December 17, 200718 yr Just looking for suggestions here. My immaculate 300 fantic is in trouble. I seized the engine last summer(I know thats along time ago but I have kids and am busy) in an event and I have just now gotten around to looking at it! Bits of metal on top of the piston when I removed the head, and the piston is jammed stuck in the cylinder. What is the best way to get it unstuck and get the cylinder off. Cheers, Steve
December 17, 200718 yr a big wooden hammer. you can spray som release oil in the bore and heat it with a heat gun to help. I get mine off that way. You aint gonna save anything by being gentile. It will need plating, new piston and probably a crankshaft. Keep us informed. Lee
December 18, 200718 yr Steve ; Reading this almost brought a tear to my eyes !!!!!$$$$$$$.................. Glenn
December 18, 200718 yr Author Tell me about it Glenn!!! its another reason its taken me so long to look at it, just didnt have the heart to know what happened. Well I got the cylinder off Ok now. Lots of hunks of metal, and a couple of nasty grooves in the piston. The rings are intact, both wristpins are too, so far havent figured out where the metal is from. I cant say for sure but the crank seems like it might be OK. I remember when it let go I had just gone up a large rock step and the motor was idling down. Keep my fingers crossed anyway. More to report tommorrow! STeve
December 18, 200718 yr Steve could the metal bits be of the sparkplug ? did you hear the engine knock under load before it seized ? Cheers,
December 18, 200718 yr Steve, a 301 barrel will fit straight on with no other mods. The porting is slightly different to the 300 so it will be softer. I can get any pistons you want here, about 250 euros each. If the engine seized the crank WILL be bu&&ered. Try it with a 301 barrel if you have one but it will vibrate as the big end bearing will have a flat where it seized. A 300 Barrel will NOT fit on a 301 motor cos the 301 has a ducati ingnition which is bigger. I
December 19, 200718 yr Author Hmmm, does anyone know then if it is an option to slip a 240 top end straight on then, Lee can you help!
December 20, 200718 yr 300 = 249.4cc. 74mm bore x 58mm stroke. 240 = 212c.c 69mm bore x 56.5mm stroke. I know Lee has lots of tricks up his 'sleeve' but haven't heard of a 240 barrel on a 300 engine. (Well Steve we would have to use FedEx to get the 301 barrel and head to you in time to put under the Xmas tree, but Santa is all out of base gaskets ..centre yes, ignition yes, inlet manifold yes, but no base gaskets. Are you handy with the scissors and a Frosties box?)
January 4, 200818 yr Author A question for Lee or anyone else who might know! Will a 303 piston work in a 301 cylinder and head then.....
January 5, 200818 yr I'm not sure but I do beleive that the 303 was a reed valve motor ? if it is than no , the piston skirts will be quite different and affect port timing drasticly I would think ... but I may be completly wrong here ?
January 6, 200818 yr 300 thru 303 virtually same, except for port timing and bottom fin hump. So the answer is yes, exactly the same piston, wasn't until the 305 that the piston changed. Your major consideration is have you got a sized piston for a particular barrel, as pistons are graded A thru E, your particular grading will be found on the top of the barrel and also on top of the piston. From new these corresponded, but being 20 + years old may have been replaced with non matched parts, maybe it'll still work, but won't be as crisp and could be mechanically more noisey. Edited January 7, 200818 yr by ask greeves
January 29, 200818 yr Author Just to let all you other Fantic fanatics know, I have a brand new 300 piston kit on the way as well as a new rod kit. I will then send my cylinder out to be re-done, although it is basically unscathed from the whole ordeal. If all goes well, the old girl should be up and running by the end of Feb. I can then get onto ordering some NEW trick bits from Chris at classictrial!!! I fancy one of his slimline 240 tanks and a 240 rear fender and side panels to start. then I can work on the suspension some. Obviously this is a long term relationship with this great bike, so might as well go all the way with it!! Steve
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