TOPIC:

i just started reassembling my engine. 900 with 1015 block bored to 1045. when i spin the crank by hand, its somewhat hard to turn, and seems to leave small scuffs on the cylinder walls. my only previous motorcycle rebuild experience is two strokes and those always spun easily by hand. also if anybody has any tips for the rest of the rebuild any help would be appreciated. thanks, ryan

It isn't clear what stage you are in... is the block/cylinder and head on the engine? When you "turn the crank by hand", what does that mean... you mean turn the crank using the 17mm nut on the crank end with a socket/ratchet wrench?

the bottom end is complete and it turned fine by itself. the top end is whats tight hence the cylinder wall scuffing. i am turning the crank by the ?alternator?. it's not impossible to turn but it just seems tighter than other engines i have done. although the other engines were two stroke except for a car and that would be expected hard to turn.

probably the rings dragging on the cylinders a little.a new motor is always gonna be a little tight till the rings get broke in,just be carefull not to break a ring.

Your two stroke engines might have also had coated cylinder walls, thereby reducer ring/cylinder friction.

Also, did you gap your rings? Could be tight there as well

Jason

Use a 17mm socket on the larger of the two nuts on the end of the crank under the POINTS COVER... not the alternator! Second, do you have spark plugs installed? If so, remove spark plugs as you are experiencing engine compression at work... the engine will be real hard to turn over.

all it is is the transmission in the cases, the crank and the piston/cylinders...no head or any other covers i had it the whole way apart. thanks for the help