[steves]

If you move to carbs from a 90-97 the choke relocates to the left control pod, so that's something to consider as well.

If you can find a way to cross check the parts... this guy might be able to help http://www.cycleorings.com/

[foxox]

Like I mentioned before, those are Factory Pro needles. Check your main jet sizes to make sure they're the stock sizes before you replace the needles with OEM.

Ah, I missed the "FP" before! Thanks for the links!

If you move to carbs from a 90-97 the choke relocates to the left control pod, so that's something to consider as well.

Thanks for the link, steves.

I think I'll stick with rebuilding these; all of the surprises seem to be out of the way.

I'm concerned about the replacement diaphragms; all of these places seem to carry "88-97" diaphragms, but the 88/89 ones appear to be different (at least going by these pics) from the 90+ ones.

http://www.carbkitscapital.com/ has them listed as for years 88-97 but also says "ONLY replaces OEM#13507-17C01/17C00." and OEM#13507-17C01/17C00 is the diaphragm part number on the 90+ microfiche; the 88/89 microfiche doesn't offer a diaphragm part; only the whole slide assembly together.

The 88/89 diaphragms have a little tab on the rim of the diaphragm to help orient the slide (so you don't flip it backward), but the newer diaphragms don't have the tab (probably since the slides aren't symmetrical on them, so you can't get it in backwards). I don't think the tab makes a difference for the seal, but I wonder if the diaphragms are a different size. I'm going to try contacting a couple of these companies and see what they say.

I think one of the reasons the 88/89 fiche doesn't have a replacement diaphragm part is that the alignment tab has to be in just the right spot, which could probably only be done correctly at the factory or with a special jig. I certainly don't mind just making sure my slides are going in the right way and cutting off the tab if it becomes a problem, though.

Here's a pic of the little alignment tab/bulge:



The main jets that were installed are all size 132 (microfiche stock is 137.5 on the outer carbs, 135 on the inside carbs). Is this a significant difference? Would the same needle size be used for 132 vs. 135/137.5? But you know what... for another $30 or so, I can just have stock jets and stop worrying...which brings me to this:

Does the size indicate how open the jet is? If larger size #s are more open and more fuel and smaller is less fuel, why did someone install smaller jets with pod filters and an aftermarket exhaust (which my bike had); wouldn't that just make it way too lean? o_O

The pilot jet is 32.5 (same as stock), and the pilot air jets are 155 (same as stock). Seems all that was changed is the main jets and jet needles.

[steves]

Those REALLY look like GS carbs. I don't have any around at the moment.... but you might be able to measure them and get someone to compare.

[foxox]

Those REALLY look like GS carbs. I don't have any around at the moment.... but you might be able to measure them and get someone to compare.

I just checked, and at least the OEM diaphragm part #s match between the GS500 and GSX600 for 90+, but I guess I still don't know about 88/89.

I just loaded up the 88GS450, 89GS500, 89GSX600, and 94GSX600 microfiches:

http://i95.photobucket.com/albums/l127/searedice/1989%20Suzuki%20Katana%20600/1989%20Suzuki%20Katana%20Carb%20Rebuild/carb_compare.png

(big image warning)

The 88 GS carbs look very similar to the 89 Katana carbs (different slides at least but mostly the same), but the 89 GS carbs are much closer to the 90+ Katana carbs (see the slides, floats, float bowls/gaskets, and choke parts for the most obvious similarities). I didn't include them here, but the 94 GS carbs are much like the 89 GS carbs; the design didn't change much if at all.

The 88 GS 450 diaphragms have those tabs I have on them too, but it looks like maybe it served the purpose there of keeping those cylindrical slides from rotating (which would probably increase wear). The OEM microfiche part #s are only for the full slide assembly, like with the 89 Kat 600. Maybe the tabs are vestigial on the 89 Kat, recycled so Mikuni didn't have to make up a new body or diaphragm design.

Waiting for these companies to get back to me now...

[foxox]

I emailed MotorcycleCarbs.com and CarbKitsCapital.com and MotorcycleCarbs.com got back to me today:

"Sir:
There is no mistake on the description. This diaphragm would fit the 89 model of GSX600F. They all have the same diaphragm although the slide body differ.
Sales Dept."

So, that's promising! I may wait to see what CarbKitsCapital says, since their prices are better, but I don't mind dropping a few extra dollars for a company that replies to emails promptly.

Also, I decided to move back to stock main jets and jet needles. I own a J/K microfiche (I scanned it and put it here if interested: http://www.seas.upenn.edu/~drake/doc...Microfiche.pdf ), and it lists the non-California needle as Mikuni part 4CZ4-1. The Cali part is 4CZ5. cheapcycleparts.com lists only 4CZ3-3 as available. The RonAyers Suzuki part # for the needle matches the Cali needle from my microfiche, which is 4CZ5

After quite a bit of searching I found an incredibly awesome list of Mikuni needle specs, which I copied and uploaded here: http://www.seas.upenn.edu/~drake/doc...eedle_list.xls

It shows that 4CZ4 is essentially the same as 4CZ3, but 4CZ3 has 5 grooves cut in the top, while 4CZ4 only has one groove. 4CZ5, the Cali needle, only differs by being longer by 0.5mm, which probably closes off the main jet slightly more than the others. It also only has 1 groove. The RonAyers needle is cheapest, but I like the idea of an adjustable needle so I think I will go with cheapcyclegear for my needles/jets. The cheapcycleparts prices still beat BikeBandit anyway.

