The YFZ 450 is a performance quad that's plugged up.
The airfilter is suffocating, the exhaust pipe is a boat anchor with a tiny hole drilled in it, no performance physics.

This is done by Yamaha to pass emissions. Easily reversable.

Simple performance silencer and jetting really brings out the power,,

I'm unleashing two YFZ 450's and it's been an adventure.

I found once you do your homework, the cheapest place to buy parts is Rockymountainatv.com.

I call the manufacturer first, find out what the part numbers are, or anything else I should know about their products that may not be on the website, or known by who I'm buying from.

I bought Sand Star Paddles on ITP C series from Rocky Mountain for about $50 per set cheaper than I could find them anywhere else. Free delivery and no salestax. Great return policy.
Multiplied times two quads =$100 bucks saved.

Yoshi stainless silencer $299 each delivered to my doorstep. That's a bargain if you've shopped Yoshi pipes.

The one scam I've discovered at Yamaha dealers is that they like to treat quad owners as "Recreational Riders", and can pull rip offs that MX riders would never stand for.

Stuff like sell you a whole set of jets you'll never use, so you can get two outta the set ya need.

Ya gotta watch the Yamaha dealers. They don't like to sell single jets or the YZ carb needle to a quad rider if they can lead you astray and sell ya extra stuff ya don't need.

They'd never get away with that crap with MX riders, and they know it.

Glad I bought the Yami. fun to ride, easy to bring out the ponies,,,

I'm sorry to hear that you have an issue with Yamaha Dealer(s). I kinda have to take issue with you about the generic statement, as I'm a Yamaha dealer and we don't treat customers this way.

While there are many jet kits available, we sell two. The GYT-R and the Pro Tec. Until recently, the GYT-R kit was produced in Japan. Both kits sell for about $ 50.00.

Stock Keihin FCR needles run, as a guess at this time, about $ 10.00 - $ 15.00 each. Hi speed jets run about $ 5.00 each. Slow jets run about the same. Each kit gives you 4 - 6 jets.

Considering there are about 10 different needles available, which have a direct influence on which hi speed jets one would use, and the time to test both on the dyno and "ride-a-bility" of the jet kits, I think they are a bargain at $ 50.00. One is paying for a mostly proven combination.

If you are looking for some advice on "powering up" your YFZ, allow me to give you some options.

Stay away from K&N filters. The flow air better than an foam filter, but they also flow more dirt and sand. Since the carb on you machine is complex, very expensive
($ 800.00 - $1000.00 if memory serves), and does not like dirt of any kind, one needs to look at the performance gains vs. the possible problems.

Public land pipes (96 dBA) for California use won't produce the peak HP of others, but the power is close. We sell and have great success with both the GYT-R and the Pro Circuit 496. Our experience and feedback from customers has been excellent.

Perhaps dollar per dollar, the best gain is to retard the exhaust cam. This adds substantial HP and coupled with the above mods, this quad rips.

Yamaha offers a forged hi compression piston and gasket kit for a reasonable price. We have not had anyone test this yet, so I cannot speak to the benefits of the same.

Be very careful about head and valve train mods. A good friend of mine works for a major NASCAR operation as a cylinder head specialist. He and his colleagues have looked very closely at the YZ and WR 400, 426 and 450 head. The flow of the head (stock) is, according to these folks, outstanding. One might do some small valve train work, but the durability of the same goes in the tank quickly.

If you need any advice or parts that you are having difficulty getting from your dealer, please PM me and I'll see what I can do to help.

Just today, I called every Yamaha dealer in the LA City and Ventura county areas and not one had single jets for sale. Not one.

Ya buy the whole GYT kit, or nothing. I got stiffed by them all. So ya get the 2 jets ya need and the YZ needle for 50 bucks, what should cost 22 bucks.

Most never heard of the ZIP TYE mixture screw which has become essential for proper YFZ 450 jetting/tuning.

OK, so I get some small jets in the GYT kit I don't or won't ever need and pay for them.

I appreciate your help in finding the jets. The YFZ must be rejetted 45 pilot/165- main 2 turns on the airscrew- 3rd YZ clip if ya add a pipe. Should be done even if ya don't pipe because the engine is super lean.

If ya don't re-jet the YFZ450, you're asking for a trip to the shop with a seized engine. And like the early Raptor tranny problem, get refused warranty coverage from the Yami Dealer.

The internet postings from owners who've gone through this has made this transparent.

If ya have the hesitation problem, go to a 48 pilot which usually cures it,, if not consider the power valve, which most always cures it.

The GYT pipes? Well, the last one I bought, last month, the insides blew out in about 20 minutes running time. I pointed this out to other GYT pipe owners at comp hill. They said: "Mine didn't !!!" Then I show them how it in fact did, and they said:" Gee I thought it was getting louder, damn,, that sucks!!"

I leaned on the YAMI parts manager and he finally admitted it's a known problem, and refunded my money. Sorry, the GYT pipe is POS, and I question Yamaha still selling them in full knowledge that they disintrigrate.

But my findings on the "Recreational Rider" label Yamaha parts managers have stuck on quad buyers I have to stand by. I imagine the Yamaha parts rep has spread that scam around and perhaps thats how this cancer started. I've heard it from too many of them.

Glad to read you're not one of them.