Jump to content
Sign in to follow this  

ktm 150sx 2013 piston change!

Recommended Posts

hey guys im at 88.8 hours on my ktm 2013 ktm 150sx its still going strong! i think it will be good for a piston change, i dont want to risk it, i heard alot of good things about weisco pistons, so i will go with weisco but i dont know what size piston to order? like bore stock or bigger? on rockymountainatv, the weisco piston is 56mm bore would that be good?

 

thanks guys ;)

Share this post


Link to post
Share on other sites

Pull the head and look at the piston, it will have the size on the top. 

We've had good luck with Vertex. They make most of the stock pistons. 

  • Like 1

Share this post


Link to post
Share on other sites

Pull the head and look at the piston, it will have the size on the top. 

We've had good luck with Vertex. They make most of the stock pistons. 

 

ok thanks but i dont want to pull the head for nothing, draining all the coolant and all, not that i am lazy but that i will pull it when i have the piston, would it say the bore in the manual or some where else? and if example it says 56.9mm would i put the same one or like 1mm bigger? 

thanks

Share this post


Link to post
Share on other sites

I think you might need some help...You need to get a Vertex B piston for your bike and yes you will have to replace the base gasket with the proper thickness gasket to get your deck height right and you will have to replace the two orings at the top of the cylinder and yes you will need a new wrist pin bearing.

  • Like 2

Share this post


Link to post
Share on other sites

I think you might need some help...You need to get a Vertex B piston for your bike and yes you will have to replace the base gasket with the proper thickness gasket to get your deck height right and you will have to replace the two orings at the top of the cylinder and yes you will need a new wrist pin bearing.

Ight thanks man :)

Share this post


Link to post
Share on other sites

He also says gasket ( .2, .25, .5 .75mm) what gasket should i get i think its for the bottom one. Thanks :)

Like mentioned above, take the cylinder off and see what's on it now. If you don't want to do that order 1 of each. They are used to set the proper dimension from top of piston to the top of cylinder.

Share this post


Link to post
Share on other sites

you seem to know nothing about wrenching on engines....you will only know which piston size you need after pulling and measuring the cylindersize...the cylinder wears and changes its size over time, especially when you risk to ride the piston 3 times longer than normal. 89h is way to much. The nikasil plating will be very used in your cylinder and it most likely needs to be honed or even plated new, when the cylinder has deep scratches. 

A piston shrinks over time, and the assembly clearance gets bigger when that happes the piston starts tipping, which will damage the cylinder. 

 

The assembly clearance between cylinder bore and piston should be at 0.05mm. the standard piston has 55.95mm (B is at 55.96mm, C is 55.97mm) as the bore is 56mm....

 

short version: let a professional take a look at your cylinder and measure it. Otherwise you won't know which piston size you need. 

 

 

 

If you've done the things above, you will need to set the piston deck height by using the right gasket. The egde of the piston needs to be parallel to the cylinder edge. But the top of the piston is not flat, so you need a special caliper to measure it. 

 

You can also measure the squish, but the method above is more exact and easier to do

Edited by eins4eins
  • Like 1

Share this post


Link to post
Share on other sites

Alright thank you, i know about engines i work alot on scooter engines, i was just making sure, :)

then you should know a 1mm piston his huge difference then standard bore. vertex pistons come in a,b,c, and maybe d sizes "standard bore size" because they are specific to cylinder bore/wear. Weisco makes a generic size for the standard bore then the 1mm piston is for boring the cylinder and replating. What scooters use an aluminum cylinder that has plating? Also eins4eins said about  you biek having way to many hours and what not. don't worry about that. Doesn't seem like your a high revver type of guy. I don't think 80 some hrs is bad on a cylinder depending on how it look. I've seen some 125-150s with 200+ hours on the cylinder and crank

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×