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Discussion Starter #1
Howdy Folks --

Mr. Spock is acting up again :(

He runs very rough at idle and dies unless I keep the rpms up around 2k. It helped to adjust/increase the idle so the rpms stay around 2k but sometimes it still dies when I come to a complete stop.

It starts easily and runs strong above 2k rpm. It's got about 1/4 tank of gas with Seafoam in it.

A few weeks ago it had different symptoms: leaking fuel from the exhaust; hard to start; running rough at all rpms. At that time I drained the carbs and some sediment came out. That took care of the problem.

Any ideas what it might be? Does it sound like dirt in the carbs?

Your input is greatly appreciated! :beerchug:
 

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I second the carb cleaning..... do it yourself or get ready to part with about 5 bills!!

Don't shoot the messenger.. :(
 

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On His Lady Vulcan
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Sense it sound like youre going to need to pull your carbs, while youre at it might as well do an ear shave. Any further issues, pulling and installing carbs becomes a breeze.
 

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I know some might say you don't need in-line fuel filters because the screen in the tank will stop contaminants, but if you are getting crud out of the carbs, I'd install some. It's gotta be comin' from somewhere!
 

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I'd pull the tank and give it a good cleaning. See what comes out. If you see rust coming out then I'd do a rust treatment to it. Drain the carbs, flush them with some fuel/seafoam, let em soak, then put it back together and see what happens. If you pull the carbs and clean them up without first cleaning the tank, you're wasting your time. The crud isn't coming from the carbs, but getting to the carbs from the fuel tank. Even if it ran like crap after cleaning the tank, I would still put half a can of seafoam in the tank full of gas and ride it like you stole it for about 50 miles and see if it clears up. Then, maybe if that didn't cure it, I'd pull the carbs and clean them thoroughly. Just my .02!
 

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Discussion Starter #8
I'd pull the tank and give it a good cleaning. See what comes out. If you see rust coming out then I'd do a rust treatment to it. Drain the carbs, flush them with some fuel/seafoam, let em soak, then put it back together and see what happens. If you pull the carbs and clean them up without first cleaning the tank, you're wasting your time. The crud isn't coming from the carbs, but getting to the carbs from the fuel tank. Even if it ran like crap after cleaning the tank, I would still put half a can of seafoam in the tank full of gas and ride it like you stole it for about 50 miles and see if it clears up. Then, maybe if that didn't cure it, I'd pull the carbs and clean them thoroughly. Just my .02!
I had Ma Kawai (Dealership) clean the carbs a few months ago (about 800 miles) but I didn't clean the tank, and there's a good chance that's my problem. :(

Can someone please briefly lay out the basic steps to clean the tank?
First thing is to remove it, right? What product do I use to clean the tank? Let it soak, etc?

My thanx to Fergy and each of you who responded! :beerchug:
 

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Discussion Starter #9
How to Clean Gas Tank?

I had Ma Kawai (Dealership) clean the carbs a few months ago (about 800 miles) but I didn't clean the tank, and there's a good chance that's my problem. :(

Can someone please briefly lay out the basic steps to clean the tank?
First thing is to remove it, right? What product do I use to clean the tank? Let it soak, etc?

My thanx to Fergy and each of you who responded! :beerchug:
Bump--I need tips on cleaning the gas tank and doing a rust treatment!

Thanx in advance :beerchug:
 

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There are different methods used to clean the rust out of a tank. My favorite is using acid. This makes some folks queasy here, but it does a really good job, is cheap, and pretty quick, compared to other methods.

After removing the tank, you need to flush it thoroughly with your garden hose. Really work hard to get everything you can out with water. You have to remove everything, petcock, fuel level sensor, gas cap etc. and tape up every opening with good quality duct tape. Use a handful, maybe 50 or so, small 1/4" steel nuts and dump them into the tank. Carefully, pour about 12 oz of muriatic acid (they sell it at pool supply stores, or Home Depot) into the tank and tape up the gas cap hole and shake the tank vigorously for about 10 minutes. Keep the garden hose handy and rinse off any leakage immediately. (wear old clothes, rubber boots, rubber gloves and eye protection, maybe a smock if you have one) The acid and nuts will eat the rust off the tank inside. You might have to vent the pressure off the tank by lifting the tape around the gas cap hole every once in a while. You'll know when it bulges the tape. Keep rinsing the outer surface immediately if any acid leaks out around the tape. It will be the color of mustard so it's not going to be hard to see. After 10 minutes or so, remove the tape and let the acid drain from the bottom of the tank, into a plastic bucket full of water that you have added about a cup of baking soda. The baking soda will neutralize the acid. The writeup said to pour the acid on a patch of old concrete that you don't mind staining to neutralize it, but I prefer the baking soda method. Then you can pour the mixture in a gravel or dirt area and it will be fine. This acid will etch the metal and your surface will be clean and rust free. Now rinse the tank very well, flushing it with the hose and shake it to make sure you get all the acid rinsed out. You can use a telescoping magnet pick up tool to get all the nuts out of the tank. (make sure the nuts are steel!) Then tape it back up and pour two small bottles of naval jelley into the tank. You need to do this immediately after you get the acid flushed out, as rust will start to form immediately on the untreated metal. Shake the tank for a minute or two and then let it set for 30 minutes, then shake it again. Do this for 2 hours. Then rinse the naval jelley out by flushing it with the hose. Once clean, dry off the outside and rig a blow drier at the warm, not hot, setting and let it dry the inside of the tank. The phosphoric acid in naval jelley will treat the metal and make it resistant to rust. My tank has been silver inside since I used this to clean it. (I did this on my KZ1000P when I first bought it, and I sold it 1.5 years later and the tank was still nice and silver inside, no sign of rust!)

