2004 800ho compression

[slednek]

This has probably been mentioned already but here we go. Just did a compression test and read just over 130. Wondering where it should be. I heard the 800's should be around 140 mark.

 

[Quagmire]

Wide open throtle. 140 sounds about right.

 

[BIG HEAD]

As long as they are with in 10 percent of each other the sled is healthy. as for max psi each one was different, I have heard of 140 but didn't kow if it was cold or hot.

 

[slednek]

took mine out for about 5-10 minutes and then tested it. thanks for the input guys.

 

[RETODD]

My 04 800HO has 5259 org. km on it!!! Even though it runs GREAT I know these little bangers don't last forever. I'm nervous bout taking a compression measurement…don’t want to queer the deal…not much preventative maintenance you can do if the PSIs are starting to slide…does Canuck Truck carry comp. testers that will fit our sleds?

 

[slednek]

not sure on canuck truck, but sure you can get one at crappy tire. My buddy is a mechanic so used his and not sure where he got it. Wouldn't be nervous, checked mine to see if it was time for new pistons and stuff.

 

[brew_doo]

My 04 800HO has 5259 org. km on it!!! Even though it runs GREAT I know these little bangers don't last forever. I'm nervous bout taking a compression measurement…don’t want to queer the deal…not much preventative maintenance you can do if the PSIs are starting to slide…does Canuck Truck carry comp. testers that will fit our sleds?

Same boat for me, 5700 km. Knock on wood.

 

[BIG HEAD]

Time for refreshing boys, they had a tendency to crack pistons and flake rings.

 

[Hillclimber]

6200 + km on mine all stock.

 

[RETODD]

They seem to be a good engine, I’ll take my compression and post if I can find a gauge.

 

[Quagmire]

Time for refreshing boys, they had a tendency to crack pistons and flake rings.

That's why I had mine replaced 2 years ago. I have 5200kms on my machine.

 

[BIG HEAD]

rebuilt my buddy's 04 800 twice, flaked rings once then cracked shirts (intake side ) went to a gallon of VP fuel per premium and never had a problem since. Figured it was deto and lubrication.(VP has lub properties).

 

[slednek]

Have a couple more rides this year so probably refresh end of the season.

 

[RETODD]

Finally did a test on the beast...120 per side at over 5400km on all original parts...gonna get another year out of her!!!!

 

[DRD]

Spend the 250 bucks and throw a couple of pistons at it.

 

[RETODD]

Recommendations? Not a dumbazz but not a mechanic either, something a weekend worrier could or should take on himself having never done it? OEM pistons or not? Thanks.

 

[DRD]

OEM pistons are good but spendy, over $200 per hole.
I'd put some cheapo SPI's in, for the price they are pretty decent, probabaly 85 bucks a piston. Get ahold of Dan at Extreme Machines 403-748-2219, good prices.
I think a weekend warrior could do it, it's not that hard. Give it a try, what's the worst that could happen? Spend extra time and look at the carb boot. I'd be very surprised if they aren't toast. I did one this spring and the boots looked good, until I pressure tested it, they leaked like a sieve.

 

[maxwell]

do not use spx,spi,kimpex

oem or wiseco (required machining)

 

[DRD]

do not use spx,spi,kimpex

oem or wiseco (required machining)

Have you had a failure directly related to SPI's?

I've never had a SPI failure, used them in 670 Rotax, 800 Pol twin, 800 series 3, 780 Rotax and in my 809 mod. Pistons Bill Cudney sell also look suspiciously like SPI's. Elko's are good but for 1/3rd the price it's hard to beat SPI's.

MCB is also selling a dual ring piston that supposed to be good also $250-300 USD for a top end "kit" bearings, gasket etc.

 

[Summitric]

Hmmmmm, interesting thread. My '04 800 has 140psi compression using my "professional" compression tester from my tool box at my shop. It only has 1200kms on it, so i'm hopin' it'll last over 5000kms before i do pistons/rings too...