2005 Summit Rev Burndowns! Please help me figure this puzzle out!

[sooboy]

This was my problem

In my 05 827,I went through some greif before finding my crank halves and cyls were warped from a previous engine failure due to frozen carbs.Runs fine now with straight cases and the decks cut on the cyls to straighten them out.
Good luck with it.

 

[whitefish]

PJ-What compression were you at with either kit? Low octane and crappy fuel? Also, have you measured the run out on the base of the cylinder on the intake side. They can warp there when they get hot.

 

[PJ-Hunter]

PJ-What compression were you at with either kit? Low octane and crappy fuel? Also, have you measured the run out on the base of the cylinder on the intake side. They can warp there when they get hot.

I cannot remember the compression off hand but I never run any lower than 91 octane. I have crank runout on my list of things to check! I hope that is something simple like carb failure and not a crank problem, I don't think the wifey will like it if I have to buy a new crank.

 

[whitefish]

Crank run out is one thing, cylinder warping on the base is another. Check for both. PM me if you want to know a fairly EZ way to check the later.

 

[sally screendour]

hope you it get figured out pj.looking forward to riding with you this year!

 

[PJ-Hunter]

hope you it get figured out pj.looking forward to riding with you this year!

I have a 2008 XP that still runs, so I'm good. This sled is my spare sled.

 

[DOODOG]

I have a 05 800 and burned it down. The carb boots were leaking. Check the boot where it is laminated to the reed housing. Also check around the bolt holes. Look from the inside out and push on the rubber at the corners and bolt holes if you can see light replace the boot. My dealer said to get the 07 boot and that will solve the problem. That is what I did and so far no problems.

 

[milehighassassin]

Crank run out is one thing, cylinder warping on the base is another. Check for both. PM me if you want to know a fairly EZ way to check the later.

You should post it up so the rest of us know!

 

[whitefish]

Although the finest engine builders may not condone this... it works well enough to to identify potential problems. First you need a good flat surface. A machined surface in a shop or a slab of scrap granite from the local counter top guy. Get a dial indicator that is mounted on a adjustable arm set and secure it to the flat surface. Take your cylinder upside down and run it over the flat surface but under the dial indicator looking for variances throughout the entire base of the cylinder. It is most common on the intake side near the corners (weak spot). I don't have any pics so if it doesn't make sense you'll have to use your imagination. All for now.

 

[milehighassassin]

Thanks

 

[PJ-Hunter]

So we got the thing tore down. But we did a leakdown test first and found nothing wrong. The mag side had a pit melted in the dome of the piston and the cylinder was scarred while the pto side was perfect. after tearing into it further we discovered that the main jet on the mag side had vibrated out. would this cause the mag side to run lean?

We are waiting on new seals, orings and bearings so we can put the motor back together and check the crank phasing to see if the crank itself has been twisted.

 

[NoSecondChances]

So we got the thing tore down. But we did a leakdown test first and found nothing wrong. The mag side had a pit melted in the dome of the piston and the cylinder was scarred while the pto side was perfect. after tearing into it further we discovered that the main jet on the mag side had vibrated out. would this cause the mag side to run lean?

We are waiting on new seals, orings and bearings so we can put the motor back together and check the crank phasing to see if the crank itself has been twisted.

Maybe and maybe not. Emulsion tubes work on a venturi vacuum, the fact that the main jet vibrated out may mean that the venturi did not have enough vacuum to pull the full column of fuel up the tube, meaning it could have leaned out that way. Or it could have flooded the motor if the main jet was not there to restrict the flow, so the motor would have been richer and not leaned out. I have never experimented with this to see which one happens, maybe someone else has.

 

[CATillak]

my 880 mt cat had loose main jets and burned down... but the reason it burnd down was a leakin pto seal!! i beleive the sled would get richer if it fell out, and when i had the leaky seal, it would be lean no matter how fat i jetted the pto side up. at one point i had it jetted 10 sizes bigger and it still was lean. some sleds are just lemons man, iv ownd a couple myself..

 

[PJ-Hunter]

my 880 mt cat had loose main jets and burned down... but the reason it burnd down was a leakin pto seal!! i beleive the sled would get richer if it fell out, and when i had the leaky seal, it would be lean no matter how fat i jetted the pto side up. at one point i had it jetted 10 sizes bigger and it still was lean. some sleds are just lemons man, iv ownd a couple myself..

Thing is it burned down on three different motors. Second time we discovered a leaky MAG side crank seal and a torn reed gasket. Fixed that and rode it twice before it burned down again. Coincidentally, the MAG side burned down and that was where we found the main jet that had fallen out. Maybe, just maybe the jet was wedged in a way that caused fuel flow to lean out into the carb. Can't think of anything else to check.

Weird thing is that I had over 1500 miles on it before I started to get problems.

 

[milehighassassin]

I know this is old, but check this thread

http://www.dootalk.com/forums/index.php?showtopic=244397

 

[byeatts]

I know this is old, but check this thread

http://www.dootalk.com/forums/index.php?showtopic=244397

Not sure where you live however Kelsey,s suggested jetting was way off using "Calif." fuel.The fuel here is oxegenated heavily and made from chicken droppings . My jetting was 3 sizes up on the main over the suggested.Using EGT,s and plug reads it,s spot on

 

[MARCUSO]

Hmmm...

Thing is it burned down on three different motors.

Make that 4...

 

[Boondock]

Make that 4...

WOW That sucks big time

 

[Alberta Boy]

WOW That sucks big time

Different sled and different owner

 

[triple7]

Sounds to me like its not oiling the mag side. JMO but I had a phazer do this 3 times before we figured it out. It would stick, burn the top off the slug among other things. I would pitch the injection and premix it. Or verify that all the orifices are open and totally clean. It seems to burn down after a wide open running. But does it pull good before it squeaks?? If its doing a lean burndown the motor generally will 'lay over' a bit. Generally lean burndowns from air leaks are after midrange running. Of course there are exceptions and plenty of them but I would suspision an oil delivery problem. Everything else has been tried...