age old secrets?

[Shade_tree]

I have question on gearing, prolly complete guide here somewhere, but I havent found it yet, most that I have found are Honda specs. We running stock 2009 Yfz 450 R with 2 brothers slip on pipe and a power juicer box, on a short mx track, no real problems navigating track. We are using stock gearing I am pretty sure 14 tooth front and 39 rear. I like to see more speed thru track without losing any on start, rear tires are dwt 8's. Any info would be great help ty

[exrider12]

So you want more top speed without losing acceleration out of the gate. Correct?

[Shade_tree]

yea more top speed, we're working on 2nd gear leaving gate

[exrider12]

The only way I can think of more top speed while keeping your acceleration is by upping your gearing and adding more power.

Since you only have a slip on you should make it a full system, add an air filter and open air box, maybe some cam or port work. Then by adding teeth on your sprockets youll get more top speed while increasing horsepower to get you to that top speed faster.

Or decrease your rear sprocket by 2 teeth. That will add a little more top speed without killing the top end because every 3 teeth on the rear sprocket equals 1 tooth on the front. This will increase your top speed a little without sacrificing much acceleration. Id suggest trying this first then if it doesnt work try my first suggestion.

[Kovatch]

Stock gearing is 14/38. I would get a full exhaust.
-Barkers or Yosh seem to be putting down some good numbers as well as Dasa.

-Ditch that programmer box and go for either a Power Commander V (cheap and relatively simple) or the MSD Blaster. The MSD will yield 1-1.5 hp more throughout the power curve w/ timing adjustments to help squeeze every HP out. I have the PowerCommander V and it's alright, but a Vortex ECu is by far the best. The Vortex is about $600 but the bike will rev faster and adds 1 hp (after a good tune) over the MSD.

-Get an FCI intake system. Read up on it first as you need to re-route a few breather hoses that catch some people off guard. This intake is way better (hp) than anything else.

-Buy a new/use YFZ intake cam and drop it in. If you can, there are many sites that have big power packages $1300 or so for the full exhaust, programmer w/ an FCI.

After all of that spend the $100 and get it dyno tuned. It makes all the difference to have it properly tuned.

Have you ever thought about buying a set of used YFZ LT front shocks & revalving the rear shock? Handling will definitely improve your lap times. You may not have the power, but you have the handling/traction to go faster and jump farther.

It sucks that you already have some parts, but when you are on a budget you have to buy what you can afford. To win races, you have to fork it over.