CRF150F maintenance

[Joe Shimano]

OK.   I give up.  I CAN NOT get this carb dialed in.   I've tried everything the online community suggested and it gets worse with each one.   I need a recommendation for a good shop that won't rob me blind or someone willing to work for beer and BBQ

[bblass]

Are you making quarter turn adjustments and waiting 15 seconds between them?

[Joe Shimano]

Its the air jetting combo I can't figure out

[Buzz]

Ok if the leaking isn't fixed, check the little spring inside the first needle.

What issues are you having with the air fuel mixture?

Bog off idle?
Bog at throttle?
Bog at wot?

I have dealt with many off these little carbs. The main issue I have had is vacuum leaks. Always start there when trouble shooting.

[bblass]

Are you in the Bham area? If so me and icecold4x4 are working on restoring an old scooter today. You're welcome to bring the 150 by and we can help out. Have you played with the air ratio screw at all? Generally it's 1.5 turns out and then tiny adjustments from there, if you've changed jets sizes or have a crack in a boot that will drastically affect things

[Joe Shimano]

Just put it back to factory jetting and runs pretty good. Slight stumble off throttle ~ OK after that. Air/fuel needs a special tool I don't have so I can't do much with that.

[Buzz]

The special tool is a little flat head screwdriver. 8)

[Joe Shimano]

No, its a D shaped head

[Buzz]

Those cheeky bastards. They changed it.

[Joe Shimano]

Yep.  Looks like the middle one

[kylepeterson]

dunk the floats in water, make sure there aren't any air bubbles. if they leak air, they will only partially seal off the float needle, part of the time.

check the needle seat for cracks/corrosion, and the float needle for deformation.

those are the only causes for an inconsistent over flow problem. for a consistent overflow problem, it's the first e height setting. there is a spec for the distance from the casting to the float, is usually +/- 1mm , which is pretty easy to set.

float height effects mixture at all rpms, but more so at under half throttle. fix that before jetting because it will throw everything off at lower rpm, and will drive you nuts because it's severity depends on what the bowl level is , and this changes all the time.

after float, pilot first, then needle clip, then main. i bet all you need is to correct the float height and get a good seal at the float needle, for that bike to run flawlessly.

[bblass]

Yep.  Looks like the middle one

If you bend in one side of a .22 casing it works perfect

[Joe Shimano]

.22 case?  Who'd a thunk it!   Will give that a try. Thanks


Kyle - I think the float height is spot on.  I used a dial caliper and set it to 0.5" per Honda specs.   

It runs good enough for junior so I'll let it go till it cools off enough to work in the garage.