Cracking cylinders on Bender 800

[Motley Doo]

I have a friend that is running a 97' Mountain Max 700 with a Bender 800 kit(pipes, porting, clutching, etc) and has been cracking cylinders! He has around 2,500 miles on the kit, 3,400 on the motor. The sled turns 8,400 all the time. The first issue was last year, he cracked the clutch side cylinder around the back, were in a pinch and had to weld it back together, then the other day, he cracked another one, clear around, and puked coolant into the exhaust. He has checked head for flatness, all bolts were tight, any ideas? This has been a very reliable sled, hard runner and this has been its only issue, any advice would be very much appreciated! Thanks!

 

[BCBOOST]

The 97 cylinders do this when you start pulling the power out of them....sorry for the bad news but seen this back in the day when we ran some pretty strong running 700's. Yamy updated the 98 and up cylinders with a gusset formed into the casting in this area. Hope this helps, when I finally sold my 700 mod it had two of this type of cylinder on the engine!!

BC.

 

[Motley Doo]

So, the 98' cylinders are a strait swap, I'll have to tell him that, the problem is matching the ports to the other 2 cylinders that Bender worked over! Oh well, thanks BCBOOST.