Yamaha TRX850 Enthusiasts Forum

hello everybody!
it's time to a big winter upgrade, due to engine broke up ;(
already found a 'new one' with polished heads & intakes, distribution chain done. minor works needed like lids and gearbox replacement with mines.
I read a lot of posts on tech tips, really illuminating but sometimes confusing. Do you mind if i try to brief what i understood?

1-What i have:
Standard carbs, K&N, dynojet stage 2.
Possible Upgrades:
Airbox holes, but not too many and only in the front. Emulsion tube replacement could help as well.
Should i go through Factory Pro for 'em?

2-What i have:
my standard fork to re-work, r1 fork (shown here not US) complete of yokes, calipers, bars, 20mm wheel axle, completely re-worked.
what i don't have:
top nut, wheel axle nut, spacers(?), bearings and wheel.
Yeah, what wheel? Read about YZF 750 one for keeping my discs (Smaller disk size, less rotating mass, which aids steering and response). Do i need anything else to fit it? I would prefer not to weld anything, other clean ways to do this transplant???
I could not find a "r1 fork conversion howto" except this one: link to post
where i don't understand this:
"Take to engineering firm to have TRX stem fitted to R1 lower yoke, shorten the stem and have a top hat shaped spacer made for the R1 top yoke."

Anyway, where i can find all linked files seen in those as many others posts? (trxfiles domain, r1forks.zip, trx850suspension.asp etc etc)

you already helped me in many other issues just browsing the forum (tyres, gauges, maintenance, and tons of other skills and improovements)
thanks in advance for unravel my doubts.
marcello

My opinion - don't mess about with drilling the airbox. Remove the foam and cut down / open up the snorkel. Then raise the front of the spacers. After that, get it jetted correctly (doesn't matter what you use - personally I liked dynojet but .....)

As for forks, don't dismiss having the standard forks professionally worked - it make a mahooosive difference.

As for R1 forks. What you need to do is press the stem out of your TRX yokes and into the bottom yoke of the R1 stem. Then isntalled forks as before using a spacer (r1 top yoke not as thick) and TRX nut.

No idea why you would want to shorten TRX stem?

Perosnally I would use all R1 front end (mud guard, wheel, discs etc) as this is the easiest way forward. But you lose the speedo drive.

You can retain speedo drive with YZF 750 front end.

As you say, if you want to retain TRX front wheel you will need to mess about with spacers, spindles and possibly disc / caliper spacing.

Good luck and feel free to ask questions

Ok for carbs & airbox!

The fork swap wasn't in my mind until i found that one "professionally re-worked and nice priced".
The stem shortening issue was took from the post i quoted, now it seems to be quite clear.

As for the speedo, i don't care a lot to keep it because... i'll go naked!!! sure i will find nice analog gauges!

I'm only a bit concerned about

spacers, spindles and possibly disc / caliper spacing

mess, if i choose for the 'YZF 750 wheel + my discs' bundle.
I'm now googling for a front r1 wheel&discs...

I'll let you know further developments..
thanks a lot.

update:
i found a cheap YZF 750 front wheel.. let's see!
i'm now looking for someone can help me with fit the TRX stem into the R1 bottom yoke, due to the 0.3mm diameter problem i read in the forum.

i had a quick look to the airbox top too, and i have some new questions:
should i remove the snorkel by cutting it completely?
i have a spare one top, so i'm not afraid to ruin it
how can i raise the spacer? I may have missed some steps..
have you (or someone else) got some pictures or links?

It's been a long time since I've seen an airbox but if I recall correctly you just need to open up the snorkel as much as possible to let as much air in (filter side) as possible.

You can raise the front of the tank with some spacers / washers

ask the source my friend....
on this forum, you ask Kayla.
she has all the info you need re conversions and she should be able to machine up any bits you require.
cheers
fung