Hey guys~
In the next couple weeks, I will be getting an HPD pipe and Delta V-force reeds. I am excited about the new power, but am a little worried if my stock Piston will hold up very long. The machine is 5 years old now and almost 3,000 miles. Will the stock piston hold up with this new power, or will it be necessary to get a new Wiseco piston right away? Thanks for all replies!

 

Hi WI Scrambler

I have the HPD pipe, with HPD roller clutch on my 96 400 4x4 Scrambler. I have just done the piston & rings for the first time, and the piston was craked slightly, so Wisecoed it. Lighter, Stronger, Better.

I have also just got my V Force II reeds today, so looking forward to putting them on.

Replace the piston after 5 years, or pay for it later!

TheJoka
400Scram 4X4

 

I put a new Wiseco in my Sport right before I added my HPD pipe/clutch kit. I was told the Polaris piston wouldn't hold up, so I figured it would be best to do it first. It took me about five hours to do the whole thing.

 

The regular Polaris piston in your quad should have been replaced long ago. I make it a habit to replace mine every 3 years or so. The stock pistons will hold up to everything except porting and high rev situations (i.e. putting a top end pipe on). Go with the Wiseco and get the piston coated to eliminate cold seizure. I did it with my Sport and after a years worth of riding it it still hard to turn over by using the recoil starter.

 

Hey guys~
First off, thanks for the replies! Now that it seems the consensus is that I will need the new Wiseco, I have a couple questions. Will I be ok getting the stock sized piston, or should I get the cylinder bored/honed while I have it apart? Also, how difficult is it to replace the piston. I've never done a top end rebuild so this will be a learning experience for me. Can I plan to get the job done in one day, or is it a whole weekend job?

 

I'm no Mr Goodwrench, and I did mine in 5 hours. All I needed that I didn't already have was a torque wrench. Just take your time. I followed the directions that came with the new piston.

 

what makes the piston break is too much clearence.new motor,pipe and reeds ok.when piston gets to around .006-.008 bore and replace.you will start to hear a rattling sound on a cold engine when it gets too much.new piston should have .0025-.003. piston is smaller at top so mic at largest part of skirt.make sure cylinder is true top to bottom.don't forget ring end gap .012

 

Keep it stock if you can. Take it to an engine reconditioning company and get them to check the sleeve. If it is OK (which it probally will be) just get them to hone it (takes the shine off the sleeve walls. Only bore it if you want to go big bore, or if you have pits or gouges in the sleeve.

I took mine to be honed, and the bloke couldn't believe that the thing was 5 years old on the origional piston and rings. Said it looked like new.

TheJoka
400Scram 4x4