Top end on 800 Etec

[new24stroke]

I got a buddy who blew the top end on his 800 Etec. I’ve never done one, but have rebuilt 2 stroke dirt bike engines. Is there a website on how to take these apart. I’m more worried about the injector system then anything. Thanks

 

[maxwell]

injector system is nothing to worry about.

1. unplug pressure and return fuel lines. 1 on back of tank, one on back of computer.
2. unplug electrical connector to each injector
3. remove 4 torx bolts holding injectors down. there is a plastic gasket underneath, thats it.

to reinstall just make sure to torque to spec 44 ft lbs. BRP does call for new bolts in the procedure as they are "stretch" bolts but i have never been able to measure any stretch that i didn't feel comfortable reusing the existing bolts.

the rest is straight forward just tedious.

Heres my procedure. ive done quite a few now

1. remove all plastics necessary, hood and console with related connectors
2. remove tank cross brace and slide tank back to remove fuel line for injectors( also gives more working space )
3. remove injectors
4. remove rave valve assembly
5. Remove lower rad hose @ water pump to drain system ( this is messy but no other way )
6. remove secondary clutch and tower brace
7. remove throttle bodies ( keep throttle connected ) and asssociated vac/heater hoses
8. remove reed assembly
9. remove pipe and y pipe
10. remove cylinder head
11. remove engine block

putting dual ring pistons ( if you go this route ) back into a monoblock is a bit challenging in that tight space, use injection oil to lube everything so it slides together nicely. i recommend a second set of hands.

Important notes for reassembly

1. be extremely careful with the base gasket, it is easy to get out of alignment when sliding the monoblock down. watch as the cylinder sets down and ensure it doesnt get pinched.
2. Cylinder block Torque 37 Ft LBs
3. Cylinder head torque 21 ft lbs - also be very careful when lowering cylinder head down that the new O rings are seated. I usually use 2 head bolts to make sure the head is in correct alignment before lowering down onto the O rings. you dont want to shift it after its lowered.
4. Injector torque - 44ft Lbs


the rest of the bolts are Snug and Half turn. LOL


some will say you can get away with changing the top end without removing some of those items, from experience its alot less frusterating and you have way more skin on your knuckles when you make the room to work.

 

[snoflake]

Excellent instructions. Do the e-tec cylinders come with tapped holes for the reeds? I recall rebuilding a 800 ptec, and the holes for the reeds were not tapped as the bolts were 3 sided at the start, and were self tapping? I'm not sure if all new cylinders came that way, but they were a real bugger to get started once the mounted on the block. i wish i would have ran the bolts in before bolting the cylinders ono the block.

 

[maxwell]

Excellent instructions. Do the e-tec cylinders come with tapped holes for the reeds? I recall rebuilding a 800 ptec, and the holes for the reeds were not tapped as the bolts were 3 sided at the start, and were self tapping? I'm not sure if all new cylinders came that way, but they were a real bugger to get started once the mounted on the block. i wish i would have ran the bolts in before bolting the cylinders ono the block.

interesting, all cylinders from CVtech are pre tapped, i guess because they are refurbished. Perhaps the one you had was brand new from BRP?

 

[new24stroke]

Thanks for the information

 

[new24stroke]

If I pull the rave valves do they need to be resynced

 

[maxwell]

If I pull the rave valves do they need to be resynced

No they do not.

 

[catrutt]

Are the dual ring pistons better?

 

[tex78]

Are the dual ring pistons better?

Yup they are

Mcb or wossner

 

[maxwell]

Are the dual ring pistons better?

I don’t know if there’s a definite answer on that. Factory pistons are singe ring and most of the aftermarket are dual
Ring. Both get the same mileage and make the same power so maybe someone can explain why dual is or isn’t better?

 

[tex78]

I don’t know if there’s a definite answer on that. Factory pistons are singe ring and most of the aftermarket are dual
Ring. Both get the same mileage and make the same power so maybe someone can explain why dual is or isn’t better?

Well

Rings are not for compression, it's a by product, there to transfer heat from piston dome to cylinder walls

So two rings transfer twice the heat

So that's how a good pull, then pull again you get power fade and heat soaked pistons

Two rings have half the power fade, way less power fade

I find two rings also stay straighter in the bore and gets less skirt slap

Draw back is two rings take some power away, as it's more if a restriction to turn

Some say a hp less, who knows lol

 

[tex78]

Oh a fawk yea, get to teach Maxwell something, it's Friday too boot lol

 

[HotShotHarry]

Oh a fawk yea, get to teach Maxwell something, it's Friday too boot lol

Tex is da man! 2 beers for breakfast for you!