I really need to know what kind of gain I can expect between a 11:1 on pump gas, and a 13.5:1 on 110 Race Gas? Will there be a noticable difference? Will I pick up time in 300ft, and do you guys think the 13.5:1 would be less reliable then the 11:1?

Any guys with opinion's or facts please feel free to let me know.

 

The 13.5:1 will give better performance; ecspecially with a big cam. The higher comp. 13.5:1 over the 11.1 will give a noticable difference in performance; better torque down low also. If you are running an aftermarket rod I would go with the 13.5:1 comp.. As far as reliability the 13.5:1 piston should be very reliable with an aftermarket rod I run the 12.1 JE with the stock rod but I consider this taking a chance. My opinion is if using a stock rod you take a higher chance the higher compression; if running a good afterkarket rod I would go 13.5:1 without thinking twice as long as everything else associated with it is set up right. Hope this helps, Slim

 

The rod is already been replaced, and Falicon did the crank work.

 

You should be good to go with the higher compression then; You want be dissapointed if you go 13.5:1. Slim

 

You need to talk to Bob or Jerry Craycraft . I think they could probly give you the Numbers#
I believe there is even a 14:1 but I'm not sure if it was 102mm or 105 or what bore .
AS far as reliablility Any time you increase the HP and Torque you decrease the life .
And then again it depends on the mods and the metal and the guy pulling the pin on the grenade .
Just think of it like a fat rubber band the width of the rubber band is the life of the engine .
the length is the Performance . Pull it make it longer and the life gets narrow . Pull it hard enough and SNAP

 

Anyone want to offer a opinion...SixsixT....RaptorOwner...1BadRaptor....? ??

 

Wshrdskin went to a 12.5 from a 11 :1 but went to a stage 2 cam at the same time and really liked it. 1BAD picked up a couple of lengths just with the piston.

 

Honestly, with the length mine was down I cant feel the difference but have raced a few people that did mods on their bikes to beat me before and I still got them. I would definitely go with the 13.5:1 setup. Your system will be exactly like mine except for the porting. Just went on Memorial Day to break it in and I sure do love the power of this machine. The first race I was with Mad Racings 727 and he got me by about 3 bike lengths and then Raced a DS730 and we were swapping wins by the end of the day. The next day I got the 730 3 times in a row, couldnt find Mad Racing but found out later his engine expoded [img]i/expressions/face-icon-small-shocked.gif[/img] But sure did want to see what it would do then. Each time I raced on it the second day the bike felt like it was getting faster. I will be swapping some gears this week and heading back to Pismo on the 26th to break it in some more before the 4th.

I do feel it pulls more at the top end now, because I never get out of 3rd gear and it just pulls and pulls all the way!![img]i/expressions/face-icon-small-happy.gif[/img]

 

Depending on the rain and everything, I will have my high comp piston within next week. There is no time to get it here this week, install, and break in before the Ky races. So I will just sit back and see if the races go through or not. If they don't, I will order my piston this week and have it ready for our local races. If we get to go to KY, then I will get the piston as soon as I get back and try to have it ready for the local races.

Hopefully I get a good pick up from the low compression pump gas cruiser style 686.

 

Lets asume you gain 3-4 lengths....is it really worth it? You can probably get the same gain by dyno jetting (or more). Have you ever had anything that required race fuel only? Beside the price, it's a pain too find depending on where you live....sometimes making ordering the stuff necessary. Just another experienced view guys...[img]i/expressions/face-icon-small-smile.gif[/img].
Gary