Taffy's APJ mod !

:D Well what can I say, went out to the garage tonight and made my APJ totally ajustable via the "Taffy" method, a 10p block connector on the steel rod into the pump and VOILA! how easy was this..? 20 mins from start to finnish including the carb removal and refit!, adjust on the side of the track/trail.

Taffy , you are a genius, thanks :)

so if you don't fancy drilling holes, or feel you are not capable, this is the mod for you! LOL :D


Thanks for letting us know how it worked for you. Did you time the spray or measure the stroke?

This works for the '98 and '99 models for those that may not understand.


what's the difference?

two ways of measuring the same thing but at least this way you can go by feel. i can tell you that the .024" was less than about .5 second.

i would still recommend that people jet their bikes without the APJ connected and for your final, final ride of the day pop it back on.

i did every test right up to the end searching for a bike that snapped hard when i hit the throttle.

what i got after a year of testing was a sharp, responsive bike that did double (let me just repeat that DOUBLE) the MPG of std bikes.

IMHO we only snap the throttle hard in first and second gear. go and try it if your not sure! i also felt that we go from closed throttle to 1/2, closed throttle to "over 1/2" in the first two gears then we go from "over 1/2" back to a 1/4 throttle and so forth as we go up.

we therefore only need that snap off the bottom from a closed throttle. adjusting it back we find that the bike only needs the lightest spit. i would think that .1 seconds would be fine if the pump could only operate efficiently.

also the APJ wants to be out of the jetting equation and so the less it does the more we can see what the rest of the jetting needs.


:) JD, I went for the time honoured "Squirt Duration" method (with a stopwatch) it is running at about .5 sec's now, though what I originally timed as about a .75 sec's squirt, was actually about 1 and a bit, I can only assume I had low fuel in the bowl on my original investigations!

To press I have only, bench run the bike, which as Taff will no doubt back me up on, is no substitute for real riding, the snap from a closed throttle produces less BOG and the whole thing seems crisper, but only riding will tell!

I am out for a ride on Sun , so I will report back any findings! :D

My initial impressions are that this is the perfect APJ mod for the less adventurous among us! lol :D:D

Since the Taffster likes to go for the BOLD, I am surprised he went with such a "sleeper" mod!! :)

You cannot replace that feeling of massive uneasiness you get with my "KL" mod and DRILLING into the carb!! :D

Hey Guy or Taff,

could you post some pics of the setup?

email them direct to me if you like.

mike@slickproduct.com thanks.

:) Yes it is rather a Un-adventurous mod for our Taffy, No throw your carb out and put a wet pig-bladder in ! Just nice, easy, no problems! LOL :D

In his defence...he was in a hurry! LOL :D

I had got my head round drilling holes in my carb...but I have to admit that given the choice, Taffy's no-nonsense, bolt it on/go back to stock if you want mod, wons hands down,

I admit it, I suffered from ring-nip at the thought of drilling! LOL :D:D


you're not still TALKING about doing this are you. no wonder you lot entered two wars near the end on the winning side!!

it's so easy you don't need a picture. it's a piece of piss to do.


just find the smallest block connector you can fit over the rod. slash the plastic off and fit it on and adjust via the two pinch screws.

measure the gap between the entrance for the rod into the APJ chamber and the connector. it should be about .024" or .6mm and it's an absolute sworn secret how you measure it! after all nobody will guess, will they? (started with .040", then .032"-still no idea?)

if you want to add work you can file down the screws which sit prominently. it then fits under the rubber gaitor.


there's no need to make the adjuster i mention in another post to go in the top of the black plastic rocker arm. owners will note a vertical oval hole that the "L" rod fits into. it's best pressed against the top so that the moment the rocker arm moves the rod moves.

although some say the squirt shouldn't touch the slide, i wouldn't worry. you're going to have the pump on such a short stroke that it needs to start as soon as possible so that it can be pumping cleanly at the moment you really need it.

it's that easy, it's painful. i put my full setting report on this link.



guy could you call this the TAPAS mod because it's light, quick, cheap, and fun!! :):D

the only thing it isn't is rich. just got back from madrid you see and i got really really p......



:) LOL! Tapas, yeah I like that one m8! :D

Excuse my ignorance but what is a block connector? I have a rough idea but could you please explain what it looks like and what it is normally used for. Thanks.


Originally posted by Jim Bob:

Excuse my ignorance but what is a block connector? I have a rough idea but could you please explain what it looks like and what it is normally used for. Thanks.


Right a block connector is usually used for connecting two cables together, it consists of a piece of metal tube with two threaded holes in it with two screws i these holes! cable in one end...tighten, cable in the other...tighten and VOILA! a connected cable! LOL


I used a bigger one that Taff did as it was all I had, but I cut mine in half so that only one screw was used sliped it onto the rod so that it acts as a STOP onto the APJ housing, Taffy uses his TOP SECRET method of adjusting the gap, I just used a stopwatch to time the squirt, furthe away for longer...nearer for shorter :D

Thanks Taff, Thanks Guy

I think I finally understand :)

The only other thing is you could make a video tape for guys like me, and act out the process using hand puppets LOL

I think I know where i can get a cool stainless steel connector!!!!! SAAWWW-weet!

Originally posted by ballistic:

The only other thing is you could make a video tape for guys like me, and act out the process using hand puppets.

I really think the hand puppets would help.

Kevin, Oh yes the kouba is part of the machine! :)

Well impressed with "our" purchase :D

My final spec's well








pilot screw 3/4 turns out (with Kouba)

Taffy mod to the APJ approx .5 sec squirt!

I am looking at going to the next needle as clip 6 is a bit extreme but at the mo I am delighted with the results...from a bike that went "BBWWORRRRRrrrrrrr" before it picked up, I now have a machine that picks it's wheels up in 1st, 2nd and 3rd without the cluth!

I am running a White Bros E series( surprise eh?)

with 7 discs and a quiet core to kill the noise a bit!

Clip #6 huh? Yep time for a richer needle.

Interesting note... the CRF450 runs an EKP with #175MJ. Good ol' EKP :)

:) LOL...I don't know. if I can do it, I am sure that you lot can! he he he he he! :D:D

:) Did my ride today, and what a differene the mod has made, MUCH crisper off the throttle, less stalling from a closed throttle, generally a good thing!!

I am going to adjust the squirt to be even smaller and see what that does, but very impressed so far!


What exhaust are you running AND what are your final jet specs (ALL of them!).

Is that Kouba installed yet?

bloody hell kevin are you still pratting about with your jetting? when are you going to admit first it isn't running right and secondly when are you going to walk the walk.

you certainly get paid by the word and not the deed don't you!

BTW guy

i ran my bike with the needle @DXM clip 8 and would have gone to 9 if i'd stayed with that needle.

i ran a DMM at clip 4 which is the equivelant of your DXM on clip 9.

also guy, measure the pump travel and not the squirt time. go by what's right for you and not what someone says.

the only reason people measure the duration in seconds and not travel is because a yamaha mechanic told everyone that way.

"he has removed a shoe as a sign, let us all remove one shoe". know what i mean. know what i'm saying here. (name that film)

"i was blind but now i can see; aaaaagghh!!!"


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