1974 Yamaha RD350 oil pump leaking 2T oil - see photo

[LexPaul]

Got this Rd350 running like a top but the 2T oil pump is weeping just a drop or two per day. The oil appears on the cable and I believe it may be a shaft leak. When I take Q-Tips and look for leakage around the pump and oil lines there is no areas of concern.

Has anyone dealt with this? Should I look for a rebuild kit or a shaft seal? Thoughts are appreciated. Thanks

[SoCal250]

I've rebuilt quite a few pumps. Not too difficult if you're careful and aware of the potential gotchas. The rebuild kit includes the case gasket, pump to engine cover gasket, and seals you'll need.
There's an oil seal on the rear behind the thumb priming wheel (also called the starter wheel),
there's one inside the front half of the body where the plunger shaft runs through to the spring and pulley, and
there's a small oil seal inside the unit in the distributor which seals the plunger in the chamber.

Rebuild kits available here.
Economy Cycle offers a rebuild service if you don't want to do it.
Site member "Arrow" in the UK also offers a pump rebuilding service.

If you decide to tackle it yourself and you've never done it, be careful when removing the internal assembly of plunger/worm gear/washers or you'll be looking for lost tiny springs and worm wheel pins when they shoot out. If you need tips on this I can provide more details.

[quocle603]

They have very unique small seals. I've had mine leak in the past and replaced fhe seals and got it back in order. Worst case senerio, premix and upjet