Cold-blooded Hawk

[Deckard_Cain]

Originally Posted by aaw611

That main jet sounds wayyy huge. Any of the idle/choke issues are going to be related to the pilot jet. That's what you should be focusing on in my opinion.

Originally Posted by manco15158

Ok, bumped the main jet up to a 135 and turned the mixture screw to 2 turns. This solved the issue in 5th gear. Have to use the choke to start it but it warms up to where no choke is needed. The valve adjustments definitely helped. I will change the pilot jet when it comes to hopefully fix the choke issue. I attached a photo of my pilot jet and carb. Thanks everyone for the help!

Yep, Delta, OH is only 122ft higher than me; guys using a 135 ish main are the ones with head porting and cams, higher compression... that's WAY too huge for a basically un-modded CG250. It's masking the problem, not fixing it.

Your issue lies within the pilot circuit, not the main. Fixing that will likely take care of your 5th gear issue as well; doubtful you're only running half to full throttle in 5th gear. Pilot circuit and needle jet are the main fuel delivery at this point.

[manco15158]

Thanks for the feedback everyone. Still waiting on that pilot jet. I had already checked for a vacuum leak in the intake manifold and added washers to be safe when I installed the new carb. I’m gonna leave it alone until I get the new pilot jet. I took it for a long ride and it started giving me issues at higher speeds again. So, when I replace the pilot jet, I’ll drop the main jet back down to a 110. I was pretty much just experimenting until the pilot came.

[Goob]

Originally Posted by manco15158

Lol, yes almost to Michigan. No I do not have a set of pilot carbs, so I’ll have to wait the many weeks for them to get shipped to my house thanks to all the slow shipping that’s been occurring lately. That has added to the nightmare of trying to fix anything.

Try ordering from jetsrus.com I have always gotten mine within 2 days. This should be what to order for a VM26 Flange mount. They have real Mikuni jets and also quality no-brand alternatives for a bit less.

Main: MIKUNI N100.604 or M21
OVERALL LENGTH = 9mm
HEAD DIAMETER = 8mm
THREAD DIAMETER = 4.9mm
THREAD PITCH = 5.0 x 0.7


Pilot: MIKUNI VM28/486 or M24
OVERALL LENGTH = 28.0 mm
HEAD DIAMETER = 5.0 mm
THREAD DIAMETER = 3.9mm
THREAD PITCH = 4.0 x 0.7
TIP DIAMETER = 2.0 mm

[manco15158]

Ok I had adjusted the valves already. I upgraded my pilot jet from a 20 to a 22.5. Still didn’t start, so I bumped it up to a 25, the biggest one that came in my set. The bike now fires up right away without any choke. However, I am still having issues with it bogging down as I’m cruising at a constant speed. It starts to stutter and will stall out. If I put the clutch in when it starts to stutter, the engine dies right away.

[JerryHawk250]

Check your float level. If it's set to low it will not get enough fuel.