Yamaha TRX850 Enthusiasts Forum

As those who follow the lists will be relieved to see, I've finally acquired another TRX! Unsurprisingly I've already got a few tech questions I'd like some thoughts on from those in the know. Bit of baseline spec first of all:

98 model. 13770 miles (verified with MOTs, history etc and an unscuffed seat pad - a first on a TRX?!). It has oval/alloy Harpoon cans on with removeable baffles - still in place for now as they're suitably loud enough!. 15T front sprocket. Shortened dog bones. K&N filter. Thundercat (?) 'blue spot' front calipers. I have all the original bits and peices i.e. OE pipes, 16T front sprocket, air filter, dog bones etc in case I wish to revert back to stock. A set of Ohlins front springs also came with the bike (to be fited idc!). NO PM'S PLEASE I'LL BE KEEPING ALL THE BITS FOR NOW!!

My first question relates to the K&N filter. As far as the previous owner knows it is just a filter replacing the OE one. No dynojet kit has been fitted to his knowledge. My concern is that with the aftermarket pipes and no rejetting that my TRX will be running a bit lean - correct? Thankfully this upgrade was only done about 1000 miles ago but I'd rather be confident that no further miles are being done and unecessary valve damage generated by this setup. Do K&N do direct replacement filters for the OE filter? Should I reinsert the stock filter which I have and keep the K&N if/when I decide to dynojet the bike? I've yet to lift the tank and investigate the filter but thought I'd enquire here first! My gut feeling is to reinsert the OE one - correct?

Shorter dog bones. This has indeed raised tha rear as planned (previous owner was well over 6ft) and as a consequence the bike leans a lot further over on the sidestand - not to the point of toppling over but it is noticeable. I'm contemplating buying a 2nd hand sidestand and 'cutting and shutting' a little extra length into it for peace of minds sake! What fixes have others done when running shorter dog bones? Is there a direct sidestand swap?

I'm sure I'll have more questions shortly but I'd appreciate some thoughts on the above first!

Regards, Corners

Firstly mate the standard front sprocket is a 17 tooth item. I would think that a 15 would promote chain wear and tear and have a slight chainsaw effect on the swingarm. Keep an eye on the guide too. Secondly with the shorter dogbones, if you drop the front end about 10-15mm it will regain it's stance on the sidestand. And last of all the TRX was a rich runner in standard trim so fitting a K&N filter helps but they still run a bit rich even with open exhaust and freer filtering so no probs there.
One other thing, mine has an unscuffed bum pad as well even tho i've covered over 100,000 km's on it. It must only be tall people who wear them out
Cheers.

As above, I dropped my front end by 25mm with shorter dog bones & it stands perfctly on the ermmm... . stand. Mine's done 16K now and the seat pad is scuffed to buggery. Some people are just clumsy getting on & off the bike I guess I catch it with their boots ?
Get some pictures up man the suspense is killing me !

at that mileage its almost certain to need the needle jets changing ,, has it got a snatchy throttle ??

K & N filter with Micron carbon race cans runs fine with no rejetting, and I can put standard pipes on If Adolf Mot tester wants them with no adverse effect (apart from weight!!) 1995 original unworn bum pad as well. (stored, as a second seat, pillion and bum pad were recovered).

Dave E

Thanks for the reassurance ref the K&N and cans plus the insights into the dog bone issue and a quick fix - obvious when you think about it really!!! Not noted a snatchy throttle but haven't really rideen it for any length of time yet.

Corners

Corners R Us wrote:... but haven't really rideen it for any length of time yet.

Why on Earth not?

Just to add to what the others have said, mine's got a 20mm lift at the back, 20mm drop at the front and has a standard filter (with a slightly chopped airbox) and open pipes and it starts and runs fine (and sounds gorgeous). Have fun

Corners R Us wrote:Thanks for the reassurance ref the K&N and cans plus the insights into the dog bone issue and a quick fix - obvious when you think about it really!!! Not noted a snatchy throttle but haven't really rideen it for any length of time yet.

Corners

Kayla, is your bike broken? I've been riding mine every day...

K&N filter doesn't alter flow enough to require any rejetting (not even in K&N's ad copy), plus as already pointed out TRXs run very rich at the top end anyway. Just clean and re-oil every few thousand miles.

Seat pad gets scuffed by moving around on the bike while riding!

idl1975 wrote:

Corners R Us wrote:Thanks for the reassurance ref the K&N and cans plus the insights into the dog bone issue and a quick fix - obvious when you think about it really!!! Not noted a snatchy throttle but haven't really rideen it for any length of time yet.

Corners

Kayla, is your bike broken? I've been riding mine every day...

K&N filter doesn't alter flow enough to require any rejetting (not even in K&N's ad copy), plus as already pointed out TRXs run very rich at the top end anyway. Just clean and re-oil every few thousand miles.

Seat pad gets scuffed by moving around on the bike while riding!

You've got the wrong person. Do try and keep up, there's a good chap. I was out on mine just yesterday in the lovely greasy coldness. Was scary

I stand corrected ! Just been fiddling in the garage and I have a 17T front sprocket in an Afam sprocket packet marked 16T so I presume thats whats on the bike and not a 15T as I suggested.

Corners

idl1975 wrote: Seat pad gets scuffed by moving around on the bike while riding!

I don't think I have ever touched the seat pad while driving. Perhaps I'm not moving around enough, or my bum just isn't big enough

I have a little dint on the edge of my pad, but thats from getting off the bike and being as flexible as a crowbar.

I agree with Zod, surely with your weight over the front end your backside shouldnt be near the bum pad!

Dave E

I think they get scuffed when mounting/dismounting not during 'driving' time!! Personally I'd never seen one on my travels that wasn't scuffed and was amazed to find the one on the bike I bought in an untouched state....which I will endeavour to keep it in!!

Corners

slow codger wrote: I agree with Zod, surely with your weight over the front end your backside shouldnt be near the bum pad!

Dave E

Depends on how long your legs are! Mine certainly hits the bum pad all the time, which is probably why it's called a bum pad.

Your not a frog are you??

Dave E