polaris66
New member
Has anyone found the cause and a cure for the 2010 800 CFI4 melt downs? Is it a to lean issue with the mapping or a cold shot and lack of warm up as i have been told by polaris?
2010 polaris 800 engine piston scoring
- Thread starter polaris66
- Start date
DiamondDave
Member
All of the above.
Although, lean burn downs are not near as common with 2010's as they were with 08's and 09's.
Can you post any pictures of the failure?
We have found that the best thing you can do for poor mapping issues with the 800 CFI-4 is to add a Power Commander 5.
The next thing that must be done is get rid of the stock (loose fitting) oem pistons and run the fix kit from MTNTK or PMS Polaris. Consists of a shim to lift the cylinder and taller, better fitting pistons that do not rock in the bore and don't run near as hot.
Warm up's before hitting the throttle are mandatory. Wicking the throttle down the trail is also mandatory unless you do the above and run EGT's to monitor. The stock pistons need much more fuel to be happy than does the aftermarket pistons in the fix kit.
SLP sells a bypass kit that routes coolant to the mag side head to help.
I have modified my t-stat with an extra drilled bypass hole that sits 180' degrees opposite of the factory bypass hole. This helps with the cold shot issue.
Routine fuel filter changes, each season and every 500 miles.
Better performance would be to add an aftermarket head or a true 08 or 09 stock head to get some of the lost compression back that was taken away by Polaris in MY 2010 along with the updates done.
If you search snowest forum for some of my posts, you'll find alot more info.
Here is one link
Interesting Fix Kit/08 Head Characteristics vs. 2010 CFI 800 Update.... My Analysis - SnoWest Snowmobile Forum
Although, lean burn downs are not near as common with 2010's as they were with 08's and 09's.
Can you post any pictures of the failure?
We have found that the best thing you can do for poor mapping issues with the 800 CFI-4 is to add a Power Commander 5.
The next thing that must be done is get rid of the stock (loose fitting) oem pistons and run the fix kit from MTNTK or PMS Polaris. Consists of a shim to lift the cylinder and taller, better fitting pistons that do not rock in the bore and don't run near as hot.
Warm up's before hitting the throttle are mandatory. Wicking the throttle down the trail is also mandatory unless you do the above and run EGT's to monitor. The stock pistons need much more fuel to be happy than does the aftermarket pistons in the fix kit.
SLP sells a bypass kit that routes coolant to the mag side head to help.
I have modified my t-stat with an extra drilled bypass hole that sits 180' degrees opposite of the factory bypass hole. This helps with the cold shot issue.
Routine fuel filter changes, each season and every 500 miles.
Better performance would be to add an aftermarket head or a true 08 or 09 stock head to get some of the lost compression back that was taken away by Polaris in MY 2010 along with the updates done.
If you search snowest forum for some of my posts, you'll find alot more info.
Here is one link
Interesting Fix Kit/08 Head Characteristics vs. 2010 CFI 800 Update.... My Analysis - SnoWest Snowmobile Forum
- Thread starter
- #3
polaris66
New member
Thanks for the info.
The failure was on the mag side, piston scoring at the exhaust port. Compression on mag cyl was 98psi 105psi on pto side, had a bad acceleration stumble in mid range.
I have also read about turning the oil pump up 2 to 4 turns.
The failure was on the mag side, piston scoring at the exhaust port. Compression on mag cyl was 98psi 105psi on pto side, had a bad acceleration stumble in mid range.
I have also read about turning the oil pump up 2 to 4 turns.
HotShotHarry
Active VIP Member
Hey DiamondDave. Welcome to S&M! Good to see you here!
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