poo primary on a doo?????

[ragincajun]

hey guys,
my doo primary is toast and it is gunna cost a sheit load of cash to fix. i like how simple the poo primary is, makes less heat and how cheap it is! anyone get the taper machined to make it fit on a doo? if so how well did it perform and how did you like it? please PM me with any info!
thanks!

 

[Dootimes2]

Have not done it but I here they work well. The problem is that the vibration destroys them from what some on here say. Sounds like if you can get a billet one they hold up fine, but I would not use a stock one.

 

[slimjim]

p-clutch

Ski doo 800 cranks do not like the light weight. It will quickly destroy your crank.

 

[Ill Named]

Did it for a season and didn't like it. Now am back to a tra.

 

[evandaigneault]

Ski doo 800 cranks do not like the light weight. It will quickly destroy your crank.

that is not true. The weight difference wont hurt your crank

 

[winter brew]

that is not true. The weight difference wont hurt your crank

Can you explain more?
I did one on my '07 and lost the crank 3 rides later. I want to think this was just a coincidence. We've all heard the stories of crank failures over the years but I have also heard of alot of long-term success stories and that is why I chose to go with the P-85 on mine. To be honest, I would have gone back to the TRA even if I hadn't lost a crank, I didn't find enough gains to warrant the vibration and cost.
I see alot of P-85 guys going to great lengths to add mass (ring gears, machined steel rings etc...) to avoid the harmonics that MAY be damaging to the Doo crank.

 

[evandaigneault]

i ran one for a long time and know a few other guys who ran their p-85's and 4-pro's for a long time no problems. They had less problems than they did with their TRA-7's, which dont work worth beans

 

[evandaigneault]

there is only like a 1.5 lb difference i believe between the 4-pro and the TRA. I think it might be like a 2 lb difference with the p-85 and the TRA. The polaris 800 has a similar crank to the 800R and the m-cat 800 runs a similar style primary, those 800's can handle lighter primary's. Its the cranks themselves that have been creating the problems on doo. Too many out of spec cranks were out there to begin with and were wrecking things left and right. The most important thing to do if you are putting a polaris primary on your ski-doo is to make sure you balance it with the weights and spring it before you put it on. That should help cut down on harmonics. The harmonics come from a crank that is out of spec or an unbalanced primary running at high rpm over time.

Thats how i see it anyways

Evan

 

[AKSNOWRIDER]

Can you explain more?
I did one on my '07 and lost the crank 3 rides later. I want to think this was just a coincidence. We've all heard the stories of crank failures over the years but I have also heard of alot of long-term success stories and that is why I chose to go with the P-85 on mine. To be honest, I would have gone back to the TRA even if I hadn't lost a crank, I didn't find enough gains to warrant the vibration and cost.
I see alot of P-85 guys going to great lengths to add mass (ring gears, machined steel rings etc...) to avoid the harmonics that MAY be damaging to the Doo crank.

winter I would think to run a different clutch you would need to balance both the clutch and the crank..I bet that would fix any vibration/longevity problems..

 

[winter brew]

The P-85 I ran was 6lbs lighter than the TRA7 with ring gear. Some guys are running the lightened TRA or the factory lightweight race dept TRA which is pretty darned light. I also had my P-85 spin balanced. It vibrated alot just due to the loss of damping from the 6lb lighter clutch....it was like one of those foot vibrators at the county fair!
I got the TRA7 on the '07 working as good as ANY clutching on any sled I have ever been around so I ditched the whole P-85 thing. JMO-