800ho head vs 800r head

farmerboy

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Is the only difference between the 800HO head and the 800R head the sensor hole? Can they be interchanged?
 

snopro

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No they are totally different heads. I beleive they use different head o rings as well.
 

farmerboy

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I know it is weird but the gasket kits are the same and the pistons are the same. My Son has an 07r and mine is an 800ho. We are doing top ends and the kits are the same. A mod guy in the states told me they put 06 heads on the 07 and 08's for more HP...???
 

tex78

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I know it is weird but the gasket kits are the same and the pistons are the same. My Son has an 07r and mine is an 800ho. We are doing top ends and the kits are the same. A mod guy in the states told me they put 06 heads on the 07 and 08's for more HP...???

the pistons are not the same between 800ho and 800r. Just a FYI
Also the block to cylinder gasket thickness is different

Yes i think the heads are the same but the Ho's had a bit higher comp ratio and different squash.

That's y 800r works so much better with a head.

12.1 to 12.3 to 1 = a 800r

13.3 to 13.5 to 1 = a 800ho



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farmerboy

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[the pistons are not the same between 800ho and 800r. Just a FYI
Also the block to cylinder gasket thickness is different]
Thanks tex I am really confused now..lol My Son and I are rebuilding our top ends. He is done and I decided to do mine while I am waiting to go sledding again. I am just about the 3000k mark. His is an 07 and mine an 05. We ordered SPX sets and they are the same part numbers, pistons and gaskets. We were comparing heads and that is what sparked the head debate. The differences we could think of is the decompression port and maybe the cooliong ports. I think the head bolts are also different only because of the mono block on this 07. I said we should put my head on his 07 and try it out because of the higher compression
Anyway maybe we got the wrong piston kits???
 

farmerboy

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I have to appologise...the pistons are different The 07 took 702-1830 and the 05 was 702-1820. Sorry tex
 

summ-it-up

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the pistons are not the same between 800ho and 800r. Just a FYI
Also the block to cylinder gasket thickness is different

Yes i think the heads are the same but the Ho's had a bit higher comp ratio and different squash.

That's y 800r works so much better with a head.

12.1 to 12.3 to 1 = a 800r

13.3 to 13.5 to 1 = a 800ho

i was wondering about this, are all the 800 revs HOs? (except 07 of course)
 

tex78

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Ya I think from about 01 or so and up are Ho's to 06. Not sure if the comp stayed the same all the way through

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Circled-Mistake

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how do you figure that....

U can use a head without the Knock sensor provision casted into the block in the middle of the two heads... Just get a longer bolt for one of the original headbolts and install knock saensor there (preferrably still between the two cylinders or close to).. My Dads got that setup and works fine.....
 

farmerboy

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Cool Is there any way of posting a pic? My Son was telling me some of the 06's had the power tech engine which was the predecesor to the 07 800R so some of the parts fit.
 
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summ-it-up

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so how about the jugs from a 06, can you bolt a pair of those on a 800r bottom end? the 800r has a mono block top end correct?
my buddy was asking me this question ^^^, thought i'd throw it out there.
 
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