Yamaha TRX850 Enthusiasts Forum

Hi all
i have owned my 96 trx for only two months and in that time i've done 8000km. the bike has been great and all i've had done was a new timing chain and the shims adjusted. the bike has 80 000km on it. just last night coming home from work i noticed that the bike has started blowing smoke from the right exhaust only. its always used oil (under 1 litre per 1000km) but i've never seen the smoke before.
so my question is would it be a valve problem or a ring problem. the bike runs fine with no issues at all just the smoke.
regardless of what is the cause i was wondering if anyone in australia knows how much a rebuild would cost.
and also how soon should i get it done. (ie if i wait will more damage occur)
cheers
Graeme

grn80 wrote:Hi all
i have owned my 96 trx for only two months and in that time i've done 8000km. the bike has been great and all i've had done was a new timing chain and the shims adjusted. the bike has 80 000km on it. just last night coming home from work i noticed that the bike has started blowing smoke from the right exhaust only. its always used oil (under 1 litre per 1000km) but i've never seen the smoke before.
so my question is would it be a valve problem or a ring problem. the bike runs fine with no issues at all just the smoke.
regardless of what is the cause i was wondering if anyone in australia knows how much a rebuild would cost.
and also how soon should i get it done. (ie if i wait will more damage occur)
cheers
Graeme

Did circumstances where different in any way eg. cold night?
The right always start to smoke before the other....Max who made this forum even uses different mainjets on the two sides because one runs hotter than the other!

Yeah it was a really cold and rainy night. today the weather was fine and it isn't as bad but it is definitely still blowing smoke out of the right exhaust. When replacing the valves in the 96 model what valves should i buy for it? i only ask as didn't they changed in 98?
i just feel its time to put new rings and valves in so that my oil consumption drops as it is getting annoying stopping to fill up the oil and check the petrol
any advice is appreciated.
regards
graeme

don't think You can get the 'bad' valves, i.e. Yamaha replaced them as spare parts as well. New valve seals and rings will probably be sufficient to cure the oil consumption. New valves and cutting the seats is good, IIRC 10 valves is about 200 Euros. If You have the means, also check for the cylinder wear, rings and honing might cure for a while but can't really seal oval cylinders...

what colour is the smoke?

it's a bluey white colour.
thank you all for the advice. i'll definitely get the bores checked for wear.
regards
graeme

bluey white? hmm.......could be moisture - have you checked your coolant?.........oil smoke is normally bluey blue

i haven't checked the coolant. i just looked at the level then and started the bike and the smoke is more blue, black than white. its hard to tell. its been pissing down with rain for the last few days and the bike is parked outside in it when i'm at work so its possible that the exhausts have just filled with water thru the course of the day. i'll ride it for the next day or so and keep an eye on the coolant level and see if it drops.
if coolant is leaking into the combustion chamber would it most likely be the head gasket? when i get the valves and rings done i assume the head gasket will be replaced also.
cheers
graeme

yup you got it

If it was just water in the exhaust pipes, it would be steam you looked at when they got hot, and it would evaporate into the atmosphere within a couple of feet of the exhaust pipe.

Dave E

Wot carbs are fitted to this bike? If it has the std setup have the emulsion tubes been done? Black/blue smoke can mean rich mixture causing bore washing (the fuel washes oil from the cylinder walls) which then gets burnt. Just a thought but as noted in many posts on this site, the TRX std carbs are prone to emulsion tube wear and tend to run slightly rich as standard as well. What is your fuel consumption like?

the bike has the standard carbs as far as i'm aware. with a dyno jet kit in them
my fuel consumption is good. i average around 56mpg. my worst has been 44mpg and my best was around 65mpg.

@ TS,

do you really need us, because you've got it 'head-on' on your own questions
Hope it isn't something which can cause (real) damage in time.

Greetz
Gerben

Some of the issues are familiar I must say... though taken care of