Yamaha TRX850 Enthusiasts Forum

Hi all, my front wheel has been mullered by a pothole and a fork seal is weeping, along with my thorough dislike for the suspension in general is leading me towards fitting a whole new front off something more modern with forks that work. GSXR600/750 stuff seems reasonably priced offering decent Showas but anyway, questions!

1) Why is there so much emphasis on swapping the stems? Is the TRX stem a strange length? Is there no chance of getting bearings that fit a different stem and the head of the frame?

2) How much does it affect your insurance premium? Being 25 insurance is still an issue, perhaps I would be better off getting emulators fitted and keeping it looking stock on the outside?

3) What do you do with the ignition switch?? Fit it wherever or can it normally be fitted to the new yokes? And I take it there is no hope of having a working steering lock afterwards?

I'm also quite happy with the Brembos the bike came with and would like to keep them if I can to try and save the cost of calipers, does the 100mm bolt spacing (I think?) mean they'll only fit other Yamaha stuff? Or are other bikes with Brembos (Aprilia, Ducati) the same?

Advice, ideas or opinions welcome!

Trx Stem isn;t an odd length as such but most modern front ends have a shorter stem..far easier to make up a spacer to fit the trx stem to newer yokes.
I have 2012 R6 forks/yokes
Never affected my insurance
I used the standard TRX ignition but modded it to suit..you may well lose your steering lock
The Euro bikes in general have a different caliper mount spacing to Japanese stuff so stick with Japanese forks to keep your calipers

Thanks Gix! I was looking at the fork conversion tool at All Balls and found that the R6, R1 and GSXR 600/750 all use the same bearings as the TRX which makes it even more of a mystery why everyone here reckons the only way to go is to swap the stem. In that case is there any known fronts with a stem about the right length? Failing that, can anyone tell me the length of a TRX stem so I can start annoying sellers on ebay?

Hi Snod

The best stem with the correct length will be the Trx one Im afraid ......... it really isnt that big a job to press it out of the Trx bottom yoke and mod it into your forks of choice

Yzf750 forks seem the most popular and easiest to fit with R1 closely following ( although the stem needs building up to fit in R1 yoke Im told .

Ive never swapped the Trx forks but I have just put a Yam front end in a Triumph and when you get the bits together and start measuring it all begins to make sense ( Honest )

Chris

I was hoping to avoid the rigmarole of getting stems swapped but okay then. I have looked into the YZF750 stuff but it's getting a bit old now and more modern setups can be had for the same money, it doesn't seem to make much sense? Keeping the speedo drive would be nice though. R1 fronts also seem expensive for what you get, and once the stem is swapped how is it easier to fit the R1 front than anything else?

I can't recommend the YZF front end highly enough.



Simple swap (mine uses R1 yokes)

Ign switch bolts straight on (no steering lock though)

Massive improvement with 320mm discs over 300's when you use the YZF wheel (with speedo drive).

'Old school' forks? Perhaps but suspension set up can be a challenge (to me at least) with too many variables and these are beautifully simple (think they only have compression damping adjustment); if the spring rate and oil grade is correct for your weight, just get on and ride it. Doesn't ever do anything horrible and to me feels a lot more stable and solid at the front end. Looks smart too.

My forks have been reworked internally though (Ohlins?); may well have something to do with how good they are. Pete on the forum (who sold them to me) may be able to add more detail.

Recall that Pete tried YZF SP forks and preferred this more simple set up in the end.

Crap. Did rotate image in Photobucket but it clearly chose to ignore me.

Reworked YZF forks are going to be mega money though, surely?

Also, after some more digging around I found this comparison of an R1 stem to the TRX item:



Now I see why the stems get swapped! There's also a lot of talk of how short the modern forks are so the front will be sitting lower, and that means that in order to maximise the ride height the clipons have to go under the top yoke - I really don't want my hands to be any lower than they are with the stock setup, it's only just bearable as it is. The whole area is a minefield!

Snod Blatter wrote: 8<
Now I see why the stems get swapped! There's also a lot of talk of how short the modern forks are so the front will be sitting lower, and that means that in order to maximise the ride height the clipons have to go under the top yoke - I really don't want my hands to be any lower than they are with the stock setup, it's only just bearable as it is. The whole area is a minefield!

I like the original position of the clipons too. That's why I use raised clipons from LSL (for R1 and more, 50mm) on a YZF750 front. They can be moved up or down a little bit. The position is now even slightly higher then stock. I'm really happy with this solution!

Adjustable clip ons would be very nice and a lot easier to deal with than handlebars which would require removal of the fairing, but there is no way I'm paying that much! I was hoping to get it all done for around £500-600 but it's looking less and less likely. I have asked Maxton how much they would want for fitting cartridge internals to my current forks, if it's a reasonable amount that'll likely be the way to go.

My standard forks have been 'Maxtonised' and the difference is huge. I wouldn't hesitate to recommend going down this route......About £400.

bubbaad wrote:My standard forks have been 'Maxtonised' and the difference is huge. I wouldn't hesitate to recommend going down this route......About £400.

Is that the full GP20 treatment? I was honestly expecting them to want more!

Do the forks now actually try and push the tyre into the road rather than let it patter about? That's all I'm really after, and it means everything still fits and works afterwards.

They were on a TRX that I bought and swapped over a few tasty bits. I have the invoice for the work done on the forks somewhere so I'll dig it out and see exactly what was done.......Rides much better, stops much better....No downside.

I used a Thunderace top yoke as it is flat just like the TRX, however you need to have it milled out (1mm radius) to accept the YZF forks as the T/ace yoke is 48mm and the YZF forks are 50mm. This allows the forks to sit lower down than using the "Gull Wing" YZF top yoke. I also used Honda CBR959 handlebars. These are 50mm and sit perfectly under the yoke and give a riding position the same as the standard TRX set up. I had to weld 25mm extension on the ends though. I found the throttle cable were the too short! I overcame this by using an R6 (2CO) throttle housing, this allows the cables to exit under the handlebar rather than going over the top, taking a shorter route. Looks neater too. The steering lock also works albeit in the straight ahead position.

if it is improved / adjustable compression damping you are after Gold Valve Emulators are an inexpensive option. I swapped my springs for new ones suited to weigh and put in emulators and after spending some time dialing everything in the difference in night and day. The front is a lot more solid and doesnt skip about like it did

viewtopic.php?f=6&t=7414&start=105

http://www.racetech.com/page/title/Emulators