It's messy to do, but it works very well, and doesn't leave a film inside the tank that you might have problems with later. This method might seem a little radical, and some of you might prefer not to mess with the acid, but it works very well.
 

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By the way, I remember that I sat a box fan up near where I was working to keep the fumes from the muriatic acid away from my face. If you get a wiff of that stuff, it will take your breath away. Try real hard not to breathe the fumes!
 

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Discussion Starter #12
By the way, I remember that I sat a box fan up near where I was working to keep the fumes from the muriatic acid away from my face. If you get a wiff of that stuff, it will take your breath away. Try real hard not to breathe the fumes!
Hey Fergy --

I keep a large fan in my shed all the time. That's a very detailed writeup, just what I need--many thanx dude!

If the rust is not too bad, is it possible to do everything else except the acid. Is there anything that can be substituted for the acid?

Your write-up is a big help!

Thanx again, Fergy. :beerchug:
 

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Mine was crust rust. Seriously, if you rubbed your finger inside the tank, it felt like an old rusted fender. And my finger would have come out covered with the rust as if I were playing with mud. If yours isn't too bad, you could probably get away with using the steel nuts and the bottles of navel jelly only. Prolly have to do more shaking and maybe more intervals of sitting/shaking. Navel jelly does remove rust and also the phosphoric acid treats the metal to prevent more rust. I'd probably do that on one that is just slightly rusty, or even if there's not evidence of any rust.

I wish I'd have thought to shoot a photo inside the filler hole of that tank before and after I did the major acid job. It would have been impressive.
 

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Discussion Starter #14
Mine was crust rust. Seriously, if you rubbed your finger inside the tank, it felt like an old rusted fender. And my finger would have come out covered with the rust as if I were playing with mud. If yours isn't too bad, you could probably get away with using the steel nuts and the bottles of navel jelly only. Prolly have to do more shaking and maybe more intervals of sitting/shaking. Navel jelly does remove rust and also the phosphoric acid treats the metal to prevent more rust. I'd probably do that on one that is just slightly rusty, or even if there's not evidence of any rust.

I wish I'd have thought to shoot a photo inside the filler hole of that tank before and after I did the major acid job. It would have been impressive.
I haven't seen any rust in mine but I haven't inspected really close yet. I'll try looking inside of the tank with a flashlight and a small telescoping mirror. If there's only slight rust then I'll forego the acid.

Thanx for your help, Fergy! :beerchug:
 

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The Professor
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I haven't seen any rust in mine but I haven't inspected really close yet. I'll try looking inside of the tank with a flashlight and a small telescoping mirror. If there's only slight rust then I'll forego the acid.

Thanx for your help, Fergy! :beerchug:
Have you drained the carbs like I had you do last time to see if there is any sediment?
 

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Discussion Starter #16
Have you drained the carbs like I had you do last time to see if there is any sediment?
Hi Lance --

Yes, I drained the carbs but this time it didn't fix the problem. It still idles very poorly like it's running on one cylinder. Then at about 1700 rpms it completely smooths out.

The left side carb had sediment similar to last time. The right side carb did not have sediment but had one small (smaller than pea-size) globule of what looked like water mixed in with the gas.

I'm thinking about removing the carb drain allen screw and spraying carb cleaner into the carbs, and also cleaning the gas tank. What else should I do? What about installing a fuel filter?

Thanx for your response, Lance! :beerchug:
 

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Discussion Starter #17
Fuel Filter?

I know some might say you don't need in-line fuel filters because the screen in the tank will stop contaminants, but if you are getting crud out of the carbs, I'd install some. It's gotta be comin' from somewhere!
Hey FliteControl --

Do you have any photos of the fuel filter installed? Where/how would you install them?

Thanx! :beerchug:
 
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