JD, some hep on the varying diaphragms for the accel pump.



3 replies to this topic
  • MN_Kevin

Posted March 03, 2001 - 07:16 AM

#1

JD and everybody else,
Do you know how the yamaha part numbers for the AP diaphragms coincide with the stroke travel of the accelerator pumps?

I see the following diaphragm part #'s:

5BE-14940-15-00 (YZ ONLY)
17 (standard on the 99 WR)
18
19
There is no standard listed for the 99 YZ...

Do you know which one has the most limiting AP stroke?

------------------
'99 WZ with all YZ mods, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, forked over by Pro-Action, OEM YZ tank and IMS seat.

  • James_Dean

Posted March 03, 2001 - 12:54 PM

#2

Last summer the local bike shop tried to get all of the optional pump diaphrams for my '00 WR and they were not available from Yamaha. It is still a mystery what the differences are.

The stock diaphram height, 8.1mm, does not limit the stroke, the cam profile does not stroke that far. At a height of ABOUT 8.5mm it would start to reduce the 3mm of stroke.

Anyone else?

James

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  • Boit

Posted March 06, 2001 - 12:11 AM

#3

JD: When I first read your response about the "Cam" profile.....at first I thought you meant the camshaft. Well, obviously you meant the little plastic cam on the carb slide shaft that operates the accelerator pump plunger rod, right? I had a brain burp.... :)

  • James_Dean

Posted March 06, 2001 - 08:12 AM

#4

Yes, that was the plastic cam on the carb linkage. :)

Does anyone know if the 2001 models use a different plastic cam to alter the pump stroke or timing?




 
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