[cdiedrick]

So I ended up having to put a new top end in my zr500 after discovering that I had a hole in a piston going back to the problems I posted last month. My question is, do I need to do anything in regards to breaking things in? I assume I need to do something, just not sure what? We are scheduled for snow later this week, so she will get a workoutRockerdude

 

[auburn6887]

well new pistons?
weisco or spi
we start the sleds and let them warm up
3 times
then ride them like we stole them with spiand weisco
before each ride we let the sleds warm up
have temp gauges to make sure they are warm before we go

 

[crash74]

Oem pistons aren't as finnicky on the break in and are much more tolerant than wiseco.
Always need to let them warm up and don't hold a constsnt rpm for break in, it needs to vary.

 

[clintonior13]

don't forget to cover everything with 2t oil as you assemble it all back together for break in. I just bought a set of SPI on Ebay for 104 shipped free. I thought that was pretty good price I got em in 2 days, also make sure your circlips face open side up some have said they'll work themselves lose in other directions. jfyi obvious and not mentioned remedy what ever it was that burnt it down before you break it in full carb cleaning and check those pilots and e tubes.

 

[pyro1955]

Oem pistons aren't as finnicky on the break in and are much more tolerant than wiseco.
Always need to let them warm up and don't hold a constsnt rpm for break in, it needs to vary.

Actually, OEM for cats are the Wiseco Pistons, if you do not warm them up properly, every time, wiesco's can be a problem. I run SPI's, initially I picked them because they are cheaper, then I read many many accounts here of people learning the hard way that they did not warm up their sleds properly. In my Opinion, If you are not going to race your sled, SPI's are fine. If you are fine tuning, and trying to get every MPH out of your sled, then Wiesco's are the way to go.

 

[crash74]

I guess I've had a different meaning in mind for oem, I've always known oem as original equipment manufacturer. Original as in factory stock equipment, not aftermarket.
Who knew!! I dunno

 

[cdiedrick]

If I put 55 miles on, if she was going to blow she would have right? This was a combinatiion of trail and ditches so the zr500 had a work out. What does everyone think?

 

[109jb]

Actually, OEM for cats are the Wiseco Pistons, if you do not warm them up properly, every time, wiesco's can be a problem. I run SPI's, initially I picked them because they are cheaper, then I read many many accounts here of people learning the hard way that they did not warm up their sleds properly. In my Opinion, If you are not going to race your sled, SPI's are fine. If you are fine tuning, and trying to get every MPH out of your sled, then Wiesco's are the way to go.

Just saw this post and I have to disagree. Cat engines do not use Wiseco pistons as stock. Cat's have cast pistons as stock the Wiseco's are forged. The fact that they are forged is why they need additional cylinder clearance and why they are more sensitive on warm up. The SPI pistons are closer to an OEM piston as they are also cast. I run SPI's personally and have never had a problem.

 

[crash74]

Cdiedrick- you'll prob want to run it a little more than that to get everything worn in and seated but yes, if it was gonna go because of an assembly mistake it woulda hone in that 55 miles.

One thing you want to be sure of during break in is do not hold a constant rpm, it needs to fluctuate so semi aggressive trail riding and dutch banging are good.

 

[pyro1955]

Just saw this post and I have to disagree. Cat engines do not use Wiseco pistons as stock. Cat's have cast pistons as stock the Wiseco's are forged. The fact that they are forged is why they need additional cylinder clearance and why they are more sensitive on warm up. The SPI pistons are closer to an OEM piston as they are also cast. I run SPI's personally and have never had a problem.

Interesting, maybe it depends on the Engine? My 580 had Wiseco's stock from the factory, and they were the reason the sled lost one of the cylinders at 800 miles. It' has had SPI's in it since, no problems, over 1500 miles.