Two Rides w/Wisco pistons. Scuffs?? Please See Pics, Suggestions??

[DragonSlayer1]

I have and 09 800 Dragon. A had a huge burn down a few weeks ago. Busted skirt on pistons and cylinders. Busted cases and killed a crank bearing. EGT's gave no warning. I atribute the burndown piston slap clearence problems.

Got new cases, sent the cylinders into Mellinum tech for repairs and had the crank repaired. Used all new gaskets as well.

I installed the Wisco slightly oversized pistons the same diameter pistons as the FIX it kit pistons ( but not as long) .

The marks on the cylinder walls feel very light. Almost like a finger nail file.

The scuffs are porportional on both cylinders, mostestly were there are no ports.

While putting the sled back together, all parts were heavly covered in oil (including rings, pistion, bearing and cylinder walls).

The sled was warmed up to 100 degrees before moving. Additional Oil has been mixed in the gas. Its Running really heavy on the oil.

Plugs look a dark chocolte brown.

The last ride the sled was running really stong. Stronger 100% stock, than when I had my power attiction head and pipe on it.

While running I have been easy on it. Varing the throttle consitantly. No midrange holding. It has not been held full throttle longer than a split second, but only after an hour or of ride time.

Please help? Suggestions?

 

[AKSNOWRIDER]

whats piston to cylinder wall clearence at with the tighter pistons? looks to me like its too tight on piston/wall clearences...I would take the cylinder and new of the same pistons down to the best local machine shop and have them hone it to proper clearence...(as long as you are only needing .001-002 )

 

[skibreeze]

Burndowns are caused from being too lean. Just throwing in new pistons doesn't fix the cause. I put a PCV on mine and that has worked so far over 700 miles.

 

[Eli]

When you did the first startup, did you let it only idle for a few heat cycles? Itseems like 3) 10minute idle sessions are recommended by a growing number of builders. PSI says (ducking my head) that if you don't do the 3 10 minute sessions that you WILL streak the Nicasil.

 

[Backcountrypro]

I have seen this many times. Clearance is a little too tight. Let the engine warm up good before you really get on it and run it! Those marks probably happen the first time you fired the engine up or put a load on it. As long as you can't feel any of the scuffs with your finger nail I would run it.

 

[DragonSlayer1]

Really?

"I have seen this many times. Clearance is a little too tight. Let the engine warm up good before you really get on it and run it! Those marks probably happen the first time you fired the engine up or put a load on it. As long as you can't feel any of the scuffs with your finger nail I would run it. "


That Sucks
I can feel the scuffs with my finger nail. Similar to a very fine finger nail filer.

Whats the risk if I keep riding it the way that it is?

 

[Backcountrypro]

The risk is that if it does tighten up it will take out the piston and probably the jug. If it were mine I would probably run it but my biggest fear would be getting it out of the backcountry if it does fail. If the area you ride is easy to access run it, if it would require a lot of work or a Heli to get you out I would take it apart and address the problem.

Personally I had a engine with marks like those, found them after the first weekend of riding. It always drove me nutts knowing the marks were there but I ran the engine for three years like that and it was still going strong when I sold it.

 

[m8magicandmystery]

i think that maybe your ring gap might be possibly to tight...??..did you file or grind them to the required specs...??...other then that she looks like she was a winner..

 

[2XM3]

Pull jug, buy new rings, have a good machine shop hone .001-.002 out of the bore.. assemble, heat cycle 4-5 times...should be good to go...

These cylinders are CRAP.. Due to the amount they go egg shape at running temp I would not run a piston tighter than .006 in them. Just bolt the jug to the case top,torque,bolt head on and torque...nice and round..now heat to120 and run your dial bore guage in there....woooooo .008-.015 egg shaped, now if you hot hone with deck plates so its round at temp. its egg shaped cold... just a horrible casting. IMHO this is the reason Polaris has .009 clearance on there pistons, they have a problem ,they know it,and there bandaid has come around and bit them in the a$$ as now with the crappy rod to stroke angle and loose sloppy piston the skirts break off, the cylinder cracks off at the bottom ect ect.

