Hey guys I'm new here and have a problem, I have a 06 klx 250s with all the free mods and a muzzy slip on, till yesterday I had not touched the carb and the bike was running very lean lots of popping and a slight lack in power so a buddy told me he would mess with the carb for me i watched everything he did, he took the cap off the a/f screw turned it out 2 1/2 without going all the way in first, then he took the slide out and drilled the vent hole with a 7/64 bit, then came the part i was sceptical about but he assured me it would be great for performance he took the main jet out and drilled it with 1/16 bit. well I put it all back together today and it's horrible I mean the bike doesn't pop anymore but any thing past !/2 to 3/4 throttle above about 5k rpm it sputters terribly and cuts out no power at all. what happened??? can I fix it??

any suggestions are greatly appreciated

 

1/16=0.063"=1.588mm.
I just checked the #132 main I had on the bench. The hole is less than 1.4mm. (as close as I could measure.) Sounds like he's gone too big to me. Do yourself a favor and just get a new Keihin #132 main from your local dealer.
BTW, the fuel screw setting isn't a given. You need to set it when the bike is running for best results. (hard to do when you have the OE fuel screw) 2.5 turns out from lightly seated should be OK to start with with the OE #35 pilot. That's turns out from lightly seated.

 

your bike is so overly rich that the motor can't burn it all during combustion. who the f**k drills out a main jet? they cost $5.00 for cryin out loud. you can fix what he did. go to your dealer and tell them you want a 125 or 128 main jet for your bike. then go home and pull your carb off and REPLACE the main jet. better yet take the carb off first and take out the main jet and bring it with you as most parts guys don't know **** either. this is an easy fix. oh by the way....... don't start that motor again until you get that fn jet out of there.

 

Thanks for the quick responses guys I will definitely go get a new jet, turns out you cant trust most BS that comes outta peoples mouths!

do you think i should get a new pilot and needle too?

 

just get the whole kt,they are chep and have everything youd need plus diff jets to try out

 

I would but you probably can't get those at you dealer. you could just order a jet kit for a klx 300. that will have everything you need.

 

A keihin N1TC needle which comes on the stock, non California model klx300 is fully adjustable and works just fine (same carb). Your dealer will have it or can order it.

As others have suggested you can also order the Dynojet kit which comes with everything you need, plus an assortment of main jets to get your upper mid to WOT dialed in. You might just be lucky enough to find it on your dealers shelves.

 

Hey welcome to the forum nova Well you learned about peoples bs, now just do your own work.....plenty of pics and such on here to walk you through it and afterward you will feel like a pro.

btw everyone else was spot on with their diagnosis. Kawi jets/needle or a dyno jet kit.....its all good. You pick.