[Wild-Bill]

Sounds like the 4CZ3 would be just the thing! That is one beast of a data table, by the way. How'd you like to be the guy who had to put that together?!

[hardlydangerous]

wow, dirty.... if you dont have one I would strongly recommend buyin an ultra sonic cleaner and dunkin them in there for a couple hours each.

for the diaphrams if you have any pin holes or abrasion areas a very light film of liquid electrical tape works wonders for a temp fix.

[foxox]

That is one beast of a data table, by the way. How'd you like to be the guy who had to put that together?!

Seriously o_______o

if you dont have one I would strongly recommend buyin an ultra sonic cleaner and dunkin them in there for a couple hours each.
for the diaphrams if you have any pin holes or abrasion areas a very light film of liquid electrical tape works wonders for a temp fix.

Like these things for jewelry/etc.? [ame="http://www.amazon.com/Sonic-Wave-Professional-Ultrasonic-Cleaner/dp/B002A8IDQI"]Amazon.com: Sonic Wave Professional Ultrasonic Cleaner - Cleans Jewelry, Optics, Eyeglass, and Other Delicate Items + Blitz Jewelry & Gem Cleaner (Concentrate 8oz.) + Professional 100% Cotton Flannel All-in-one Jewelry Cleaning, Buffing and Tarnish Shielding Cloth: Electronics[/ame]
Is it hard to get one big enough or are they usually a decent size?

I've blasted nearly a whole can of carb cleaner through these. I went over each carb 3 times just spraying it into each hole for a couple of seconds. Then, I checked every internal passageway more carefully by covering up extra openings if that tube had more than 2 sides and making sure the cleaner sprayed through the un-covered hole easily. I tried to made sure a mist came out of the 4 tiny holes in the barrel, but I should double-check those. I also cleaned off the exterior of the carbs with a toothbrush and cleaner

How temp of a fix does the liquid electrical tape make? I think I'll just wait for legit replacements, but I can keep the old ones around in case something crazy happens to the new ones.

[steves]

Get a can of Berryman's chem dip from autozone for like $20 each. Dip each body over night, then rinse out in soapy water. Follow that with a boil on the stove if you are feeling like it.

[Kreylyn]

Like I mentioned before, those are Factory Pro needles. Check your main jet sizes to make sure they're the stock sizes before you replace the needles with OEM. Good sources for carb parts:

http://www.carbkitscapital.com/carb_kit_list_model.php?make=Suzuki&model=GSX600F

and:

http://www.motorcyclecarbs.com/Mikuni_Jet_Needles_C37.cfm

and:
http://www.partsnmore.com/parts/suzuki/gsx600f/?filters[fitting]=custom
and:

http://www.cheapcycleparts.com/

and Harbor Freight sells a metric viton o-ring kit for about $6 that has just about all the o-rings you'll need.

Those are not Factory Pro needles.... they are Dynojet needles.

Irregular taper, 6 slots for the eclips... Definately DJ needles. If there are DJ needles, then it's probably DJ jets. Don't mix/match jets with needles. DJ jet sizes do not use the same # system for the jets. A DJ 120 jet is not the same as an OEM 120 jet. OEM jets are by flow, DJ are by hole size, and differently shaped.

I would suggest just getting a Factory Pro kit.

As for the egg shape on the Needle Jets, look specifically at the inner lip/ring. That is where the wear occurs. Use one of the needles inserted into it to give you a better idea if there is wear. They should fit pretty close and not leave alot of play, and of course not be out of round.

Krey

[Wild-Bill]

Maybe you're right. I see the 6 slots for the e-clips. I looked at blunted ends and thought FP. In any case, those things don't need to back back into anything anyone cares about.

[SPOKES]

WOW! I've seen some bad carbs but not this bad. From the looks of the deposits, corrosion, the needles, the float valve, etc. I'd be very surprized if you can get all of the internal passges clean enough to work and that the internal passages haven't eroded due to corrosion and sediment to the point where they flow differently, think I'd be looking for replacement carbs, sorry.
Also, the erosion may be due to fuel additives and/or high levels of methanol.

[steves]

Er, other than the pitted needles... this isn't that bad. I've had worse.

[Wild-Bill]

"Your arm's cut off"
"What? It's just a scratch. Have at you!"

Monty Python, Quest for the Holy Grail

[foxox]

I would suggest just getting a Factory Pro kit.

As for the egg shape on the Needle Jets, look specifically at the inner lip/ring. That is where the wear occurs. Use one of the needles inserted into it to give you a better idea if there is wear. They should fit pretty close and not leave alot of play, and of course not be out of round.

Should I get a Factory Pro kit rather than stock? I was thinking I would move it all back to stock, but I haven't made any purchases yet.

The emulsion tube inner lips look round, but there is a tiny bit of wiggle room; less than 1mm.

WOW! I've seen some bad carbs but not this bad.

It ran like this! But if I let the bike sit for a week, it would take 10 minutes and jumper cables to get it started. And I couldn't get it to idle at less than 2500 rpms or so. It's my first bike and I only rode it a few times before this project... I always felt dumb at stoplights with the engine revved up to keep it alive lol. I'm hoping it will all work out

"Your arm's cut off"
"What? It's just a scratch. Have at you!"

lol.

I'm going to try to get to an Autozone tomorrow after work for the Berryman chemical. I would go today, but apparently my car is also having some fuel system problems Damn you, mysterious EFI "system too lean" OBDII codes!