October 21, 200916 yr I have stripped down the top end of a Fantic 245. If I buy new piston rings are they all one size? The barrel has C stamped into the top fin I assume this is the clearence code. The bore looks very clean without any marks so should be OK. The reed windows in the piston are just two small holes (approx 10 to 12mm) with a single hole high up just below the rings is this normal? What is the thickness of standard base gasket as the one I removed is very thick approx 1 mm. What is the method to ignition time the engine? Spark will kill a horse! What are the standard carb settings as mine has a Dellorto 55 slide, 98 main and 40 pilot jet. Any useful mods that can be done on these engines.
October 21, 200916 yr Hi Matt, you should find a C also on the piston top. If the piston says asso, then the holes are correct as this was std. There were some lower cost pistons made, not from asso but the holes were more or less the same. The piston rings were all one size but different for asso and other pistons. if they are pattern rings, check the end freeplay when assembled If you replace the piston, a D might fit. Measure the bore about 5mm below the top ring mark twice, 90 degrees from each other. The old piston will be oval but the new one is not. You need a clearance of about 0,05mm. If it is less than 0,035mm, do not go for the D, stay with a C. If it is more than 0,07mm, an E may fit. The bike WILL rattel very soon after assembly. Even with a new bore and piston, these bikes did rattle. The pistons with the holes are better for this than those with two windows. The base gasket is about 1mm thick. The timing is not adjustable, just line them up - stator to casing. Jetting sounds about right A flat slide carby will work wonders on the bike, are both flywheel weights still there. If none are ther try finding some or making some. Very useful in mud! if the tailpipe is b Edited October 21, 200916 yr by Lee Harris
October 22, 200916 yr Author Lee, Thanks for your answer, indeed there is a C on the piston which was made for Fantic by Galardini (spelling) as both names are cast on the inside. At least I know it is a standard piston and not mucked about. Matt
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