2 Strokes Down Under

I have got the RG400 on the road now and after decoking the pipes and setting up the carbs new plugs etc I still have an issue and I think i need to rejet the bike to solve it. Basically when I give it some and the power valves open the bike just stops reving and bogs down totally just like its out of juice. As the bike is an import and I am the first owner here the carbs would be set for the Japanese climate.
Does anyone know how many sizes to go up. Has anyone done the same with a 500.

Its not really something you do by what someone else did.
Each motor is different.
You need to go through the steps of jetting it propperly.

First thing id suggest would be pulling all the carbs off and stripping them right down and cleaning them out. Replace the jets with new ones of the same size as whats in it if any of them look anywhere near sus.
And you aint stripped and cleaned the carbs if you havent remove the emulsion tubes from the carb body.



Bob.

No I did all that stripped cleaned balanced the carbs and decoked the pipes. I only asked about the 500 to get an Idea of how many sizes up to start with and work from there and also to see if it is normal practice.

Running pods or airbox?

Needle position standard?

Everything is standard. I am going to go up two sizes and see what happens. I can get to the mains without removing the carbs or airbox scoops. Results at the weekend.

With a fresh set of spark plugs it should run pretty well, even on standard Japanese jetting. I'd say you have an issue other than jetting. Have you double checked the fuel flow and float heights on each carb?

Follow this link for the jetting sizes for the 400 vs the 500 (and other differences)

http://rg500gamma.com/rg500rg400differences.html

As it says on this page, Japanese market two strokes were typically jetted too rich as a measure to keep the horsepower down for licensing and insurance reasons.

So if anything you'd want to go leaner, not richer.

Cheers, Markus.

Being too rich did cross my mind too as it is drinking petrol which I was expecting but a bit over the top. It will be next week before I get the time now anyway. I will have a look at that site.
Pat

According to that site the jets are correct but liker you said it suggests to go leaner.

they are bad on gas my rg500 will do 120km then hit res when pushed realy haed .
allways a race to to the gas station as i was slowing the group dowm by gassing up all the time.
got cought out of gas a few times & thanks to those 4 jokes for some of there gas .
cheers peet

Got it sorted this afternoon. On the carbs there is a breather hose that connects to both carbs on each side then loops foward and vents under the motor. This hose had at some time been resting on the exhaust and melted shut. So I cut the end off and yee ha an extra 20 hp straight away.
Thanks for all the suggestions people.

Pat

good to hear
love all those urban myths that come out
cheers

peet wrote:they are bad on gas my rg500 will do 120km then hit res when pushed realy haed .
allways a race to to the gas station as i was slowing the group dowm by gassing up all the time.
got cought out of gas a few times & thanks to those 4 jokes for some of there gas .
cheers peet

I used to get 200kms plus before reserve back in the day on my original RG500 on country roads. 160ish kms around town (and fouled spark plugs until I went to the warmer ones).

got better km out of it over here in qld on country km
can go from blackwater to emerld 150 + km & com on to res
let reg ( wa )go to give the bike a birthday
bit tied started to foul a plug ,
60 km
+ droped in wa 10 year ago in wa
looking for a upper fairing to
if ay 1 knowing of some thing around

cheers peet

Gave it some this morning and its better but still not fully right. Going to strip the carbs back again and have another look.

It's interesting to hear how you're getting on with it, Pat.
That blocked breather hose was a good find! As Markus says, they were jetted on the rich side at 135 compared to the 500's 120 jets, so I would try going down to 130 125, or 120 as it's still on the standard jetting to see what difference that makes.

I'd be very interested to hear, as I've just bought an RG400 to go with my other 2smokers. The first thing I'll do is try 125 jets to see how much this leans it up and probably drop the needles by 1 notch too to see if going leaner gains power.

It would've been good to join you for that blast near Wollongong on Sun, but I won't be picking mine up until the next weekend now. I can't wait!

Enjoy the ride & keep us posted!

Cheers, Paul.