OK, so I don't know as much as I thought I did.

[nedfunnell]

Today I tried to clean my carbs but only got as far as disassembly. I read through Carbs 101 and even had it printed out with the pictures while I was working. However, I quickly realized that the carbs I had in front of me were not the same ones as in the picture. I have an 1988 GSX600F, which I thought made it a Pre (right?) which means that Carbs 101 should be the right instructions- however, I found that not to be the case. Does that mean that someone frankensteined some other carbs on there? The ones I have are Mikuni carbs. Here are pictures of them:




I've never done carbs before so I didn't know how to do anything. I took them apart and found a decent amount of rust dust in the bowls and around the jets, but that was about the extent of my cleaning so far. The jets all looked clear and unblocked.

The symptoms I am trying to fix are hard starting, low idle and dying, and dying after warming up. Can anyone tell me where I can find a resource on how to clean these carbs, as well as general advice on how to cure the problems I just mentioned?

Your help is greatly appreciated. When I realized I couldn't just follow the directions I started to get really worried because I'm in over my head- I really don't know what to do, especially with adjusting these things after they're cleaned. I'm mortified that I might not be able to ride my new-to-me bike before the weather gets too cold if I can't get this sorted out. Thanks in advance!

[DClark]

Cleaning out the carbs is good, they should run well for like a minute. if you are finding rust and crud in your bowls. you have a rusted gas tank. You need to get a KBS tank rust kit from KBS, follow the directions and treat your tank, then reclean you rcarbs. Your bike should then run good.

[BlackKat Joe]

I'm no expert on the Kat years, but I do believe what people call "Pre" start at 1989... might be an older model of carbs on there? They look right to me though...


Carb cleaning is relatively easy, but you have to be EXTREMELY thorough.

I have been battling this same problem for a couple years. Your tank has to be rusted. Rust gets in your jets, clogs them up and causes your bike to start rough, not idle or fluctuate idle speed, and stall.

You can clean the carbs but until you get rid of the rust, you'll end up having these problems again within a few 100 miles.



As for the carbs, I prefer to disassemble them one at a time. Brush out all the rust and crap in the bowls.

Pull out both jets and take a strand wire to the inside and ream out the hole to make sure it is fully open (not once, do it for like 30 seconds). Do this even if it looks good.

Disassemble the rest of the pieces, make sure everything is clean. Spray down all metal parts and inside the carb with cleaner. Make sure all the passageways are open.

Spray the housing with compressed air to blow out any gunk.

Reassemble the same way you took it apart.


To be more thorough, get a gallon of carb cleaner (chem-dip or the like) and soak the metal parts. Also remove each carb housing completely and soak individually too.

I don't recommend you soak the carbs until you get rid of the rust in the tank though.



As for your tank there are several options -
* Get a new tank (~$200)
* Put nuts and bolts, washers, even BBs in the tank and shake the crap outta it (pad it and put in dryer!)
* Use chemicals (plenty of store bought treatments are out there, but hard to dispose of)
* Use electrolysis (lots of sites have walk thru's and methods)
* Use Rusteco (kinda expensive ~$100, but its biodegradable and easy to dispose of)
* Call some radiator shops to clean it (~$50)

I heartily recommend using several methods to truly remove all possible rust from your tank

For some more detailed info, read:

http://www.motorcycleanchor.com/motorcycle/how_to/mc_tankrust.html

Good luck!

[Wild-Bill]

Those look like GSXR carbs to me. Very nice! Not a big deal but if the jetting's a hair off then that may be the cause of your troubles. If you still have trouble with the idle after a thorough cleaning I'd try backing the AF screws out a half a turn.

As for cleaning methods, DO NOT stick a wire or anything else metal through those jets! They're made of brass and the potential for scratching the inside of the passages and changing the flow rate is huge. (An irregularity on the surface of a passageway will increase laminar flow resistance, producing the same effect as installing a smaller diameter jet.) If you really feel the need to use something other than solvent and compressed air (all I ever use) then try a piece of fishing line.

[DClark]

As for your tank there are several options -
* Get a new tank (~$200)
* Put nuts and bolts, washers, even BBs in the tank and shake the crap outta it (pad it and put in dryer!)
* Use chemicals (plenty of store bought treatments are out there, but hard to dispose of)
* Use electrolysis (lots of sites have walk thru's and methods)
* Use Rusteco (kinda expensive ~$100, but its biodegradable and easy to dispose of)
* Call some radiator shops to clean it (~$50)

I heartily recommend using several methods to truly remove all possible rust from your tank

For some more detailed info, read:

http://www.motorcycleanchor.com/motorcycle/how_to/mc_tankrust.html

Good luck!

