Originally Posted by franchi

Hello all:

As some of you have read, I have been having a large amount of black exhaust residue being produced by my MVVS D7. It was not the fuel or poor needle valve settings. I think that it is being caused by the con rod rubbing on the back plate. However, I have taken steps to determine how I may remedy this problem. Thus far, I have been dumbfounded in my search.

I coated the bp with Prussian Blue and made three additional baskets totaling .0625" to move the bb away from the con rod. This did not help. The rubbing on the cr is about 1/2 inch long on the rod but the area where the crankpin goes through the bottom end, does not touch the bp. Only the rod is rubbing! Is this a sign of a bent rod? I can not see where the bp as been rubbed even after applying the Prussian Blue to the backplate. The PB is transferred to the conrod.

I noticed that the crank pin is about .0625" short of being flush with lower bushing. It also appears to be well away from the crankdisk. The lower rod bushing is protruding about .0625" out of the conrod in the rear. It appears that the conrod should go further towards the crankdisk to cure my problem.

I have carefully broken this engine in on a stand and flown it a couple of times in the air. No electric starter has ever touched this engine. It has never had had been crashed or been crashed. It was always an easy starter. I dislike the idea of taking the engine apart as it has a great p/c fit. However, if I must then I must.

Any suggestion and or suggestions?

Where may I purchase spare parts for this engine?

Be well,

franchi