AP Mod tonight

[StPeters21]

Alright.... I went out and bought a 65 and a 70 leak jet. I bought a NFLR (or a NLFR) needle, anyway the '07 one. I have my handy wire available. Any other things that you all can think of that I could use or watch out for????

Thanks Chad

[dwnlowx]

what year is your bike

[Baron Von Beard]

Before you wire it up, set the AP initial timing and then sheck for a gap at WOT. Hold the throttle wide open and see if the black plastic link touches the screw. If it doesn't you need to shorten the rivet. If that is the case and you aren't sure about it, shoot me a PM.

[StPeters21]

Hey Baron,

I got everything done except the leak jet. I shortened the rivit and and wired it up. Changed the needle, pilot, and main jet. My question is why do you suggest a leaner leak jeat when everything else is richer??? The bike runs incredable right now. 50 pilot/ 168 main/ nflr needle. There is no bog or hesitation right now. And the bike revs much much quicker now. Its great.

Thanks Chad

BTW, my bike is an '06

[grayracer513]

What you are defeating by the use of the wire is the spring in the linkage that limits the pressure applied to the fuel in the pump. The principal of the mod is to initiate the pump squirt sooner, and also to have it end as soon as you stop opening the throttle. Without the larger leak jet, the modified pump would deliver too much fuel, and you'd have a too-rich condition, resulting in a bog again.

[StPeters21]

What you are defeating by the use of the wire is the spring in the linkage that limits the pressure applied to the fuel in the pump. The principal of the mod is to initiate the pump squirt sooner, and also to have it end as soon as you stop opening the throttle. Without the larger leak jet, the modified pump would deliver too much fuel, and you'd have a too-rich condition, resulting in a bog again.

A #70 leak jet is leaner than a stock #55. The whole leak jet thing has got me really confused. I understand the concept, but why would you lean out the leak jet???? I don't have any bog right now. But I might as the weather gets warmer.

Chad

[grayracer513]

I think I just told you. Here's what von Beard said:

I find that the pilot is too lean, the AP squirt is too long and squirts too much fuel and the main jet is too rich...

When you wire the pump linkage, the duration of the squirt will become shorter, but the volume will not be reduced, just delivered in a shorter period of time. The way to reduce the excessive pump delivery volume with a wired linkage is to increase the leak jet size.

[StPeters21]

Thats my thought. So why do you suggest I put a #70 in whenever it is a leaner jet.

Thats why I'm confused...

[grayracer513]

Once again, the #70 leak jet, which is leaner because it's larger, and therefore leaks off more of the fuel, is necessary to make the excessively rich pump shot leaner.

[grayracer513]

If you're still scratching your head, read this:

https://www.thumpertalk.com/forum/showthread.php?p=4415330#post4415330

[StPeters21]

AHHHHHHH. If you beat a horse he will finally get it. Thank You, I think that explanation finally made me get it.

Thanks Chad.

P.S. My bike is running great now. Should I go ahead and switch out the leak jet???

[grayracer513]

Baron has spent a lot of time with this mod on the '06 YZ450. It's always best to start out with such mods by following the instructions and doing the mod in the same exact way that it was done originally. That way, you can reasonably expect results similar to what the Baron got. If you want to tinker with it from there, then have at it, but when you're exploring new territory, it's a good idea to start from a known waypoint.

If you do less than all of the same steps than he did, you may get a different result. and not be able to sort out why. Try it his way first.

[StPeters21]

I'm sorry, I didn't explain. I already did the mod last night without changing the leak jet and ran it last night. It runs perfectly now (almost too good for me). Could it run better with changing the leak jet?????? Should I try the #65 or the #70??? Since it has no hesitation or bog with the #55 after the other mods.

[grayracer513]

That's up to you.

[SXP]

I'm sorry, I didn't explain. I already did the mod last night without changing the leak jet and ran it last night. It runs perfectly now (almost too good for me). Could it run better with changing the leak jet?????? Should I try the #65 or the #70??? Since it has no hesitation or bog with the #55 after the other mods.

You just don't want to open that damn thing up again, do you:busted: And, I can't say I blame you either.

[StPeters21]

Not really. but, if it could help as much as the other mods did the OHHH YEAH!!!!! I'm wondering if I'm gonna be able to hold onto this thing.........

[Baron Von Beard]

I say it needs the larger leak jet for a reason. I have tested and come to the conclusion that the larger leak jet helps. If it didn't I would say it.

Put the jet in, it will get better. I have had folks that aren't up to the task so I have richened the shot with a smaller leak jet so give less snap, but that's up to the rider.

BTW - Gray is the man for helping out while I'm busy at work. Thanks Dood!