FYI the 2010 cylnder is a better design but case needs to be bored to fit it if ur using a 08-09 case

 

[JUDD]

Test your pumps

Make sure the fuel pump and oil pump are working properly. seen a few probs with those.

 

[DragonSlayer1]

New Pics of Piston

Please check out pics of the pistons. @ the top.

Keep in mind I have 50 miles on them.

Do yours look like this. I can feel some light scaring. both pistons looks similar in scare characteristics.

Comments???

I have not found out the clearence specs yet. Still working on that.

 

[754bigbore]

clearance specs(piston to cyl wall) are .004 " minimum. it says on the instruction sheet that came with the kit. ( you had the kit installed at a shop?) to me it looks like the ring end gap was too small. the spec is .019 to .028". for that. hope that helps. BTW I had to file my ring end gap, were too tight.

 

[rmk727]

4 corner score, take a moment and carefully inspect the throtle body boots for cracks and delamination

 

[rmkboxer]

wiseco pistons expand more then stock pistons, wisecos are also notorious for cold seizing

 

[DragonSlayer1]

wiseco pistons expand more then stock pistons, wisecos are also notorious for cold seizing

Good to know.

 

[Adobe-Al]

Burndowns are caused from being too lean. Just throwing in new pistons doesn't fix the cause. I put a PCV on mine and that has worked so far over 700 miles.

I will second "skibreeze's opion" If you you have a tight fit(piston clearence) and you run lean for only a few seconds-it could cause scuffing like this- I also think if you are not running a PCV you are not covering a proven problem. (IMO)-I know it sucks to have to spend more money on this sled- I can tell you this my stock sled with a PCV out performed (1 stocker(No PCV) and 1 SLP pipe/can sled) and I know it is not running to lean. JUST MY 2Cents! Good Luck-

 

[live2beel]

I have ran Weisco's for the last 20 years. The cylinders alway look terrible. Just like you after a 50 mile ride I would look at the cylinders and say OMG. If it was me I would put another set of rings on. Check end gap. Run a hone down it & put it back together. My stuff always worked good at .0055- .006 with forged pistons. As long as performance is there, just ride it. Afer it's together take it easy for awhile, then beat on it for the rest of the day. I think you will be fine. How long Did the motor last with the cast pistons?

 

[crashnbash]

If you are going to run forged pistons you better know how to measure and set all the clearances up properly. You also need to understand what it takes to cold seize a motor. If you don't understand either one, you will destroy alot of cylinders and pistons and I recommend you stick will cast pistons. The pictures look to me like the clearances were a little to tight.

 

[skitter]

Just out of curriosity, while you were riding did you ever stop for more than 10 or 15 minutes at a time to take a break, fire the sled up, and grab a handfull of throttle and take off without letting the sled warm back up for a few? I too have had my fair share of problems I know how you feel!!!

 

[DragonSlayer1]

I have ran Weisco's for the last 20 years. The cylinders alway look terrible. Just like you after a 50 mile ride I would look at the cylinders and say OMG. If it was me I would put another set of rings on. Check end gap. Run a hone down it & put it back together. My stuff always worked good at .0055- .006 with forged pistons. As long as performance is there, just ride it. Afer it's together take it easy for awhile, then beat on it for the rest of the day. I think you will be fine. How long Did the motor last with the cast pistons?

It lasted for around 800 miles with the stock pistons.

Just out of curriosity, while you were riding did you ever stop for more than 10 or 15 minutes at a time to take a break, fire the sled up, and grab a handfull of throttle and take off without letting the sled warm back up for a few? I too have had my fair share of problems I know how you feel!!!

I have been extra carefull with these. I have always waited for coolent temp to level out before taking off.