Some of you guys even scare me. I have been running a 102mm 12-1 for a year and a half with no motor problems. I just had my 2003 cyclinder bored and honed for .0045 clearence for a stck bore 12-1 build up. Most of these failures appear to be the stock bore build ups. I am going back together with my 2001 raptor that tossed the trannie in Glamis at FSW's. I am putting in 02 gears this time. The 2001 had been a 102mm 12-1 for well over a year. Hope it does not get pissed off that i am downsizing to a 100mm. So what do you guys think?? I am going to be a 2001 frame and lower end, 2002 gears and a 203 top end and carbs.[img]i/expressions/face-icon-small-wink.gif[/img] The lower ends passed Bob craycrafts inspection with no signs of wear.

 

Are you going to keep the rod stock or upgrade?

Has anyone thought about perhaps having their tranny gears nitrided? Just thought that maybe Yamaha's hardening system might leave something to be desired.

 

The only real concern could possibly be the smaller bore schrouds the combustion process....since the head was probably ported / reworked for the larger bore. This would kill power.

 

Alaska- Cyro treating is a option

Gary- I have a brand new untouched raptor head to use from my 2003. At glamis we robbed from the cyclinder up to put on the 2003, no i am going to put what ever i do to the 2003 on the 2001

 

I would check with Bob too see whats best for max power. If Bob does a standard bore AND and an oversize bore port job....most-certainly the oversize bore will breathe easier and make more power. If one is gonna be your "runner", I would have everything built for it......and go with a compromise on the lesser machine. The lesser machine just has too get you around when the "runner" is under the knife. JMO.

 

Gary- I want to make my stock bore the runner, so when i beat those 727's, 770's and 686's i can say i have a stock bore. Also at the sand drags they tend to group them as 672cc and over in one big group, and 660 and under i another

 

Anyone built a raptor engine to rev yet? balance everything, all light weight parts, special top secret build up to run like 12k revs up the hill? Blah Blah Blah, you just lose reliability and dont gain any power....... thats true, if you dont build it right......