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
KAWBOYBILL

04 WR450 Carb Tuning

24 posts in this topic

Anybody used one of the aftermarket Quickshot accelerator pump covers with any succcess ?

Share this post


Link to post
Share on other sites

Not needed. Do the oring mod or the stiffer Merge Racing AP cam spring. Then check/set the AP timing. Then select the corrst size leak jet. However, some do replace the AP cover the an Adjustable Leak jet to save them the hassel of swapping leak jets.

Share this post


Link to post
Share on other sites
Anybody used one of the aftermarket Quickshot accelerator pump covers with any succcess ?

Yes. But not that brand.

I did all the mods: JD Jet kit, stiffer AP return spring, Stiffer AP pump spring, 35 leak jet. After adding the R&D powerbowl and power pump cover (with adjustable leak jet) I noticed a significant increase in throttle response off idle, and going down hill.

Now it feels like fuel injection....

Share this post


Link to post
Share on other sites
Not needed. Do the oring mod or the stiffer Merge Racing AP cam spring. Then check/set the AP timing. Then select the corrst size leak jet. However, some do replace the AP cover the an Adjustable Leak jet to save them the hassel of swapping leak jets.

I bought an 04 also and about to tear into the carb.

Why would I need a stiffer AP spring and what is the O ring mod?

How do you set the squirt timing?

Share this post


Link to post
Share on other sites

How does the snorkel come out, does it pull out or are there screws somewhere?

DSCN8557.jpg

Are these the two areas you cut on the air box?

DSCN8558.jpg

Share this post


Link to post
Share on other sites
I bought an 04 also and about to tear into the carb.

Why would I need a stiffer AP spring and what is the O ring mod?

How do you set the squirt timing?

Either the oring or the spring, the spring is longer lasting. You need/want it to provide a more positive response from the AP.

You look in the carb throat, engine off, and nail the throttle, confoirm the squirt just misses the slide. Read this thread about the O-Ring Mod and AP Tuning

How does the snorkel come out, does it pull out or are there screws somewhere?

DSCN8557.jpg

Are these the two areas you cut on the air box?

DSCN8558.jpg

It pulls out, not sure if the plate also comes out.

And yes, those areas you cut out.

I assume you have a jetting kit and have done the grey wire and the throttle stop already.

Share this post


Link to post
Share on other sites

No jetting kit, I will be buying leak, pilot and main jets.

Want to save the dollars from the JD kit. Can I use the 04 YZ needle jet, is the needle jet the same but has grooves for adjustment?

Grey wire will be done today.

Share this post


Link to post
Share on other sites

Where do I run the breather tube at in the air box? From my understanding the 04 has no AIS

Share this post


Link to post
Share on other sites
No jetting kit, I will be buying leak, pilot and main jets.

Want to save the dollars from the JD kit. Can I use the 04 YZ needle jet, is the needle jet the same but has grooves for adjustment?

Grey wire will be done today.

Still would be better off with the JD kit, trust me.

How about the throttle stop??

Where do I run the breather tube at in the air box? From my understanding the 04 has no AIS

What breather are you referring too? Crankcase?? Correct, you do not have an AIS.

Share this post


Link to post
Share on other sites

Yes the breather tube from the crankcase that comes out of the top of the heads. I read were others are rerouting or add a "T" for starts in water.

Thanks for your help William, so you think I really need the JD kit :excuseme: , hmmm, on my WR250F I rejetted w/o the needle and was fine so I was thinking I could do the same here OR add the YZ needle IF it had the slots cut to adjust, you are saying this thinking is incorrect? I am in Dallas at about 500 ft. above.

Share this post


Link to post
Share on other sites

JD kits typically include two needles, five or so mains, a couple of pilots, a leak jet or two, some AP orings. But all kits are different as they are taylor made for each bike.

Share this post


Link to post
Share on other sites

Don't need a JD or DJ. both are too expensive and you only use a couple of parts from the kit.

Share this post


Link to post
Share on other sites
No leak jets in the Dyno Jet kit we bought.

...and that is one of the reasons, no one reccomends a DynoJet kit. James Dean is the only one worth buying.

Share this post


Link to post
Share on other sites

If I have my old on in the garage I can tell you, I tried the smallest 35 or 40? didn't work, soldiered mine shut, that helped a bunch.

Found it, mine was a 60 and I tried a 40.

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