Motor problem?

[chadman]

I was out riding around and I came up of the trail and I thought that I fouled a plug. I changed the middle cylinder plug and the motor still ran the same. So I drove it home less than half a mile. I checked the compression and the middle had 0 compression. Mag and clutch had only 75. The spark plugs looked good no aluminum on them. I don't understand what happened. I have it jetted down one size and I have the pistons coated but they are wiseco. I ysed to run with 2 sizes smaller jets and never had a problem. Any ideas?

 

[bluemonster1]

I think you have some major work to do now.Does not sound good.

 

[chadman]

Does anyone know what a new set of yamaha pistons cost with rings and pins?

 

[terret725]

befor u start pricing pats best thing to do is pull teh head and see whats wrong. could be anything for detination to a broken ring or just a burn down.

 

[vibeline]

parts

These guys ship fast. They are usually cheaper than my local dealer

http://www.ronniesmailorder.com/fic...ry=Snowmobiles&make=Yamaha&year=2000&fveh=978

1 PISTON (STD)
8DN-11631-20-A0 (replaces 8DN-11631-10-A0) 3 $93.88


2 PISTON RING SET(ST
8DN-11603-00-00 3 $18.92


3 PIN,PISTON
8J0-11633-00-00 3 $12.13


4 CIRCLIP,INNER
93450-21053-00 6 $2.07



3 SEAL, CYLINDER HEAD
8DF-11355-00-00 3 $3.49


4 SEAL, CYLINDER 2
8DF-11356-00-00 3 $3.70

10 GASKET, CYLINDER
8DF-11351-00-00 1 $26.38


piston kit on fleabay

http://cgi.ebay.com/ebaymotors/3-Ya...egoryZ100456QQihZ020QQitemZ300071308869QQrdZ1

 

[chadman]

My dealer gave me a rough guess of about 500 to 600 dollars to do the top end tear down and put back depending on what is wrong.

 

[mrviper700]

if its a 2000 srx and you jetted down 1 size from stock? stock was 146.3146.3,147.5. Well your already too lean for winter type conditions, there is a service bulletin out that the 2000 jetting was too lean and they raised the jetting up from burn downs. The only way that the 2000 jetting was safe to use was with the 02 srx that was equipped with DCS. I would be willing to bet you have aluminum smeared on the ringlands and that the rings are pinched closed from being too lean. Even with pistons coated you cant protect the ringlands from melting from being too lean on the exh side of the piston, once the aluminum becomes molten and smears the ringlands closed the engine loses compression and is done. Take off all 3 cylinders and inspect the pistons, youll see what I am trying to describe to you, the rings will be pinched closed.

 

[chadman]

Thanks for the info guys.