QuestionHere is the deal, I have a 1993 zx600c ninja and i just baught it and it set up for about 3 years, well the gas tank isn't on it, it is in the shop getting cleaned out and lined. here is the question, when I start the bike after it has set and is cold it starts right up but it idles really high like 5 g, then sometimes going up to over 10k, Then it only runs for like a minute and it gets really hot but the gauge is only showing normal, then it dies not to start back until it has cooled, I have no ideal what this could be.. please help I can't afford to take it to a mechanic.. i can work on it just don't know where to start. The carbs have supposedly been cleaned before I got it, the bike set up and someone else baught it cleaned the carbs and some of the gas tank, i just took it to get that liner put in it to make sure no more rust happens. help..
AnswerHi Aron,
I return tech files by email. There was no email address with your question as requested and explained in my instructions.
Email makes my volunteer time here possible. See sample tech files below.
Respectfully,
Mark Shively
Bad Gas
By Mark Shively
Gasoline goes bad with time and in as little as 3-4 weeks. This effect is known as varnishing. Jets and passageways within carbs become obstructed when varnishing occurs.
Liquid gasoline changes chemically into a gel like substance. Advanced stages of varnishing results with the solid gel changing into a crystal powder substance. Interior carb surfaces are etched in the process and may require carb replacement.
The choke and pilot circuits with most motorcycle carburetors share passageways. When pilot jets become obstructed, the choke circuit compensates and allows engine to start and idle with choke, but stalls without choke.
See carb cleaning information below. See microfiche parts, check parts prices, and order repair manuals here: www.bikebandit.com
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Rusty Tanks
Contributed by KZCSI
One of the most common tasks associated with bring an older bike back from the dead is figuring out how to deal with the varnish and rust left over from years of neglect. After cleaning many gas tanks, I've finally settled on this method as working best for me. I'm sure there will be refinements and improvements, of which I'll write more about as they evolve. Also, I'm looking forward to trying lye for tank cleaning.
Cleaning a Gas Tank: Why do fuel tanks attract moisture?
Here's why it happens. You park the bike with a quarter tank of fuel probably during the day when it's warmer. That night the temperature drops and as the air inside the tank cools it becomes less able to hold moisture so some of the water vapor condenses. Now this amount of water is insignificant and over night or even a couple of weeks won't usually be a problem. But over a longer period of time, usually months, the tank will breathe in every time it cools. That new moisture will condense then when the day warms up the tank will breathe out the air that gave up some of its moisture yesterday. That night as things cool down the tank will take a new breath of damp air and the process starts over again.
What to do if you find rust in your tank.
Is the tank leaking? If it is, either “Pour 15” or “Kreem” will solve the problem. Pick one and follow the prep instructions carefully. If the tank is still holding fuel, I like to check the quality of the steel at critical locations before I go further. To do so, I use a Popsicle stick and test the areas adjacent to the seams. Set the tank down and run the Popsicle stick along the seams using moderate pressure. Find the lowest part of the tank and test this area as well. If the Popsicle stick can't push a hole through the steel there's no need for epoxy sealers. Great, you're bucks ahead and your bike will be worth more as well. As a collector, I've learned to always check the gas tank, not only for rust but to see if the previous owner has had the tank sealed. I judge a sealed tank as hurting the value of a bike more than a rusty tank.
If the Popsicle stick reveals soft areas but doesn't actually puncture a hole, it’s still a good idea to go with a sealer as the cleaning process may well cause the tank to leak after all.
There are plenty of methods used to clean gas tanks.
I've used sand with steel nuts and kerosene and tumbled them for hours. I gave up on abrasive methods because they take too much time and the sand is too difficult to clean out when finished.
I've used mild acid preparations such as Naval Jelly. These I gave up on because they don't really attack the rust enough to get rid of heavy build ups of scaly rust.
I tried the electric method, using a battery charger and a steel rod. I'm not sure this one accomplishes much. It didn't touch the scale and getting at the top of the tank is tough.
I've read about using sodium hydroxide (lye). It's supposed to be a good method because it doesn't erode the base metal. I'm looking forward to an opportunity to try it out. Most recently, I've settled on a Muratic acid wash followed by a dose of phosphoric acid as the best method, mostly because it always gets the job done and doesn't require a lot of physical effort. To do the job you first have to decide if the tank has scaly rust or just surface rust. If the rust hasn't gotten to the point where it's scaly you can skip the 1/4" nuts, referred to later.
