How to: Valve-stem carbon removal?

I've heard of using water to clean the valves like this, and even done it a few times on cars over the years. But I never took anything apart afterwards to see if it actually worked.
But I've also heard that transmission fluid will do it too, but I wouldn't recommend it on a motorcycle engine. I'd be worried about scoring the cylinder walls.
But since you can actually look in your exhaust ports and see the valves, I don't see where it would hurt anything to paint some tranny fluid directly on the carbon deposits. Maybe it'll soften it up and blow out next time you run it.

warmed up motor.just take a spray bottle and blast a little in there while working the throttle a little,motor will stumble a little.water wont compress it basically turns to steam and blows carbon off.do one carb at a time and watch the carbon blow out exhuast,might need to do each cylinder couple times depending on how bad it is.

riverroad wrote:

But since you can actually look in your exhaust ports and see the valves...

Just don't run the engine with the headers off...

yeah!!!!!!!!!!!!!!!!!!!!!!! :laugh:

Ok! How long should I do that for each carburetor? You're saying you can actually see the carbon come out the exhaust pipe? That sounds gratifying, I'll have to give it a try.

hold your hand back a couple feet from exhuast,youll feel the little chunkshitting your hand!:laugh:

PLUMMEN wrote:

hold your hand back a couple feet from exhuast,youll feel the little chunkshitting your hand!:laugh:

All right...what the hell is chunkshitting!?!?!?! Never mind, I really don't want to know...

You might as well bite the bullet and do a valve seal job. I had a bike with the valve seal completely missing and the buildup was not that bad. As posted above, a wire wheel on a bench grinder does the job real quick. You are wasting your time trying to clean your valves while in the engine because the root cause is leaking oil....chris3

Mcdroid wrote:

PLUMMEN wrote:

hold your hand back a couple feet from exhuast,youll feel the little chunkshitting your hand!:laugh:

All right...what the hell is chunkshitting!?!?!?! Never mind, I really don't want to know...

chunks hitting!:laugh: i type with one finger and you expect me to be able to spell also?:woohoo:

The use of the word chunkshitting made me think there was a stomach virus involved somewhere in this discussion.

I doubt water will clean the carbon off valves where it is baked on and thick. One of the gas station companies sells gas with a chemical called Techron which is made to remove this stuff. You can buy bottles of the stuff to use in higher concentration but I doubt it will remove burned on carbon. I think a wire brush wheel on a drill or Dremel tool would be the best bet. If the stuff has crept up high enough, the stem seals will be toast. I would buy a new cylinder head gasket and remove the head and do some cleaning and have some new seals on hand.

Plummen- Thanks for the advice. This past weekend I successfully steam cleaned carbon out of my combustion chambers and valves with a spray bottle using a fine mist of water. I was surprised to see how well the engine ran despite the healthy dose of water. Small chunks of carbon flew out the exhaust pipe. I'll admit I was extremely skeptical about it. I've heard horror stories about hydro-lock and bent connecting rods and valves; fortunately this was not the case. Everything went smoothly, although it was time consuming to "mist" a decent quantity of water through the system. Thanks again for the advice! After the steam clean, the throttle response was much crisper and more responsive! One thing I didn't realize was that water would mix with the oil in the crankcase, creating a newfound "sludge" problem the likes of which I have never seen.. I changed the oil right afterward, but unfortunately, the water and oil formed to combine what I can only describe as a foamy, light colored petroleum mucking the entire innards of engine casings and the powerplant's bowels..Fortunately, life goes on. Although next time I think I will just spray a mist of Seafoam directly down the carburetor throats until stalling engine. Restart engine 5-15 minutes later and watch the smokefest! Thanks All.

i have used bg 44k fuel system cleaner seems to work pretty
well.i work at car x and we do induction services in the upper intakes and i have seen first hand that there products just melts away built up carbon may take a few times but it will do it