Engine Noise

[firefighter]

Greetings all, I have a 02 MM 700 with a slapping noise coming from the #3 cylinder on the mag side (starting side). It sounds like a valve tappet, something that you would hear on a v8 motor. However, I know there are none of these in there. Compression is good and no loss of power. Any ideas on what it might be. I do not want this thing to let go when my wife is out riding it. Thanks

Also was wondering if there are any reasonable places to buy parts from. The local dealer quoted me $160 for just the 3 base gaskets and the top gasket.

 

[revrider07]

mm700

Had same issue pulled head nothing wrong with motor. Pull the recoil off and get to the mag it is comming loose in there half moon key has maybe already came out dont run it anymore than you have to if you catch it in time all it will cost you will be your time. Revrider07 still have my 99 max with all the goodies

 

[M.M. 700]

Also was wondering if there are any reasonable places to buy parts from. The local dealer quoted me $160 for just the 3 base gaskets and the top gasket.

PM "Free Agent" on here. Or call Oregon Trail Sports and ask for Shell.

 

[firefighter]

Thank's for the information. I am hoping to tear into it tomorrow when I get off of work.

 

[firefighter]

Tore the recoil starter and flywheel off today and it all checked out ok. The key was still where it was supposed to be. I am told that if this key had come loose then the flywheel would have turned, in turn throwing off the timing and then it would not run. But it was worth a try to keep things simple and cheap.

 

[BBNytro]

Exhaust leak??

 

[firefighter]

All of the exhaust checked out ok. I started with the simplest things 1st. Now it is all torn apart. See my other posts for more info.

 

[mark]

noise

A slapping noise in the engine could be a cracked piston skirt. The last time I heard that noise was on a phazer with broken skirt.

 

[mark]

Cheap Yamaha parts

www.yamahasportsplaza.com/

Check out this place for yammi parts, they give 30% off. I buy a lot from them. Your dealer overcharges you like mine did!

 

[firefighter]

Top end of engine is torn down. 2 of the 3 pistons have to be replaced due to scoring on the intake and exhaust side. Was told that scoring on the intake side is lack of fuel. So I tore the carbs apart and they were clean. Scorring on the exhaust side is lack of oil. It seems to use about what my other sleds do and is properly adjusted. #1 cylinder looked great. Needle bearings looked good as well and the big rod end and small end are withing specs. No play up or down. None of the piston rings were broken as the machine had good compression. Sent the cylinders out to U.S. Chrome in WI to be stripped and replated. There wasn't any excessive oil usage either. I guess it might have been a combination of a bad piston skirt and a needle bearing but who knows. Now just waiting for every thing to come back so I can put it together. I hope I get this done before all the snow is gone.