Rusty Tank 1978 KZ750 Twin

DanMadBoy wrote:

 Would any lingering WD40 mess up the fuel lines or carbs when it flows through the system?
 

No

Awesome! Thanks so much!!

I've derusted a bunch of gas tanks. I use EvapoRust and rinse with diesel to prevent flash rust. Once the EvapoRust is done pour in a gallon of diesel, shake it around and drain into an old clear milk jug. Wait a few minutes and the sludge will settle to the bottom. Pour the diesel back in for another round and dump the sludge. It takes a few rinses to get it clean and when done the diesel coats the tank to prevent flash rust and it won't hurt anything when you fill it up with gas.

Thank you for this Kelly.

It seems that everybody has a slightly different method on how to clean a tank.  Keeping with that thought, my preference is to use phosphoric acid (Kleen Strip Metal Prep, or Etch and Clean, as sold by Home Depot.)

First step is to clean any varnish, because you can't strip though varnish.  For removing varnish, some carb dip or at least some carb spray is needed.

Fashion proper seals for all the various openings, don't use the petcock, fuel cap, or sending unit.  Use metal plates with rubber seals, or a rubber stopper.

Phosphoric acid can be diluted quite a lot and still be effective.  One gallon, followed by topping up the tank with water works well.

It will take some time to eat off all the rust, and during that time be sure to allow the tank to outgas, or the sides of the tank will pooch out.

When the rust is gone, dump the sauce and quickly rinse with a garden hose.  Next, shoot a bunch of WD-40 in the tank and swish it around.  That will reduce flash rust to just a tiny bit.

To dry the tank, I use a hair drier blowing into the filler opening.  Don't cram the drier into the hole, let it blow from a few inches away, and come out the petcock opening.  Done this way, the tank will be fully dry in less than half an hour.  Use compressed air first, to get out any standing water or remnant WD-40

This is all very helpful. Thank you so much. Im learning a lot (Im 19)

To reduce flash rust you could use fogging oil to fog the tank after doing the rust treatment.  I think the stuff is commonly used for snowmobiles.

Thanks Martin. You know of any good brands of fogging oil? Ive never heard of it.

Here's what I use, and as Kelly said diesel is a great alternative to prevent flash rust. That bike looks great, take care of it body parts are hard to come by these days. You owe your uncle many thanks for giving you such a nice bike, also you should change the oil and filter before start up if the bike has sat for a long while.......Welcome to KZR!

How often do you change your oil filter?

Every time the oil is changed.
Be sure to use motorcycle-specific oil that is designed for wet clutches. Unlike cars and trucks, Japanese motorcycle engines have a common sump, meaning that the engine, transmission and the clutch share the same oil. Automotive oils include friction reducers that can damage the clutch plates. Look for the JASO-MA certification on the bottle to be sure. Some Diesel engine oils like Shell Rotella also carry the JASO-MA certification. Also buy a high quality filter. Genuine Kawasaki filters and NAPA Gold filters are good choices.

In case you do not have a hard copy, here is a digitized factory service manual.

www.kzrider.com/modules/ServiceManuals/K...l%20KZ750%20Twin.pdf

Just an FYI. Shell Rotella T 15W-40 regular in the white bottle has the JASO-MA rating for Japanese motorcycles. The rotella is a heavy duty oil marketed for diesel engine use & has the same type of anti-wear ingredients as motorcycle-specific oils. Chevron Delo & Valvoline Premium Blue are a couple of other heavy duty oils, but the Shell product typically goes on sale &/or is usually cheaper. Delo sometimes goes on sale. Only caveat is that the 15W40 may not be suitable for cold weather starts.

ps: fogging oil is fogging oil. probably nothing special to look for.