Piston Wash Guru's.....i Need Your Help! - Snowmobile World : Your #1 Snowmobile Forum

SDRENE800RER · 01-25-2005, 04:37 PM

Hi all, please check out these pics and let me know what you think after looking at rundown of parts and specs.

02 SD 800 running hi test pump fuel and SD injector oil(mineral)
All parts as are in my sig line.
RKT Heads for 0=3000 ft
RKT .047 base shim
Pro-X Pistons from LA Sleeve(dual ring) modifyed to work with domesby RKT
RKT intake mod done to cylinders
Stock Pipe w/HPS muffler
Bickfords Clutch Kit

480 main jets
942 needle set at 2nd from bottom w/washer
17.5 pilot jet

The PTO side seized at @+15F at 20ft above sea level. This was the first ride jetted down to 480 mains and richened up the needle to be on the safe side. Plugs are a great tan color, just slightly dark....PTO was slightly lighter.

This happened at @100 miles on pistons. Please let me know what you think. It happened just a mile from my house...I think it was warm enough, the heat exchangers were warm to touch.

The only other thing leading up to this was EXCESSIVE feul use. I was only getting @5 miles per gallon and was getting back firing inside the pipe.

TIA SWRules

note...I did edit the piston brand name after discovering that I made a mistake saying they were ART's.....Todd

SDRENE800RER · 01-25-2005, 04:40 PM

a couple more pics of damage

I have heard that the aluminum from the piston can be cleaned off the cylinder walls with oven cleaner....is this true? As long as the scuff didnt harm the cylinders I have 2 more ART pistons/rings and new base shim to put right back in available

Thanks again
Todd

idooski · 01-25-2005, 04:51 PM

I'd like to get a closer look at the top of the piston and some more pics after you have the piston out. I've been there with these exact same parts and it happened in very similar circumstances. I wasn't lucky with the cylinders. Both were junk. I'll be glad to try and help, but I won't do it on here.

Hit the e-mail button in my profile if you would like to work on this privately.

What does Kelsey say about it? When and how did you come about this kit? Did you just get it or have you had it for a while?

Take Care -

Keith

NorthernBoy · 01-25-2005, 10:05 PM

Something does look different with that piston, the wash looks really rich. I noticed looking at the head there is a little mark in the bottom corner. Could it be coolant leaking in which caused this? Take a closer look at the head or try to get a better picture and post it.

I am running the same pistons in my 01 800 without cylinder mod and stock exhaust and no problems so far. My wash is fairly even. So far I am jetted down to 430 & 440.

Let us know what you find.

kid rocker · 01-25-2005, 10:20 PM

Quote:

Originally posted by SDRENE800RER@Jan 24 2005, 11:02 PM
a couple more pics of damage

I have heard that the aluminum from the piston can be cleaned off the cylinder walls with oven cleaner....is this true? As long as the scuff didnt harm the cylinders I have 2 more ART pistons/rings and new base shim to put right back in available

Thanks again
Todd

[snapback]393831[/snapback]

The wash looks rich to me. Need more info.

SDRENE800RER · 01-26-2005, 05:54 AM

Northernboy. No coolant leaks. That spot is where I wiped that area with a finger as I was lifting the heads off.

kid rocker....not sure what other info I can add. Ill post more pics this weekend when I get the cylinder off.

The only other things that come to mind; the very center of the pto piston is missing some of the carbon. I was dabing at it with a rag to remove some collant and the carbon wiped off....otherwise it was totally covered in carbon. This was the first ride without pre-mix in the tank. For the first couple tanks I had SD injector oil mixed in at 75:1. Prior to the season with only @15 miles on this kit, so not realy broken in yet, both cylinders had 142lbs of compression warm.

It was running quit well and making alot of power from 6000rpm to 8100rpm. My only complaint was the excessive fuel use. Bone stock my sled was a typical 02 800 gas hog that was averaging 8 mpg. I know that while waiting for rings to seat, engines generally get poor milage, but right up to the seizure, I was only getting 5mpg.

NorthernBoy · 01-26-2005, 07:14 AM

Once you remove your jug just should be able to see how much oil is in the crankcase and it is possible you might have a bad check valve.
Just seems strange that it happened after you stop mixing your oil.
Was the wash pretty much the same as the mag side before you wiped it off?
The only other possibility is ring gap set too tight.

Post pics with jug off.

Have you talked to Kelsey yet? He is a good guy and will help you out. I know he has found a few other bugs in these engines. (eg. oil injection, thermostats).

NB

mxzwfo · 01-26-2005, 08:25 AM

I ran that same set up 2 years ago. During off-season inspection and tear down I found that the mag piston was starting to scuff in a "4 corner" fashion. Jetting was good...ect
If you are interested in the conclusion that we came up with, shoot me a pm.

Brian

SDRENE800RER · 01-26-2005, 11:29 AM

Thanks mxzwfo, I pm'd you.

NB

I havent heard from Kelsey yet, but Im sure I will.

Lack of lubrication is a possibililty. I will hope to track down the problem saturday after I get the engine and carbs apart to start checking for a few different "could be's".

I only wiped the carbon from the very center of that scuffed piston, and didnt wipe the area's that show the transfer wash. The scuffed side looks way rich to me. Whereas the mag side looks like my jetting was getting close to good. Same jetting both carbs.

The excessive fuel use keeps bugging me. Im wondering if there was a problem that was causing enough raw gas to dump threw that carb to not only give the overly rich piston wash on the pistons, but to be enough in cold conditions to wash the oil from the piston so that I got a dry seize.

Sunday afternoon after riding @ 55 miles with no problems I checked my plugs and they were a little dark and wet. So thats when I dropped from 500mains to the 480's. I also raised the 942 needle to richen it up on the bottom and mid, just to be on the safe side. When I pulled the carbs off to do this change raw fuel did slosh out of that carb. Not something that Ive ever noticed before. Usually you have to turn them over to see gas run out of them in any quantity.

Thanks
Todd

NorthernBoy · 01-26-2005, 11:44 AM

Todd

It does sound a little strange that you had fuel coming out of that carb. I know I need to turn them over to get to come out the vent lines. It might be possible you have a stuck valve and alot of fuel will wash the oil off of the piston skirt. You were ok when you had premix. What did you set your ring gap at when you assembled it? I would check your carbs closely, I found on my that a higher needle jet caused a real lean mid range and guess what happened next.

NB