Now it's time to re-install the carb onto the bike.
Install the rear shock
After that I installed the subframe and the new YZ header and exhaust:
Why YZ exhaust?
The YZ exhaust is a direct bolt on, has a larger diameter than the WR and offers a "straight through" exhaust can design (vs. the chambered restrictive WR). However, you will have to change both the header and the exhaust. There are some differences between the later model exhaust systems. The '06-'07 YZ450 header has a little smaller diameter than the'08-'09 and the exhaust can is a full size similar to the stock WR. The '08-'09 YZ450 header has a larger diameter as well as a little different profile. The exhaust can was a "shorty" design and is mostly hidden behind the number plate similar to the MX 2-stroke silencers. The later model exhaust systems will give you more top end performance, but you will sacrifice a little bottom end. You can mix and match these systems (i.e. an '06 header with a '09 exhaust can). Basically, if you have a steel frame '98-'06 you can use any '03-'05 YZ450 exhaust(s) and if you have the aluminum frame '07-'11 then you can select from '06-'09 YZ450 exhaust components. Also, I would be careful with the '08-'09 YZ450 exhaust components. Yamaha was toning down the power on the 450's during this time and the exhaust will reduce the bottom end power.
This is a stock WR header inside of a YZ ehxaust.
YZ exhaust on the left compared to a stock WR exhaust:
Stock WR exhaust:
This is the TPS plug. Every WR from the 400 to the 450 has one. The TPS is located on the left hand side of the carb and for a street application it will give you non-stop problems. If you have ridden at constant throttle, with the TPS plugged in, you'll notice a lot of cutting out and sputtering. Yamaha builds some of the best motorcycles/ATV's in the world along with musical instruments, electronics, even a super car engine, but a properly functioning TPS sensor on the FCR carb has somehow eluded them. This is a minor problem at best. Simply unplug it, secure the ends with electrical tape and tuck/zip tie the two ends out of the way. You will not harm the bike in any way by leaving this unplugged, but will definitely notice the bike running better. I have spent some time trying to adjust the TPS and the only known remedy is an aftermarket ECU.