Oil Pump Worm/Ring Gear

[svgarage]

on my r5, i rebuilt the pump and used an rz lower part of the body, and yes, it had 1 pin, no spring.

if you don't plan on using the priming wheel there's no need for the clutching mechanism. even yamaha stopped putting them on pumps ;)

My bike is a 1977 RD400D- there is no priming wheel. That explains that.

[SoCal250]

I was suspecting that the later pumps without the starter plate may not have 2 sets of springs and pins since those are used to disengage the pump from the worm drive for manual priming. Good to know. I haven't done a 400 pump yet, only 250, 350, R5, and CS5.

On a side note, if anyone is in need of replacement springs/pins Economy now sells them:
https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/engine-related/oil-pump/oil-pump-worm-gear-pins/

[1976RD400C]

When you guys say 1 pin do you mean 1 pin goes all the way through the shaft to the other side so both sides engage the gear wheel? The 400 pumps I've tinkered with, that have the primer wheel, it's a blind hole on each side where the spring bottoms out and then the pin goes in.

[m in sc]

1 pin 1 side

[2 Smoker]

Its like gunsmithing with some of those tiny pins and springs and definitely a containment area of some kind (learned the hard way) always is a must.