O-ring carb mod ????

[Summit]

I keep reading about this mod but I can't seem to find a detailed explanation or pics to describe it. Can anyone steer me in the right direction for more information? Thanks.

[KennyMc]

https://www.thumpertalk.com/forum/showthread.php?t=604077

Here is a picture of it. It's the o-ring right above the spring with the blue on it.

[byggd]

I'm trying to remember. Does this mod apply to pre 03?

[GCannon]

I'm trying to remember. Does this mod apply to pre 03?

I think not (however I could be wrong)

WR 400 = taffy mod

WR 426/400 = BK Mod

WR 450 = Leak jet, Oring mod, diaphram change

I think this is how they apply

[byggd]

I think not (however I could be wrong)

WR 400 = taffy mod

WR 426/400 = BK Mod

WR 450 = Leak jet, Oring mod, diaphram change

I think this is how they apply

Thanks! Already did the BK mod so I guess it's good to go

[GCannon]

Thanks! Already did the BK mod so I guess it's good to go ?

You already new that!

[crooks420]

So do I assume correctly that the o-ring mod will apply to my 05 WR450??? Who has done this, and how do you like it?

Jesse

[Summit]

So do I assume correctly that the o-ring mod will apply to my 05 WR450???

I'm wondering about this too. Anyone??

[Pooley]

Another O-ring mod discussion. In this thread there is also the direct link to Redbeard's pdf

https://www.thumpertalk.com/forum/showthread.php?t=521725

For my 01WR426, O-ring mod was FAR superior to the BK mod, which is now disabled.

[beezer]

I noticed in the Dirt Bike article on the the 08 WR450 Dr. D. turned the accel pump screw in half a turn.

A buddy tried it on his and said it made his bike have much better throttle response.

I don't know what the screw does to be honest.

[MotoGoalie]

I noticed in the Dirt Bike article on the the 08 WR450 Dr. D. turned the accel pump screw in half a turn.

A buddy tried it on his and said it made his bike have much better throttle response.

I don't know what the screw does to be honest.

It times (sets) when the accellerator pump gives the squirt of gas as the throttle is opened up.

If you take the carb off and twist the throttle, it shoots a stream of gas, right into your eye and then you erupt into a ball of flame.

[GCannon]

Pooley:

what was the differnce in performance between the BK mod and the Oring mod? It sounded like you made significant jetting changes after the oring mod.

I may not be understanding correctly (supriseing I know) the oring mod as Readbeard describes it makes the AP squirt duration longer then uses the leak jet to reduce the AP squirt volume? How do you reduce the squirt volume on the 01 WR? or do you adjust the jetting to compensate?

How do you adjust the AP squirt timing with the Oring mod same as the BK Mod, in particular the initial squirt timing?

Thanks

[beezer]

If you take the carb off and twist the throttle, it shoots a stream of gas, right into your eye and then you erupt into a ball of flame.

I guess to make this work I should be smoking a stogie when I do this.

I think the o-ring does the same thing as the stiffer spring that comes with the R & D Powerbowl.

The JD kit I had came with two o-rings a skinny one and a fat one.

The directions said the fat one gave it better throttle repsonse then the skinny one.

[yz-dwg]

The JD kit I had came with two o-rings a skinny one and a fat one.

QUOTE]

I used the skinny one and like what it did to my throttle responce.

[byggd]

Another O-ring mod discussion. In this thread there is also the direct link to Redbeard's pdf

https://www.thumpertalk.com/forum/showthread.php?t=521725

For my 01WR426, O-ring mod was FAR superior to the BK mod, which is now disabled.

I think not (however I could be wrong)

WR 400 = taffy mod

WR 426/400 = BK Mod

WR 450 = Leak jet, Oring mod, diaphram change

I think this is how they apply

Q: Is a JD Jetting Kit worth it/what does it do?

A: The JD Jetting Kit contains two triple-tapered needles that are bike specific and give you a year-round solution to the WR’s jetting needs. The kit also contains an assortment of main jets and several O-rings to modify your AP linkage on the '03's and up for better throttle response.

Wait, so the o-ring mod does apply to the wr426 as well

[bg10459]

Wait, so the o-ring mod does apply to the wr426 as well

I believe so, however, without a leak jet you won't be able to bleed the additional pressure the o-ring will create at the AP nozzle.

I'm pretty well versed in the O-ring mod, but not with the older WR's, so I cold be totally wrong.?

[bg10459]

How do you adjust the AP squirt timing with the Oring mod same as the BK Mod, in particular the initial squirt timing?

The AP timing screw still dictates the start of the squirt, no matter which mod you do.

[Pooley]

Pooley:

what was the differnce in performance between the BK mod and the Oring mod? It sounded like you made significant jetting changes after the oring mod.

I may not be understanding correctly (supriseing I know) the oring mod as Readbeard describes it makes the AP squirt duration longer then uses the leak jet to reduce the AP squirt volume? How do you reduce the squirt volume on the 01 WR? or do you adjust the jetting to compensate?

How do you adjust the AP squirt timing with the Oring mod same as the BK Mod, in particular the initial squirt timing?

Thanks

The difference in performance was huge. Instead of goofing around trying to time the squirt perfectly like I had been (BK mod), the O-ring mod basically squirts all the time whenever the throttle is opened. Maybe I had my squirt WAY off, but the bike was closer to an open pipe feel with the O-ring. VERY responsive and much less bogging/stalling at low RPM. I was a happy customer about 30 seconds after starting the bike.

As far as jetting "changes", I actually only changed my pilot from a 42 to 45. I just switched pilot and mods and went for it. There is no leak jet to adjust, however I believe we could get a different diaphragm or spring to adjust the pressure. I didn't change a thing with the diaphragm.

The initial squirt timing, such that it just misses the slide I had set previously, and did not adjust it at all. I never re-checked, but would assume it still just barely misses the slide. That screw is NOT removed, and is still in the same place, its the one you wrap the o-ring around.

[crazycarl7]

i have a 2005 yz 250f. So, if I do the oring mod, I dont necessarily have to mess with my leak jet? or do I need to change. Also, my stock pilot jet isa 42, should I go to 45?