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
Dnnap

2007 YZ450F Jetting with stock exhaust

3 posts in this topic

I just got a 2007 YZ450F with some engine mods, but the guy I bought it from sold it to me with the stock exhaust as opposed to the DRD he was running.

The bike has NO bottom to mid pull, so my question is would this stock exhaust be the culprit to the power loss and if I go to a DRD would this solve the problem?

The engine mods are as follows:

-Modified Head - ported and polished

-Web cams

-Carb work by Tokyo Mods

-New HC piston and rings

Carb settings:

main jet - 165 was running a 170 with DRD before I bought it.

clip position = center position

Fuel/air screw = 2 1/4 turns out

Any help or advice would be greatly appreciated.

Share this post


Link to post
Share on other sites

The pipe may not be helping you, but it isn't hurting that much, either. The cams are likely the problem. If you switch to a stock set, especially one for an '06, your low/mid power should improve.

You may want to verify that the cams are timed correctly, too.

Share this post


Link to post
Share on other sites

Thanks for your help.

Well I checked the cam timing and the markings are as per the manual at TDC. The exhaust markings at 9 and 12 o'clock and the intake at 12 and 3 o'clock.

I also checked the valves while I was there and all are in spec.

I'm new to the 450's so I'm gauging the low to mid range on my '07 YZ450F to my friends '09 YZ450F all stock, and the '09 has much more pull in the mid range, while my '07 feels like it has no mid and revs out very quick.

I'm not sure what to try first.

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