Yamaha TRX850 Enthusiasts Forum

Hi, does anybody know this carb modification? In slide bottom other vacuum hole is blocked and other is drilled to 3 mm. Needle is aluminium and it has thinner mid section. There are no markings in parts. Bike has came from Holland and mod has been done there.
I think I will order original needle and emulsion tubes but what will that slide drilling make in future??

With the Tovami kits, this mod is done to increase throttle response. It comes from the right part of the world to have a Tovami tuning kit, so that is a possability, or perhaps someone has just done similar mods.
They have Stage 1,2 and 3 set ups with their kits.
Have a look here
http://www.tovami.com/UK/index.php

Dynojet also ask for it with their stage 2 and 3 kits. All much of a muchness I would've thought.

Snod Blatter wrote:Dynojet also ask for it with their stage 2 and 3 kits. All much of a muchness I would've thought.

Yep, pretty similar. Ruud Fredericks, (Tovami Tuning), used to work for and design kits for Dynojet. He later moved back home and started his own performance tuning business.
Can't remember the whole story, so that is the nutshell version.

Main jet has no markings. Pilot jet is std #45, Main air jet is Mikuni #75 ( parts cataloq says #60 ). edit - this last jet is actually starter jet.

Stu99 wrote:

Snod Blatter wrote:Dynojet also ask for it with their stage 2 and 3 kits. All much of a muchness I would've thought.

Yep, pretty similar. Ruud Fredericks, (Tovami Tuning), used to work for and design kits for Dynojet. He later moved back home and started his own performance tuning business.
Can't remember the whole story, so that is the nutshell version.

Wow, so this guy is known on the other side of the globe?

Tarwetijger wrote:

Stu99 wrote:

Snod Blatter wrote:Dynojet also ask for it with their stage 2 and 3 kits. All much of a muchness I would've thought.

Yep, pretty similar. Ruud Fredericks, (Tovami Tuning), used to work for and design kits for Dynojet. He later moved back home and started his own performance tuning business.
Can't remember the whole story, so that is the nutshell version.

Wow, so this guy is known on the other side of the globe?

I learnt of him via one of Gerben's modification threads, then contacted them by e-mail and ordered their tuning kit.
Very nice kit, it had everything, various jets, needles, clips, o-rings, drill bits, tap, threaded nylon plugs etc.

if you are looking to go back to stock the diaphragms can be bought for reasonable money here

http://www.motorcyclespareswarehouse.co ... iaphragm-2

Here comes more.... when I gave cleaning to my other set I found that left airpassage was plugged in this modificated set. I was wondering if this could be some year model modification and was a bit afraid to start drilling it awae, but yes it was a plug and under that there is a airjet which is not replaceable. This jet gives air to main jet, maybe it has something to do with atomisation?
I will go back to factory settings also with this since I trust that they know in Mikuni how to do cabs

It is more of the same; a dynojet-ish modification.
Everything has to be set up to work with each other.
I know now by experience Drilled slides in completely standard carbs don't work.

I will get back original jets and needles and try that slide with only one drilled and keep that other hole plugged. Lets see what happens.
I'm still wondering that there are better carburator engineers in every garage than in Mikuni factory