Kawi2strokes.com Forum

The oil pump on my S2A is hanging up intermittently. When opening the throttle the pump works as it should, but it won't always return to"zero". When I move it to zero manually, I can feel some resistance before it decides to move.

Is this a sign the pump needs a rebuild? Anyone else have this problem before?

Terry

I recently did, Terry. The banjo bolt at the end of my H2 pump farthest from the inlet was too long by a tiny amount and jamming the works. It was barely hitting, so it did just what you described.

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If it surges, that's normal, upshift.

Jm, are you talking about the banjo bolt on the oil supply line from the tank?

Terry

motor running or not? The vibration from a running motor shakes it to zero.

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

Yes Moo it does vibrate to zero .... sometimes. I'd feel better if it operated smoothly in both directions. Just need to know what is hanging up in there.

Terry

No, the banjo that's farthest from that one.

edit: OK, here's the deal... My pump behaved like yours. In working on something else, I noticed that far bolt was slightly too long and was hitting the pump guts. I shortened it and put everything back together and the pump cable pulley didn't hang up any more, so I thought the two were related. I just checked my pump, and it again does what you described. While it was hung up, I kicked the engine a few times and it released. I therefore conclude that this is normal.

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If it surges, that's normal, upshift.

I think you will find allot pumps do this when the engine is stopped. The shaft the operating lever is attached to is an eccentric. This intern applies pressure on the end of the pump plunger (which has cam lobes on its end). The plunger rotates during operation and it is the interface between these two parts that determines the stroke of the plunger hence changing the output of the pump.

If the pump happens to "park" with the plunger lobe so its peak is contacting the eccentric shaft maximum mechanical pressure is applied to these parts and hence the lever "sticks". This seldom happens during running operation.

To prove the point the next time your lever sticks kick the bike over (to rotate the pump plunger slightly) and watch the lever spring back to its normal parked position (provided the operating cable is free)

J

Very interesting. I will definitely do some experiments after work. Hopefully to this point I've worried about a problem that doesn't actually exist.

Thanks to all!

Terry

Kicking the engine over several times with the pump stuck slightly open had no effect, but with the engine running it seemed to be OK.

Terry

I would "guess" the oil flow to the engine is a bit less critical for lubrication when the motor is not running..........

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........