carter 0 Posted April 3, 2001 Tom, Just finished a Briggs 243431 overhaul on my Big Ten. Had to go +.010" oversize to clean up the bore. I couldn't get a definitive answer from a dealer or the B&S organization. Consensus among the local small engine guy's was to fit the piston to the bore with .005" total clearance on diameter. Got a couple of hours on it and it is running better than ever. As far as the Magnetron I can't help as I converted mine to battery ignition. Ron Share this post Link to post Share on other sites
TOMT 0 Posted April 3, 2001 I AM REBUILDING A 10 HORSEPOWER B&S CAST IRON ENGINE & WOULD LIKE TO KNOW THE DESIGN CLEARANCE BETWEEN THE PISTON & THE CYLINDER. THE PISTON REMOVED INDICATED A CLEARANCE OF APPROX. .010-.012". I HAVE CHECKED SEVERAL SOURCES INCLUDING B&S CUSTOMER SERVICE & CANNOT GET AN ANSWER TO THIS ???. I KNOW I'LL GET A RESPONSE ON THIS SITE. SECONDLY,CAN ANYONE POINT ME TO THE WIRING DETAILS FOR INSTALLING THE MAGNETRON ELECTRONIC IGNITION SYSTEM. THANKS IN ADVANCE, TOM Share this post Link to post Share on other sites
Al 6 Posted April 3, 2001 Hi, I had that number once, but don't remember what it was or how I got it. Briggs philosophy is bore it to exactly 010 or 020 or 030 from stock and all will be OK. Thatis how they are built new. I suspect the .005 clearance number previously is pretty near correct, as it is in the norm for this size bores. Good luck, Al Share this post Link to post Share on other sites
JP 0 Posted April 4, 2001 I would tend to agree with the above. In some racing two strokes we went .0025 , .005 sounds in the ball park. On the mag unit, did you repolarize the flywheel? I think on the cast iron ones you do, the aluminium you don't. Good luck, JP Share this post Link to post Share on other sites
dlcentral 1 Posted April 4, 2001 .003-.004 is the right clear.That's what you get when boring out to .010,.020 or.030 past std. size dimensions as per briggs recommendations. Share this post Link to post Share on other sites