engine mods?

might be doing a top and bottom end rebuild soon on my 99 yz400f. when its apart i plan on doin some mods. what are some of the best mods out there for power and price. i'd want to keep running pump gas.

Shane if you are doing your own work, and have the ability, buy a set of Falicon adjustable cam sprokets, and set your LC's to 105. If you are using a 450 type auto cam you'll only use the Falicon stuff on the intake. Engine wise, after jetting and carb work cam timing is an easy cheap gain.

I would recommend if replacing a crank to update to an 01 crank and gear to eliminate the key issues on the CB gear.


Sorry about the crank comment, I hadn't yet read your other post, but it is the truth.

got a link to falcon pmk?

cool thanks. I wonder if the adapter will press onto a hotcams intake cam.

The Hot Cams for the YZ250F, and YZ400/426, already have adjustable intake sprockets. :cry:

But not for the 450's, as best I can tell in the online catalog. If you do I would definitely appreciate the info on it.

I already have both the exhaust and intake cams on both 04yz250f's. They are a huge improvement over the stock cams. :cry:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By faizakhtar125
      Hey guys I just bought a bike last night. So the seller said the bike will turn on but then die. We didn't try it because it was really late at night and it was raining (seat was wet). But he said if you bump start it, it will turn on and ride. So what do you think the problem is? I just want to make sure it runs... I probably won't be able to bump start it till Saturday (rain)... It's a four stroke, and I know absolutely nothing about them. Thanks.
    • By dpenn1
      I could use some feedback, My son is getting into off road riding so I have starting getting back into it as well.  We mostly do trail riding but did some MX track riding last year and he loved it andso did I.  I have a 2003 TTR 225, it's nice that it has an electric start but the suspension is too soft and it doesn't have enough power for my liking.  When I was riding the MX track I was having issues bottoming out on the larger jumps.  I want to change to a more off-road capable bike.   I won't ride it much and don't want to spend a lot of money, I think I prefer a 2 stroke, when I was younger, in 1990, I raced an 89 RM250 and loved it.  I am looking at a 96 RMX 250  and a 98 YZ400F, both bikes look to be in good condition and around a thousand dollars.  I like the RMX because I think kicking a 2 stroke 250 should be easier than a 4 stroke 400 and the simplicity of the 2 stroke engine.  The 400 sounds good because of the low end torque I assume it has but the cost of rebuilding the 4 stroke if needed worries me and I have heard they are hard to start. Should the RMX be decent for an occasional trip to an MX park?  Any thoughts on these two bikes? 
    • By yz480doinwork
      Brand new, still in the packaging Lexx end cap fits the stock muffler of 2006 & 2007 YZ450f and 06-13 YZ250f. Comes with a forest service approved spark arrestor and two different size tips. Don't spend hundreds of dollars on a slip on, this tip can be quiet and forest legal or loud and make power! Also a note for WR450 guys: get this tip and find a used 06/07 YZ muffler, fits directly on 09-15 WR450. $80 shipped free to the lower 48. PM, call or text 406-223-8789
    • By Woody Oakson
      So I have a 2008 yz450f and I would like to add some LED lights to it to make it street legal. Mainly just a headlight and a tail light and turn signals if I need to (which where I live hand signals work).
      So where I need help is getting power from the stator to a battery. Wiring from a battery to anything else I got and understand and don't need help with (but recommendations are welcome). So my questions are.
      What type of power is coming from the stator. AC or DC? Will I need a regulator or rectifier? How do I wire something from the stator to charge a battery? What would that wiring look like? Would this stator http://www.rickystator.com/product/stators/yamaha/yamaha-yz450f-35-watt-lighting-stator-assembly-06-09 work? Anything else I should know? Any help would be appreciated. Thank you.