Yamaha TRX850 Enthusiasts Forum

Hi Everyone,

Just a couple of technical questions about rich settings on a TRX 850 and any upgrades regarding mapping to improve fuel consumption
and torque/power settings.

After reading other enthusiasts complaining of there TRX having too rich a mix I know mine seems rich also. Is there a kit or fix one could do
to fix this. The other point is does anyone know of an upgrade regarding mapping? I am hoping to get my twin to get a little more efficient
and to see if we could increase the power band a little. My TRX has had no upgrades and the tyres are Pirelli set at the standard settings I
am just concerned how little it does to the gallon compared to the similar sized straight fours like the YZF 1000 and ZX 10 I have let me know
about your upgrades, it will be very much appreciated.

Regards

Tony

Keyster carbie kit and drop the needle down by 1 to lean it out .
Std ECU is a fixed program but programable ignitions are available which give you better fuel economy, smoother wider power curve and take the snatchy jerky feel away under 3500rpm and smoother gear changes.
Cost for the kit and ignition is about $300 but will totally transform your TRX.

cobbadiggabuddyblooo wrote:Keyster carbie kit and drop the needle down by 1 to lean it out .
Std ECU is a fixed program but programable ignitions are available which give you better fuel economy, smoother wider power curve and take the snatchy jerky feel away under 3500rpm and smoother gear changes.
Cost for the kit and ignition is about $300 but will totally transform your TRX.

Thank you very much.. I have dropped the needle and tweaked the bottom slow running jet, it goes like hot poop off a greasy shovel and not a smelly bit of rich coming from
the Venom cans, at last a sweet running beast which I am now very proud of Thanks again.



Tony

I get between 3.7 and about 4.5 ltrs per 100km on mine, this is with a standard engine and carbs, aftermarket cans and a K&N air filter.

As Cobba says grab a Keyster carb kit. Most likely your needle jets are worn and the cause of the drinking problem. Link below, you will need 2 kits obviously and you want the $45 one which includes all the jets. The main stock main jet is too large. It is a 142.5 I dropped mine to a 137.5 but you might want to get a pair of 140 also and find what works for you.

So far as setting for the carb personally I am running the following

2.25 turns out on the fuel screw
5mm float height
1.37.5 main jet
needle clip on position 2 of 3