Carb set up please help
 

Apologies I am from the UK !!! I thought I would ask the experts >
I have a 2002 EC250,..Ineed some help with settig up the carb, I live 300 feet above sea level I am currently running all stock needle and jets 178 high and 38 pilot.
In my manual it saysthe throttle valve cutaway is 7 what is this ?
Are the jet sizes ok ?
Should i change the stock needle if so what to?
Where should the needle clip go ?
What does LTR mean ?
And finally do the reeds have to be flat against the valve body, or do they have a small gap, I have boysen reeds, and dont know if i should change them or not ?

Thanks in anticipation guys, :)

I rate myself "fair" in the mechanical category - so I'll get things started and some others can chime in with more suggestions...

For the stock needle (that year is probably an N1EC or N1ED) - those are okay jets to run. But in my opinion, the needle is too rich and the pilot too lean - they kind of compensate for one another but it causes other problems; Like the mixture being too dependent on idle setting, the carb being too susceptible to environmental changes, and the transition from low to mid is rough. I have heard some refer to this transition as "burble", a "lurch" or "stumble", etc.

This is the shape of the slide at the bottom - it effects airflow/mixture at lower rpms. A #7 slide is a good one to have. I have attached an illustrations from keihin that provides details on what components in the carb control the mixture and which throttle settings they are effective.

LTR is LT-Racing - www.lt-racing.com. The owner is Les Tinius (and a good friend of mine - just so you know my bias!). He produces and sells a jetting kit for the gasgas that includes a different needle and jets. So when folks say "LTR needle" or "LTR jetting" - this is what they are referring to. He also provides technical support.

The reeds may not lay completely flat as they age. This probably won't cause any problems as long as the reeds are not warped or frayed. You can flip the reeds over to get them to lay flat again. If the bike has a bit of time on it - I would probably replace them.

I noticed in your other post yesterday that you said the bike ran rough at various rpms. The LTR jetting kit cleans up the bottom-mid transition and makes it pull cleaner through this rpm range (providing everything else is right). Sounds like you have some other issues to work through. I would do some general checks to make are getting fuel and have a good spark...

• Put in a fresh plug
• Check the ground wires to the coil/cdi, etc. and make sure they are not corroded/loose - use some sandpaper to rough up the contact area and reattach them.
• Put in a fresh spark plug.
• Remove the carburetor and remove all the jets - spray down the carb/jets with carb cleaner and blow everything out with compressed air.
• Drain the fuel tank out and put in fresh pre-mix fuel.
• Clean the air filter and make sure you don't over-oil it before you put it back in.

Oh and FYI - check out the tech articles section of the website here for a good write-up on servicing the reed valve...

You are very welcome. Hope you like it here!

jeff
aka webmaster of this website...

Thankyou
 

Thanks for taking time to reply Jeff, everything is much clearer now. I will take all your advice, and think about aquiring an LTR kit (if they ship to the UK)
Thanks

Matt