About Carbs and Airbox

[Cona]

Greetings from Finland.

I have ´97 TRX which has stock carbs and Full Over racing Exhaust. I bought a Dyno Jet Kit and installed it as in the instructions in package. After installing the Dyno Jet Kit it feels that the TRX isn´t accelerating as fast as before and sometimes it cuts when turning throttle fast to the max.

Does anyone know what would be the best position for the "washer" in the needle and do i have a too big main jet (i installed the biggest in the pack)?

I´ve also removed the original airfilter element from airbox and put an oval Ram Air filter into carbs` throttle body. Should I get a rid of the whole airbox or put the TRX:s K/N-filterpanel instead?

I know that probably the best option would be to get the bike in to dyno, but it seems that nowadays workshops can only modify the ECU, not tune carbs anymore.

Sorry my bad english, please help!

-Markus

[phuk72]

I know that probably the best option would be to get the bike in to dyno, but it seems that nowadays workshops can only modify the ECU, not tune carbs anymore.

Is the correct answer - you need to find someone who is familiar with carbs.

FWIW, I'd guess you have overjetted.

Re the air filter, CV carbs are very difficult to set up without an airbox - and very hard without a dyno.

Personally, I would use the airbox with a K&N, cut the air box snorkel off and raise the front of the tank using some spacers

[Killerwhale]

Greetings from Finland.


I´ve also removed the original airfilter element from airbox and put an oval Ram Air filter into carbs` throttle body. Should I get a rid of the whole airbox or put the TRX:s K/N-filterpanel instead?
-Markus

My experience when tuning the FCR´s with ram air filter is that a bog/hesitation occurs when the bike is lean...it splutters and coughs when getting to much fuel. And lean sounds just about right when you have put a ram air on there.
If not finding a pro, buy mainjet´s in steps and try/error it. But bear in mind, all tuners can measure A/F ratio on your bike carbs or not so when you think it behaves as you want go test A/F.....

[Cona]

Thank you for your advice.

I guess the snorkel you mean is the "chamber" over the original filter?!

Has anyone made a "ram-air" system for TRX, simply some tubes/pipes going to the front that would force the air go faster in?

Maybe I´ll start by cutting the snorkel off and replace the Ram Air-filter with the K/N which was in the bike before.

This picture inspired me to get rid of the original filter but I guess it takes the mixture to lean... I`ll try my best to find a dyno-pro.



-Markus

[alextrx850]

the picture above had the origional snorkles and carburettors,...the airbox was drilled and the inlet removed..lovely sound.
The carbs were newly jet fitted and had no mixture problems..even if i had, i would have simply adjusted the needles.
The ram filters will allow more air in...simply adjust your needles to suit.
A good indicator to a lean mix is the headers going red hot on idle for a short while..

[Stu99]

CV carbs like a still air environment and as mentioned are very hard to set up with pod or ram filters.
Choices are:

K&N filter and snorkel mod as Phuk mentioned. Set it up and you are good to go. The search function will find you various threads and info on this.

K&N pod filters or Ramair filter. Carb mods and/or lots of tuning. Don't even think about it unless your carb internals are perfect. Almost guarenteed you will need at least new emulsion tubes to go with your jet kit and you may need jets not included in it. Be prepared for numerous Dyno runs if you want it right, because just when you think you have it right it will be rich or lean somewhere. When you get it just right, the weather will get hotter or colder and more or less humid and you can start over again. Fine if you love tinkering and tuning, which I do.

If you want more than the snorkel and K&N filter, save all the money you will spend on Dyno runs, further carb mods, carb parts and jet kits and just buy some FCR's. at the end of the day it won't cost you a whole lot more and you will get more performance than you can ever get out of modifying the stockies.

In case you are wondering, I have run K&N pod filters, with Tovami stage 3 jet kit, which included slide mods, air jet mods, needles, jets etc etc. Yes it runs great, but it took patience, money and more patience.
I am in Melbourne, with it's trademark blustery weather and temp changes, in the end for daily practicality's sake I re-employed the air box in a Stage 2 type set up.

Note, this bike is no longer a daily ride now, so it will go back to a Stage 3 set up.

If I was to start over, looking from a $ spent for performance view, I would go straight to FCR's.

All that said, I see you are a certain way down the ramair path already, so the choice is yours. Hope it works out for you.

[Cona]

Ok, thanks for the opinions. I think i Cut off the snorkel and put the K/N back and then if it doesnt work properly I`ll adjust the needles.

Edit: And I hope Santa will bring me a pair of FCRs.

[Stu99]

Ok, thanks for the opinions. I think i Cut off the snorkel and put the K/N back and then if it doesnt work properly I`ll adjust the needles.

Edit: And I hope Santa will bring me a pair of FCRs.

You can also find some good CV carb tuning tips on the Factory Pro website.

If Santa is carrying FCR's this year make sure to send him to Australia.