Just so you guys know , some of the early rx1 snowmobiles experienced some kind of cracking on the oil tanks because of vibration. It may have been caused by all the bouncing around that a snowmobile goes through which shouldn't be a factor in a plane but I would mount them with some kind of rubber bushings between the tin and the frame. Check out this link.
If you pull those carbs apart be real gentle with the needles. The plastic part that holds them in place is real easy to break if you push them down too hard and Yamaha doesn't sell just that part. Also don't forget the tiny o-ring underneath the carb cap.
The RX1 engine is designed to run at a peak of 10500 rpms and has a gear reduction built into it that makes the output shaft rpm about 8500. That and the gear reduction on the gearbox will get the prop speed down to where it needs to be. I've run my turbo RX1 to 11000 when I was grass dragging it.
I don't know what the deal is. I just talked to Terry and his says it'timed out also. I can click on either one and they both come up. Maybe c5engineer can get his videos to work. Anyway Terry told me to put the particulars of his plane on here. It originally had a 503 with a Warpdrive prop on it and weighed 405 pounds. Added new landing gear 4 caliper Matco brakes Matco 8'' wheels with 22' manco tires RX1 engine ,radiator,oil tank,and all the goodies to make the 4 stroke work Matco 8'' dual fork tailwheel 74'' Prince P tip prop. Empty wieight was 560# and 15# had to be added to the tail
Do you have any pictures or a link to these aftermarket headers to fit the RX1 sled. I've never seen or heard of any headers,(other than the ones for turbos) just an aftermarket muffler to cut some weight.
The sled didn't get the nickname (RX1 Ton) for being lightweight. Mine weighed in at 715 pounds full of all liquids. The complete exhaust system weighed in at 42 pounds and the muffler was a good part of that.