[BBIII]

Wes inside the acclerator pump there is a jet just bump the size up, i am not 100% for sure what size is in there but go with a bigger jet.
I think you bump it up to a 50 or something.

Also why a 42 pilot jet?

 

[BBIII]

The pipe usally gets red because it is lean on the pilot with any kind of aftermarket pipe.
Thats why i always use a 45 pilot with my 450 and the air screw @ 2 turns out.

Just let me know Wes if you get a piston get a CP piston they are about the best one out there for the yfz, oil mod is no problems just let me know.

 

[BBIII]

I would @least try a 45 but only change that then check it out, these carbs are a little finicky some times.

I get my gaskets from vitos but might see what RMATV charges for them.
Also pistons run about $200 for a cp shelf piston and get a comp. ratio of 12:5-1that way you can still run pump gas.

On the carbs it does make them run better and cost around $150 to get them bored to a 42mm and it will help it alot.