Hi all! I recently picked up a 96 xp800, and both cylinders are registering 205# of compression. Do I need to be running av gas or will premium do? Traded an 800 dollar rifle for her non running. Replaced the fuel lines, pulled the carb, put a new battery in and she seems to run great. Everything appears to be stock. It sat outside unused for four years so the decals are coming off and the polisher is doing wonders. Any advice? Thanks all!
Need advice! new to me 96 xp800 high compression
- Status
Hmm....thats odd unless there was a ton of oil in the cylinder. It is also possible someone cut the head. Or...if your gauge adaptor you are using is the wrong one its surprising the range you can see from different adaptors.
205 is definately 100% race gas compression...180 is the cutoff point between premium and race.
205 is definately 100% race gas compression...180 is the cutoff point between premium and race.
soccerdad
Well-Known Member
Are there any other mods on the ski? I would not expect that they did work on it to push the compression up that high without doing anything else. I would test it with another gauge. If it is that high, then race gas.
I have never had good luck with octane booster on race motors.
I have never had good luck with octane booster on race motors.
I'd like to see some pics please. We may be able to point out some other alterations.
+3 on 205 being race gas territory
+3 on 205 being race gas territory
Sportster-2001-951C-Stock
Well-Known Member
205psi - Mildly curious, wondering what they had in mind?
68ragtop
Well-Known Member
Something seems odd. If it's cut that much you could probably measure it on the outside & find its short. Also like others mentioned, it seems strange that it has a stock air box, pipe etc. As far as octane booster. The stuff does almost nothing except make you feel like spent the equivalent amount of money. Most of them would be hard pressed to turn 87 into 87.5 let alone, 91 into race fuel. The rest won't do anything at all.
What brand gauge do you have? I would hook it up to a compressed air line & check it against some other gauges. Maybe it was dropped at some point? The only thing that separates a compression gauge from any regular PSI gauge is the spark plug hole adaptor & the check valve thats at the very tip of it.
soccerdad
Well-Known Member
If you think the gauge is correct, then I would download a manual for the ski. Free to paid members here but also easily found free by googling. Then look in the engine section and do the measurement for the squish gap. You can do it with the head on using solder and a good set of calipers. That will tell you for sure what is happening.
Could be a shaved head (as others have said). The head bolts have definitely been removed at some point. Also could be a thin base gasket. (do they make those for these skis?)
Could be a shaved head (as others have said). The head bolts have definitely been removed at some point. Also could be a thin base gasket. (do they make those for these skis?)
Nice clean ski! Yup, it looks pretty stock from what I can see.
that seem out to lunch to me have you ever done a squish test. milling a stock head that far cant be good. I wouldn't get to crazy riding it till you no you squish from what you saying that motor is on the boarder of detonating.
Yeah at 205 you would think the motor would have torched in no time.
In my race boat it's about 205, I ran 50/50 c12 and non ox 91 for two years without incident
Sent from my HTC6525LVW using Tapatalk
In my race boat it's about 205, I ran 50/50 c12 and non ox 91 for two years without incident
Sent from my HTC6525LVW using Tapatalk
Sportster-2001-951C-Stock
Well-Known Member
If you can get that up by another 100psi you could run diesel fuel.
- Status
