Anxiety over carb body wear

[ovlovder]

So, I feel like this carb body wear thing is hanging over my head...  I have a 91 with 18k, and the previous owner was sure that the issues the bike was having were related to this.

I am hoping not, but I have the stock carbs and a second rack I bought on ebay. 

Im wondering how common this is, and how to identify it while I have the carbs off the bike.  I have searched and not found much. 

Finally, what can be done to prevent it from occurring?

[tomacGTi]

Carb body wear 101:

-There is nothing you can do to keep it from happening. It is inherent in the design of the carb. Obviously mileage and how the bike was ridden will factor into it but it is going to happen.

-Tell-tale signs of body wear

Easy version:

-Pop off the airbox and see if you can look at the body slide: you'll have to move the black nylon vacuum slides up and out of the way. If you can still see the molded plastic "dots" (there should be several), then the slide body and slide are still good. You can make life a little easier by popping off the carb top. Be careful not to lose the o-ring! You can also clean/polish/lightly oil up the black nylon slide while it's out as well.

Hard version:

Disassemble the carbs (make sure you have new o-rings if you've never been in there or know how fresh they are) and pop the plastic slide out of the carb through the top. Inspect the slide and see if the "dots" are intact. If you can still see them, you should be fine. The lowers of the body slide wear at a faster rate than the uppers.

If they are, I'd recommend to clean them as best as possible and use a very light oil to lubricate the surfaces. This will help a slight bit and if you do a slight "polish" on the black nylon surface with some fine grip sandpaper, it'll help as well.

-If the slides are worn:

You'll see wear in both the emulsion tube as well as the needle jet.

The needle will saw away at the emulsion tube (or jet needle) and ovalize it causing a rich condition. Dropping the needle only helps somewhat till it comes around again. Suzuki are the only ones that carry the emulsion tube and replacing it only buys time as it's bound to happen again if the body is worn. You'll probably need new needles as well.

Interfuse had the worst case I've ever seen, I don't think his pics are up anymore though.

Jury is out on if aftermarket needles; brand or otherwise are harder on the brass tubes versus the aluminum stock version.

-What causes it?

From what I've read on here through the years, lots of smaller throttle inputs such as in stop and go and city riding will exacerbate the situation as the needle is constantly going up and down in the carb.

WFO throttle application just snaps the needle open and keeps it there. Backroads riding and track riding mainly.

Hope that answers your question

[tabby]

Thanks tomacGTi, that was helpful. I've looked at mine, and so far they look OK. I have the carbs completely dis-assembled, and new o-rings are on order. I think I'll take some measurements and do some head scratching. Has there been any mention of being able to buy replacement slide bodies. I'm wondering if, in the extreme wear cases, a replaceable "SS" or brass shim can be glued{silicone say} onto the worn surfaces. The shim stock would have to be lightly clamped to insure even glue distribution. Then light sanding/polishing could be done to insure even contact surfaces. Like I said, head scratching. I gotta stop doing that, as I don't have much hair left. 

[tomacGTi]

Here's the rub: the only way to get new body slides is to buy a new carb from Suzuki. There is no other way. They are not available separately, even from Sudco (AFAIK anyway).

I'm sure if you're crafty and have access to a mill, you can make some liners or even replacements for the worn slides but as you've seen, there isn't much room to play with. There is very little room to work with as it is a "slide" and not bearing'd like an FCR.

One of the other thoughts I had was to epoxy in some thin brass material to the existing body. You can find this stuff in hobby shops from K&S but the idea never went further than that. I'm sure this could work but I'd be sure the sliding surfaces were parallel first (sanding both sides to match) before all else. The other downside is the fact you'd have to do 4 of them.

-Randy

[tabby]

One of the other thoughts I had was to epoxy in some thin brass material to the existing body. You can find this stuff in hobby shops from K&S but the idea never went further than that. I'm sure this could work but I'd be sure the sliding surfaces were parallel first (sanding both sides to match) before all else. The other downside is the fact you'd have to do 4 of them.

-Randy

That is exactly the direction I was thinking, except I was figuring on silicone instead of epoxy. My logic was to make it not so permanent, so once fitted properly{sizing notes taken!!}, after it wore out, the shim could easily be removed and fresh shim stock could be re-applied. I don't think I'm anywhere in need of this, but I will store it in this cluttered mess I call my brain for future reference. Maybe this will give someone else an idea or two.