i got two 2000 yamaha warriors. one runs great. the other one knocks like crazy as soon as i crank it. i took the engine apart today. the valves appear to be n good shape. the piston looks good. i dont know much about the crankshaft, but there is quite a bit of play on the connecting rod. is that my knocking noise? please help

 

up and down play is not good. Should not have any. It is normal for a little side to side play. Where is your slack?

 

my slack is side to side. i no i should have a little, but i have a half an inch. i looked a little closer and i saw some broken pieces of metal. i believe i broke a bearing.

 

half an inch is way out.. it should be closer to like .020 or so... you definitely have a bad something!!!

 

this may be a dumb question but are you saying you have a half inch of side to side on the crankshaft rod bearing or the wristpin in the piston? If you have half inch in rod bearing you missing some rod. like other guy said .20 is average. If it is half inch in piston pin that could be norm. can you post some pics of crank. Usually hard knocking comes from up and down play not side to side. You need to find out where the metal came from. post a pic of it if it is large. Is there any cylinder scaring? Look and see if the end of the rod has turned colors.

 

yes, i have a half inch of play on my connecting rod. the counterweights are blue on the top. its overheated somehow. im getting my other warrior jetted this weeknd and whenever i have time i will work on this problem. i will try to post some pics.

 

don't get to worked up...it is susposed to be blued on the counter weight from the heat applied when putting the crank pin in. There shoud be 2 thin washers one on each side of the rod at the bottom. Side to side noise will not knock. does the rod feel tight up and down? I have seen the cylinder be out of round bad enough to cause a knock.