Bore or Hone

Edward Edwards /

I'm putting on new rings & piston on my '78 Batavus. I noticed some scratches on the piston & cylinder wall, should I hone it or bore it? The engine had compression of 85psi before I took it apart. Thanks

Re: Bore or Hone

If its the common M48 engine, it has a cast iron bore, so you hone it.

If the scratching is really light, try honing it with really light oil, like 3 in 1 or Pyroil penetrating spray. Wipe it clean and look for the marks and scratches. If it looks okay, take the NEW stock sized ring and squeeze it into the bore as if it were on a piston. Measure the gap between the ends of that ring. If the gap is between 0.2mm and 0.5mm, there is no need for an oversized piston.

The piston is 40mm, and the oversized piston comes in 40.20 mm. Rehone the cylinder to a minimum of 40.245 to a max. of 40.555 mm. for an oversized piston.Okay? don-ohio

Re: Bore or Hone

Edward Edwards /

Thanks for that great information Don.

Re: Bore or Hone

Sure,Ped58! I've got a Batavus, and even though I never run it, I always wanted to have a shop manual for each of my bikes. I finally accomplished that goal the other day when I got a shop manual for my Hero Majestic Ankur. don-ohio (:^D

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