o ring change interval

OK did the o ring AP mod with DR.D full system on my 07 YZ450, my question is how long do the #78 o rings usually last before needing replaced? As in run hours :thumbsup:

I was told they should last a couple of years, if installed correctly. P.S. at my local Ace Hardware the oring is a number 58.

Should last a long time. Easy to replace on the bike it it does fail, a one minute job.

How do you do it in one minute?

1) Remove the cover over the throttle wheel

2) Using long smooth tipped needle nose pliers, remove the old O-Ring (if one was previously installed)

3) Install the new O-Ring, using the same pliers

4) Install the cover

Took me almost as long to type that as the change takes.

When I did mine I had to tear down the subframe and shock to get near the throttle wheel cover. Seemed too tricky to get it done from above exhaust joint :thumbsup:

Easy to replace on the bike it it does fail, a one minute job.
I'm curious as to whether you have tried this on your aluminum framed WR, or a late YZ450, or not.

Yup, I did the install the first time this way. Used a ball end allen to get the cover off. May help in that I have small hands.

Thanks I was just wandering for maint check purposes after someone said theirs kept breaking. It didnt look as if it had much strain on it to me.

I was told they should last a couple of years, if installed correctly. P.S. at my local Ace Hardware the oring is a number 58.

I think I used a 78

who all here did te O ring mod, what differences did you notice, i might be intrested in doing it on my bike

You can get a box of ten for 2 bucks. Charge five friends $2 each to oring their carbs, and get a free lunch and have spares left over.

It makes a difference, even on my 08 that supposedly has a stiffer spring from Yamaha.

William1, did you back out the AP squirt adjuster screw as much as you could or did you left it like it was?

The timing screw is the last part you tweak. You turn it to get the squirt to just miss the slide. Screwing in makes the squirt sooner, out, later. Leak jet controls volume and sensitivity of the squirt.

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