Flush out any oily varnish that may be coating the lower regions of the tank with acetone or any of those engine degreasers. If you choose the engine degreaser flush the tank with water.
Remove the fuel level sensor. Seal it's opening with GOOD duct tape.
Remove the petcock and seal it up with an appropriate plug or capped section of hose.
Dump 30 or so 1/4" nuts into the tank.
Pour in a pint or so of Muratic acid. Seal up the fill spout with GOOD duct tape. Wear gloves, old clothes, and safety goggles. Agitate the tank for 10 to fifteen minutes. During this time you can monitor the pressure in the tank by watching the duct tape bulging at the fill hole. If too much pressure develops, carefully vent it by peeling the tape back than reseal and keep shaking.
Next pick a piece of concrete that you don't particularly care about. Remove the tape from the sender opening and fill hole and flush the tank with cold water. The acid that has not already been consumed will neutralize itself on the concrete. You're still wearing goggles and gloves right?
Now dry off the openings and reseal them with GOOD duct tape. This time pour in a pint of naval jelly, or milk stone remover or tile haze remover. These are all phosphoric acid formulations. Phosphoric acid is not as aggressive as Muratic acid and therefore is mostly a waste of time if you're trying to really remove rust. What phosphoric acid will really do well is leave the inside of the tank coated with iron phosphate, which is somewhat rust resistant. For this step you do not need much agitation. Just tumble the tank over several times and let it set for a half hour or so and then tumble it again. After about two hours of this go back to the concrete slab and open the tank and flush it out thoroughly, THOUROUGHLY.
Now bring it back in the shop and secure a blow dryer to the fill hole and force dry the tank. This may take two hours. Position the tank in different orientations during this process to make sure that no seam holds water. Once it's really dry you're done. If you skip the phosphoric acid step the inside of the tank will flash rust before you can get it dried out. I've probably cleaned ten tanks with the method I described and never damaged the exterior paint or eaten through the steel.
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RED-KOTE® FUEL TANK LINER
STAYS FLEXIBLE - Will never crack or peel off.
ALCOHOL RESISTANT - No expensive come-backs.
BRIGHT COLOR - Both you and the customer can see results.
COVERS RUST - Seals old rust in and prevents future rusting.
SEALS LEAKS - Gets the multitude of pin-holes you can't find.
Damon Industries, Inc. P.O. Box 2120 Alliance, Ohio 44601 E-mail: Rad@DamonQ.com
Phone: 330-821-5310 Fax: 330-821-6355 Toll Free in North America: 800-362-9850
Red-Kote® is a new polymer coating developed by Damon Chemical. Red-Kote® is resistant to gasoline, diesel fuel, alcohol and other fuel additives. Its major use is to seal leaking fuel tanks. Solvents such as methyl ethyl ketone, acetone, methylene chloride and propylene oxide will completely dissolve the polymer. Other industrial solvents will affect the coating but, not completely dissolve it.
Red-Kote® is easy to use if the directions are followed closely. It seals the multitude of small leaks that often form where the straps wrap around the tank. You fix the obvious leaks and Red-Kote® seals the rest. Contrary to what some people will tell you, rust does form inside gas tanks. The cause is condensation and water in gas. Red-Kote® seals rust under the coating so it cannot flake off to plug fuel-line filters or cause engine damage.
Further rusting is reduced also. Red-Kote® is a safe and sure way to solve your customer's problems and increase your own profits. Since most of the time is spent in drying you can be doing other work while Red-Kote® makes you money.
Red-Kote® also offers the advantage of not interfering with the reinstallation of the tank. External coating, especially fiberglass, are sometimes too thick to allow reinstallation with the original straps and bolts. Some of the specific advantages of Red- Kote® are as follows:
1. The coating is very flexible and does not crack as do some of the others. This gives the repair a much longer life. Tanks coated in 1984 are still doing well.
2. The polymer was specifically chosen because of its tight adhering qualities. In comparison to some other coatings, Red-Kote® does not peel off even when the metal is bent. This protects against loosening of the coating by vibration or denting of the tank.
3. Red-Kote® is resistant to methanol. In fuels with a high percentage of methanol the coating is bleached, but remains tightly bonded to the metal. In 1985 the federal government allowed 5% methanol in fuel. Standard Oil's ice-guard is 0.5% methanol. The cheap gas tank anti-freezes are methanol. (The good ones are isopropanol.) Some
gas tank liners are dissolved by methanol into sticky lumps and strings that plug the fuel line. This will not happen with Red-Kote®.
