Piston Recommendation?

[forrest411]

Getting ready to do the top end .020 over. The bike is mostly stock except for Tommey T6 pipes, K&N Filter w/ open airbox. Question is Wiseco forged or Namura Piston cast piston kit. The difference in price is $50.00 I have used Wiseco is the past, haven't heard anything good or bad about the other. Thanks for you feedback in advance.

[Profilact]

Wiseco for the win - you'll see!

[forrest411]

Thanks

[frog]

Getting ready to do the top end .020 over. The bike is mostly stock except for Tommey T6 pipes, K&N Filter w/ open airbox. Question is Wiseco forged or Namura Piston cast piston kit. The difference in price is $50.00 I have used Wiseco is the past, haven't heard anything good or bad about the other. Thanks for you feedback in advance.

 

 

 

Only use forged wiseco pistons the cast will let you down.

Edited April 30, 2010 by frog

[John1975]

[i agree w/ that guy. Everytime I rebuild a motor weather it's a jetski/sled/etc. use forged. Cast will heat up alot faster and expand quicker then the cylinders. You can get a cold seize on your bike. Meaning the piston(if cast) will heat up fasster then the cylinder and expand in side the bore, if the cylinder isn't equally as hot it will lock the piston into the cylinder and then you're done for. They have complete rebuild kits on ebay for 175. shipped to your door. Complete being: All top gaskets(which you should replace), wrist pins,bearings,clips rings,and of course both pistons. Good luck with your rebuild, we've all been there before. Oh, and don't forget to put just alittle oil around the sides of the piston, your premix you use will be great for that.

[forrest411]

[i agree w/ that guy. Everytime I rebuild a motor weather it's a jetski/sled/etc. use forged. Cast will heat up alot faster and expand quicker then the cylinders. You can get a cold seize on your bike. Meaning the piston(if cast) will heat up fasster then the cylinder and expand in side the bore, if the cylinder isn't equally as hot it will lock the piston into the cylinder and then you're done for. They have complete rebuild kits on ebay for 175. shipped to your door. Complete being: All top gaskets(which you should replace), wrist pins,bearings,clips rings,and of course both pistons. Good luck with your rebuild, we've all been there before. Oh, and don't forget to put just alittle oil around the sides of the piston, your premix you use will be great for that.

[forrest411]

Thanks for thhe response. I ordered the Wiseco Kit (off ebay) this morning.

[forrest411]

The local shop that I was planning on using to bore and hone the cylinders says that they would normally fit the forged piston a bit looser than what the Wiseco instructions say to fit it. He says the the clearance that the manufactor says will be very tight. Has anyone been told this before. He is willing to do it his way or to the manufactor's (Wiseco) specs. Any thoughts???

[forrest411]

The local shop that I was planning on using to bore and hone the cylinders says that they would normally fit the forged piston a bit looser than what the Wiseco instructions say to fit it. He says the the clearance that the manufactor says will be very tight. Has anyone been told this before. He is willing to do it his way or to the manufactor's (Wiseco) specs. Any thoughts???

 

 

Anyone?

[overrevtricky]

Since the piston to cylinder gap only gets bigger after a top-end job, I would go with the factory specs. Same thing as gapping a plug to the upper limits, it makes no sense because its only going to get bigger!

[forrest411]

Since the piston to cylinder gap only gets bigger after a top-end job, I would go with the factory specs. Same thing as gapping a plug to the upper limits, it makes no sense because its only going to get bigger!

 

Thanks for the input. I was thinking along the same lines.

[shanYE west]

[i agree w/ that guy. Everytime I rebuild a motor weather it's a jetski/sled/etc. use forged. Cast will heat up alot faster and expand quicker then the cylinders. You can get a cold seize on your bike. Meaning the piston(if cast) will heat up fasster then the cylinder and expand in side the bore, if the cylinder isn't equally as hot it will lock the piston into the cylinder and then you're done for. They have complete rebuild kits on ebay for 175. shipped to your door. Complete being: All top gaskets(which you should replace), wrist pins,bearings,clips rings,and of course both pistons. Good luck with your rebuild, we've all been there before. Oh, and don't forget to put just alittle oil around the sides of the piston, your premix you use will be great for that.

 

 

Actually.. the cast pistons are effected less by heat and expand less.. hence the tighter tolerances for cast pistons. Forged pistons require a looser spec to accomadate for the expansion.. you put a forged piston in a bore setup for cast pistons and you'll get cold seizing.

[toytech]

The local shop that I was planning on using to bore and hone the cylinders says that they would normally fit the forged piston a bit looser than what the Wiseco instructions say to fit it. He says the the clearance that the manufactor says will be very tight. Has anyone been told this before. He is willing to do it his way or to the manufactor's (Wiseco) specs. Any thoughts???

 

 

I would go with wiseco specs and break it in correctly! and make sure the shop chamfers the ports correctly. I send all my 2 stroke cyls to the guys that do them only so they will last longer

[bansheesandrider]

I would go with wiseco specs and break it in correctly! and make sure the shop chamfers the ports correctly. I send all my 2 stroke cyls to the guys that do them only so they will last longer

X2, as a bore only gets bigger, I would set it to the Wiseco spec and then make sure you break it in properly so that it does not sieze right away. Also let it warm up before you hammer on it. Make sure that your machinist is aware of the proper way to measure a Wiseco piston as they are egg shaped when they are cold and become round when they warm up, therefore the machinist has to measure them in the proper location to establish the proper dimension and therefore the correct clearance.

[SLORYDER]

I would also consider vitos superstock pistons. Proven 5-6hp