The KBS kit I recommended goes for about $40 delivered to your home. It has a cleaner, rust remover/etcher and sealant. it is similar to the POR kit, but cheaper. Takes about a week to do the tank, most of that for the sealant because they recommend that you let it sit for at least 4 days before using it.
I strongly recommend sealing ANY tank because even if you get your present tank squeeky clean and free of rust, the e10 gas will cause that rust to return and you'll eventually have problems again.

[nedfunnell]

Thanks for your input, everyone! I appreciate the knowledgeable and helpful replies. Interesting that I might have GSXR carbs. I want to ID them for sure- but last night I read through the service manual and found that 88s have BST31SS carbs whereas 89 and later have BST33SS carbs. I'm not sure if these are the BST31SS carbs or if they've been replaced as Wild-bill suggests, but I will try the generic cleaning procedure as best as I can.

One difficulty I ran into yesterday is that I couldn't get the floats out. I gather that I should remove the pins that they hinge on, but I can't. They don't want to slide at all. I tried using some force to press them out, but didn't go whole-hog on them because I wasn't sure if I was doing it right. It looks to me that sliding the pins out is the only way to get them out, but if someone has another suggestion I would be glad to hear it.

Will normal air-compressor air be OK for blowing passages out, or do I really need to get a filter somehow?

As far as tank rust: I am set up to do electrolytic cleaning. I read up on it and figured it would be necessary no matter what I did due to the bike's age so all I need to do now is mix up my solution and let 'er rip. I would value some commentary on what sealant to use.
I've heard Kreem = sucks, POR-15 = better than Kreem but still not recommended, and brand-specific OEM sealers = better. A google search reveals a bounty of epoxy-based options. Can anyone with experience with one of the sealer options chime in? After the electrolytic process has done its magic I definitely want to seal it.

Thanks again!

[DClark]

I have not anything bad about POR or KBS. Electrolysis is not needed as the prep product converts the rust into primer for the sealant. I know that the KBS prep etches the metal and leaves a slight zinc phospate residue. I am pretty sure that before you use either companies sealer, you have to use their prep, or at least that is what they say.
Now is a great time to seal up the tank as it has to be dry and it will dry better in the summer heat than in the winter cold.

[hardlydangerous]

POR15 is hands down the best way to restore a fuel tank. its not just better it is the BEST. Ive restored dozens of tanks thought impossible to reuse with no problems.

Just because you have rust in your float bowls does not mean you have rust in your tank as is the case with the Kawi Concours I just had in my shop. The tank was inspected after a major carb cleaning was needed and was found flawless with only a bit of sediment in the bottom , but two carbs has 1/8" layer of rust in the carbs. The PO used to always get fuel from the same gas stations hwere they obviously had rusty tanks in the ground

[steves]

The 88 carbs are slightly different, but the "how to" on cleaning them is essentially the same... in fact all carbs are mostly the same once you get the hang of it.

[Wild-Bill]

... I'm not sure if these are the BST31SS carbs or if they've been replaced as Wild-bill suggests...

Did some digging in the electronic Haynes (My paper Clymer doesn't cover the 600s) and sure enough, BST31SS carbs (on an 88 600) look just like yours. Sorry for the red herring!

...It looks to me that sliding the pins out is the only way to get them out, but if someone has another suggestion I would be glad to hear it...

According to Haynes, "Carefully pull the float pivot pin out of the carburetor body, then remove the float." Try tapping on the end of the pin with a drift or the tip of a nail. It may take a little force if they've been there a while. Trick is to use as little force as you can manage.

Will normal air-compressor air be OK for blowing passages out, or do I really need to get a filter somehow?...

I just use the wall mounted in-line filter that I use for my air tools. Never had a problem. Make sure you look in both ends of the passage before blowing it out with the air. The BST36SS carbs have a metal orifice in the float armature that can be driven out with a blast of compressed air from the wrong side. I don't see anything like that on the 31s but I'm just looking at a drawing...

