JR50 Jetting Q

I am not familiar with the carb on this model but a sub pilot may be akin to a choke or idle jet which some carbs have. During normal engine operation this jet would not come into play (only during starting). I doubt that this jet would need to be changed unless there is a starting or choke issue.

Hey There,

Not sure if you got your answer on this question but I have a 98' JR50 that ran like crud so I started tearing into it.
The previous owner had already removed the washers in exhaust and intake and also removed the muffler so I concentrated on the carb. I also checked the plug, buildup, air filter but they were all fine.

After reading some posts on the uncorking the jr50 many said to remove the 2nd pilot screw from the carb (there are two in the hole) which I did. Considering how easy it is to work on these little things and tear into the carb I moved the main jet setting 1 notch lower (richer) or to #4 thinking I could always put it back.

When I got it back together, fired up and adjusted idle and let it warm up for a bit to test it. I was surprised how much better it was. I'm a pretty big guy and this thing could never pull me up the driveway but it did this time. Ripped up the driveway (lol ripped...well faster for this bike), down the lawn all the while laughing my butt off. It was fun. Anyways long story but for now the little mods I did seemed to help a lot! I might fool around with the jetting and mix some more to see if I can get more out of it.

Here's my theory with these little things. Everyone pulls the restrictors washers out of them and opens the pipes up or even mods the air box. You simply cannot do that without adjusting the carb and going to larger jetting or richer.

Just my $.02 on it. Good bike to start the kids on. Wish I could get the CRF50 but thats a little out of the budget for now.

Later!

Smack