[Pau1parker]

Hey so heres the story , i bought a banshee about 6 months ago, pulled the engine out to do a little rebuild and thought while it was out ill put new reeds and bought a noss cool head , i went to put it on and it wouldnt fit , looks like the people before me had stripped a thread on the right cylinder and replaced them all with bigger bolts ! Please dont say iv wasted my money , is there any way i can drill bigger holes on the head to fit it over the bigger bolts on the right cylinder? Wich looking at the stock head they have done that .. Please help!

 

[John Tice]

First figure out which holes are off, compare it with the other cylinder so you can tell how far off it is. This is how you figure out how much larger you need to drill the head. If it’s only a few thousands off, drill the appropriate holes larger. CLAMP the head down & use a drill press.

 

[Pau1parker]

Thanks for the reply, just been looking at it , the 5 holes for the right cylinder are too small , there 2mm bigger than the left , i know itl slide on perfect once there drilled out but will it upset the way it works/sits or will it still work the same?

 

[John Tice]

So you have 10mm bolts instead of 8mm? That’s the PITS, the same procedure.
I’ve got 8-10 step down studs, this is a stock Yamaha part on the larger bore engines. Check to see if your Yamaha dealer has some stepped studs before you start drilling the beautiful new head.
John

 

[Pau1parker]

Yeah , the left cylinder is 8mm and the right is 10mm , ill give them a ring tomorrow when there open and see what they say!

 

[John Tice]

The stepped ones may need to be counterbored.
John