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Who's doing what mods ?

MJT said:
iam doing a bikemann head and thinking of doing a small degree timing key, What are thoughts about those? also going to go from my stock cobra track to a 1.5 Talon track, already had bikemann pipe and bullydog prog. with put together clutch kit from words of wisdom on this site, adjustable weights, 1.86 gearing, didnt have a problem with belt last year, and could do 100mph on any type of snow, I also weigh 290, reason that i went with low gears... also cut od into clutch... could pull a 2015 800 xrs ski doo that would beat me on mid and top previous years.. sled is a pro x so not really built for speed to begin with.. sled went into sever det once on flowage that I kept it wide open for way to long, guess i was just trying to push the limit with it..
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I wouldn't do a timing key as it adds timing everywhere and that's not what you want. Ask Neal from bmp if he can add 2-3 degrees timing to you're bd program that you already have after the valves open(7300-9000rpm). Or piggy back it with a pc5 to do it.

Glad you're sled worked well for you
 
Is that with rings,wrist pin, wrist pin bearing and c clips?
 
I'm glad u guys see the light as light pistons and Polaris compression height is key . Not the 1/4" more.

Many of race shops have been doing this for years as piston weight has gotten waaaaaay heavier the last decade

I'm doing the light pistons along with the Polaris compression height.

Porting and cylinder work is the key too
 
One motor will have normal compression height as Brock calls it and the other will not. Both motors are completely different in configuration. I'm not worried about running a longer skirt with a different wrist pin location. Main focus is on the 800..
 
My goal is 20+ hp and 10+ torque out of a stock bore.
The bb 28+ and 15+ torque
Both way different and main goal is reliability plus power. Lots of stuff out there that doesn't do both . Should be able to get 5000-6000+ miles out a powerful motor thats trail riden and raced without doing a thing.
 
IMG_0703.JPG
 
82mm pistons with 20 mm pin?????????????
 
So you're putting in 82mm pistons vs the stock 85mm pistons???

What am I not getting here?
 
A problem that is plaguing the HO motor ....The transfers are to small, smaller bore will correct some of that....have you ever heard of Advanced Sleave?
 
I have

All 800 motors are plagued with flaws.

You have the luxury of making bore smaller because of you're longer stroke. More or less like a doo bore n stroke then?

Personally, I'd be working on getting rid of half of the positive piston clearance on the stroker and keeping same 85mm bore. Projects are awesome though Div20

Keep us informed Letitsnow
 
What is positive piston clearance? And yes it will be stroked ,but has nothing to do with the 840,that is complete.. this is a ground up build,complete motor..
 
Guess I left the word"deck" of of it

Positive piston deck height
 
Brock said:
I have

All 800 motors are plagued with flaws.

You have the luxury of making bore smaller because of you're longer stroke. More or less like a doo bore n stroke then?

Personally, I'd be working on getting rid of half of the positive piston clearance on the stroker and keeping same 85mm bore. Projects are awesome though Div20

Keep us informed Letitsnow
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I need education!

What are the typical 800 flaws?

Do 600s have less flaws?

If you had mega bucks and time what size and configuration trail motor would you build?
 
For the axys 800 it's about the small size and weight savings. It's the lightest strongest 800 motor out there. Being small makes the transfers a little small as said. The piston weight along with the huge taper is another flaw.

Things I would fix
Weld the side of cylinders and make the transfers bigger, get the piston weight down to 500 grams with way less taper with the pistons being the tuff 2618 alloy but strength of 4032 alloy. Keep the same compression height as stock.Reposition intake in case to allow longer cylinder (longer skirt) with no obstructions . These are a few that would make huge improvements and big reliable power.
 
Does Polaris do the large taper for cold start safety?

It would be cool to see some welded cylinders. I remember the pictures of reed cages welded on 650 triple cylinders back in the day.
 
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