1989 GSX600F carburetor rebuild project

[foxox]

The 90->98 carbs are not the same as the 89 (K revision) carbs, and that's what I have started rebuilding here, so I thought I would put together some pics of the process to supplement Carbs101. So far I just got through disassembly; cleaning happening later today, and then maybe a few days of waiting for some replacement parts, then reassembly/synchronization.

Disclaimer: I don't think these are totally stock (jets, etc. may have been changed).

I do have a couple of questions, but mostly I just want to share pics for other people who might decide to clean 89 carbs.

The entire collection of carb rebuild pics (including new ones as I add them):

http://s95.photobucket.com/albums/l127/searedice/1989%20Suzuki%20Katana%20600/1989%20Suzuki%20Katana%20Carb%20Rebuild/

Question: When I drained bowl 4, it was totally empty and when I disassembled #4, it was the cruddiest one of the carbs. The others had a bit of sediment, but #4 was a freaking mess (see pic below). When I rode a couple of weeks ago, #4 header pipe got plenty hot like the others so I believe fuel was getting through, but why is just #4 so messy? The others were nothing like it.

Pic of gross bowl #4. The farther from #4, the cleaner they got (#1 was nearly spotless).




And some other highlights from disassembly (full set of pics in the link above to the photobucket album):



Impact driver from Sears = awesome for undoing these screws holding the body parts together.




There are these little filters in each bowl's fuel supply float valve... do the later carbs have these?




Like carbs101 says, PUSH hard down into the jet's screw head with your driver when removing these jets; I messed up one of them by not pushing enough and slipping.




Easiest way to get the mixing/emulsion tubes out: remove jet screw, remove washer, replace jet screw, then tap on it until it comes out the top of the carb body, through where the slides were. There will be some resistance but it goes right through. You can see that I took out the plastic thing the slides ride in on carb #4, but I left it in for the others. I don't know yet if I need to totally remove them for a good cleaning or what. It was held in with torx bolts with lock rings AND loctite, so I think maybe I wasn't supposed to be messing with that...




Remove the pins on the floats by tapping something like a philips head into the end. Pulling on the head wasn't working, but tapping on the other end worked great.




Watch out for these springs between the throttle control sections if you opt to separate the individual bodies (I did this and good thing too cause there was a lot of crud in the tubes between the carbs).




QED... (Quod erat demonstrandum or as I prefer, Quite Easily Done)




The smaller hammer didn't survive the impact driver... head broke right off!
A couple of bolts were too messed up by a previous mechanic to even come off with the impact driver, and the vice grips worked great for those.
I'd like to thank mom for use of that hors d'œuvres tray thing.


Peace

[steves]

Just because #4 had more dirt in it, doesn't really mean anything specifically.

Did you happen to snap a pic of the rack fully assembled before you started?

This is interesting as they look like old GS carbs... and they are different than '88 carbs.

[Wild-Bill]

I don't know about the '89 carbs but the others have an o-ring under that plastic block you pulled out of #4. (#7 o-ring from Lowes plumbing section) The 90-97 carbs don't have the removable float needle seat so no filter screen or o-ring there.

[foxox]

Just because #4 had more dirt in it, doesn't really mean anything specifically. Did you happen to snap a pic of the rack fully assembled before you started?

Yeah:

And another pic of the other side from an old thread:


I have higher-res versions if wanted too

I don't know about the '89 carbs but the others have an o-ring under that plastic block you pulled out of #4. (#7 o-ring from Lowes plumbing section) The 90-97 carbs don't have the removable float needle seat so no filter screen or o-ring there.

Yeah there were actually 2 orings there on the round part of the plastic block... thanks for the size! I pulled them off almost right away, but they were in these grooves. They were smushed/flattened from being sealed in there; maybe I'll replace all 8 of them just to go 100% on this project.

[Wild-Bill]

Ummm... Don't count on the size. That's way different from the 90-97 emulsion block. On those you don't have the round tube like on yours. The (one) o-ring goes on the bottom end of the block, around the emulsion tube.

You getting rid of those pods while you're at it?

[foxox]

You getting rid of those pods while you're at it?

Yes, getting rid of the pods! I'm hoping that the 89 carbs are close enough to the 90+ ones that I can go to the local scrap yard for a new airbox.

I don't know yet if these are custom jets or what, but I should be able to move back to the stock airbox either way, right? This is some kind of aftermarket exhaust and I suspect all three were changed (pods, jets, pipes) as a performance mod by some previous owner. The pipes are very rusty and the muffler is scratched up so if the stock airbox and existing jets/pipes doesn't work, I will move it all back to stock.

Also, what are "flatslides"? My slides are flat but are these "flatslides"? Someone told me that if they are, they are "the shiznit".

