Motobecane engine sludge

I recently purchased a 50v and out of curiosity I opened up the engine to check the shape of the rings and piston. Turn out there is a bunch of oily sludge sitting down in the crank. I'm afraid that some of the sludge will break loose and scar the piston or cylinder walls. Any suggestions with this? Clean it out? With what? Etc.


Re: Motobecane engine sludge

steveintoronto /

have you tried a really thorough oil change? drain the TF, run the motor with new fluid, drain it again etc...

just a thought

Re: Motobecane engine sludge

Mike Scouty McScoutington /

mbk does not have a wet box so that is not going to help. brennen can you shoot a pic and post it so we can see how bad it looks?

Re: Motobecane engine sludge

See Ya Moped Army /

Pour some Marvel Mystery oil in the case, turn the crank over several times, and let the Marvel Oil sit in the case overnight. Drain it out the next day. That should clean all the sludge out of it.

If there's a lot of sludge in there, there's a good chance that water got in the case and your crank bearings could be rusty. The crank should turn very quietly and smoothly. If not, it may need new bearings.

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