I would be tempted to do the gaskets, clean out the rest of the system where the oil has got to and run it for a bit with fresh oil let it get up to temp, change oil and filter again.
As I said before though the only way to really be sure is to strip it down to the bones, damage due to no oil getting to the crank parts will be pretty obvious scoring.

cal wrote:Its under load that you would notice the big end bearings knocking the most, but it is good if it runs and revs freely.
the fact that it still had 2,5 ltr of oil in it is pretty good also, and i would suspect that everything will probably be okay,
however you will only really know for certain if you strip the engine down completly so you can look at the big end bearing shells, if they are scored or damaged then you will need to get the crank reground with some oversize big end bearing shells to suit,
Given that it still had a fair bit of oil in it, and was probably still pumping that round the system, just that there was not enough oil in the engine to let it show in the sight glass i would be thinking that there was no damage done to the crank and it overheated due to lack of coolant.
IF it were mine I would be tempted to do the gaskets, clean out the rest of the system where the oil has got to and run it for a bit with fresh oil let it get up to temp, change oil and filter again.
As I said before though the only way to really be sure is to strip it down to the bones, damage due to no oil getting to the crank parts will be pretty obvious scoring.

thanks cal,
i have stripped down the engine and have an update. left hand big end had disintegrated and turned itself into tiny bits in the sump. main bearings had got badly scored so also need replacing & camshaft seats on the inlet side melted and wore down by 1/2mm so head is shagged, but cams are fine. head gasket had defo blown. i have managed to get the crank sorted so can at least rebuild the bottom end. i am using this oppertunity to re-build and tune up the engine. got some 878 pistons going in, having the new head skimmed, ported and polished and sending the cams off to kent for a regrind. so along with the fcr,s and big bore system should be good once again.

Might be worth fitting an oil pressure light - plenty bumf on here about it.