2000 YZ426 AP Mod done

So I did the AP mod to my 2000 426 yesterday and went riding today to test it and only one word is neede to describe it, WOW!!!:lol::eek:

Talk about a night and day difference. No more bog or hesitation off idle.

Many thanks to Red Beard.

Couple of points for the 426 owners doing this.

1- No leak jet was found accessible in my carb so I disregarded this step.

2- The rivet on my diapragm was only 3mm (vs 4mm). So I went ahead and used a dremel and took it down to 2mm.

Only two differences I found. Other than those two, the instructions were clear, concise, exact, and well detailed.

Again, thanks to Red Beard.:lol:

BTW- I already had the Boyessen quick shot and still had bog until I did this mod.......:applause:

So I did the AP mod to my 2000 426 yesterday and went riding today to test it and only one word is neede to describe it, WOW!!!:lol::eek:

Talk about a night and day difference. No more bog or hesitation off idle.

Many thanks to Red Beard.

Couple of points for the 426 owners doing this.

1- No leak jet was found accessible in my carb so I disregarded this step.

2- The rivet on my diapragm was only 3mm (vs 4mm). So I went ahead and used a dremel and took it down to 2mm.

Only two differences I found. Other than those two, the instructions were clear, concise, exact, and well detailed.

Again, thanks to Red Beard.:lol:

BTW- I already had the Boyessen quick shot and still had bog until I did this mod.......:applause:

When I did this mod on my 06, I felt no noticable improvements so I went back to stock. I followed the instructions and even changed leak jets, but didn't feel anything. Kinda disapointed, but maybe the ZipTy mod will help. Not sure.

I definately felt a difference. Mostly the fact that there is no hesitation now.

I am still considering the Zip Ty mod as it is supposed to actually increase hp (albeit only 1-1.5hp).

I am still considering the Zip Ty mod as it is supposed to actually increase hp (albeit only 1-1.5hp).
Only? :applause: People pay $900 for exhaust systems that don't do any more than that. In fact, I challenge you to name one other mod you can make to the bike that will get you 1.5 hp for $100.
Only? :applause: People pay $900 for exhaust systems that don't do any more than that. In fact, I challenge you to name one other mod you can make to the bike that will get you 1.5 hp for $100.

i heard a good airfilter over stock will give about 1-2 hp over stock. some on here dyno'd there bike with a stock air filter, uni or twin-air and got like 1-2 hp. and then they used no airfilter and it made close to nothing more then with a uni or twin air(whatever they used)

i heard a good airfilter over stock will give about 1-2 hp over stock. some on here dyno'd there bike with a stock air filter, uni or twin-air and got like 1-2 hp.
I'm not buying that, sorry. You'll have to show me the test.

The stock YZF element is nowhere near that bad, and in fact, except for its relatively poor durability, it's better than some aftermarket stuff. If the filter were that restrictive, replacing it would require re-jetting.

Only? :applause: People pay $900 for exhaust systems that don't do any more than that. In fact, I challenge you to name one other mod you can make to the bike that will get you 1.5 hp for $100.

Oops...what did I start.

Oops...what did I start.
:lol::eek::lol:

:naughty::lol::worthy::applause:

There is a noticeable difference on any bike if the AP is tuned correctly. If someone doesn't feel it then perhaps they have too many calluses and/or they did something incorrectly. I've never done the mod to anyone's bike and not had them first admit to realizing a huge improvement and/or complaining about new found arm pump.

It does work, but some folks just don't feel things like others. I can feel the difference between a plastic valve stem cap and a metal one, no kidding. While some folks couldn't tell if I turned their suspension clickers every which way from Sunday.

Personally I'd rather be part of the latter group for less brain damage, but alas, I've been cursed with sensitive receptors and will be forced to jack with crap until the end of my days! :applause:

I'm not buying that, sorry. You'll have to show me the test.

The stock YZF element is nowhere near that bad, and in fact, except for its relatively poor durability, it's better than some aftermarket stuff. If the filter were that restrictive, replacing it would require re-jetting.

im not trying to convince anybody that it does. i was just stating the fact that i read on here that someone did some tests and i would show you but i forget where i read it. it does sound like bullsh** now that i think about it. i forget if he showed the dyno chart or not.

So I did the AP mod to my 2000 426 yesterday and went riding today to test it and only one word is neede to describe it, WOW!!!:eek::naughty:

Talk about a night and day difference. No more bog or hesitation off idle.

Many thanks to Red Beard.

Couple of points for the 426 owners doing this.

1- No leak jet was found accessible in my carb so I disregarded this step.

2- The rivet on my diapragm was only 3mm (vs 4mm). So I went ahead and used a dremel and took it down to 2mm.

Only two differences I found. Other than those two, the instructions were clear, concise, exact, and well detailed.

Again, thanks to Red Beard.:lol:

BTW- I already had the Boyessen quick shot and still had bog until I did this mod.......:applause:

what is this mod and where can i find instructions? thanks :lol:

So you did this instead of the BK mod, I am not sure if one is better then the other or if they both work in the same principle, I could use a little help understanding.

edit: I have a 2001 YZ426 & am considering one of these mods even though I do not have a bog.

So you did this instead of the BK mod, I am not sure if one is better then the other or if they both work in the same principle, I could use a little help understanding.

edit: I have a 2001 YZ426 & am considering one of these mods even though I do not have a bog.

The BK mod shortens duration, but that can also be done by simply installing a diaphragm with a longer rivet. The BK mod is outdated. The AP mod increases squirt response.

I did the BK mod before finding out about the AP mod. Forget about the BK and do the AP. You will notice a huge improvement.

BTW- I am sending my carb to Zip Ty in a couple weeks...

I'm not buying that, sorry. You'll have to show me the test.

The stock YZF element is nowhere near that bad, and in fact, except for its relatively poor durability, it's better than some aftermarket stuff. If the filter were that restrictive, replacing it would require re-jetting.

http://www.thumpertalk.com/forum/showthread.php?t=442434&page=3

on a yz250 it gave 1 hp as he said and he has some charts

One hp is different than 1-2 , and it's on a two-stroke. Different dynamics. Interesting, though.

we still friends though, right?:applause:

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