how do i test my crank - Snowmobile Forum: Your #1 Snowmobile Forum

96 xcrspcrankn · 10-19-2009, 11:22 PM

how do i test to see if i have a bad crank

justmytailights · 10-19-2009, 11:49 PM

for starters,does the engine have an unusual noise?is there chatter or a rather obnoxiuos rattle?when and if the engine is running and you spray a mist of gasoline behind the primary clutch,does the engine respond? when you hit tke throttle and the rpm increases does it chatter?does the rpm increase smoothly.now a closer look.what is the timing?when it ran before was the timing spot on or advanced,retarded now?does the primary clutch have movement laterally and horizontally.do you still have top dead center?is there power on ecceleration? i think you get my point?

96 xcrspcrankn · 10-19-2009, 11:57 PM

no unusual noises fires right up n seems to run great the guy i got it from says it wont go over 60 and he took it to a polaris dealer and they told him it needed a crank $900 they said so Im wondering if they just said that because all the other 96s had crank problems

justmytailights · 10-20-2009, 12:02 AM

does it run

IRONDOG · 10-20-2009, 12:16 AM

Do this by measuring down through the spark plug holes with a caliper:
1. Put the pto piston at the very bottom- called bottom dead center.
2. With the pto piston a bdc, measure through the plug hole to the tops of the center and mag pistons. Measure from the gasket surface of the plug hole to the center of the piston.
3. If both the center and mag piston are at the exact same distance down from the plug hole gasket surface then your crank is "in phase" and is probably OK. Do this several times to assure accuracy.
4. If there is a noticeable difference between the center and mag piston depths after several careful measurements then your crank really may be "out of phase",

This is a crude method and is not intended to replace a degree wheel and a TDC gage, hopefully the tools used by the Polaris dealer to diagnose the problem originally.

The '96 XCR SP did not have any crank problems. Your motor has three separate cylinders with three separate heads, correct?
Jerry

**smallengineguy** · 10-20-2009, 07:12 AM

It doesn't need a crank. It may need a piston or something like that.

**kccats** · 10-20-2009, 07:43 AM

Never take what a Stealer says as the absolute truth! GET a SECOND OPINION!!!!!