4. Red-Kote® dries faster than many other sealers saving you time. You can reduce time further by thinning with Methyl Ethyl Ketone and using two thin coats instead of one thick coat.
5. Red-Kote® levels very well. You will not get a wide variation in thickness as with some other coatings.
6. Red-Kote® is thicker and usually requires only one coat as opposed to two coats for many other coatings. Holes up to 1/32nd may be coated and sealed safely. Rust is sealed in so that it cannot flake off.
7. The bright red color is easily visible to you and the customer. You can be sure you didn't miss a spot and the customer can see you did something. Some coatings are almost invisible. The new dye does not leach into gasoline (turning it pink) when the vehicle is not used for long periods of time.
Packaging: Red-Kote® is available in one quart metal cans packed 9 per case or in one gallon metal cans packed 1 per case. It is backed by our guarantee and our over 53 years of service to the radiator industry.
Directions:
1. Empty all fuel from tank.
2. Remove sending unit, float, feed lines, filters, anything that could be clogged by the coating.
3. Remove any loose rust by tapping on the tank with a rubber mallet or by tumbling with a piece of chain in the tank. Flush out debris.
4. Clean tank by steaming for about 15 minutes. Boil out is not recommended because the high alkalinity removes the tin from the terne plate. A standard water soluble degreasing chemical works well.
5. Any leaks larger than 1/32nd of an inch should be repaired by soldering or your usual method.
6. Make sure that the tank is completely dry before continuing. This is very important. Without a blower, drying may take up to 12 hours. The use of a blower to circulate air through the tank will cut the time to an hour or so. The fastest method is to drain the tank for 5 minutes and then pour 1 pint of Methyl Ethyl Ketone into the tank, slosh thoroughly and pour out. Repeat with a second pint of M.E.K. and you are ready to use Red-Kote® immediately. Do not re-use the first pint of M.E.K., instead let it evaporate safely away from flames or sparks. The second pint of M.E.K. may be used as the first pint on the next job. One quart of M.E.K. will only absorb up to 3 ounces of water. This is why it should not be reused.
7. Cover all open holes in the tank by plugging or covering with tape, except the one to be used for pouring in the coating.
8. Pour one to two quarts of Red-Kote® into the tank and cover the last opening. You can get by with one quart on tanks of about 12 gallons or less. We recommend two quarts for larger tanks to make sure you get the coating to flow behind all the baffles.
9. Tip the tank onto each side and slosh the coating around to completely cover the inside. Use a rocking motion rather than shaking. It is important to do a thorough job or you may miss parts of the tank behind baffles.
10. Drain out the excess coating and cover tightly to save for reuse. The best method is to stand the tank up with a corner drain hole over a can to collect the excess as it drips out. It is very important that you do not leave puddles in the tank.
11. Open all tank openings to allow the best air flow. Air dry for 8 to 24 hours. When cured there will be almost no solvent smell left in the tank. If the coating is not completely cured before fuel is added the curing process will be stopped. Do not use open flame or an electric element for drying or an explosion may result. Do not blow air into the tank until at least 60 minutes of drying time have passed. Using air sooner may cause bubbles may form in the coating.
12. If the leaks or rust are severe it is a good idea to use a second coat after the first coat dries completely.
13. Reassemble and install the tank on the vehicle.
14. For clean-up use methyl ethyl ketone, acetone or a quality lacquer thinner with no alcohol in it.
Tips & Hints:
Do not leave the can open to the air as it will thicken or form a skin on top. When Red-Kote® is reused after pouring it back out of a gas tank it may need thinning before reuse. Red-Kote® may be thinned with M.E.K. or Acetone. Do not use lacquer thinner to dilute Red-Kote. For removing water from the tank prior to coating you may use acetone. Acetone absorbs much more water than M.E.K. and is less expensive. We do not sell acetone. Most shops are punching a hole in a corner of the tank to aid in draining it completely. Then they solder in a drain cock. Do not solder or weld on the tank after it has been coated. The coating will turn to ash if heated above 250°F.
