AP pump problem?????


8 replies to this topic
  • Goosenest

Posted March 14, 2009 - 02:57 PM

#1

Hey guys.. first post here... ive had issues recently with my 08 wr450, darn thing just plain and simple wont start. So i threw a new plug in it first off and its getting great spark, still no luck. I yank the carburator and throw in a JD jet kit since im in there, clean the heak out of it and throw on a powernow, still nothing. I tried some ether and it will fire up and then die after fumes are burnt. So today I pulled it again, but first i pulled the airbox off and left gas tank intact to see if im getting any squirt into engine. Guess what... NOTHING. Shouldnt i be seeing a squirt of gas shooting into engine while blipping throttle?? Is this my Ap pump perhaps.. I did notice my Ap pump diaphragm was very rusted so i have ordered new to replace. Thanx guys for any feedback.. IM LOST. Also while having this whole thing apart I did airbox and the grey wire mod. Others were already done when I first bought the bike. Thanx again.

  • William1

Posted March 14, 2009 - 04:17 PM

#2

First, you are jumping about. The AP is for acceleration. If you found rust in there, it is possible the AP nozzle is clogged. But that is not why your bike will not start.

First, remove the powernow.

I assume when you pull the carb, the float bowl is full of fuel? Next, if the pilot jet is at all clogged, replace it. Confirm these two things before we move on.

  • Krannie McKranface

Posted March 14, 2009 - 06:20 PM

#3

Hey guys.. first post here... ive had issues recently with my 08 wr450, darn thing just plain and simple wont start. So i threw a new plug in it first off and its getting great spark, still no luck. I yank the carburator and throw in a JD jet kit since im in there, clean the heak out of it and throw on a powernow, still nothing. I tried some ether and it will fire up and then die after fumes are burnt. So today I pulled it again, but first i pulled the airbox off and left gas tank intact to see if im getting any squirt into engine. Guess what... NOTHING. Shouldnt i be seeing a squirt of gas shooting into engine while blipping throttle?? Is this my Ap pump perhaps.. I did notice my Ap pump diaphragm was very rusted so i have ordered new to replace. Thanx guys for any feedback.. IM LOST. Also while having this whole thing apart I did airbox and the grey wire mod. Others were already done when I first bought the bike. Thanx again.


Rusted or full of rust colored dirt? There is nothing in there that will rust that much. William1 is right: check for clean jets first, find the source of the dirt/rust, and go from there. You have something clogged...........but if it's the AP, that would not prevent starting at all.............

  • Goosenest

Posted March 14, 2009 - 06:31 PM

#4

I agree sorry for that scattered sounding post William. :)
Let me give you the steps in which I started to where I am right know.
First I changed plugs after noticing bike would not start.(Gapped plug)
I then proceeded to try and start numerous times to which bike would not even cough. After this I checked plug to see if it smelled of fuel or was wet, it was neither. I then attempted to drain float bowl, it turned out there was a little amount of fuel in there(I would say a teaspoon maybe). I removed carburator and then broke it all down and cleaned/soked every bit of it including all stock jets(all internal carburator parts where very clean and in good shape except for the AP diaphragm which was very rusted?) I then installed a new JD kit, Needle JD Red #4, MJ 168, PJ 48, PAJ 45(stock), LJ 60(stock), SJ 65(stock). I went ahead and removed Ais with gytyr application/installed adjustable fuel screw/ installed scary fast powernow/removed snorkles from airbox and grey wire mod. Then reassembled and installed carb. I attempted to start it and again the exact same thing not a single burp. So here I go for the second time. This time the float bowl had zero gas in it when I removed the drain plug(I know there is a gas flow to the bowl because the gas line coming off the tank is flowing). I dont get it.....:banghead: but again this is my first time working with a carb, im sure its probably something simple. I have a new Ap diaphragm and boyseen quickshot 2 cover on there way so it will be a couple days before I get to install carb again. Any Suggestions before I get the carb reassembled? Also why do you recommend removing scary fast powernow mod? Thanx again William.

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  • Goosenest

Posted March 14, 2009 - 06:39 PM

#5

Kranni, the plate that the diaphragm is attached to is steel and has severe rust on it.. Would this be from sitting around for a couple months? Maybe gas left in there had water in it and rusted this piece. I dont know. Any thoughts. Any suggestions are well appreciated.

  • Krannie McKranface

Posted March 14, 2009 - 08:18 PM

#6

Ah-ha! If you are getting rust on that stainless steel plate at the top of the APump, you must have water in your gas, or water has gotten into the carb. Or there has been no fuel in the carb for a long long time.

If you have no gas getting into the float bowl:

- petcock off, or clogged
- feed to carb clogged
- float is dislodged from the carb in such a way as to keep the float valve seated all the time.

- if the float were ldisloged oose, you would get excess gas (valve would not seat)
- if the float valve had fallen out, you would get excess gas.

If the gas is old, it will varnish. This varnish can get bad enough to completely clog the petcock filter in the tank.

You should also check the slide vacuum plate, as it doesn't like being without gas fumes too long either: it can become loose or fall out. Nothing to do with no gas though.


I would start the tank and work down. And change all the gas if necessary.

  • Goosenest

Posted March 14, 2009 - 10:49 PM

#7

Krannie, all gas has been swapped already, petcock when turned to gas on position has good flow. I dont follow you when you mentioned the slide vacuum plate, cant find this in my manuel. Can you tell me where this is located on the bike. Also where is the petcock filter? Is this in the tank itself?
Im a rookie when it comes to this stuff.

  • William1

Posted March 15, 2009 - 02:20 AM

#8

Dry float bowl.

You have a clog in the carb between the fuel inlet and the float needle valve. Many of the needle valve seats have a fine screen. You will need to pull the needle valve seat. Be sure to carefully inspect the oring on it too.

  • Goosenest

Posted March 15, 2009 - 08:31 AM

#9

Thanx william, i had a feeling this was where the problem was after looking at the manual last night. I have carb completely stripped down once again but have failed to take the float needle junk apart for it looked to complicated. Ill give it a shot. Thanx again William.:)




 
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