I am a goal driven person and I like to set goals for myself, so I usually pick two big goals each year. The two goals I set out for myself this year was to race the AMA Lucas Oil Pro Motocross nationals and of course the Dubya USA World Vet Championships at Glen Helen. We all know how the AMA outdoors went for me so we are moving on to Glen Helen this weekend. I chose to race two different bikes again this year at the World Vets, but wanted to have one of my race bikes fairly stock, just like your average weekend racer. Of course I chose the 2020 Yamaha YZ450F as my stock-ish race weapon, because it simply provides the most comfort and engine performance to go race in stock trim. I did manage to tweak a few things on the Yamaha and I wanted to fill you in on what you guys can do to your YZ450F. Doing these simple mods could help you check those boxes next to your yearly racing goals.
Pro Circuit Ti-6 Muffler System: The exhaust note on the Pro Circuit Ti-6 is not near as loud as the stock exhaust note as the Ti-6 has a deeper and slightly quieter pitch, which I personally like more. The power delivery is slightly smoother down low, but only on initial throttle opening. This is a good thing for the 2020 YZ450F as the smoother initial delivery will help you roll your corners better. At 0-5% throttle position there is a slightly softer RPM response, which I didn’t mind on nasty, dry, choppy tracks in Southern California. If I needed more bottom I simply ran a more aggressive map and that helped the “pop” I was looking for out of corners. I usually ran the TP 3.0 map with the Pro Circuit system and it made me happy with the amount of smooth roll on power I had. The rear wheel definitely feels more connected to my throttle hand and in comparison the PC system has more bottom end power than that of the Yoshimura system that I tested on the 2019 model. The mid-range is where I wanted more power out of the Yamaha and this is where exactly the PC system delivers. The meat of the Ti-6 power out of corners and accelerating down the next straight is much better than stock. I am able to use second and third gears longer with the PC system (compared to stock) and even though the low RPM response is slightly softer than the stock system, the mid-range RPM response is much more instant (AKA, recovery time). Mid- range RPM response is crisp and makes the Yamaha feel “lighter” when trying to hop over square edge choppy areas of the track when accelerating. Top end pulling power is as good as stock as the PC Ti-6. Another feature that I liked about the Ti-6 was that I was able to shift into fourth gear sooner on long straights and can use fourth gear longer than I could with the stock muffler. This power character that the Pro Circuit Ti-6 muffler provides is built for Glen Helen. Slippery corners, with long straights that require fourth gear.
Twin Air Power Flow Filter Kit: If you want to get rid of the somewhat janky stock air filter cage system of the YZ450F, go with the Twin Air Power Flow Filter Kit. To me the Twin Air YZ450F PowerFlow kit is the best all-around filter system for the YZ450F airbox. Why? With this kit, Twin Air replaces the stock sealing ring with an anodized aluminum mounting plate, gets rid of the backfire screen for uninterrupted airflow, adds an internal filter cage (that supports a bigger air filter), and finishes it off with a CNC-machined aluminum knob to hold the filter in place. This design brings in more air volume, increased air velocity, better sealing around the edges and better throttle response/bottom end pulling power. The downside is that some dirt particles are more prone to fall into your air boot if you’re not careful with removing a dirty filter. If you do find yourself in that situation simply get a shop vac and suck out any particles that have found its way inside the air boot. If you DO NOT open/twist your throttle after the particles have found its way inside the air boot, then nothing will get past the throttle body and you’re engine will not get any dirt inside of it. The Twin Air Power Flow Kit takes a little more patience when changing filters, but can add power to your YZ450F. Just be sure to check air boot and use suction as needed.
Mapping: With the handlebar mounted map switch I found my two favorite maps to go between while racing. I use the “Exciting Power Character” map in the morning hours while the track is fresh and the “TP 3.0” map in the afternoon when it’s drier and beat up.
Stock Suspension Setting: Since Glen Helen gets abnormally more choppy on “Vet Weekend” I try to stick with softer suspension for comfort, so I am sticking with the stock suspension. Bumps form differently when more older/slower riders are on the track so having a softer setting could make your second moto way more comfortable than having a stiffer set up. Glen Helen doesn’t have huge jumps nor does it get ripped very deep for vet weekend so we rebuilt/freshened the stock suspension and are using these settings:
Compression: 10 clicks out
Rebound: 9 clicks out
Low Speed Compression: 10 clicks out
High Speed Compression: 1 turn out
Rebound: 9 clicks out
Tall Seat: Once the stock YZ450F foam is broken down (around 15 engine hours) it can feel like you’re riding in the bike too much instead of on top of it and that can make the rider triangle feel uncomfortable for riders 5’11 and up. Installing the GYTR taller seat helped with the rider triangle feel for me when sitting. The seat wasn’t so tall through the middle where I felt like I was too high above the machine, but instead had a firmer feel than stock and enough height to help my form on the bike. I am fan of the Yamaha stock bar bend, but with the stock seat it can almost make the bar bend seem too high at times because of that pocket feel. With the taller seat it puts me into a more neutral/attack position coming into corners, which forces my arms to stay bent, instead of dropping down and relaxing too much.The transition from sitting to standing is better and requires less effort under throttle. Seat bouncing is needed at times, but when you’re taller (and old), it’s tough to get off your ass to soak up a jump immediately out of a corner. Having just that little bit of extra foam in the middle of the seat makes it easier for me to get off my ass because I don’t have so far to travel to stand. Yes, 3/4 of an inch doesn’t seem like a lot, but it actually makes a difference. In fact I think a 1/2 an inch would have been enough, but I am not hating on the flatter profile of the 3/4 inch height. I had a couple other testers try this seat that were shorter than me (5’9-5’10) and they even thought it was better for them. The gripper cover that comes stock on the GYTR tall seat is as good as the stock seat, but if it was me, I would be looking into getting a GUTS ribbed cover for increased traction while rolling the throttle on out of corners. GUTS seat covers are made well and last.
Gearing = Stock 13/49
Grips = Stock (Yes, stock grips!)
Tires = Dunlop MX53 front tire/Dunlop MX33 rear tire
Fuel: VP MR Pro-6