Some of our customers have reported a way to speed up the process significantly. They are thinning Red-Kote® about 20 - 25% with M.E.K. (1 part M.E.K. to 4 or 5 parts Red-Kote®). This allows the Red-Kote® to dry in only a couple of hours in many cases. They also report that using air to dry the inside does not cause the bubbles that form when straight Red-Kote® is dried with air. You will get a much thinner coating.
We are told that two of these thin coats still take less time to dry than one thick coat. Red-Kote® does not stick well to plastic tanks or to plastic parts inside a gas tank. Do not coat over other coatings. Remove old coatings completely first, using M.E.K. or other solvent. Call us if you have a problem. The two most common problems we see are:
1) Not completely drying the tank of water before coating. Red-Kote® will not stick to wet metal. When it dries it will peel off in sheets.
2) Not allowing the Red-Kote® to dry completely. If Red-Kote® is not completely dry or has puddles left it will form strings or flecks in the gas. These may get past the fuel filter and plug carburetors or injectors. Puddles of Red-Kote® left behind baffles or in corners may never dry completely. This is because a skin forms over the puddles and prevents drying underneath. Once the skin ruptures Red-Kote® forms strings in the gas. Damon Industries guarantees the product only, not your application of it. After application to over 50,000 cars we have seen 7 problems. All were application errors as described above. We have never seen failure due to ageing. Both of these conditions are prevented easily by proper drying. All problems are correctable by stripping out the Red-Kote® with M.E.K. and recoating. We recommend that you tell your customers not to use fuel additives containing methanol or methyl alcohol. We have had instances of methanol pulling the red dye out of Red-Kote® which turns the gas red. This has not caused any damage to our knowledge. Usually only "cheap" additives contain methanol. Good products contain isopropanol or other solvents. Most engine warranties are voided by the use of methanol anyway.
Do not rush the job. In many cases it will take more than one day to do a job worthy of your time and guarantee.
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Carb Cleaning 101
By M. Shively
The elements of internal combustion engines are: correct fuel/air ratio, spark at right time, adequate cylinder compression.
There are many passageways and openings to check and clean. All are important in function and when obstructed or not working properly, have subtle to radical effects on engine performance. Vacuum leaks and carburetor synchronization also have effects on performance and should be inspected and adjusted following the below procedures.
Carb Cleaning 101
Warning: Remove all rubber parts before you begin. These parts usually include vacuum diaphragms, needle valves, o’rings, hoses, and other parts. Spray cleaners will damage these parts. Do not disassemble individual carbs from the carb bracket.
Air & Fuel Passageways: Trace and learn individual fuel and air circuits from beginning to end. Machines can only drill straight through the cast passageways. To change direction, another angled passageway must be drilled. The union is plugged with a brass or bronze bead. Inspect and clean each passageway with spray cleaner, brushes/pipe cleaners/etc, and compressed air. Remove any discoloration and debris. Look for spray cleaner to exit from one or more passageways.
Jet Cleaning: Inspect jets by holding to light and look through them. You should see an unobstructed round hole. Clean the jets with one or more of the following: jet cleaning wires, soak solutions, carb spray cleaners and compressed air. Re-inspect jets after cleaning and install when clear of obstructions. Some main jets have paper-like gaskets. Most have metal spacers between the jet and the emulsion tube. Some screw directly into a brass emulsion tube which is machined for a 7mm wrench at its float chamber exposed base.
Inlet Fuel Valve: Inspect the needle valve & spring. Press down the tiny metal rod that protrudes from the butt or float end of the needle valve. The spring should move freely and return the rod to its location. Check the needle valve’s seat area for a groove or other wear. It should appear highly polished. Some needle valve seats are rubber and wear may not be visible. Inspect the needle valve jet seat. You can clean the jet seat with Q-tips and semi-chrome polish if necessary.
Carb Body Castings: Blow air through the atmospheric vent holes located on the dome of each float bowl chamber. Air should exit via hoses or brass nipples. Inspect the emulsion tubes and passageways (cast towers that jets thread into) for discoloration and debris. Clean interior emulsion towers with a soft bristle gun cleaning brush. Clean each Venturi (main carb bore).
