HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
dmoney1074

Autodecomp. cam in a 99 yz400?????

11 posts in this topic

I already read the sticky, and it says the 450 cam applies to the 400/426 model... but then it goes on to say that it works on 2000 steel valved , and 2001-2002 titanium valved heads. What about the 99? Is there something different that wont allow for the 450 cam?

Thanks all?

Share this post


Link to post
Share on other sites

Yes, it works on YZ400's as well. There are also after market cams for YZ426 engines with auto decomp built into them. These will also work in a YZ400.

There are 3 principal differences between the AM and OEM cams:

> The OEM cam costs less. You can find them at TT OEM Parts and elsewhere for about $110

> The grind. The OEM 450 cam works very well with the original intake cam, producing what most describe as a wide, smooth, strong power curve. The AM cams will also work with the stock intake, but are often better in pairs.

> Timing procedure. AM cams for the 426 drop in and time just like the stock one. To use the OEM 450 cam, you have to get the intake cam timed first, and time the exhaust off of that. Not difficult, not even really tricky, just different.

Share this post


Link to post
Share on other sites

Thanks gray... I actually did the OE 450 cam on my old wr426, so I know all about timing it. I just needed to know whether or not it would work on the 400....

I just recently bought a yz250 after selling the 426, and i really regret it now. I HATE the yz for the type of riding I do... so I had a guy that was looking at my 250 offer me his yz400f plus like $500-600. It was supposedly fully rebuilt from the bottom up.... but you never know right?

Is there a big difference in the feel of the 400 when compared to the 426 (mine was a wr)? I LOVED my old 426....

One other question, besides the ss valves, and the bore size, is there any differences between the 400 and 426 motor?

Thanks!!!!!!!

Share this post


Link to post
Share on other sites

IMO I doubt you would notice a differance between a 426 to 400

Maybe a 400 to 450

I wished they made a bigger bore kit for the 426/400 20CC bigger Not even worth the time or money

Share this post


Link to post
Share on other sites
Not unless you change the crank. The 426 has a larger wrist pin.

And as for the feel between the 426 and 400? Any discernible difference?

Thanks for the help! :thumbsup:

Share this post


Link to post
Share on other sites

I haven't ridden that many 400's, and it was a while ago, but the YZ426 is stronger and lighter than the 400, probably enough of both to be noticeable.

Share this post


Link to post
Share on other sites

Okay thanks GRay... Im gonna consider trading for the 400 just because it will be more capable on the trail than my FIERCE yz250.... that damn thing needs to be on a track!

One more question.... I have a spare set of wheels for the 01 yz250... will they work on the 400? I thought I read somewhere the hubs are compatable from 97-02... but just to make sure?

Share this post


Link to post
Share on other sites

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
Sign in to follow this  
Followers 0