Does this look right? AP mechanism. Photos included


7 replies to this topic
  • efini7

Posted July 19, 2009 - 10:05 PM

#1

I have come across two problems i have now with my bike since rebuild which i never had before hand.

I recently rebuilt my bike (piston, rings, gaskets) and i have come across a problem with off idle bog. The black plastic braket that is connected to the throttle linkage seems to have a space between it which looks like it shouldnt have. Because of this gap it doesnt appear to be doing anything with the accelerator pump mechanism. You can see this by looking at the picture below... Can someone look on their WR400 99 model and tell me if they also have a gap and maybe take a photo if possible.
http://i235.photobuc...0/wr400003e.jpg


Also my throttle gets stuck, it wont return back to the initial position. i have noticed some wear on the side of the carby where the throttle linkage arm is rubbing up against. I have cleaned out the cable guides with purpose made cleaning agent for this task also. Please see the picture below. Does this look right?
http://i235.photobuc...0/wr400004e.jpg

  • efini7

Posted July 20, 2009 - 09:59 PM

#2

Anyone? Im desperate here

  • arctic954

Posted July 22, 2009 - 04:54 PM

#3

Not an expert on the the whole AP mechanism.... but, have seen plenty of posts on the 'AP MOD' which has pics... and setting precedures...

As far as your throttle sticking? Just realized on my WR426, if the throttle cables at the carburator are set tooo tight (in other words, no mild free-play at the grip), your throttle will stick. Set both cables connecting to your carb loosely, then re-set your throttle grip free-play. Its easy to get everything too tight when you pull and re-install the carb. Also make sure your throttle cable routing is correct and that the cables aren't getting pinched anywhere.

  • arctic954

Posted July 22, 2009 - 05:01 PM

#4

other things to check.....

Did you clean the air filter? and possibly do other things?

Your AP circuit may not be tuned correctly..... but, don't rule out the obvious....


Start by making sure your Idle Mixture screw is properly adjusted. Maybe now that everything has been re-built and cleaned --- the jetting and previous settings on your carb. aren't being friendly to the new changes.

I was able to drastically reduce my off-idle bog by simply putting the bike up on the stand while lightly blipping the throttle from off-idle..... and adjusted the Idle Mixture screw in small increments. I now have mild off-idle bog while the bike is on the stand......but is completely un-noticable while on the trail. (I'm sure once I getting better at calibrating the AP circuit....I can get it even better....)

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  • Krannie McKranface

Posted July 22, 2009 - 06:25 PM

#5

I have come across two problems i have now with my bike since rebuild which i never had before hand.

I recently rebuilt my bike (piston, rings, gaskets) and i have come across a problem with off idle bog. The black plastic braket that is connected to the throttle linkage seems to have a space between it which looks like it shouldnt have. Because of this gap it doesnt appear to be doing anything with the accelerator pump mechanism. You can see this by looking at the picture below... Can someone look on their WR400 99 model and tell me if they also have a gap and maybe take a photo if possible.
http://i235.photobuc...0/wr400003e.jpg


Also my throttle gets stuck, it wont return back to the initial position. i have noticed some wear on the side of the carby where the throttle linkage arm is rubbing up against. I have cleaned out the cable guides with purpose made cleaning agent for this task also. Please see the picture below. Does this look right?
http://i235.photobuc...0/wr400004e.jpg


I bet the AP is full of dirt. The linkage boot is loose, and, well, it's a bit messy in there!

  • efini7

Posted July 23, 2009 - 01:44 AM

#6

Thanks mate, ill loosen the throttle cables and start again as you suggested, hopefully its just something simple.

Ill have to pull the carby off also and check the AP again. My mate done most of the work, and i know he pulled the carby apart so im not sure if he had been diligent in putting it all back together or not so i guess thats the first place i should start.

oh yeah and it has a brand new air filter in it also, so that shouldnt be the cause.

  • ncampion

Posted July 23, 2009 - 06:22 AM

#7

No offense meant, but that is about the dirtyest carb I've seen in a while. I would start by doing a total carb clean and adjust to factory specs. then see how it works. The other suggestions regarding cable free-play and fuel screw adjustment are also critical and should solve the problem. Not sure about the AP plastic space, as I swapped my FCR for an Edelbrock long ago.

  • efini7

Posted July 24, 2009 - 11:52 PM

#8

I agree the carby is filthy which i will be cleaning now that it is off.

Went to go for a ride today and oil started to leak out of the rocker cover gasket, so i pulled that off to get a new gasket and thought i might as well pull the carby off also and found that the AP rod was getting stuck inside the AP hole it runs through, which is why it wasnt doing anything, and now that gap has completely disappeared since fixing that. Such a stupid little error that has caused such an annoying problem. Must have been the last time we pulled it apart we didnt insert the rod straight.

I also loosened off the throttle cables and it is no longer getting stuck. Thanks for the advice people. Cant wait to get this gasket and do some riding!




 
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