Damn Yankees
Aug 17, 2001
Hi All,

I recently posted about seizing the piston in my RM. Today I'm going to clean the bore. Right now I have the exhaust valve and reeds still attached.

I plan on spreading a thin layer of acid on the bore with a cloth, then brush/sand it. Then wipe it out with a rag and blow it out. Will it hurt other parts of the sleeve if it gets on it? I know the acid is potent. Any hints, suggestions, precautions, appreciated.

Thanks in Advance

Joe Chief


Super Power AssClown
Aug 24, 2000
I've been in contact with Joe over the phone and here is an overview for your information.
I believe that the engine seized because Joe leaned the jetting to clear up the sputtering problem and also used pump gas with Ethanhol which causes the left crankshaft seal to swell and leak. I told Joe how to visually check the seal by looking for a fuel/oil stain at the bottom of the case under the left side cover.
I also told him how to remove aluminum deposits from the cylinder wall using Muriatic acid (weak sulphuric acid) and an acid brush (used for soldering) both materials available from a hardware store. Joe found that the nickel coating peeled under the aluminum seizure marks so now he's sending the cylinder to me for replating.
Some of the jetting and engine changes were doing include switching to the next leaner jet needle, modifying the slide 1mm, lowering the compression ratio of the cylinder head, and switching to pump gas with MTBE instead of Ethanhol. Note: Amoco and Shell stations use MTBE,but always check the labels on the pump for warnings of Ethanhol. Ethanhol and Methanhol are bad for 2 stroke engines because the left side crankseal is prone to failure which causes air leaks and piston seizures.
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