YZ400F for tails?

I have a mint condition yz400f and Im looking to make it into a more trail oriented bike. What are some first things to do to the bike to make it more trail friendly? I have been riding a 1999 cr 250 most of the summer while my bike is being worked on. I live at 8000ft so Im getting the jetting issues worked out of the 400. Will the yz400f be a better bike for trails? I have gotten use to the power and ease of the cr. will the YZ be a huge difference?

Any help would be awesome!



oh yea its a 1999

I went with a 12oz flywheel weight and absolutely love it. I can lug it down or ride the crap out of it. Easier to start and much funner on the trails now.

That sounds nice. How much does a new fly wheel run? Is this a major overhaul?

They run around $120 and it takes all of 15-20 minutes to install one if it's a prefabbed complete weighted flywheel. If it's a add-on weight that needs to be mounted to the existing flywheel, it takes a little longer.

Who makes a 12oz fly wheel weight for the 400? Im only finding ones for 450's.

Google "Steahly flywheel" and see if you can find a contact for them. Not 100% certain, but a 426 flywheel may work.

Who makes a 12oz fly wheel weight for the 400? Im only finding ones for 450's.

Looks like STEAHLY makes a 6 or 10oz FWW for the 400. I'm sure the 10 would do what you are looking for.

I also used to have a '99 CR250,I ride lots of trails and I recently scored a '99 YZ400f.In my opinion the YZ feels like it has more TQ and the power delivery is smoother.It doesn't seem so "all or nothing" like the CR250.After owning my first four stroke dirt bike I wont be switching back,unless of coarse I some day end up with the aluminum frame CR500 I've always wanted.

fly wheel weight, auto decomp exhaust camshaft, side stand, larger tank, o-ring chain, auto clutch, gearing, soften suspension, hand guards, more comfortable seat foam.

that's what i would do to my 400 to make it into a strictly woods weapon.

If you choose to go with a Steahly we can get that for you. As already recommended, I agree a kick stand, hand guards and lower gearing a must. Once you have some ideas of which brands you are interested, or if you would like more suggestions, you are welcome to give us a call and we can make ordering easy! :)

That sounds great. What is your price for the Steahly weight?

TNE, according to Steahly, they are out of stock on the 10oz. leaving the 6oz. as the only option at this time. Take a look at their page:


I have been warned its a "tricky install" requiring drilling and tapping, the tools are included but im not sure what your skill level is, or if you are interested in attempting it! =)

They are having issues with the current supplier for the 10oz. meaning they will most likely just discontinue it. =(

Hey think I'll order one.

I've had my '99 for over 10 years now and am looking to do

some fun mods just for the sake of trying something new. What effect would a 6 oz. have on the power delivery ? The bike has the 420 Wiseco kit.

and I do 50/50 trails / mx track. If it keeps it from stallling in tight woods then it would be a plus. Also can it be removed again without damaging anything ? I have no problem with install, am a machinist by trade.

Any weight added to the flywheel is going to help stalling issues. 6 oz. isnt a huge amount but anything is better than nothing! I have not done the install but from what they told me its just drilling and taping a few mount holes so that should not be "irreversible". You would just end up with some tapped holes with nothing in them.

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