Yamaha TRX850 Enthusiasts Forum

Bike was running fine 2 weeks ago.

Got a shop service about a month or 2 ago at 66,000kms.
Noted that I had a stuffed front Pilot Power and a half worn rear PP.
Got both replaced with Metzeler Sportec M3s. Ever since then the bike feels like it's dragging something behind it. Can simply changing tyres have such an effect on the feeling of a bike?
Tyre pressures are fine, no dragging on front or rear discs, and all wheel bearing seem ok.
Bike is not burning any oil. Chain properly tensioned and in alignment (wonderful things, those laser alignment tools )

Bike is still on original clutch, std carbies with Factory Pro Emulsion tubes and needles (done 2 years ago - 10,000km - could they be worn already?), std air filter and std exhausts. Valves were checked at 30,000km (fine) and checked again at 42,000km (quite a few closed down - can't remember if they were inlet or exhaust ). I'm thinking that at 3 years later and 67,000+kms it's probably time to get them checked again. I'm not having starting problems, it's just that the bike feels very sluggish and doesn't have any get up and go until 4,000+ revs and the 3,000rpm flat spot seems more pronounced.

I would easily go back to the std Yamaha emulsion tubes if that would be a step in the right direction.

Short of getting a set of FCRs (around $2000AUD - thanks to the Global Financial Crisis - god knows where people get these used sets for 300GBP I can never find them, even on Ebay. Cheapest i can find is a place in the US called http://www.motorcyclecarbs.com where they have a set there for TRXs for $929.90USD which works out to be around $1300AUD - with cables)
and a set of more open pipes (currently looking at a set of Megacycle round alloy slip on cans for $660AUD - a set similar to what davamb got) am I looking in the right direction?

Bob

Were all the spacers put back on correctly?

As Pete said, put it up on bike stands and check the wheels spin smoothly, Check that the calipers are releasing after you have applied the brakes. If it feels as though the brakes are on give the caliper a whack with a mallett. Wheels should turn smoothly Look at the rear tyre to see if it is catching on anything, like the rear hugger.

Dave E

Wombat what exactly do you mean by shop service? Did they do any tune up work to the motor?

It's not going to be your tyres.

Did they forget to tighten up the carb or airbox diaphrams by any chance? Do you have a K&N filter fitted that they might have over-oiled? When were the carbs last balanced?

Wombat wrote:Bike was running fine 2 weeks ago.

Got a shop service about a month or 2 ago at 66,000kms.
Noted that I had a stuffed front Pilot Power and a half worn rear PP.
Got both replaced with Metzeler Sportec M3s. Ever since then the bike feels like it's dragging something behind it. Can simply changing tyres have such an effect on the feeling of a bike?
Tyre pressures are fine, no dragging on front or rear discs, and all wheel bearing seem ok.
Bike is not burning any oil. Chain properly tensioned and in alignment (wonderful things, those laser alignment tools )

Bike is still on original clutch, std carbies with Factory Pro Emulsion tubes and needles (done 2 years ago - 10,000km - could they be worn already?), std air filter and std exhausts. Valves were checked at 30,000km (fine) and checked again at 42,000km (quite a few closed down - can't remember if they were inlet or exhaust ). I'm thinking that at 3 years later and 67,000+kms it's probably time to get them checked again. I'm not having starting problems, it's just that the bike feels very sluggish and doesn't have any get up and go until 4,000+ revs and the 3,000rpm flat spot seems more pronounced.

I would easily go back to the std Yamaha emulsion tubes if that would be a step in the right direction.

Short of getting a set of FCRs (around $2000AUD - thanks to the Global Financial Crisis - god knows where people get these used sets for 300GBP I can never find them, even on Ebay. Cheapest i can find is a place in the US called http://www.motorcyclecarbs.com where they have a set there for TRXs for $929.90USD which works out to be around $1300AUD - with cables)
and a set of more open pipes (currently looking at a set of Megacycle round alloy slip on cans for $660AUD - a set similar to what davamb got) am I looking in the right direction?

Bob

Well the more I ride it the worse it seems to become. Bike has now done 68,000k. To me it seems in 2 areas. Clutch - still original, never been touched ( What's the go between std plates and Kevlar? - EBC do both) and carbs, as mentioned before, emulsion tubes(Factory Pro) done only 10,000k ago.

Bike starts ok, but even at idle sounds off (as if out of tune). Up to 4,000rpm vibrates and shakes, with a definite sluggishness around 2,500, and once above 4, starts to work ok.

