[Roundsworth]

Today I removed my 30mm flatslide carb to swap pilot jets. Needless to say, the carb came stock with a '38' and the extra jet kit had a '25'. I though that the carb came with a '19'. I assume that the higher number flows more fuel. While I had the K&N air filter off, I decided to try Vince's water spray de-carbonization treatment. I observed the tailpipe and did not see anything flying out. I put everything back together and went for a toodle. I had ridden for about 2 miles through town, so it was warmed up sufficiently. As I accellerated from a stop sign, the motor lost all power and died. I kicked her over a few times with absolutely no resistance. I pulled the plug and it appeared to be fine. Then I pulled the tappet cover and observed the pushrod action and adjustment, which was just where I set them. I scratched my head for a few moments and decided to spin the motor with the electric starter. The starter worked fine and also started the motor! Anyways, to make a long story short, I would assume that a big chunk of carbon came loose and held a valve off its seat long enough to give me a good fright! I just thought I would pass this along in case any of you try the water spray treatment. Cheers!

[baird4444]

   Don't forget to check your oil after this process...   The time I did it there was enuff water in the oil to warrant changing.
                     - Mike
                                 

[cyrusb]

My flatslide also came with the 38 pilot instead of the advertised 19. Which is good ,because I don't think  it would have been rich enough . I tried the 25 and it was way too lean. CMW must have learned this themselves while testing. I have mine adjusted a little fat (air screw in) for a perfect idle. One odd quirk I've noticed with mine is the way it runs out of fuel. When mine gets to the end of the tank(reserve time) there is no sputtering or bobbling to warn you. It's just dies, like an ignition failure. It's so sudden, that If I'm not doing 60 I won't catch it. Hows yours?

[UncleErnie]

Holy Cow!  What the heck is "Vince's water spray de-carbonization treatment"?!

[Rick Sperko]

My flatslide also came with the 38 pilot instead of the advertised 19. Which is good ,because I don't think  it would have been rich enough . I tried the 25 and it was way too lean. CMW must have learned this themselves while testing. I have mine adjusted a little fat (air screw in) for a perfect idle. One odd quirk I've noticed with mine is the way it runs out of fuel. When mine gets to the end of the tank(reserve time) there is no sputtering or bobbling to warn you. It's just dies, like an ignition failure. It's so sudden, that If I'm not doing 60 I won't catch it. Hows yours?

My Mikuni TM32 was acted the same way when I ran low on fuel. It is better since I leaned it out a bit.

-Rick

[mbevo1]

Unc Ernie -

The "water spray treatment" outlined by Vince, et. al, involves spraying water in the carb and using the resulting steam to clean the combustion chamber. 

I've been doing it at oil change time using distilled water.  Take a ride to get things warm, spray in a dozen or so squirts from a mist bottle, run for five more minutes, then change the oil. 

Supposed to work well enough that the decarbon procedures listed in the manuals may not be necessary.

Mike and Stumpy in Michigan

[UncleErnie]

oh... I thought he was sticking the end of a pressure washer in there or something.

So this sounds interesting.  Anybody got a link so I can read about this and how to do it?  Like, if you spray a little water in there- do you just let it idle for a while, or ride for a few miles?  I assume you do the initial spray with the plug out so it doesn't get wet?

[mbevo1]

I assume you do the initial spray with the plug out so it doesn't get wet?

Water gets squirted in the carb intake with the motor running and a fast idle... you can actually squirt an impressive amount in there without the motor dying...

Mike and Stumpy in Michigan

[ScooterBob]

I've decarbonised really bad engines by letting them "inhale" a bunch of rice from my hand. THAT works wonders in one. The only thing you have left is a slightly nutty small and a bunch of gray dust out the tailpipe ...... Water works well, too - but windshield washer fluid works even BETTER because it has alcohol in it. I disconnect the PAV tube at the bottom of the intake and connect it to a dip-tube that will go into the jug, then rev it up and let it suck away ..... Clean-O combustion chamber!!

[gtdohc]

There is a product call Sea Foam which advertised to do that kind of job too.

[ERC]

Mercury Marine makes a product called Power Tune that is made for removing carbon from both 2@4 stroke engines.Have used it many times over the years with no problems.    ERC

[dogbone]

Should there be any concern about hydro locking ? Steam expands  at a much higher rate than petrol.
My wonderful wife drove through a massive puddle in her Taurus, sucked in enough water to saturate the air cleaner, end result, a bent rod   ooi.

[ace.cafe]

Should there be any concern about hydro locking ? Steam expands  at a much higher rate than petrol.
My wonderful wife drove through a massive puddle in her Taurus, sucked in enough water to saturate the air cleaner, end result, a bent rod   ooi.

Yes, that is a concern, and it should only be a misting spray into the carburetor, and not enough to choke out the engine.

Too much water in there will definitely damage the engine.
It doesn't need Niagara Falls going in to work.
You just want to generate a little steam, and that's all.

I"ve used ATF squirted in for the same purpose, many years ago when I worked in a shop. Alcohol can do it  too.

Basically, there are alot of products like Sea Foam and fuel additives that will keep the intake system pretty clean if you use them regularly.
I really don't see a big need for doing the water treatment.
Just keep the carb adjusted correctly, and if you need a de-coke, then pull the head and do it.
It's not like it's a 32-valve V8 with bucket and shim valve adjustments, or anything like that. It's just a simple little single. You can have it done in an hour or two.

[UncleErnie]

Oy -always another opinion.   So you think if I out some Sea Foam in a galoon of gas occasionally, I wouldn't need to take the head off and scrape carbon?  Or is that just part of the deal?

I'm so confused...

[ace.cafe]

Oy -always another opinion.   So you think if I out some Sea Foam in a galoon of gas occasionally, I wouldn't need to take the head off and scrape carbon?  Or is that just part of the deal?

I'm so confused...

Stuff like that helps to remove some deposits that are built up in the head, and helps avoid getting more deposits.
It's like a gradual cleaner.

Truthfully, if the carb is set right, it shoudn't need any de-coking for at least 10k miles, even if you don't do anything else to it.