[Wild-Bill]

If you're looking for an airbox, I've got one from a '94 750. (36mm carbs) $20 plus shipping.

[foxox]

I took off the remaining plastic slide blocks; should let me clean things out more thoroughly.

If you're looking for an airbox, I've got one from a '94 750. (36mm carbs) $20 plus shipping.

You have the airbox boot things too? What dimension is the 36mm? The airbox side of these carbs have 50mm outer diameter and center-to-center distances of 78,88,78 mm. Engine side outer-diameter is 38mm, inner 31mm. I'm not even sure if an airbox from a 90->98 600 would work, not to mention a 750.

[Wild-Bill]

I've got the boots, clamps and even the drain tube. I'll take some measurements for you tonight after work.

[steves]

Those look A LOT like flat side carbs..... stupid 88 & 89 being different.

[Wild-Bill]

...What dimension is the 36mm? The airbox side of these carbs have 50mm outer diameter and center-to-center distances of 78,88,78 mm...

Looks like the 750 breather box has intake boots with an inside diameter of roughly 56mm and spacing of about 80-85-80mm.

I just checked my dealer's parts fiche and sure enough, the box is the same part number for a '89 600 and a '94 750 but the boots are different. (Except the J&K models. They've got a different part #. Is that the '88-89 years?)

[foxox]

Maybe someone can help me determine what needs to be replaced besides the orings and hoses (I looked through http://katriders.com/wiki/index.php5...rburetor_Parts and BTW I qualify as #5).

I'm already pretty sure at least this needle needs to go:
(it's bent too, can't see at this angle)

One of the other needles (second from bottom) has a bit of corrosion on its tip:


And the diaphragms all have worn spots like this. The material seems to be 2 layers thick, though, so I think they still seal.


AFAIK, the float needles are alright. You can see marks where they seat, but they don't look worn down much if at all:


I am not sure if I need to replace the bowl oring gaskets... they seem intact but also don't stick out much (from being squished down for so long).
Here's how they look:


This

left this sediment after a night of soaking and a few swirls:

I just checked my dealer's parts fiche and sure enough, the box is the same part number for a '89 600 and a '94 750 but the boots are different. (Except the J&K models. They've got a different part #. Is that the '88-89 years?)

Yeah I have the K model (it's stamped on the VIN plate) 1989, and J should be 1988. I think they use the JKLMN/etc. to distinguish design revisions, probably mostly as a way to avoid confusion with bikes manufactured during months between model years (when dealership stock changes). I should probably just go with an airbox/boots from an 89. If for some reason I wind up deciding to replace these carbs (still tallying up the cost for replacement parts I need and deciding if it's worth it), I'll surely get newer ones and will contact you about the airbox. That said, there are two different cylinder head part #s for 1989 (one that matches the 90+ # and one that does not); maybe one of them is only compatible with the old carbs and one with the newer ones... blah! This bike is some oddball nuisance but at least it has character lol

[Wild-Bill]

Let's start from the top.
1. Wow! That needle looks ugly!
2. Those are FP needles.
3. Hold the diaphragms up to a light. If you can see light through them then they've got to go.
4. General rule is if you can still see a ring around the tips of the float needles after cleaning then they need to be replaced.
5. Bowl gaskets need to be soft enough to seal. If they've hardened up to where they don't expand back out then I'd replace them.

The letters do correspond to production years. My airbox might fit but it's not the right one. I'd be looking for the earlier one for sure.

Good luck. Those carbs need a lot of work.

[foxox]

3. Hold the diaphragms up to a light. If you can see light through them then they've got to go.
4. General rule is if you can still see a ring around the tips of the float needles after cleaning then they need to be replaced.
5. Bowl gaskets need to be soft enough to seal. If they've hardened up to where they don't expand back out then I'd replace them.
Good luck. Those carbs need a lot of work.

Light shines through all of them! Crap!
The gaskets aren't in super shape and seems these usually come together in rebuild kits with the float needles so I might as well go that route and replace 'em all. Thanks for the pointers!

The emulsion tubes (needle jets, mixing tubes, whatever they are actually supposed to be called) look okay, ya? No "egg shape" I can see.




So I'm looking at spending something like this:

$50 for four rebuild kits with float valve, float needle, orings, bowl gasket
4x $12.23 for the oem jet needles from bikebandit
4x $20 for diaphragms
+ a few bucks at HomeDepot/Lowes for other orings
= at least around $180 to fix up carburetors that are as old as I am...

...or try to see if the 90+ carbs fit on an 89, buy a newer set of carbs for $50->$300 that don't need as much work, and maybe recoup a few bucks by selling the remains of these? It might be easiest just to fix these, and I think I like the mechanical design of them more than the newer ones.

I will sleep on it

[Wild-Bill]

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.