So my brother and myself have been experiencing RPM loss, he rides a 163x3 and I have a 163x2.6 after trying about every different clutching combo under the sun with new belts and washing the clutches we finally decided to return them both to dead stock. Both machines seem to be very sensitive to altitude change, losing about 100RPM for 800 ft of elevation change (6400-7200ft). Currently I'm running between 7950 and 8100, the later being difficult to achieve. so we finaly decided to pull the plugs and do a compression test. First off, plugs looked terrible, have an obvious bad burn, half the plug (exhaust side) is way lean and the ceramic coating below the electrode is actually being removed. Then the intake side of the plug is cruddy and fat looking. Anyway compression for mine is: PTO 120 MAG 115 and my brothers is 115 in both. Thats WOT and about 2500ft here at the shop. We also tested a third AXYS that has been running great, its got 125 in each and his plugs look like a plug should. All three machines have about 600 miles on em. I'm going to be talking with my dealer about it, but does anyone have any theories?
AXYS RPM fade/compression numbers
- Thread starter edi1967
- Start date
Same here, down on compression 90 and 95.
Loss of rpm/compression
I was wondering the same thing. When my Axys was under 500 to 600 miles it pulled 8350 to 8400 rpm with Polaris 64g weights. Now I'm struggling to get 8250 with 64g slp mtx weights. Had the dealer check the compression at around 700 miles and they said 110 and 105.
The sled runs great but it just feels weaker by 10 to 20 percent. Just put the SLP pipe on and I can't appreciate any difference from the stock exhaust and I had to go with the same weights I ran with the stock pipe.
Any ideas? Is that enough compression loss to result in significant hp drop? Sled has 1100 miles now.
I was wondering the same thing. When my Axys was under 500 to 600 miles it pulled 8350 to 8400 rpm with Polaris 64g weights. Now I'm struggling to get 8250 with 64g slp mtx weights. Had the dealer check the compression at around 700 miles and they said 110 and 105.
The sled runs great but it just feels weaker by 10 to 20 percent. Just put the SLP pipe on and I can't appreciate any difference from the stock exhaust and I had to go with the same weights I ran with the stock pipe.
Any ideas? Is that enough compression loss to result in significant hp drop? Sled has 1100 miles now.
Anyone know the spec on what compression reading will get you a rebuild on Polaris warranty?
M
MBR44
Active member
I had problems last year with dropping to 7800rpm. I would take it to the dealer and have it flashed, relearned, beaten with no changes. I would ride it but within 100 miles it would be back to 7800. I was actually going to trade the sled in. I ran compression tests and was 120 for both cylinders. I then took out all my mods off and clutching out to started over. I put in 11-70 weights instead of indy dan weights, added a delrin washer so run 3 instead of 2 and the stock 40 straight. All of a sudden it pulls 8350-8400(for now). I am guessing mine was self inflicted? I will find out. Another member had the same issues and found it to be injectors, ultra sonic them or replace them. Others say the power valve cable stretches and the valves don't open all the way. Who knows, polaris won't admit a problem
J
jhurkot
Well-known member
At 100psi they will do a new top end. Last year my dealer did just pistons and it only lasted 250 miles. They needed to do the monoblock but didn't.
