Weird oil pump issue

[idr5c]

I recently pieced together a basket case 71' R5 that I got awhile back. It's had a storied history, but it's all there and runs well. Anyway, prior to startup I put on new oil injection lines (feed and delivery), bled the pump, and everything appeared to be working well (cam turns, plunger works up and down, oil advanced up the lines, etc.). On my test ride though, I was getting lots of smoke, way more than my 72' R5. This bike has 14k miles on it so I figured it was just the pipes burning off, but it never died down and was mosquito fogging everywhere I went.

After 25 miles or so of test riding I looped the injection lines back to the tank, capped the fittings on the jugs, and filled it with 32:1 premix. Smoke dissipated within 5 miles and no more issues.

Hmmmmm... I've never had an oil pump fail, much less flowing too much. Pump plunger still moves as expected (up and drops to the cam position). What am I missing here? 

[Czakky]

Did you check the clearance at idle? It should just barely move. I've had the throttle cam not settle back down to the bottom some times too....

[m in sc]

ive seen the wheel intermittently get stuck down as well. this puts it the pump wide open at low rpms. its rare, but ive had one out of a junkyard do that once.  have you ridden with the cover off and watched it? easy fix, putt eh cable wheel off and make sure its smooth operation up and down as well as around. might be the cable hanging as well. not sure. might be a job for a go-pro mounted and review the video of the pump under normal operation.

[idr5c]

Great ideas! I pulled the cover and zoomed around, no sticking of the cam. Clearance in the idle position is in spec. I need to pull the side cover to freshen up the clutch (has the classic R5 slip) so I may just swap the pump, but I hate to throw parts at it.

[Striker1423]

Don't just assume the pump's bad. They aren't that hard to rebuild, and a few folks can do so for you. But, a common issue s running the pump at stock settings with today's thinner and better 2t oils. I run mine delayed a few mm's. Cleared my fouled plugs and mosquito fogging issues right up.