Calling James Dean about Diaphrams
Posted August 29, 2008 - 01:05 PM
Also James Dean is there any way to verify the low throttle studder from the ignition and is a Dynatek a good replacement for an ignition?
Posted August 29, 2008 - 02:24 PM
We have no idea about what bike/year, what carb (stock or otherwise), what is your current jetting, any other engine/exhaust mods, where you ride (altitude and temp). I'll guess you have a WR but to help any more, we need to know what we are talking about
Posted August 29, 2008 - 02:52 PM
Posted August 29, 2008 - 09:58 PM
Posted September 02, 2008 - 07:45 AM
Posted September 02, 2008 - 01:59 PM
I don't know if the Dynatek ignition will reduce the common WR450F ignition stutter at low throttle/low speeds. I have not tested one to compare results on the dyno.
Diaphragms with different length studs below, and the longer stud will bottom out first, shortening the pump stroke.
Leak jet effects below, and the shorter stroke diaphragm is the lower curve (less fuel when twisting to full throttle).
The leak jet is located in the bottom of the carburetor float bowl for those that may not know about the part. The leak jet bleeds back a portion of the fuel pumped from the diaphragm cavity, returning the fuel back to the float bowl instead of squirting it into the motor's intake port. A bigger leak jet is bleeding off more fuel, and therefore is making leaner jetting.
Posted September 02, 2008 - 03:03 PM
Also if I may hi-jack my own thread.......what will we gain and lose by going to EFI because I read long ago it will be hard to get instant throttle response with EFI like you can with the current carburetor.
Posted September 03, 2008 - 02:51 PM
The accelerator pump has the advantage of instantly pumping as much or more fuel than needed, whereas fuel injection will pause to sense the drop in pressure before increasing the fuel supplied. The FI won't bog, but also seems smooth (or sluggish) and still favors slipping the clutch or downshifting.
See the Honda accelerator pump linkage differences below-
(Roller cam on right)
(Newer CRF pump linkage on right)
Posted September 03, 2008 - 05:14 PM