Yamaha TRX850 Enthusiasts Forum

Hi Folks,

Just bought myself a TRX after wanting one for years. Been searching the forum for info on various things and am now wondering if I should be checking valves and changing the camchain a lot sooner than I'd intended. The bike's got just under 23,000 miles on it. It's had it's oil changed every 6 months/3,000 miles since new and runs and sounds sweet. I was planning on checking the valves next winter but I keep coming across posts mentioning tight inlet valves and stretched camchains...it's got me worried! Are there any tell-tale signs for either condition? I'd rather do it all next winter but don't want to risk burnt valves etc. Any advice most welcome. Thanks in advance!

Chris

PS How the hell do you get to the screw for balancing the carbs? (Mine were spot on but it seemed impossible to reach the screw if they had needed tweaked!)

Take off the cam cover and rotate the engine to ascertain if the timing marks are out.If they are the camchain is stretched,as for clearances,there should be light tappet noise evident.
As long as there is you can bet that the valves still have clearances.
And the carb balancing `act`,you`ll need to rig up a dummy tank(old lawn mower ones work well)so that you can run the bike without the tank in situ.

Cheers. Thinking I may leave it til next winter as I've got chasis sorting and other mods ongoing at the mo. Just wondering if most trx's need the valves and camchains done earlier than Yamaha state in service schedule or is it just a few? As to the carbs- got a dummy tank ok, just couldn't see any way of getting to the adjustment screw without removing the airbox!

I see you`re in Edinburgh,so am I and another member on here.
If you`re only wanting to balance the carbs it`ll likely run fine for balancing with the airbox off.I`ve FCR41`s on mine,easy to balance.
Obviously if you plan to do fuel mixture,slow running etc,you`ll need to put the airbox back on.
What are your poor running symptoms?

Nice one! Don't think I've seen a in TRX Edinburgh for years- glad to hear there's a few stalking this far north of the border. (Or north of the equater for that matter- seems most of them made their way to Oz or New Zealand!)

No symptoms to report as yet- the bike seems to be running fine. It's just that I've seen so many posts on the forum reporting tight valves and stretched cam chains at lowish milages I'm wondering if I should be stopping everything and checking now. Just about to junk the silencers (gotta be half the weight of the bike!) and fit a pair of stubby straight throughs so keen to get out and rattle some windas round town. If the damn snow would just f*** off...got the bike just before the recent ice age so haven't actually had a proper chance to check it out...

Me and the other Edinburgh member are out of the city,west of town,whereabouts are you?

I stay on Lothian Road. Got a lock up east of here so as soon as the roads clear I'll be buying a tax disc and heading for the coast road.

Anyone else got an opinion on the valve/camchain thing? Not sure if I'm being sensibly cautious worrying about it or just paranoid!!

If Its running sweet and quiet, then i would leave it alone. Mine has 35,000 miles (i have done 25,000 of them) and it has never had the clearances touched, or tensioners.
Dave

Yeah, but how do you measure quietness? zero valve clearences are quiet!
If you're concerned, whip off the cam cover and check, otherwise you'll worry every time you ride it IMO

I would have thought starting would become an issue if the valve clearances were way out. I measure quiet with the satndard cans on, you get a better idea of mechanical noise that way.
Dave

bought my bike at 50,000km and did another 50,000km before I even checked the clearence and then treated it to a new cam chain at the same time.. So I'm happy with 87hp with fcr's n pipes at 100,000km on the clock.. Not bad for a 99 model that constantly gets a good work out. Just keep those reg oil changes n filters..

What year is your bike? The inlet valve stretch problem seems to be an issue with pre-'97 models only. If you were going to the point of checking cam chain stretch, clearance checks would only take another 10 minutes

Thanks for the info. The bike was first registered june 97 so I guess its a 97 or a late registered 96. Hopefully a 97! Haynes don't list frame nos for 97 on so I'm not sure. Reckon I'll take the cam cover off and have a look. Is it possible to just unbolt the radiator and move it out the way or do you have to remove it completely? Thanks again.

Chris

You`ll find it best to whip the radiator off,that way you`ll get the most clearance to work in.
At the same time you can refill the coolant system when you`ve checked your timing marks and replaced the cam cover with a 50/50 mix of ethylene glycol antifreeze and deionised water.Both can be sourced cheaply and easily from any large supermarket or in Edinburgh`s `poundstretchers`.
I never use the ready mixed and overly expensive coolant mix`s,they`re a rip off,a bottle of 99 pence universal antifreeze and another couple of bottles of deionised water(sold for steam irons)and you`ll have the same thing anyway.
Dandywarhol`s right,to ease your mind take a wee look,check your camchain tensioner and timing marks.
There may be a need to replace the cam cover gasket,it`ll likely be cracked and hardened and you really don`t want to resort to silicon around the top end of a motor.There`s a real risk of stray silicon getting into oil galleries and creating oil starvation.
From memory the cam cover gasket is around 20 quid,I got one last year from Carricks but there are pattern ones available too.
Wemoto do plenty of TRX stuff:

http://www.wemoto.com/bikes/Yamaha/TRX_850/96/

http://www.wemoto.com/bikes/Yamaha/TRX_850/97-99/

The first link is for the 96 TRX,the other link for later models.I don`t know why they have two seperate pages,many of the part numbers are identical!

Thanks for that. I'll order a gasket and have a look. Also- a quick question about oil quantities: did an oil and filter change yesterday and I'm puzzled about the oil level. I put 3 litres in, let the bike idle for a minute, added another 0.6 as per Haynes, started the bike again and let it idle for a few minutes. Stopped the motor and I couldn't see any oil in the oil level window. I then added another 0.4 making a total of 4 litres, ran the motor for a couple of minutes again and still can't see any oil! I remember reading posts where people mentioned needing 4 litres but surely it should be showing in the level window by now? Not sure how easy it is to blow seals in a dry sump motor but I'm wary of adding more oil. What do you reckon? Cheers in advance!