We've got an SST pipe on the bike and the new 02/03 CR125 three stage Boyesen Rad Valve...
Back to back with the stocker is no comparison I don't have a YZ125 to match it up against in drag races, but so far this is a big gain over stock CR125 which is just terrible in my opinion. We haven't rejetted yet, and the bike probably needs to go down 2 sizes in mainjet so can't wait to see the top end when it's leaned out.
The bike PULLS much harder than the stocker - it's not even close. I'd suggest that whomever said the intake was a huge problem was correct because with the Rad Valve installed it started accelerating much harder. I’m a big guy well over 200lbs, and I would cruise along slowly click into 2nd, then third and then roll it on to see if the engine had enough torque to pull me up onto the pipe (just slang for into the powerband) with the SST it didn’t want to do it so well, with the addition of the Boyesen Rad Valve it did it much better and when it started pulling it was very linear and got stronger and stronger no sudden burst or yank, just stronger and stronger. Nice smooth feeling power, hope it translates onto the track as well as it does in just straight line testing by the seat of the pants.
We have a "Phat Head" high compression head on the way as well. It's coming with three domes, stock/higher comp and even higher yet. So we'll see how that works. If the compression is too high and the bike loses some top end, we'll adjust the engines timing to see if we can give it back some over-rev.
Sir Eric Gorr of the Wisconsin “Gorrs” (no relation to Al Gorr) will be doing the third stage which happens to be cylinder mods. At that point we’ll be taking the Phat Head back off, because Eric does extensive work to the CR125 head… so we’ll let you know how the two other stages work (phat head and then Eric Gorr cylinder). www.eric-gorr.com
MP