- Location
- Lawrence, Kansas
I have a couple older 650sx jetskis that are indestructible. I've done just about everything possible to them and they just run and run and run. recently, I noticed compression wasn't where it should be on one of my 650sx's so I pulled the head and found it had standard bore wisecos. The rings were pitted like they had rusted a bit or something. I believe it happened before I bought the standups last fall. Got new wiseco rings in to replace what was there. Did a light hone job and replaced the base and head gasket and exhaust gasket.
Long story short, yesterday I checked compression. It had been 125/137 before the ring job and now is at 180/180. This is with about 25 hours on the re-ring job so they are fully seated and compression is really up there. I know my gauge is accurate--Ive had it tested. I've been running 87 octane premixed to 40:1 ratio. The plug looks like dark chocolate so I'm obviously a bit rich. I turned in the high speed adjuster 1/8th turn and put new plugs in last night. Will test next time I go out. From what I could see through the spark plug hole, I don't see any signs of deto. I'm running a stock 34 keihn with the integral fuel pump.
Should I be going with 93 octane with the same 40:1 ratio @ this compression? I get my gas at either hyvee or texaco.
My other 650sx is at 121/130 compression so in october or november I'll pull it apart and check it out as well. New rings made all the difference in my other jetski so maybe thats all this needs as well. rings run approx $54.00, plus about $35.00 for gaskets so its about a $100.00 job when its all said and done to just re-ring the cylinders.
Long story short, yesterday I checked compression. It had been 125/137 before the ring job and now is at 180/180. This is with about 25 hours on the re-ring job so they are fully seated and compression is really up there. I know my gauge is accurate--Ive had it tested. I've been running 87 octane premixed to 40:1 ratio. The plug looks like dark chocolate so I'm obviously a bit rich. I turned in the high speed adjuster 1/8th turn and put new plugs in last night. Will test next time I go out. From what I could see through the spark plug hole, I don't see any signs of deto. I'm running a stock 34 keihn with the integral fuel pump.
Should I be going with 93 octane with the same 40:1 ratio @ this compression? I get my gas at either hyvee or texaco.
My other 650sx is at 121/130 compression so in october or november I'll pull it apart and check it out as well. New rings made all the difference in my other jetski so maybe thats all this needs as well. rings run approx $54.00, plus about $35.00 for gaskets so its about a $100.00 job when its all said and done to just re-ring the cylinders.
