Jump to content

yz250f top end rebuild questions

Recommended Posts

Hello Everyone. 

I have a couple of questions about rebuilding my 2006 yz250f top end.

You should know the bike is in good condition, it is a low hour bike, despite being 11 years old but I took the head and cylinder off anyway. My first question is, torquing the camshaft caps to 7.2 foot pounds seems like it would be hard to be that precise with a torque wrench with the engine in the frame. Any tips or suggestions?  Would a 1/4 drive beam type torque wrench that is calibrated in inch pounds work? All of the ones I have found have a limlt of 80 inch pounds which is not quite  7.2 foot pounds. 

Second question, my cylinder and piston are in very fine shape, cylinder still has a lot of cross hatch left. I have no way of measuring piston or bore diameter,  but since it is apart, Will I be safe in putting a new std bore oem yamaha 2008 piston and ring set in? I mean will the clearances be okay?  l am thinking of the 2008 piston since it has a higher compression ratio. I realize these questions are worded very poorly. Thank you for your patience. 

 

 

 

 

 

Share this post


Link to post
Share on other sites

I am no pro engine builder. My 0.02; if you really want to drop a newer piston in it, have someone with the tools measure the cylinder. As far as I know, they would like to have the piston there as well. Have a shop manual handy so you can look up clearances.

If you can return the piston, I would just order what you want so that everything is there. But be able to return it if you arent able to use it.

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:


×