[nedfunnell]

Fantastic, thanks for your help, all. I can't find where I heard something back about POR-15 so in light of all the positive news about it here, I am going to order some. I have the electrolysis process running now- think it would be okay to skip the preliminary rust-removal step, substitute plain phosphoric acid for their acid prep, and buy only the sealer itself? I am trying to do this on a shoestring budget.

Thanks for your research on the carb ID, Wild-bill. I will try again to remove the float pins. When I tried to remove them before what I did was vice-grip the tip of a flat-bladed screwdriver to the flange below the pin's bottom and used the screwdriver as a lever to press on the pin- It budged but only to the point of being flush with the flange, so now I don't know what to do. Any suggestions?

Thanks!

[DClark]

Fantastic, thanks for your help, all. I can't find where I heard something back about POR-15 so in light of all the positive news about it here, I am going to order some. I have the electrolysis process running now- think it would be okay to skip the preliminary rust-removal step, substitute plain phosphoric acid for their acid prep, and buy only the sealer itself? I am trying to do this on a shoestring budget.
Thanks!

I wouldn't skimp as you would be saving yourself maybe $10. If the sealant doesn't stick right to the tank, it will fall apart and you will have to spend about $30 for some nasty paint remover with methyl chloride, hope that you don't get any on the outside of the tank and spend a few days trying to get all that crap out.Just do it right the first time.KBS, POR, doesn't matter...if you don't follow the directions to the "T", don't be surpised to find a mess on your hands and feel the urge to unfairly blame the company on the 'net (KREEM is crap though).
Just $43 gets this delivered to your home:

http://www.kbs-coatings.com/KBS-Cycle-Tank-Sealer-Kit_p_31.html

If you are handy with electrolysis, one thing I wonder- can you remove the rust with it, then use electrolysis to apply a layer of zinc to the inside of the tank? Would that keep the tank from rusting?

[nedfunnell]

I wouldn't skimp as you would be saving yourself maybe $10. If the sealant doesn't stick right to the tank, it will fall apart and you will have to spend about $30 for some nasty paint remover with methyl chloride, hope that you don't get any on the outside of the tank and spend a few days trying to get all that crap out.Just do it right the first time.KBS, POR, doesn't matter...if you don't follow the directions to the "T", don't be surpised to find a mess on your hands and feel the urge to unfairly blame the company on the 'net (KREEM is crap though).
Just $43 gets this delivered to your home:

http://www.kbs-coatings.com/KBS-Cycle-Tank-Sealer-Kit_p_31.html

If you are handy with electrolysis, one thing I wonder- can you remove the rust with it, then use electrolysis to apply a layer of zinc to the inside of the tank? Would that keep the tank from rusting?

I read through the material on their site as well as the MSDS. It looks like the first treatment is only to knock the rust off (doing that with electrolysis already) and the second treatment is primarily phosphoric acid. Their documentation says the second treatment's primary purpose is to acid-etch the surface of the steel and I think I can do that just as well with generic phosphoric acid. I can save about $30 by buying only the sealant, so it is tempting to go that route. I'm going to research and think on it some more before I pull the trigger.

Regarding electroplating- it is certainly possible to plate the inside of a tank, but I don't think it is something that is practical for hobbyists. Electroplating requires a specific low voltage with a very high current, which requires a special power supply rather than just a battery charger. I'm also not sure that zinc is the right choice to plate it with. Zinc works great for protection from weather-related corrosion but only because it corrodes away before the steel does. I'm not sure if zinc would leach into the gas or not. Who cares if raindrops coming off of a light pole have a few PPM of zinc in them, but it might be as bad as rust in a gas tank. Nickel would be a better option, I think, but if I recall correctly it requires several intermediate layers of other metals because it can't be plated directly onto steel. I could be wrong about that- it might be gold that I'm thinking of. I know that electro-less nickel plating chemicals exist but they cost so much that it'd be hundreds of dollars to plate a tank and probably wouldn't get as thick. I've only ever encountered that in lab environments though. Once you get through buying all the equipment you'd need for a setup, it's cheaper, easier, and probably equally effective to just use an epoxy-based sealant. If a shop wanted to get into plating customer's tanks by the dozen, then maybe it'd be worth it- but it's not like the easy-at-home rust removal electrolysis process.

[dragoncutlery]

i just ran the gas out of the tank threw some coffee filters a few times and fill the tank as far as i can when storing it for long periods of time it took 3 cleans of the carbs before i realized it was rust in the tank cosing the problems