OzVMX Forum

Marque Remarks => Yamaha => Topic started by: Marc.com on January 19, 2009, 08:18:48 am

Title: measuring Wiseco piston MX250
Post by: Marc.com on January 19, 2009, 08:18:48 am
so just measuring the piston 13mm up from the skirt on exhaust inlet axis is the largest bore size, so piston is maximum 70.42, so bore at a hair under 70.5, that should be correct, rest of piston is all sorts of shapes.
Title: Re: measuring Wiseco piston MX250
Post by: Freakshow on January 19, 2009, 09:30:50 am
The largest size is its largest size, you can only bore to that, seems like its a second over size .50 slug
Title: Re: measuring Wiseco piston MX250
Post by: Marc.com on January 19, 2009, 11:24:44 am
The largest size is its largest size, you can only bore to that, seems like its a second over size .50 slug

yep that the way I figured it, that gives bore of almost bang on 70.50
Title: Re: measuring Wiseco piston MX250
Post by: Freakshow on January 19, 2009, 01:43:23 pm
What are you doing with the piston ? if its going in a barrel just take it to the machiine shop and they will take it out to the size of the piston with the right clearance anyway. the size is only relivant to the rings you fit really.
Title: Re: measuring Wiseco piston MX250
Post by: Marc.com on January 19, 2009, 01:54:28 pm
What are you doing with the piston ? if its going in a barrel just take it to the machiine shop and they will take it out to the size of the piston with the right clearance anyway. the size is only relivant to the rings you fit really.

no what I am doing is doing my first home rebore, why should machine shops have all the fun.
Title: Re: measuring Wiseco piston MX250
Post by: Freakshow on January 19, 2009, 08:00:43 pm
Ahh well that will be interesting, make sure your in square and dont go oval when you try to get out the old thrust groove