I figured if you go back to as close to stock as you can, it eliminates the carb. The valves were checked, so it's not a floating intake. From what I'm seeing, I wonder if a pipe is even worth the power gain/response smoothness from a bike with less than 30hp. May be something as simple as a stuck float.

I see much more similarity with this pic than the original pic. You're calling it the "stock" needle, meaning the one that came with the bike? Isn't the N1TC mentioned here from a KLX300R? The N1TC seems to be tried and true with this bike but it makes me wonder if that needle works better with bikes that are bored than a mild mod pipe/air cleaner. The DJ has a much more aggressive taper for extra fuel at higher rpms, which should be a good thing here. That makes sense for this mod, if you have to move away from the stock needle at all. Usually, just a shim under the stock needle works on most multi-cylinders I've worked on. I don't know if the slide was drilled here or not, but do you think it could be drilled too big causing the needle to slop about?

 

I already ruled that out, it was the first thing I did by doing the clear tube test on the float drain. It tested spot on, so the float is not the issue. Valve were in spec so its not that. That leaves something with either the pilot jet, main jet, or needle.

 

As he said in his post, its not the best picture. But neither of those needles look like the stock needle that came out of mine. As you can see in the first post the stock needle I posted does not have any shaft about the flat head that sits on the slide when installed. It appears by his picture both have a shaft protruding up.

Did you buy the bike used? Maybe the needle had been swapped before you owned it. Those both have close to the same taper, so I wonder if it was replaced with a different DJ kit at one point.

I did buy mine used, but the carb had never been messed with until I opened it up to do mods. The fuel screw cap had not been removed.

 

Short soak doesn't do much. Let 'er rest in the hot water, then she'll set right in the groove without any need for poking and prodding.

 

No. I'm interested in the straight section on the upper part (before the taper starts). That's the section that is in play at smaller throttle openings.

Ron

 

I don't know that this is the best place for this, but I just found this video. Its pretty informative for a noobie working on carbs like myself. Really give you the whole picture of whats going on and how the carb works.

CV Carburetor - YouTube

 

Very cool. Never seen it like that before and it really simplifies the visualization. I hope this works out for you because you've really put a lot of work into it. You mentioned buying the bike used but doing the mods yourself. Was the mileage OK before the pipe? Did the mileage drop right when you did the pipe? Did you drill the slide? If you didn't drill the slide, go back to stock all the way, even the air box. That will eliminate the fuel system, top end and just about everything else. I did a lot of silencers with CV carbs on twins and fours and never replaced the needle, just a washer under it. Never had an issue with that. It sometimes took a while to get the jetting just right but the needle was rarely the issue. Only when I drilled too big.