FCR 39mm no TPS questions

Please share your secrets! What mods have you made to your TRX?

Moderators: trixynut, Mincehead, dicky, phuk72, Jak, Kevtrx849

Post Reply
User avatar
epsilon
TRX-Enthusiast
Posts: 4
Joined: Mon Jul 15, 2019 5:13 pm

FCR 39mm no TPS questions

Post by epsilon » Sat Sep 19, 2020 3:49 pm

Hello everyone,
Hope we're good and safe.
A short intro to understand better my thougths.
I have a tdm 4tx late model with electic pump and different carbs than TRX.
Found a spare tdm 900 engine to take parts and make full 900 mod with barells,crank,conrods etc.I was planning to use the carbs i already have, with maybe higher jets.Found a pair of FCR 39mm for a fair price,but with no TPS.
So i'm viewing the flats but i do not know what promblems i will face when i put them,if they will work,if bike needs maybe different ignition or something
else that i can't think of right know.
I need your opinion,suggestions if the bike will work well,not perfect,fair enough,DAILY USE, with these carbs or to just forget it and stay with the save CV's.
Thank you

User avatar
dicky
Site Sponsor / Administrator
Posts: 1051
Joined: Thu Jan 06, 2005 11:26 am
Location: Ruffy, Victoria.

Re: FCR 39mm no TPS questions

Post by dicky » Sat Sep 19, 2020 11:57 pm

My opinion, and others may disagree, is that FCR's offer nothing for daily use riding.
They are made for racing where you need instant throttle response.
You might get a couple of extra HP if you tune them correctly. At the top end, where you don't usually ride when putting around town.
For the money I would buy an Ignitech ignition unit, it offers improvements that you can use in everyday riding.

The 39's will work on your bike, you don't need to change the ignition, but you do need to spend time (and or money) getting the jetting properly set up for your bike.
There is no point putting them on if you don't set them up properly.
dicky
OOOSDC #5

User avatar
Tarwetijger
TRX-Enthusiast
Posts: 1537
Joined: Tue May 15, 2007 9:31 am
Location: Netherlands, Assen
Contact:

Re: FCR 39mm no TPS questions

Post by Tarwetijger » Sun Sep 20, 2020 6:46 pm

I didn’t know what to answer but your repsonse makes sense Dicky.
Go for an ignitech, if only just for fun to fiddle around with!

User avatar
Rod.s
Site Sponsor
Posts: 1404
Joined: Sun Apr 25, 2010 11:01 am
Location: Brisbane, Australia

Re: FCR 39mm no TPS questions

Post by Rod.s » Mon Sep 21, 2020 6:15 am

if you are going to use the TDM900 head...
The TDM (efi)900 head inlets are a different design to account for the injector nozzle, you'll have to first check that the inlet rubbers are the correct size for either the FCR's or original (850tdm) carbs ...

E:g 900efi
https://www.ebay.ie/itm/Yamaha-TDM-900- ... 3663679445

TDM850
https://www.ebay.com/i/274040962361?chn=ps
If it's not made in China, it's a fake!

Post Reply