Question about accelerator pump timing screw...
Posted July 22, 2002 - 05:35 PM
I was playing with the timing screw when I had the carb off today and noticed that the squirt does not come anywhere near the slide even when the timing screw is all the way in or out, (and yes there was gas in the carb). The squirt would start at approximately 1/2 throttle with factory settings and all the way out. Squirt started barely at full throttle with it all the way in.
Is this abnormal since it never even comes close to the slide, or just be happy and leave it alone?
Thanks for the help.
Posted July 22, 2002 - 11:08 PM
Posted July 23, 2002 - 02:03 AM
Please someone, correct me if I'm wrong but-
Your squirt should start as soon as you crack the throttle open, not at half throttle or later. There is no point having a spit of fuel after half throttle at all.
The AP is there to give you crisp throttle response by spitting in a dash of fuel when you first crack open the throttle.
At low rpm there isn,t a continuous or strong enough stream of vacuum pulses being created by the engine to accurately suck the required amount of fuel out of the pilot jet when you crack it wide open. All you get is a lean "bog" as the engine sucks too much air and not enough fuel.
This is when you want the AP to spit a dash of fuel in and then stop, once she starts to boogey.
By the time you get to half throttle the engine should be wound up and sucking harder and more cosistently. The required amount of fuel is pulled out of your jets more accurately at higher rpm due to the stronger and more frequent vacuum pulses created by the engine. Therefore not requireing an unmeasured amount of fuel coming out of the AP nozzle confusing your upper midrange jetting.
Posted July 23, 2002 - 07:37 AM
However, did you have an off-idle bog? If not, put the AP pump screw back to where it was and go on!
If you have an off-idle bog, then we will have to readdress the issue...
Posted July 24, 2002 - 01:57 AM
Definately doesn't start at half throttle.
Posted July 24, 2002 - 04:09 PM
I have found that when wheelieing at low speeds to loft the wheel over logs and debris that its very difficult to predict when and how hard the wheel will come up, and when it does it is in no way controlled. I suspect it is due to a big burst of fuel and not my technique. I am not a racer or real aggressive (yet) and ride trails and woods. The last thing I want is to get a burst of fuel at 1/2 throttle in 36" wide trails!
Does the BK mod and the limiting of the acc pump also affect when the squirt starts? Something inside the carb may be plugged, bound or otherwise not functioning?
Like I said earlier, even if it causes no major problems I will know its not correct and it will drive me crazy...And no one needs an obsessive, sleep deprived rider anywhere near them.