Trying to fix a PW50 thats dumping a heap of oil into the carb.

Pulled the pump and adjusted stroke using a ruler to measure (bit of a guess but close enough, i dont have a dial indicator/mag base).

Seemed to pump fine in the vice and the plunger moves in and out.

Once in the bike though and nothing, seems like the gear isnt engaged.

Getting annoyed now as the plunger was moving before i pulled the pump.
The gear in the motor looks fine.
Any ideas appreciated.

just take the gear out and run premix.....thats what I would do

or drain the oil tank and run it dry with premix....heard of people doing that

As a last resort i will go that route.

you really want to use a dial indicator, I don't think you'll get anything accurate enough with a ruler.
Check to make sure your cable is not sticking, as you roll on the throttle, the pump will pump more oil, perhaps in your case, it's stuck at WOT when it's at idle?
I agree, keep the pump. People who recommend running pre-mix right off the bat don't understand the effects and what's required to do it right. It's not an easy solution and in most cases, not the right solution.

Good call on the cable, will check that one.

Dial indicators are expensive right.

Good excuse to buy one i guess.

Checked it again before , and it felt like the plunger moved, may set a bit richer and try from there.

So the plunger action is for idle and cable mechanism for increased revs?

BTW, i have another PW50 (newer) and the pump started leaking so i disassembled it and found alot of dirt had worked its way in.

The shaft seal is buggered i think as it still leaks a bit, can you get this seal seperately?

The cover on the pump dosent seal out dirt very well.

I honestly don't know, I don't have one either. I have lots and lots of tools I don't use as it is.
See if you can borrow one? I don't think they're that expensive though. Google shopping has them starting at $20 to as much as you want to spend. The good news, they're quite useful, you can use them for truing wheels and such.
I'm not sure how the PW50 oil pumps are, I've never messed with one. The PW80 cover isn't so hot at keeping crap out either. But I think the internals are sealed pretty well, so if yours has dirt in it, it probably got in the oil tank and made it's way into the pump there. At least it didn't go into the crank case, dirt does a good bit of damage to smokers over time. Not that it's good on four strokes either.
I'm pretty sure you can purchase any piece of the oil pump individually:

This is from http://www.powersportspro.com select your make, year and model, they'll give you the Yamaha part number, so you can just call your dealer for a price or find a place online.

Oh, and that's $20 US, so I think that's like 1 Euro or 2 Australian dollars, cause we've been trying to make our money match the Peso for the last year or so. (yes, I'm aware the current exchange rate is about 21.50 AUD = 20 USD, political commentary)

Thanks for the pic Smacaroni, #6 is the culprit i assume.

As for the dial indicator (once i checked ebay)seen them as low as 28aud so not a big deal.