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Katana worn out Carb pics? not sure...

  • Thread starter Thread starter rongant
  • Start date Start date
R

rongant

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Hi there guys... I'm working on my brother's 1988 Katana 1100.
I'm taking the carbs apart to see why the hell it just rains down fuel into the engine when the vehicle is off. The petcock does seem to be leaking, so we're looking into getting a repair kit (any suggestions on where to buy that?) but also, we took some close-ups of the needles, the main jets, and the needle jets.
The needles have some pretty clear wear on them, where 95% of the needle is that brass colour, and in the pic you can see the worn part is silver coloured.
Also, the main jets, 2 of them were ok, but 2 of them seem either pitting or just plain dirty.
And, on the needle jets, there is some pitting on some of the holes, though all of the holes are open and clean... not sure how that pitting would have occurred or how it would affect things though...

So if you have any suggestions your experience can let me know, I'd be greatly appreciative in particular about the suspected wear on the jets and needles... Thanks!

Dave
 
Needle Worn also, need replacing??

Needle Worn also, need replacing??

should these be replaced?
 
If it's leaking gas, you have a float issue. Looks like you might have some other (wear) issues, but your main issue is stuck float(s) or leaky float seat(s).
 
The reason for the pitting looks to be corrosion. Could be from water contamination or maybe just chemicals in the gas. Not sure. While the jets don't look optimal, my guess is that they will be servicable enough though. Wouldn't hurt to take some scotchbrite and rub down the rough spots. The needles look pretty bad to me though; looks like some plating on the outside is worn down. Could be the mating part is worn as well (not sure what it's called). Wear will lead to a more rich mixture so keep this in mind if you try to use these parts as is.

Not sure this helps. Good luck.
 
The needles & emulsion tube (needle jet) needs to be replaced, You will never get it jetted correctly with those parts Tyme for some carb rebuild kits
 
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Yeah, corrosion... now sure how/ why it happens, but I had one needle out of four corroded and pitted in my old Kat1100.

As SqDancer says, replace them. For correct fuelling it is critical to have the jets, needles, etc. all spot-on.
 
Hi there... thanks alot so far folks...
I went to Ron Ayer, and the fiche says the needles are discontinued.
But, I went to Dynojet's site, and they sell a $130 kit that has them, as well as probably the floats and o-rings etc...

The thing i want to understand more about though, is how the float works.
We corrected the float height, it was about .8mm too high.
Upon further inspection, we removed the floats and checked out that little spring loaded jet underneat the float that has a little screen on it. None of the little springy needles underneath the floats were sticking. Also, they were all in their spots fairly tight, no play at all. It took a little bit of effort to remove them for sure...

I haven't seen anything at all that's sticking, nor have I seen any tapered needle seats or needles that are worn at their tips, which is what I was expecting to see given the leaking problem...

The leak was so bad that when I went to pull his airbox off there was probably a litre of gas in it, and the #1 cylinder (it was on the sidestand) was completely hydrolocked full of gas.

I'm gonna get that DYNOJET kit I think, cuz it seems to have all the parts that we need, and I'm also going to see about a new petcock or petcock repair kit...
I saw some on ebay that weren't too expensive.. have any of you ever bought things like that off ebay?

thanks!
 
While you should take a look at your worn jets/needle, they have nothing to do with the leak.

Judging by the late year, you don't have a "real" GS Katana, so your carbs are different. But I'll assume the float valves work the same. When the gas level reaches a certain height, the float floats and pushes the "springy jet" (float needle) against its seat, which stops the flow of gas into the bowl. If it doesn't seal properly, the carbs will overflow. Assuming both the seat and the needle look good, the other potential leak area is the o-ring that seals the seat against the carb body. Even if it's snug it can be leaking.

If you replace those o-rings, you'll probably solve the problem. One good way to test for proper sealing is turn the carbs upside-down, push all the floats down at once (so they should be sealing), and blow into the gas line. If they're sealing properly you shouldn't be able to pass any (or hardly any) air through. I'm not sure if you have dual gas feeds on these carbs or not, so account for that when you do this test.

I'm also not sure where to get o-rings for your carbs. For Mikuni CV carbs, cycleorings.com is the best place. But you have flatslides, right?
 
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By the way, be sure not to confuse the two different needles being referenced here. The jet needle is the thing attached to the slide and is responsible for metering fuel output under throttle; it has nothing to do with your leak. The float valve needle is in the float bowl and seals against the float valve seat to regulate the flow of fuel into the bowl.
 
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That would be a jet needle not a needle jet.

Not trying to needle you though. That would be worngfully pedantic.
 
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