Got a few days off now, so I'm gonna start from the beginning.

Bought wheel bearings all round - last done 5 years ago
Motul 5100 10W40 - mechanic said at first they put in 20W50, and then said later 10W50 (Summer hasn't arrived here really in Sydney, so I think a 50 weight is a tad heavy)
New plugs - changed at last service, but whose to say they're not f&^*%d
Fit new clutch cable

If none of this remedies it then new clutch kit and get the carbs serviced (cost?)
" " " " " it might be electrical but I doubt that.

Looks like a few months on the "treadlie" to get to work then ..............ah well, it'll do me good and help loose a few pounds or kilos, I should say.

Bob

Just a thought but have you checked the throttle position sensor to make sure it's in the right position?

Wouldn't the tacho needle be going mental if it were out of whack? As it says in the Haynes manual?
Still something to think about.

Over the weekend, fitted new front and rear wheel bearings and the sprocket carrier bearing. Drive feels a lot smoother now. So that's one thing.

Gonna go ahead and fit new clutch plates as a precaution. I think it was Quan that said ages ago that its wise practice to renew the clutch at around the 60,000k mark. Seeing that the TRX's achilles heel is the clutch. A well competent mechanic ( as anyone here in Sydney knows - Lloyd Penn ) suggested the best setup was EBC or Goodridge std aftermarket plates with genuine Yamaha springs. Only prob is there are no supplies of EBC clutch plates in Sydney until mid January so it would seem that I'll probably go with the Goodridge ones. I'll let you know how I go.

Bob

G'day Bob, bloke on Ebay selling clutch plates for $142 posted (non branded) How does that compare to the prices for EBC/Goodridge ?
Also i remember an easy mod was to fit R1 clutch springs to beef up the feel.

Kev, I think EBC are $142, Goodridge are $150 and EBC Kevlar are $190

Bob

The tacho will only go mental if the wiring or throttle position sensor is faulty, what I mean is that the sensor must be in the correct rotational position to function correctly. Mine was a few degrees out and the bike hesitated and run poorly.

If you look in the Haynes manual it tells you on Chapter 5 section 6 (5.6) 'Adjustment' how to set the TPS in the correct postion by turning the ignition on, then disconnecting the sensor wiring connector, this sets the sensor to 'adjustment mode', slacken the sensor mounting screws and rotate the sensor until the tacho needle reads 4000 rpm, tighten screws. Switch ignition on/off , Bob's your Uncle!

This may or may not be your problem but is worth knowing about.

I understand what you mean Tim. Hadn't ridden the bike for a week ( been cycling). Rode it down to the shops this afternoon. God it felt like a bucket of bolts! Mind you it was 31 deg C. Felt a bit better on the way back as it had warmed up a bit. Right hand muffler had a bit of a pronounced petrol whiff?

Gonna ride it to work tomorrow and then on to the bike shop for them to take it for a ride to see what they think might be the matter. This bike was running perfectly 6 weeks ago, had a service only 2 months ago, and all I've done is put on a new set of tyres and done all the wheel bearings.

If the prognosis is bad ( engine wise ) I might be scouring the wreckers for a new motor ($$$$?)

Bob

If that's all You've done, I don't think it has anything to do with Your worries, at least from your descriptions.

The clutch is probably not the answer either. Bad clutch would mean clutch-slipping, i.e. engine revs rising more then normal while accelerating.

Yo say it runs bad also on idle, this excludes the chain/sprockets, wheel bearings etc.

Did the bike feel different immediately after picking it up from the workshop?
Could you by mistake have loosened any of the vaccuum pipes?

Otherwise it must be a coincidence, i.e. that problem is not related to the service you've done. This will make it hard to diagnose over the internet though...

Well.........rode it down to the bike shop this morning, after my boss kindly let me off work for an hour or so

The mechanic, Lloyd, took it for a spin round the block and came back and said that it wasn't the clutch, more likely to be the carbs or electrics, and he even doubted that it was the electrics. He said try and run it on Mobil 8000 premium fuel as he said that it was the best fuel to run bikes on bar none, especially with the dishwater that we call petrol here in Sydney. He said that if that didn't cure it, it would more likely be a carb strip down. Which $$$$$$$ - wise is not too bad.

I'm a lot happier now

Bob

Mark,

If it helps, I've got a pair of standard carbs sitting in the garage your welcome to try. Helena's working in St Leonards these days and could drop them off at your sisters place? (if i remember right)

Anyway I'm sure you've got it under control - just thought i'd mention it.