Help FZR250 3LN3 carb problem.

indeed, the owner is a top bloke !!!!

 

As per our PM ruckusman, I think the best way to go would be to replace the needles and tubes, and then fit a washer and spring like what the zeal has:

 

Hey Glenn what do you mean by "chugging" problem? I've struggled to get my bike absolutely perfect, but it's still rideable. I started with some flooding problems and some strange things through the rev range but was able to resolve them... unfortunately a new cam chain has put everything out of whack slightly again and I'm back to square 1. I love carby tuning heh...

My needles all look like this, and from what I can tell they all have pretty even wear.

 

Hiya Joker,

I haven't had my carbs apart in a long time, hopefully Grey can chime in and give you the skinny on the condition of your needles.

What I mean by chugging is that at random times when coming to a stop, usually at lights just when I'd lane split all the way to the front, the damn thing wouldn't rev, it would just sit there and labour, below the usual idle speed, running rich, even with the throttle full open. Letting the throttle close would usually cause it to stall.
I incorrectly misdiagnosed this as being float level, fuel height problems.

This could continue for minutes and would cure itself almost as suddenly as it appeared, if this sounds like something you're experiencing the solution seems to be replacing both the needles and emulsion tubes, though I'm yet to do that myself as I've only just learned about that solution.

 

Interesting. No mine is pretty consistent, nothing "mysterious" so to speak. It runs rich, it floods. It runs lean, it plays up. It's finding the happy point that is the fun part.

I've been holding off new tubes/needles for a while because I believe there is built in compensation in the form of notches/pilot screws etc to compensate for wear such as this. Simply replacing everything may be a "quick fix" but it doesn't help me learn to tune things properly and it's pretty expensive. For a bike like this I'm not looking at pouring money into it, there are some niggles I can live with I suppose. With that said, if there is significant wear on one side of the needle, as has probably been experienced by others then that's a different story.

I was able to get my bike happy for a while I've just taken a few steps backwards with some adjustments I have made.. domino affect and all that. Bit annoying but such is life.

 

Hey guys that's a long thread, can someone give me a synopsis?
Mine wasn't the only 3ln1 to blow a shaft because of the sprocket?
Will the new sprockets that you have fit onto a 3ln1 shaft at all, or is the 3ln3 shaft physically longer?

 

The 3LN3 shaft is longer, the proper sprocket for it will be too thick for the splined legth of the 3LN1 shaft, I think.

 

thanks Grey, I did actually read the whole nine pages of the thread and understand completely now

Now I'm hoping to get my hands on a 3ln3 or higher shaft

 

Like anything there's a certain point of no return on wear parts where they just need to be replaced - but up until that point there are often ways to compensate that are in built into the design. My point is that although I agree that replacing a substantially worn part is necessary, replacing a part just because it has some wear is probably a "quick fix".

But everyone is entitled to manage it how they see fit I guess.

 

I like what I am hearing, my carb kits just arrived, yet to fit them however as I have the sprocket countershaft to replace beforehand

those carbs look nice and shiny clean, what's the fuel height set to on the 3ln3?