What have I done (wrong) to my 24mm PWK?

[shocky]

i dont remember that part being loose ontop of the atomiser its the spray tube and is normally a press fit in there ie not loose but can be drifted out if need be

[dansuper]

i dont remember that part being loose ontop of the atomiser its the spray tube and is normally a press fit in there ie not loose but can be drifted out if need be

Yep, just checked mine - it is pressed in and has never previously come out.

[dansuper]

Ok, disassembled carb again, checked all parts, sprayed carb cleaner through jets, airways, etc. Reassembled carb, started scooter - still has the same symptom (cuts out just off closed throttle). Decided to try again with choke on and it revs out cleanly, idles etc. Choke of again and it cuts out.

Aaaaaaaaaaaaargh!!!!!!!!!!

Anyone ideas?

[dapper]

Ok, disassembled carb again, checked all parts, sprayed carb cleaner through jets, airways, etc. Reassembled carb, started scooter - still has the same symptom (cuts out just off closed throttle). Decided to try again with choke on and it revs out cleanly, idles etc. Choke of again and it cuts out.

Aaaaaaaaaaaaargh!!!!!!!!!!

Anyone ideas?

That would point to the pilot being too small, hence requiring richer mixture to start and rev through cleanly. Are you absolutely sure you've re-assembled the carb correctly? What jets do you have fitted at present? Are you sure you aren't sucking in extra air via the carb to manifold rubber hose, hence weakening the mixture?

[storkfoot]

That would point to the pilot being too small, hence requiring richer mixture to start and rev through cleanly. Are you absolutely sure you've re-assembled the carb correctly? What jets do you have fitted at present? Are you sure you aren't sucking in extra air via the carb to manifold rubber hose, hence weakening the mixture?

Agreed. Consider whether you've moved the air mix screw when you 've stripped the carb.

Also, on the 24mm, is there a diaphragm attachment on the top of the carb (on the top behind where the throttle attaches)? If so, this needs blanking otherwise it sucks in air.

Make sure both floats are set at 21/22 and also just check you've fitted the throttle cable right in the carb. If you're not paying attention, you can set it so the needle is flapping around in the slide (allegedly )

[dansuper]

Thanks Storkfoot and Dapper. I think the carb has gone back together properly as there aren't too many parts to screw up.

Yes, refitting the throttle cable into the slide is a royal pain in the arse, so I will double check that the needle is in properly.

I'm running a 32 pilot, JJH needle (middle clip) and 110 main. This is the same configuration prior to the strip down.

Will also check for leaks around the manifold rubber and see how it goes.

Cheers,

Dan

[dapper]

Jetting seems OK, but you might need to play around with the needle taper a bit to get it spot on. JJK, GJH ? Did you double check that the pilot hole next to the main jet was clear? You can unscrew the two halves of the top section of the carb with a very well fitting driver to the two screwheads, but I'd be careful as the alloy is fairly soft. I tried on mine, but was afraid of doing damage to the carb, so used the torch method previously described.

[storkfoot]

When you set up the carb originally what pilots, needles, and mains did you try?

Also, is the needle a proper Keihin one that is stamped JJH?

[dansuper]

Jetting seems OK, but you might need to play around with the needle taper a bit to get it spot on. JJK, GJH ? Did you double check that the pilot hole next to the main jet was clear? You can unscrew the two halves of the top section of the carb with a very well fitting driver to the two screwheads, but I'd be careful as the alloy is fairly soft. I tried on mine, but was afraid of doing damage to the carb, so used the torch method previously described.

I've probably negelected needle taper and have been chasing my tail as a result. I've only ever had the JJH in it, although I also have an untried JJF. Never used it as I thought my 1/4 throttle bog was due to richness, and would only be made worse. If I can get the thing working again, will try other tapers.

Sprayed carb cleaner through pilot hole and it came through fine.

Yep, I removed the carb top section (destroyed the screws in the process ) and I think my problem is around here. Lot's of loctite/crap came off from around the screws, and I was pretty sure it would result in 'something' being blocked. Even worse, the tiny rubber seal between the two halves doesn't want to seat properly. It seems to have been installed with a small amount of silicone/glue. Could it be that air is getting past the seal?

When you set up the carb originally what pilots, needles, and mains did you try?

Also, is the needle a proper Keihin one that is stamped JJH?

I tried pilots from 32 to 38, and mains from 108 to 116. Haven't changed the needle, but tested every clip position. I have to admit I could have been more methodical about it, but the settings were still rideable when I pulled it down. Just that damned bogginess.

The needle is stamped JJH but am not really sure if it's genuine. Doubt it, as it came from a ScootRS kit.

[storkfoot]

dansuper, if the seal in the carb housing is not seating properly (I've seen this on the copy PWKs too) IMO, for the sake of your sanity, scrap it and buy a better (non-copy) carb

Irrespective about what carb you have, you do have to be methodical when setting up a carb unless you strike lucky and get it right almost first time (never happens to me ) So, marking the throttle with tape, and making notes about what happens when you change stuff, is important. Good luck