Yamaha TRX850 Enthusiasts Forum

Hi everyone, first real post and unfortunately not a very positive one.
Bought my TRX 2 weeks ago, '97 with under 9000 miles on the clock, stored for 2 years previous other than MOT trips.
When bought it started on the button but trailered it home and wouldn't start
Replaced petrol and squirt of Easy Start into air box and started and run fine
Started every other day and left to warm, no problems.
Went to work today, started first time @ 06:30. showed a mate at lunchtime and started the bike, fine but after 20 seconds it stalled, wouldn't restart
On finishing work, filled with dread I was dismayed to find it wouldn't start.
Eventually it did start but wasn't responding to throttle very well and firing on one cylinder only, stalled and wouldn't restart
I suspected it was fuel and having trawled the forums I'm drawn to the conclusion that it is probably Fuel tap, Fuel pump, needle or emulsion tubes, in that order
However
I'm open to suggestions
cheers

Ian

Change the spark plugs first, its a good start point.

Hell mate and welcome aboard.

Sorry you've got a prob with the TRX, not a good start!

But thats why forums like this exist with lots of friendly advice, some of which is actually good!!

I'd be thinking fuelling.

First off, do the 'free' checks: fuel lines for kinks, fuel in the tank (!), and stuff like that.

Maybe have the tank off completely for a drain and remove fuel tap for a clean inside and out.

Then start the stuff that 'costs': plugs first maybe (remove the bottom rad bolts and swing it forward a bit for better access, but its still a pig!). Check the plugs are both sparking whilst you've got them out the engine. Could be a HT lead or plug cap if they're not.

After that, you're into maybe checking coils, carb strip (could be full of gum from petrol sitting in them and blocked a jet) or fuel pump etc.

Good luck.

BTW where in the world are you? Handy if you put that on your profile info page

When it was running, did it tick over ok? Throttle response from about 3000 revs? could be the emulsion tubes, mine ate plugs until I changed the tubes, and was a pig to start. Just a thought for easy checks, side stand switch, and engine stop switch.

Dave E

sounds like shit in the fuel system/carbies.
drain and flush the tank.
clean out the fuel strainers in the fuel tap.
drain and clean the float bowls.
if it looks gummed up, Yamaha make a great carby cleaner(not cheap tho).just be careful as it is extremely carcinogenic!! WEAR GLOVES AND A VENTED MASK.
just another thing to check, is the two black air strainers that come off the back of the std carbies.
these things come apart and can be cleaned.
they give the carbs atmospheric pressure to work with.
if they're stuffed, you can replace them with small inline fuel filters, just make sure the flow is towards the carbs.
cheers
fung

Fuel flow first. Then ignition. Fuel tap in the "Prime" position?

A bike only needs 3 things to run (fuel, compression and a spark) so thoise are you starting points.

I presume the bike ran ok whne you bought it? This probably rules our serious problems with spark and compression (although it doesn't mean you haven't got valve clearance issues or shot plugs). As the bike has been stood, I'd be looking at the carbs first. Assuming you are getting fuel to the cyclinders (you've had it running so I'm guessing yes) and we've provisionally ruled out spark and compression, your problem is ..............

a kinked hose. Either vacuum or fuel line.

Check them all (ask away if you don't know what connects where) and then be very careful not to kink any of the hoses when you drop the tank

Thanks for all the assistance here.
Bike was left at work last night, returned this morning, set tap to prime, wouldn't start.
Lifted the tank, gave a squirt of Easy Start, started on the button (and ran for 2-3 secs)
Another squirt of easy start and again started on button a bit stuttery for about 5 seconds and then running perfect. Turning the tap to run from prime causes stuttering again.
Turned tap back to prime and then rode home (10 miles) along dual carriagway, running at 60/70/80 no problems at all plenty of power and smooth (for a twin!)
Got to 500 metres from home and engine just cut out and wouldn't start again (didn't try the easy start). I agree this seems to point to contamination somewhere and/or probably an obstruction or leak in the vacum system.
I think I'll remove the tap and pump and examine/strip down all components. I'll check the rest of the fuel system except for carbs (but drain the float chambers to check for contaminants) and see how we go. If that fails its a carb strip down I guess.

you didn't run out of fuel did you, no reserve on prime!, have you checked fuel cap? make sure its breathing through it and not causing a vacuum in the tank.

Dave E

2| don' think so, if I have I'm only getting 10 mpg

Haven't checked filler cap so I'll do that

Sounds like fuel contamination by the sound of it - simple & quick check - remove drain bolts from bowls on carbs, connect a length of hose onto the fuel inlet on the carb body & blow down the pipe with both an open & closed throttle. Refit drain bolts & before refitting tank drain a little fuel from it & see if there are any particles of shoite in there? If fuel looks clean reconnect everything up & give her a go? If it runs ok you've found your problem & should flush the tank to take out any build up from its period of storage. If the small sample of fuel taken out in earlier stage looks contaminated in any way flush & seal the tank to avoid future problems.

Contamination would make sense I think
2 years storage and a 100 mile jaunt tied to a trailer bouncing along British roads, asking for trouble I guess

i recently had an issue of poor low revs running on a 660 yam single motor. Bike had been standing for a year.
Stripped carbs and the unleaded had changed literally to gel, like bathroom sealant stuff, and blocked pilot jet up.
All stripped and blasted with carb cleaner and was fine.