carb cleaning / rebuild

Hey all, haven't posted in a while. Not that anyone would remember me.

I've posted a bit on the saga of my '82 KZ550C3. When I took it to my buddy's garage in November to bed it down for the winter it still wasn't firing up or running great. Have done all the diagnostics, coil power mod, compression (though no leakdown), valve clearances, etc. It comes down to carbs, so I took them off the bike in the hopes of rebuilding them in the winter. I took 'em down to bare bones yesterday, even separated them out and took out the annoying idle air screw plugs. Coupla questions:

(1) I think I have all the rubber out of the carb bodies -- throttle shaft seals, idle air screws, the works. Is there anything hidden I should beware of before I dunk the carb bodies in cleaner?

(2) Before I took the idle screws out, I checked their postition. #1 and 2 were 1-1/4 turns out, #3 was 2 full turns, and #4 was 1-1/6. As far as I can tell these carbs have never been cleaned or the idle screws touched since she left the factory. Any reason why #2 should be so different? Otherwise I plan to set them all at 1-1/4 to start with.

(3) Speaking of idle screws, I've had the carbs off since November, and I drained the bowls before I took 'em off. I noticed that #1 and #2 were wet when I took them out, #3 and #4 were dry. Any cause for concern here? Maybe some passages were blocked?

(4) The float needles on all four had circumferential scoring around the needle cone. Not too bad, but enough that I could catch a fingernail on it if I tried. Clymer says to replace them if this is the case. Should I?

(5) #1 bowl was the dirtiest, as were all components. Even the venturi looked like it had light oxidation on the output side and some splatter pattens. Is this something that would likely be seen if one or more of the jets were dirty?

(6) The Clymer and parts diagram indicate that I'm supposed to have an O-ring between the needle jet and the carb body right under the venturi. I didn't see this O-ring in any of them. It's item 670 in the BikeBandit parts catalog, under "carburetor parts".

www.bikebandit.com/houseofmotorcycles/ka...550-ltd-1982/o/m9907

I'm hoping this is the year I finally get to ride the beast. I've put less than 100 miles on it since I bought her in the late summer of 2006. The carbs are my last source of gremlins as far as I can tell. I've never done a carb rebuild before so I'm likely going to screw something up. Yeehaw!

Nick in MA

nick_borer wrote:

Hey all, haven't posted in a while. Not that anyone would remember me.

I've posted a bit on the saga of my '82 KZ550C3. When I took it to my buddy's garage in November to bed it down for the winter it still wasn't firing up or running great. Have done all the diagnostics, coil power mod, compression (though no leakdown), valve clearances, etc. It comes down to carbs, so I took them off the bike in the hopes of rebuilding them in the winter. I took 'em down to bare bones yesterday, even separated them out and took out the annoying idle air screw plugs. Coupla questions:

(1) I think I have all the rubber out of the carb bodies -- throttle shaft seals, idle air screws, the works. Is there anything hidden I should beware of before I dunk the carb bodies in cleaner?

(2) Before I took the idle screws out, I checked their postition. #1 and 2 were 1-1/4 turns out, #3 was 2 full turns, and #4 was 1-1/6. As far as I can tell these carbs have never been cleaned or the idle screws touched since she left the factory. Any reason why #2 should be so different? Otherwise I plan to set them all at 1-1/4 to start with.

(3) Speaking of idle screws, I've had the carbs off since November, and I drained the bowls before I took 'em off. I noticed that #1 and #2 were wet when I took them out, #3 and #4 were dry. Any cause for concern here? Maybe some passages were blocked?

(4) The float needles on all four had circumferential scoring around the needle cone. Not too bad, but enough that I could catch a fingernail on it if I tried. Clymer says to replace them if this is the case. Should I?

(5) #1 bowl was the dirtiest, as were all components. Even the venturi looked like it had light oxidation on the output side and some splatter pattens. Is this something that would likely be seen if one or more of the jets were dirty?

(6) The Clymer and parts diagram indicate that I'm supposed to have an O-ring between the needle jet and the carb body right under the venturi. I didn't see this O-ring in any of them. It's item 670 in the BikeBandit parts catalog, under "carburetor parts".

www.bikebandit.com/houseofmotorcycles/ka...550-ltd-1982/o/m9907

I'm hoping this is the year I finally get to ride the beast. I've put less than 100 miles on it since I bought her in the late summer of 2006. The carbs are my last source of gremlins as far as I can tell. I've never done a carb rebuild before so I'm likely going to screw something up. Yeehaw!

Nick in MA

My factory manual says never to dunk carb bodies in anything that can destroy plastic. There are internal parts in some that can be damaged. I personally use carb spray (which is mainly acetone) and have never hurt anything. I would not dunk them in the super nasty dips like Berrymans or the like.

I use that for cleaning gun barrels and it makes my skin burn if it touches it.

My factory manual says never to dunk carb bodies in anything that can destroy plastic. There are internal parts in some that can be damaged. I personally use carb spray (which is mainly acetone) and have never hurt anything. I would not dunk them in the super nasty dips like Berrymans or the like.

I would generally agree, but I have taken the carbs down to their bare bones. The only bits left in there seem to be those that have been pressed in. Does anyone know of any leftover plastic / rubber in the carb bodies for an '82 KZ550? I think the carbs are TKs, Clymer lists them as K-22P-2D for this model (KZ550C3).

I'd really like to get the passages a good cleaning so I don't have to dive into these things again. If a standard carb dip solution isn't good, how can I ensure I've gotten everything with a spray? For that matter, why wouldn't the spray be just as bad on plastic / rubber as the dip? What about ultrasonic cleaning? Do they use a caustic dip as well or is it a more benign substance?

Thanks in advance,
Nick

As far as I know, any plastic part in a carb can handle acetone because that's what carb cleaner is. The dip tanks use much hotter solvents including benzene. I don't know if it would hurt anything, just going by what the manual says.

I think ultrasonics should work OK.