how to prevent engine blowing

[Reg2view]

Surprised you people left out one major point; piston-to-wall clearance. Why some run 500 miles and fail while others run 3000 miles with no issues (my belief)./QUOTE]

Yep, you're absolutely right, and it applies regardless of year, but not much you can do until you crack it open. It's a matter of luck stock, without checking. I replaced pistons on my 11 at 1100 and the clearances where still within tolerance and pistons in great shape. Oiler was turned up after the second tank of fuel, and always heat soaked. On install of Wosners, clearances were excellent, top, middle, and bottom, and ring gap meticulously set. I do believe excessive clearance from lack of QA, poor oiling, lack of warmup, led to broken piston and cylinder skirts on many of the 11/12 failures. After the word got out to add oil, however you did it, warmup, and thicker skirts appeared, failures decreased dramatically.

 

[4strokeperformance]

Fix kit

I got lucky I guess. I got 3200 miles on my 13 with RKTech piston kit all with Yamalube with zero problems before I sold it. I always did the warm up procedure tho.

 

[diamonddave]

Find a set of 2011-2012 cases and have them bored to fit the 13+ cylinders with as little clearance between the skirts and the cases. I have them bored so you can barely get the cylinder into the cases. My 2015 Pro has 12 cases on it now, and I have 3 sets of 11/12 cases sitting here for others when they decide to upgrade. I have run 09 cylinders on 600r/800 mono block conversions for years with no issues with the skirts at all (very tight tolerances), one is even an 860 with 09 cylinders. Besides the fact that Polaris is using hot garbage pistons, they are leaving to much clearance for good skirt support in the cases. That along with not setting the oil pump properly from the factory seems to be a common issue. Amazing the difference in stock pistons from one with not enough oil and one that has had the pump turned up.

If the fix it kit that basically lengthens the piston is a bandage so is the long-rod that lengthens to rod, one just costs a whole lot more than the other. They both move the piston up to change the angle and re-leave some of the pressure put on the cylinder walls. Now granted if you want to pay $3000.00 so you get a warranty go for it.

All that being said, I install Fix-it Kits, BMP, RK-TEK's (drop in's), Hanson Racing Engine's, and my own, which are just M8 aftermarket pistons and plate/bolt kit. Honestly think they do help a bit with more case volume on a engine that is already suffering from a case volume deficiency. Plus again using good pistons is a plus compared to stock.

I agree with almost everything...I used to just reinstall the 09 Cylinders on the 08-09 Dragon's with a Fix Kit from MTNTK (the first company to come out with a kit for the 800 CFI that actually fixed the issue.) RKT, BMP, the rest copied their kit. The only time these motors ever blew a piston or cylinder skirt was when they had been recalled with the 2010 dual ring pistons/head. The 2008-2009 single ring pistons never blew skirts, just simply scuffed pistons from poor mapping and poor 4 injector overlay patterns that caused significant part throttle lean issues.

The case volume issue is noticeably better with MTNTK's kit. The runnability is much better and normally I will always install a 2 gram heavier weight at the same time I install a fix kit.

 

[sledhead_79]

I got a 2014 1000 miles, no fix-it kit, no long rod, no issues. I do recommend a new top end every 1800-2000 miles.