79 kz650 carb parts and boil

I'm in the middle of rebuilding my stock 78kz650sr's carbs. I'm using kits that I got from Z1 Enterprises. They have all the parts except the choke cap, plunger and spring. The gaskets fit nice. The mains in the kit only go up to 102.5. It comes with a few extra parts 97, 97.5, 102 mains, pilot screw and another different air screw. The 78 doesn't have an accelerator pump.

All of the rubber bits come off, floats, throttle shaft seals, air vent and gas tubing, O rings etc. Check the diagram in the manual. I'm soaking them in carb cleaner from NAPA and blowing out the passages with compressed air. It seems to do the trick, but its expensive strong smelling stuff. So the gargage doors are all open and I wear the thin rubber gloves Costco sells for working on cars and painting - like surgical gloves. The cleaner can't be good for the skin.

mariozappa wrote:

My service manual warns against using strong solvents on the carbs as the may have plastic parts inside. I use acetone spray to clen carb parts.

Wouldn't you consider acetone a strong solvent?

It's definitely stronger than naptha or mineral spirits, but it's a lot less hostile than the nasty stuff in those Berryman dip tanks. I believe those are too strong for any material but metal.

I have been using lacquer thinner and acetone for cleaning so long I don't notice the smell. I clean my hands with it sometimes. Not really a great idea.

Acetone will absolutely melt many plastics, but the plastics used in carburetor parts nearly always are immune to it simply because it is the main cleaning chemical in most commercial carburetor cleaning sprays. making parts that would not survive it would lead to immediate carburetor failures....

I have never seen a carb part that couldn't handle acetone.

YMMV

Post edited by: bountyhunter, at: 2008/02/05 17:52

KawiConvert wrote:

Isn't it possible to get all of the plastic parts out? Other wise did they cast the aluminum carb bodies around the plastic? Just curious, mine really need a dip in the (chemically) hot tub.

I think in the old days, some carbs had parts installed and then "sealed" in with press in metal caps or plugs. I don't know where the "internal" plastic parts are, but the factory manual does warn not to dunk them.

wiredgeorge wrote:

Acetone is an especially nasty chemical that is a known carcinogen and dissolves plastic faster than any other chemical. In some manufacturing processes, acetone is used to wash plastics that have been sanded or filed to restore a smooth and shiny finish... in other words it melts the plastic.

True in general, but it's pretty easy to make plastic which resists acetone. if you look at the polymer (PLASTIC) receivers that Glocks and SIG 's and all the other "plastic" pistols use, they are impevious to acetone. That's mainly because like carburetor cleaner, nearly all the gun cleaner sprays are acetone. If you spray the plastic with them, it doesn't affect them. It turns white because it strips the oil, but the plastic is not actually changed.

The needle holders in my Mikunis are plastic and they are unaffected by acetone.

bountyhunter wrote:

KawiConvert wrote:

Isn't it possible to get all of the plastic parts out? Other wise did they cast the aluminum carb bodies around the plastic? Just curious, mine really need a dip in the (chemically) hot tub.

I think in the old days, some carbs had parts installed and then "sealed" in with press in metal caps or plugs. I don't know where the "internal" plastic parts are, but the factory manual does warn not to dunk them.

What an odd way to build things. Anyways, I am looking at other ways to clean them out. They really need something strong though. On the areas I could get to with a brush I found that the spray in carb cleaner worked, but only with the assistance of a brush. Lots of varnish in these carbs.

Also, I did find out that the accelerator pump isn't necessary, as stated above they were added for epa checks. And I also found that the bowls off of my 78 (non-accelerator pump_ carbs will bolt right up in place of the 79 bowls. All I have to do is to pull the accelerator pump injectors out of the carb bodies with a pair of vice grips (slides right out I found) and sand of the bowl end so it is flush with the bottom, and if I want I can cut the other end down so it is flush with the intake. Now I just need to get some kits, some larger jets, a stainless bolt kit and I should have a running bike.

Thanks for the help and the info about the carbs.
KC

I have boiled many racks of carbs in a pot of lemon juice with amazing success. The acidity of the lemon juice will eat through all the gunk but not attack the rubber and plastic bits. I have experienced NOTHING but great results with this technique. Just make sure you spray the carbs through with carb cleaner or wd-40 afterwards to wash out any stickyness that the lemon juice leaves behind.

KTA wrote:

I have boiled many racks of carbs in a pot of lemon juice with amazing success. The acidity of the lemon juice will eat through all the gunk but not attack the rubber and plastic bits. I have experienced NOTHING but great results with this technique. Just make sure you spray the carbs through with carb cleaner or wd-40 afterwards to wash out any stickyness that the lemon juice leaves behind.

Thats the first I have heard of that method. Of course when I was a kid and I heard that I needed to "boil" my carb I actually tore it down and suspended it in a pot of boiling water (not on a gas stove thank goodness). Oh the things my mom put up with. Anyways, I may look into that as mine have some bad varnish and other crud in them.

Ok, I tried the lemon juice and then cleaned them off with a spray can of cleaner and they are definitely clean. Didn't do as much for the brass though, but that is less important as I am replacing the jets.
Thanks for the suggestion, saved a bit of time and trouble.
KC