If it was me and I was getting a larger throttle body I would get +2mm intake & +1mm exhaust......Stock 700XX intake is smaller than XR650 intake but larger in capacity; 686cc vs 650cc.
This would not be going overboard; the 450R responds to +2mm in, +1mm ex very well. The intake charge velocity will still be very high even with the larger TB mainly because the stock 700XX is so strangled in stock form.........DS450 has 48mm TB & the new CRF450 has a 50mm TB!!!!
Hell yea!!! That saves allot of trouble. They make a 37, 38 & 40mm Intake valve plus 32 & 33mm Exhaust valves for the XR650R. I'm not sure if the years are different but the package said 2000. I'll have some headed your way tomorrow.
We were mainly talking about aftermarket brands of cams, For example Hotcams makes a stage 1, 2 & 3 for the XR. Since they will bolt in we can get one, install and make more HP. I'll prolly use the stage II
The bigger valves are not necessary to have if you get your head ported but help make more power when combined with the cam and port work.
oh ok i see what your saying, im in awe of how honda makes stuff to be so universal. i can't wait to see it at the dyno. im looking forward to what i can do to my bike, just gotta get past the first maintaince and full break in period first.