top end refresh ... when is it time to do it

[shwantz34]

Good morning guys,

I would like to have your input , on when its time to do a refresh on motor.

I have a 2017 Rush XCR-800 now 4800 km (3000 miles)
i have done a meticulous breakdown when new, run it with Ves gold only
and run 91 octane from shell, Esso or Ultramar exclusively ( no Ethanol fuel).

Brand new my idle was around 1900 -1950 rpm
It have all time star 2 pull cold, 1 pull any other time than the first start of the day.

My observation:

Now it run 1750-1800 idle
and lately when hot, it doesn't start all the time in one shot
and it start slow then take its rev to 1800 ( like a too rich carburated sled)

For me it was symptôme of low compression.

so yesterday after my last ride i take my compression
My tester as always be a bi on the low side, so don't take the absolute but more the difference beetween cylinder.

so this is my result
test full throttle,
test hot

right cyl (muffler side)
first quick 90psi
maximum 120psi

Left cyl (clutch side)
first quick 80psi
max 112 psi


Test cold
right cyl (muffler side)
first quick 90psi
maximum 118 psi

Left cyl (clutch side)
first quick 90psi
max 115 psi

so i don't see any alarming stuff for now, but it seems that a refresh this summer will be good.
what do you think about it ?

Also , i have a 4 years Polaris warranty, does Polaris cover for ring/piston wear ???

 

[Dr.Notadoo]

Did you do a compression test when the sled was new with that tester? This would need to be documented at ur dealer and most likely have to have more of a difference side to side. I'm sure there is a tolerance they go by. Something also would need to fail I suspect , don't think wear is a covered item.

 

[shwantz34]

Did you do a compression test when the sled was new with that tester? This would need to be documented at ur dealer and most likely have to have more of a difference side to side. I'm sure there is a tolerance they go by. Something also would need to fail I suspect , don't think wear is a covered item.

i have done some test since new, after brak in (1000 km)
120 each side , eqaul

also done one at first tune up at around 1500km at the dealer
same things (different gage) 120 both side equal

 

[Ottawaair]

I always test mine from day one.

If you wait for a problem to arise, you don't have a baseline to compare to.

Mine, new was 121 both sides , on my gauge.

400 miles it's at 123 mag, 124 pto.

My gauge may be little high or low, but I always use the same gauge.

It's the baseline compared to current that matters.

 

[shwantz34]

I just find my old note from last year.
Last year i was riding my 2015 Switchback Pro S , i have in my note the compression test that i perform at 5000km
about the same mileage as my XCR. The reading was 130/130 equal each side with my old tester.

So i perform an other tes with the old tester (the test i perform first was with the new one)

Test cold
right cyl (muffler side)
first kick 110psi
maximum 130 psi

Left cyl (clutch side)
first kick 115 psi
maximum 130 psi

same as my 2015 witch i have done an other 5000km before selling it
also the idle on my 2015 was 1700 too

so i think that everythings seem to be ok , engine wise, the motor rips as hells.
it seems the few time that it start slow, is more a fuel issue than anything else.
I run 2 new plugs yesterday, and it strat first pull and idle right each time yesterday.

I would prefer to put my idle back to 1900 thought.
Do they have an Idle setting screw ?
i look for it this morning and does not see that

I also read in the shop manual, (2012/2014) not axys but pretty similar the folowing note:

Minor adjustments to the engine idle speed may be desired if the engine idle is too low or too high due to extreme external environmental factors such as altitude. In addition to environmental factors, normal throttle body component wear and tear may cause changes in idle speed over the life of the vehicle. The idle speed screw can be adjusted to compensate for these changes.

My idle is in the spec, since it run 1700 to 1750, but i prefer to run it in the higer end of the spec at 1900

 

[Brock]

As doc said.
It needed to be tested when new. After break in and now with the same tester.
Also at operating temp (120f)

As for hard starting, that's usually, tps, throttle cable tension, plugs and throttle idle to low.



Set your throttle cable tension, change plugs.

Also, you can change idle set screw on throttle body , it's a pita though .

 

[shwantz34]

Throttle cable is ok, plug are new from last compression test, i did not test the tps.
Is it something that is subject to be adjust regularly ?

Do you need special tools, or just a regular tester

I do have done that on my motorcycles, ( gsxr and Ducati) but never on a snowmobile.
From what i have seen, its seems to be a pretty picky job on Polaris.

To acces to iddle screw i suppose that i hav to remove all the air box etc ?

 

[Brock]

Digital wrench tells tps voltage
It's not to common on the 16's and 17's as the 15 model year was terrible for tps being out of adjustment