carbon in exhaust tube

michael Culbert /

I have a 2003 Tomos Targa. It is experiencing a loss of power, difficulty starting. I've checked the spark plug, air filter, fuel line, air strainer, muffler baffle and brakes. I've tried using SeaFoam in the gas and carburator.

I think one of the problems is in the exhaust tube. I cleaned off the baffle with gas and filed away carbon deposits, and removed and rinsed out the exhaust tube with gas. It ran better for about 20 miles then it has slowed down worse than before. Going around the block without the exhaust tube seems to indicate that is the location of the loss of power. Is there a better way to clean out the carbon? Even without the exhaust tube it has problems excellerating. Could this indicate there is also a problem with the timing and/or piston rings?

I live in a small town where there isn't a dealer or moped repair shop, so I'm trying to do the repairs myself. Can anyone offer some advice? Thank you

Re: carbon in exhaust tube

have you thought about a biturbo system? evryone i know with tomos bikes swear by them. carries them new for about $70, and ships anywhere. the other thing might be to check your mixture. i've had similar problems with my garelli, and i get the same answer everywhere. Biturbo. check it out

Re: carbon in exhaust tube

michael Culbert /

thanks, I don't know what a biturbo is, but I'll check it out.

I have an automatic pump that mixes the oil and gas. It has enough oil, but if it stopped working I wouldn't know. I'll check it out. Thanks Dave

Re: carbon in exhaust tube

A bi-turbo is one of the popular performance exhaust systems.. it's an "expansion chamber". They do improve two-stroke performance withonly minor drawbacks.. one is they are loud as hell. Another is the bike is no longer "stock" and will require some tuning skills of various sorts to maintain the bike's reliability.

it does sound like the exhaust has carbon build up.. One of the Seafoam products has been known to work on carboned exhausts.. Since carbon doesn't dissolve, the burned fuel and oil residues and junk that holds the carbon together is attacked.. and it falls apart and can be flushed.

Search this forum for lots of threads about carbon and techniques for removing it.. it's not easy in the best of circumstances.. Also, put some effort in the direction of fine tuning your air:fuel mixture and perhaps select a new type of oil .. and maybe adjust the fuel:oil mix..

If you manage to get everything right the bike will run great and there will be adequate lubrication without a lot of carbon buildup.


That thing about soaking in gasoline followed by a worsening problem reminds me of something i once did..

Planning a long trip in an old car, i put a can of radiator rust remover/cleaner into the radiator. About 10 miles later the car overheated. The cleaner had loosened all the rust and that rust was then free to circulate.. and it formed a total clog in the water pumping system.

same thing may have happened to you.. the gas loosened and dislodged a bunch of junk, which was then free to move and get packed together in some narrow spot.

Re: carbon in exhaust tube

If you want to keep the stock pipe,remove it,stick a plug in the ehhaust end,lean it up against something,with the end that attaches to the engine up,fill it full of Castrol Superclean,let it soak overnight,then thoroughly rinse it out with water from the end that goes on the engine.Let it dry completely,and reinstall it.This has worked for me.If you want to go with a bi-turbo,the only other modification you will NEED to make,is to go up a few jet sizes.You may have to try 2 or 3 before you find the right one.Whichever way you decide to go,I DEFINATELY recommend removing the oil injection system,and using premix at 40:1 to 50:1.Tomos oil injection systems are of very low quality,and are not reliable.

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