accel pump mod for drz question

6 replies to this topic
  • yeagermiester

Posted January 11, 2002 - 06:30 PM


would pinching the two tabs together limit how much fuel the pump draws in? and in turn would this limit how much fuel the pump sprays out?

basically rather than limiting the time and how much gas it sprays can i limit how much gas the pump sucks up, to begin with?Posted Image

  • Hick

Posted January 12, 2002 - 07:49 AM


I was about to answer your question, or try to, until I realized I may not know what I was talking about.

Was the throttle on or off when you took that picture?

  • Taffy

Posted January 14, 2002 - 12:33 AM


in that case that makes two of you!!

hello hicky you old bastard how the devil are you? got that bike running so lean she's on fumes yet?

meister don't piss about with the tabs just do the Taffy APJ mod and we even have some pictures for you now. so go see.


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  • Hick

Posted January 14, 2002 - 11:39 AM


Since my prior post I have since seen the pictures posted of the Taffy mod, or whatever you would like to call it.

Everything is so clear to me now. I’m planning on trying this trick on my friends’ KTMs (one 520, one 400 EXC). Like most good ideas it is very simple.

Taffy you are the man. BTW I have a press, dare I try to affix the cam wheels from Falicon myself? I have no other viable options. If I recall correctly you had a friend do this for you, did he just stick the cams into a press, or is it more involved than that?

I’ve spoken to the folks at Falicon about this and they were noncommittal as to my ability to do this myself with only a shop press to help me.

  • Taffy

Posted January 14, 2002 - 11:52 AM



no i did it myself and you have better equipment than me. in all honesty i couldn't see where i could go wrong with the following;

i opened the jaws of the vice and laying the wheel across the two jaws so that the cam was horizontal i tapped from the side with a copper hammer. that was easy.

i then put a falicon wheel inner on the bench and tapped the cam in, then turned it over so that the cam rested on wood and i was looking down at the wheel inner and with an oversize socket tapped it down to the shoulder. it's worrying how little friction there was!

as long as the shoulder of the cam is clean you should have no problems.

while you're there you may want to get some 2 degree increments marked on the outer wheel. my engineer did this and then he scribed two lines on the inner wheel so that one line was always in line while the other fell exactly in between!

this way 1 degree at a time can be measured and there is no need to do the degree/protractor/crank game.

hope it makes sense. good luck and if you need any help-just don't ask me (just jestin!!) :)


  • Hick

Posted January 14, 2002 - 06:20 PM


That is just what I wanted to hear Taffy. I guess we’ve hijacked this thread but I have you down for:

Intake: 108 (atdc)
Exhaust: 110 (btdc)

Is that accurate? Will that work the best for a 97 mm (444 cc) motor as well? One thing about the big bore is it seems to kill a bit of the over-rev, or it could be that the extra grunt down low just makes it seem so. Any thoughts?

As for the marks on the wheels, yes, I believe I do understand the two degree increments and the single line on the inner wheel.

I think I’m going to call Falicon and order the wheels. Please keep your eye out for any questions I may have.

Thanks Taffy.

  • Taffy

Posted January 14, 2002 - 11:36 PM



the timing was meant to be 109 for both. near to 105d was for top end power and near to 110 was for torque. if i had my way i would go straight to 110d.

as it was when i finally pulled the head down and rolled the crank two or three last times it had mowed. this isn't unusual.

i'm told that the 400 to 426 adds more top end which i found suprising.

i would expect a drop off in top end due to the flame path the squish band slowing the piston down. high compression creates more torque, low compression more top end.

don't forget that compression is the biggest killer of all your bearings so it might pay to just take it easy.



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