Rotax 503 OVERSIZE bore re-ring set. Comes as shown with top gasket set and 2 sets of rings. for your 503. 72.25 mm bore this is 1st oversize.
This is enough to re ring 1 complete engine.
ALL sales are final, no returns, ask question before buying, not after.
Promptly shipped from the usa.
We carry kits for all rotax UL engines up to 583.