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Discussion Starter · #1 ·
What to do for 850 topend
What'd you pick?
MCB Forged for $460216.67%
OEM for $5501083.33%
Rings and gaskets for $17000.00%
 

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I'm back after a spring jet skiing hiatus.

I got a motor on here and the pistons look like they are worn out? Idk. cylinder and pistons have all sorts of carbon build up.

The coating on the skirts is almost worn off on the bottom edge. Supposed to be around 2000 mi or km.

My pistons on my 3100 mile motor look better except for the scoring, of course.

Do I get an:

MCB forged topend for $460?

100% OEM topend pieced together for about $550+

Clean the carbon, put on new rings? $120+50 in gaskets.
 

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This is a spare 850 engine that you bought from someone here on Dootalk? Is it still together such that you could run a leak down test and a compression test on the bench?

Is the intent to have a fresh engine sitting on the shelf so that when the current one gets tired, you can just drop in the fresh one? If this is the case and you want it to be as fresh as possible, I would just get new Doo 850 pistons and rings, as they have the cast iron insert ala a diesel engine that the ring groove is in, and the big/heavy piston ring rides in the cast iron groove which doesn't get pounded out like a groove in a regular aluminum piston be it forged or cast. Plus with this cast iron insert you are not going to lose the ring anti rotation feature like can happen to an anti rotaion pin pressed into an aluminum piston.

And if you were old and lazy like me, I would box it up and send it to Big John and let him go through it and check it out, do a light hone and assemble it with new Doo pistons and rings. And while I was at it, would probably have it ported.. Easy for me to spend other people's money.
 

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Discussion Starter · #4 ·
no, my 3000 mile burned/melted a rod big end oil feed and locked up.

I guess I will just spend the $600 on an OEM topend.

Sucks to be $8100 into a $6000 bluebook sled now.
 

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Did BRP help in any way?

Oil line caught.... fire? *%@
Started By Utah-Doo-Doo, Apr 04 2020 10:24 PM

Hey Utah-Doo-Doo, thanks for reaching out. We're sorry to hear of what happened with your unit and really hope no one was hurt. BRP takes safety very seriously and we would like to get an opportunity to find out more about what happened so we can ensure to build even safer vehicles in the future. Please email us to [email protected] with your VIN number, and a reference to this forum, or to your username. We are looking forward to hearing from you. Talk soon, Vanessa-BRPcare
 

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Discussion Starter · #6 ·
Did BRP help in any way?

Oil line caught.... fire? *%@
Started By Utah-Doo-Doo, Apr 04 2020 10:24 PM
I got sent instructions to fill out their incident form and 2 days later was informed my "case" was closed. So... not really, no.

I'm mostly upset that they wont sell rods, where my old motor would have been fine with a new rod and bearing, and some machining on the crank journal, instead of $1800 for a new crank for a $200 rod and bearing....
 

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What the heck...?

They made YOU fill out an incident form because of THEIR safety concerns and THEIR will to "build even safer vehicles in the future" (as their initial post said). Only to tell you the case is closed...?

That does not sound right. You do realize YOU performed work in order to improve THEIR product, without any kind of reward...?

I would try to take that further.
 

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Discussion Starter · #8 ·
What the heck...?

They made YOU fill out an incident form because of THEIR safety concerns and THEIR will to "build even safer vehicles in the future" (as their initial post said). Only to tell you the case is closed...?

That does not sound right. You do realize YOU performed work in order to improve THEIR product, without any kind of reward...?

I would try to take that further.
Trust me, i wish it would have burned to the ground so I could claim insurance. Nope, just a soot covered engine plate with 1 oil line missing.

Do any sponsors of dootalk drop ship OEM stuff for discount?
 

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I would do a piston to cylinder wall clearance check first.

Dont worry about the coating so much at this point, its a few microns thick, not a few thousand thick.

From 3/8" inch up from the bottom of the bore, what is the i-diameter.

From 3/8"~7/16" inch up from the bottom of the piston, what is the mic'd o-diameter.

Uhhh...if I remember right, it should be .009 or less. .010 is replace. If I remember i'll dbl chk the shop manual, but I think I seen that value.

My friend owns a machine shop says a good rule of thumb is to look at the maximum clearance. Say in this case .009. Multiply that by .8 and replace at that value, because if you are going to keep the sled into the future for as long as you've had it to this point and have the engine apart. then at (.009 x .8) =.007 change out the piston so you'll have the same piston life span again [wear from .003 to .007] and hopefully by that time of next-wear interval, you're in for buying a new sled.
 

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I got sent instructions to fill out their incident form and 2 days later was informed my "case" was closed. So... not really, no.

I'm mostly upset that they wont sell rods, where my old motor would have been fine with a new rod and bearing, and some machining on the crank journal, instead of $1800 for a new crank for a $200 rod and bearing....
Fractured rod replacement needing laser alignment is one of the details that was left out of the original welcome to the 850 campaign.

Fractured split connecting rods on 850
Started By Roamer7, Apr 13 2019 09:58 AM
 

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There is a bottom end for sale on DooTalk. The owner is currently asking $750 USD.

850 bottom end
Started By cgoff1984, Jun 07 2020 06:11 AM
 

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