well i figured out my problem. First i checked my valves they were good, then timing chain it was good. then decided to try to pull start it. It started right up. There was a horrid tinging. So tore the top end off and sure enough the piston was toasted. The weird thing is that it ran like normal up to when it died and wouldnt start no smoke no symptoms. Heres where the fun starts. The rebuild im Boring it to 87mm 416cc. My question is what compression ratio 10:1 or 11:1 what gas do they run on? Also i ordered stage 2 hot cam. How does the 416 run compared to the other big bores? Im excited to get started on this.

 

come on anyone?

 

A 10:1 will run on pump gas. The 11:1 is close, some will run good with pump gas and some do better on race fuel. With the 11:1 you are going to want to use HD studs.
What do you have for mods?

 

Full hmf, k and n, jetted, I'm putting in hot cams as well as the bore.

 

10:1, 416 with a stage 2 cam, full exhaust and filter will be a fun bike.
Might want to look into some cooling mods and suspension upgrades.

 

Yeah after this I'm thinking 450 carb and front suspension also do oil shrouds help cool?

 

How much horsepower will this add?

 

Instead of shrouds look for a 4" Spal puller fan. You can zip tie or make brackets to fasten the fan behind the oil cooler. They are simple to wire to a switch.
I had the 450r front shocks on my ex. They were a big improvement over stock. Getting them re valved and having the appropriate springs makes a big difference.

 

With 10:1 do I run 91 pump gas?