CRF150 Wandering Idle

[Yardstick]

It seems like I've had this happen on my XR600 and it was due to misadjusted floats. I can't find any real useful info searching here, so...

Has anyone seen this in an '04 (or similar) CRF150: It starts fine on full choke. It carburates cleanly through the RPM's once it is warmed up. The problem is, if you let it sit in one spot at idle, the RPM's wander high and low almost randomly. The baffle is out, but the snorkel is still in place (the girl riding the bike doesn't need more power -yet). There could still be remnants of bad gas from the previous owner letting the bike sit for too long. How much affect could that have (my 600 will practically run on anything you can ignite with a spark...)?

What is the float level supposed to be set at on these bikes? Found it! 12.5mm I found the idle mixture screw is supposed to be at 1-5/8. Is that correct?

Still looking for any possible reasons the idle wanders high/low. Any ideas?

[jsmith811]

I have a 06 CRF230 that does the same thing, it's extremely cold natured of course, but even after 10 minute warm up the idle knob needs to be adjusted occassionally up or down, although the bike runs out smooth. The pilot is Not clogged on this bike.

[Jigggawatt]

If the cable isn't hanging up or you don't have an air leak. I'd richen up the pilot jet. If you leave the choke a little closed , does it help?

[Yardstick]

The cable doesn't seem to be hanging up. It actually revs up by itself without anyone being near the throttle. After a little while it usually calms back down. It goes back and forth just sitting there with nobody near it. I'll go through the carb again more thoroughly and with the specs I've found and see if that helps. If not, I guess the hunt will be on to find jets.

[wilber]

I have the same problem with a 06 150 my wife rides. Very cold natured.

[Yardstick]

I did a super thorough cleaning on the carb last night and checked/adjusted everything to specs. It seems better now, though it still idled a little low (died a couple of times warming up) and I didn't let it warm all the way up since it was late and the bike doesn't have the baffle in.

I'll search some more, but is there a recommended pilot/main/needle clip position for having the snorkel in and the baffle out? How about both out? The plug certainly didn't look lean, but it does almost seem like it could use just a bit more fuel.

Edit to add: Is there supposed to be an anti-slosh or some kind of little splash guard in this carb? This carb doesn't have one and of course I'm used to my 600 that does.

[849racing]

Check your valves. a tight intake valve will sometimes give you a similar symptom to a air leak. clearance should .004"

also try this jetting: airbox open (helps to balance the increased exhaut flow and won't increase power that much). only remove plastic baffle not the the outer rubber piece.

42 pilot

115 main to start with

honda "full power needle set" PART #16012-KPT-921

pilot screw as needed usallly between 1 1/2 to 1 3/4

[Yardstick]

Heh... I forgot to mention that, but the first thing I did was check the valves.

Intake is .004", Exhaust is .005" and the intake started off just a hair tight. It didn't help.

Is there a preferred jetting with the stock needle? Going from 98 (stock) to 115 on the main seems pretty drastic.

[849racing]

I've seen specs on tt w/o the needle kit I personally haven't tried them but every needle kit I do I get good results and don't have to play with the jettting a whole lot, maybe a size up or down on the main. 115 main is what honda reccomends you start with.

[Yardstick]

The girl who owns the bike is just on a sort of limited budget and I know the needle is the most expensive part. Since we don't have the baffle I'm looking for the cheap/easy solution to the jetting problem.

[849racing]

the price is around 25 bucks and you get a needle, needle jet and two clips (adjustment and retainer).

just another thought, chk the vacum hose for the air cut valve it's the one on the on the top front of the carb if it is split or damaged or not connected it will cause an air leak also.

yes there should be a plastic baffle that goes around the main jet but that should not cause the problem your having. it only might be a problem when you get into some rough terrain.