Wr400 AP timing screw
Posted June 20, 2015 - 10:20 AM
Just bought a 2000 Wr400 and the bog off idle is ridiculous. I did the BK mod, so the duration of the AP squirt Is about 1/2 a second, and the jetting seems perfect. Can anyone tell me how many turns out their Ap timing screw is so that I can use that as a baseline? Also, should I change my leak jet, or is it fine after doing the BK mod?
Posted June 20, 2015 - 06:25 PM
It's not about turns, it's about gap.
Do you have the slant carb or the CR carb?
Posted June 21, 2015 - 05:17 AM
Your factory manual has an AP timing gap setting procedure
You can also do a visual to make sure it just barely misses the slide, everytime.
For a precision measurement of that, you really need to use a video camera.
Squirt distance is a function of the AP diaphragm type (short/ medium / long rivet. You want long for a 426)
Squirt duration is a function of the leak jet size
You really want closer to 1 second, especially for on/off/on throttle situations. That would mean a smaller leak jet (50/55)
Posted June 21, 2015 - 06:07 AM
Posted June 21, 2015 - 04:37 PM
Posted June 28, 2015 - 04:27 AM
Posted June 28, 2015 - 05:32 AM
Do you mean the air boot? It has no gasket on either end....
You still have not stated weather the pump is squirting, for how far and for how long.
Posted June 28, 2015 - 05:42 AM
There is supposed to be a gasket between this black rubber piece and the carb, but there isnt, so there is a gap between the carb and this piece.
The AP squirts about 6 inches for 3/4 of a second.
Posted June 28, 2015 - 06:25 AM
That is the air boot maniford.
It needs a gasket.
It will cause a hanging idle / lean condition and a massive loss of vacuum pressure over the needle jet.
Might cause bog, I've never seen it missing before.
Your pump should be squirting 6 FEET for about 1 second
If you have no leak jet, than that is not the issue, as you are running what would be essential the largest leak jet, and still having bog. Pleanty of fuel.
So the 'pump' is not pumping hard and deep enough.
You need to look at the diapraghm to see if it has the long, medium, or short rivet. You want the short rivet (longest 'pump' distance).
Edited by KRANNIE, June 28, 2015 - 06:30 AM.