Needle Jets & Jet Needles: Clean the needle jets, jet needles, and passageway or tower that needle jet screws into. Clean the emulsion tube (pipe between needle jet and main jet) (Main Jet may screw into emulsion tube). Jet needles are part of the throttle slides. See below…
Throttle Slides: There are several types of throttle slides: Mechanical linkage, vacuum, diaphragm, and cable. Disassembling the jet needle from the slide is not always required for cleaning. If you have vacuum piston type throttle slides (large diameter solid metal slide), avoid cleaning the lubrication from sides and caps. If piston type check cap vents and passageways with air. Clean if necessary and re-lube. If you have rubber vacuum throttle diaphragms, inspect for dry-rot, defects, and tears by gently stretching rubber away from center. Do this until all areas around diaphragm have been inspected. Replace any defective part as described above. Clean carb body areas around diaphragm including air passageways and air jets. Diaphragms have a locator loop or tab fabricated into their sealing edge. Observe this locator upon reassembly. Avoid pinching the diaphragm when reinstalling caps.
Fuel Screws: Fuel screws have sharp tapered ends. Carefully turn one fuel screw in while counting the turns until it seats lightly. Warning: These screws are very easily damaged if over tightened into their seats. Record amount of "turns-in" and remove the fuel screw, spring, washer, and o'ring. The fuel screw is part of the enrichment (choke) circuit...clean passageways as described above. When carbs are assembled, spray low PSI compressed air into diaphragm air vents located at intake side of carbs. Throttle slides should rise, then fall when air is removed. Lightly lube external moving linkages. Reinstall carbs and follow through with carburetor synchronization.
Throttle Cables: Lubricate cables periodically. If cables are disconnected from carbs or removed for replacement, etc . . . remember cable routing and ensure proper reinstallation routing. Avoid bread-tying, sharp bends, and pinching cables. Adjust cables so throttle grip has about 5mm of play or throttle slides or butterfly valves may not open completely (full throttle)(wide full open).
Float Bowls: Inspect float bowls for sediment, gum or varnish, crystallization, and defects. Clean all pipes, tubes, passageways, and embedded jets with cleaners and compressed air. Remove and clean the drain screw and area. Inspect bowl gasket and replace if necessary. Clean and inspect overflow pipes and tubes, look for vertical cracks.
Floats: There are several types of float materials: plastic, brass, black composite, tin, and others. Handle floats carefully. Avoid bending, twisting, denting, or other means of mishandling. Most floats are adjustable by bending a small metal tab near the float axle end. Do not change the float adjuster tab unless tuning fuel service levels. Clean metal floats by soaking or by spraying cleaner and wiping clean. Other material type floats may require replacement if cleaning is necessary. Inspect the needle valve (float valve) and seat. Check needle valve’s spring loaded pin. It should depress and return smoothly and without resistance. Check the needle valve’s tip for a worn groove. Replace needle valve and seat if either symptom exists. These parts wear together and must be replaced as a set.
Choke Plungers: It is common for Mikuni slide carburetors to have indented or hardened choke plunger pads. If the pads are worn, indented or hardened with age, then the idle of your bike will vary wildly as the pads no longer seal well.
Synchronization: This is a fine adjustment performed usually and preferably with the carbs installed and the engine running. The unusual part is performed with gauged wire with the carbs on the work bench. Carburetor synchronizing balances Venturi vacuum at the exhaust side of each carburetor, resulting with smooth idling and optimized performance at all throttle openings. Synchronization is checked using a set of gauges which are either air vacuum type or liquid mercury type. The gauges are connected to vacuum ports on the intake manifolds via nipple tubes or if sealed with screws, sync gauge adapters will be needed. With the engine running at temperature, and with a fan or means of forced convection aimed onto the engine, the carbs fuel screws and idle are adjusted, then the synchronization is adjusted via adjustment screws on the carbs. A reserve fuel tank is recommended for convenience of accessing carbs during this procedure. See gauge instructions and repair manuals for detailed use of synchronization gauges.
Notes: While carbs are apart, record the jet sizes. Look for a very small number imprinted on the body of the jets. Verify that numbers are the same for all jets on models with in-line cylinders. A few transverse-4 models and V-engines, the inner and outer carbs use some different size jets and it's important to not mix them up. If you have dial or verneer calipers, measure and record float heights. Perform measurements with floats just touching needle valves, though not depressing the needle valve rods. Replace fuel and vacuum hoses. Be sure to use fuel rated hose for fuel. Install or replace in-line fuel filters. It’s a good time to remove and clean interior petcock fuel filters. Inspect carb manifolds for dry-rotting, inspect all clamps and air ducts. Inspect, clean, lube, and/or replace air filter(s).
