Exhaust de-coke ??

[Nitram]

I have this lovely little 200 twin Yamaha- CS3. This is not it, but it looks the same:



Very good compression, ignition timing spot on, clean air filter, no big rattles, but it won't do more than about 60mph on the flat. The acceleration is OK, but not much top speed.

So I'm wondering if the mufflers could be carboned up. I can't seem to get the baffles out-they're just stuck in tight, and there's nothing grab onto without wrecking the baffle, so I was wondering if anyone knows of something that can be poured into the muffler that will dissolve the carbon. I have a vague recall of someone talking about using caustic soda. I guess the idea is to put a bung in one end and pour the stuff in the other........ does that achieve anything, or will the caustic just go cold and hard and choke the things up even worse ?

Any suggestions ?

Cheers,

Nitram

[KayAitch]

Much more experienced people will chime in here but I've been working on a little KH100 and I did the caustic soda trick.

Take the muffler off at the header-muffler, shove a potato in the header end (makes a great plug! choose a potato bigger than the diameter of the pipe.), hold vertical with potato on the ground and fill with caustic soda and place in a a large bin filled with water up to the length of the muffler. I was told to do the last stage, but I'm still unsure why, contamination? You could probably just lean it against a wall provided no one is going near it. I did mine twice for a 5 hour soak each time and plenty of carbon came out. I then shoved a piece of wire coat hanger down the pipe and scraped away. I also got plenty of black cornflakes out this way. Put the pipe on the bike and the thing went much, much better.

Still, if you can get the baffles out and do it properly that would be better but I got good results my way.

[Nitram]

Thanks K, It does sound promising then. It could be that they recommend the big barrel of water so that any caustic that gets spilt wont tarnish the chrome. Dunno.
Anyway, I'll give it a go.
Cheers
Martin

[joexr]

Diesel fuel works well to dissolve carbon. Done this on many 2-strokes and its not corrosive.

[Nitram]

So what do you do with the diesel ? Soak it in the pipe just the way described above for caustic ? For how long ?
Cheers.
Martin

[supershaft]

The mufflers? I have seen more trouble in the exhaust port itself. With the piston on TDC and, if you are careful, you can clean them without taking it apart.

[JonnyCash]

I recently cleaned out the intake manifold on my Golf TDI, it was choked up with oily soot, they do that. I saw a number of videos of people burning the carbon out of these by first igniting the deposit with a propane torch. Once it is burning, a lazy smoky fire, you use an air gun attatchment for your air compressor to fan the fire. Once you do this, and quit with the torch, then the fire burns cleanly an fast and hot. After a minute of this, flaming chunks of carbon start coming out the other end from where you're fanning, and after about five minutes, the manifold was open and clean, (and hot!). I had to stop a few times to let the aluminum manifold cool, but damn if it wasn't fun and effective. Next time I have to clean out the pipes on my RD 350, I'm definitely going to give it a try.

[KayAitch]

Originally Posted by Nitram

Thanks K, It does sound promising then. It could be that they recommend the big barrel of water so that any caustic that gets spilt wont tarnish the chrome. Dunno.
Anyway, I'll give it a go.
Cheers
Martin

Goodo. I'd definitely do the chemical approach in tandem with some physical cleaning too - i got just as much carbon out poking around with some wire. Whatever you can manage. If you can't get the baffles or any internals out definitely poke around in there with some wire - I made the wire into a less extreme \/\/\/\/\/\/\/\/\ shape and spent ages sliding it in-and-out - and then hold the pipe vertical and bang it out onto a bench. I was fortunate in that my pipe seemed to be straight through with a baffle system around and I could get some wire in there to scrap sticky bits loose in the immediate area. Obviously whatever you can get out is good. I found mine was very choked up and now I have a little power band for the first time.

[joexr]

Originally Posted by Nitram

So what do you do with the diesel ? Soak it in the pipe just the way described above for caustic ? For how long ?
Cheers.
Martin

Plug one end and fill it up . Overnight should be long enough , then pour out half and shake. Then empty and let stand up to drain. You could try it twice if you think necessary. Any fuel residue left inside will just vaporize and smoke until you wind it up thru the gears a couple of times , then it will be gone. Years ago we used to put it in the ends of the pipes. You could ride around conservatively all day and it wouldnt smoke much , but whack the throttle and you would have the cars behind you pulling over.

[stainlesscycle]

i just load each pipe up with a can of ez off oven cleaner, and let em sit a while. don't buy the generic stuff, it doesn't work. diesel is interesting - never tried it.