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Thread: Tired SUV

  1. #1

    Tired SUV

    Hey all so I have a SUV with unknown hours and all three cylinders have about 104 for compression. It still runs pretty good but feels a little tired. When is a good time to maybe refresh the top end to get those numbers back up and how would you go about that. Is it as simple as new rings and a light hone or more involved.. or should I just Jeep running it and let it go? Any help is appreciated!

  2. #2
    Myself's Avatar
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    Well, that's a 65u engine which is pretty reliable. For most of the older 2-stroke machines 200-250 hours and they're ready for a top end. You will need to bore the cylinders and go with new oversize pistons. While your at it send the head to somebody like Newmiller machine or GroupK to be fixed. The squish band is messed up from the factory.

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  4. #3
    steve45's Avatar
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    If there is no scoring or other damage to the cylinder, you may not need to bore it.

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  6. #4
    So would the smart decision be to tear off the head and see if the cylinders are scored up and if not can I just put in some new rings and put it back together and call it a day and maybe prolong the life of the engine for a little bit longer or is that not a good idea.

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    Suv, before you 100% conclude that your cylinders are low on compression, let me give you my experience.

    I have an older, 35 yr old, made in USA compression gauge. It always reads my Yami, 2-stroke motors low. Like about what you posted. That being said, my 1997 GP1200 has 135 hrs on it and the engine is perfect. It runs like brand new. Very strong. My 1994 Raider compression numbers are also low. The 701 engine runs strong as well. I have no idea how many hours are on the Raider but I've owned it since new and it's been well cared for. It has also sat unused for a number of years in the late 1990s. These days, the Raider is lucky if it gets more than 5 hrs a year. If I had to guess, I'd say it has 150 hours.

  8. #6
    steve45's Avatar
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    Yes, check your compression numbers with a different gauge. If still low, look into the cylinders with an inspection camera to see if there is scoring, or pull the head. If you do end up replacing the rings, replace the pistons, too. Don't buy pistons & rings until you measure/bore the cylinders. They all must match.


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