Ski Doo, used 600 SDI motors, whats a good compression number

[john w]

When i purchased a used 05 gade 600 sdi the compression was 150 and 152 when i bought it with 7200 miles on it, It was never rebuilt or touched internal.

Guys with these motors please do a compression check when you get a chance and let me know some numbers please. Thanks

I recently had a guy try to tell me 125 and 130 was ok. I firmly disagreed.

 

[ezra]

150 sound like a happy gauge to me unless the head was cut did u only check with that 1 gauge?
I ask cuz I have 3 and they all are diff but the biggest diff is 7 lbs
ever do a squish test on that thing?
I dont know what a 600 sdi should be stock but your dealer will.to do a squish test you take a piece of soft solder and make a L. with the L almost as long as the spark plug hole to the edge of the jug.pull the plug turn over till piston is at bottom of stroke.then insert solder and hold solder so end of L is pointing to the edge of jug try to keep it parallel to rod pin{so side to side or from clutch to muffler]and sloloy turn over till piston crushes solder and is back at bottom of stroke then check it with a micrometer.that will be your squish.
the only sleds I have seen with 150ish have had 9tho or so cut from the head.it is poss that your sled was used at 8k feet or better and lots of those guys cut the head before they leave the garage. with a stock head my sled will be at about 120 comp at 10k and at home 136 comp.

but yeah 130 135 at midwest elevation is about right

 

[skiroule]

If you go on DooTalk, you'll see SDI compression numbers all over the map. Gauge readings almost always vary from one gauge to the next. The dealer's gauge gave me five more pounds than mine did at home.

150+ lbs seems really high. High 130's to mid 140's would be more in line with what most SDIs actually run. If it starts good, runs good, and the reading on both cylinders is close (very important), your engine is most likely pretty healthy and has no ring issues. I would just use your gauge readings for reference from year to year to see how the cylinders are holding up.

 

[opt8low]

My SDI has been 140 to 145 since it was new and with 8300 miles it will get run until they get uneven or drop a lot.

I have always used the same Snap-on gauge too. Also seems to be the same numbers whether it was a hot or cold test......


My 2 cents,


Dana

 

[hermi]

My 05 sdi and my friends 05 sdi are both 150psi give or take 2 psi. been that way since new.

 

[ezra]

My 05 sdi and my friends 05 sdi are both 150psi give or take 2 psi. been that way since new.

what will your guage read on say a f7 zr600 dragon 6 or any other sled.sounds happy.
I have 3 1 of them I bring to buy a sled one I have to sell and the cheepest one is right between the 2.
on same sled I can have 140 144 and 147

 

[russholio]

My 05 sdi and my friends 05 sdi are both 150psi give or take 2 psi. been that way since new.

This is similar to my experience, too, and mine has just over 10k. Now, I can't say that my gauge might not be "happy", and I've only checked the sled with one other gauge (got similar numbers). But, much like blood pressures, I'm not as concerned with the actual number as I am with the CHANGE in numbers -- and there just hasn't been much change from year to year, and I check it twice a year. So, although my gauge might be a bit happy, I seriously doubt that it's off by a big enough number that I would be worried that my compression is getting too low (I'd start getting concerned around 125 or a little less, unless it's showing other signs).

 

[russholio]

When i purchased a used 05 gade 600 sdi the compression was 150 and 152 when i bought it with 7200 miles on it, It was never rebuilt or touched internal.

Guys with these motors please do a compression check when you get a chance and let me know some numbers please. Thanks

I recently had a guy try to tell me 125 and 130 was ok. I firmly disagreed.

125 and 130 are ok (though not great), provided the reading was taken with the same gauge so you're comparing apples to apples. That is, unless last time you checked it it was 150 and 152, and now suddenly it has dropped by 20. Then I'd be concerned.

 

[john w]

Thanks all, great information. I would feel much better if i was buying a sled with a 140 lbs + per cylinder.