GTR Has Life Again

[bsforever]

Has been a 3 and a half year project, but finally had my GTR in a running mode. I started it up about a week ago for a few seconds to check on things ( had a issue concerning the condenser and was waiting on a new one coming in again). Anyway, i got the new condenser,installed it, mixed up some pre-mix again and lo and behold, finally was running on both cylinders ( woooo- hooo was i a happy camper ). However, i do have issues with the oil injection pump, and it might had been the original problem with what happened in about 1980 ( that was the date on the license tab when i first bought it and the left cylinder was the one i would say that had the problem as there was scorching in the cylinder wall ). The pump does not seem to be pumping any oil to the check valves. When i did give it a little throttle, nothing. I had read some information on oil pumps in the manual and opened the oil pump control lever wide open and i did see on the one oil outlet hose ( both are clear to see oil movement ) and did see about a quarter of an inch of oil in the hose from the pump and as soon as i released the control lever it went back to seeing no oil again. Is there any 'timing' of the pump in relation to the crank or any other 'specific' timing in relation to another gear or ??  OR do i just need to replace the pump?  Thanks, bsforever

[OldSwartout]

In the service manual there are instructions on repair of the oil pump.  There is gear timing required within the pump and if it was previously disassembled and reassembled wrong, that could explain the problem. Something could be stuck also. The pump plunger is moved via a spring, so it is possible it doesn't move.  Probably not likely, unless some debris got into it, though.

There is also a very good writeup on this forum by Graham Weeks (disc_valve) on rebuild of a 350 oil pump.
http://bridgestonemotorcycleparts.com/index.php?topic=3629.0

He also did a writeup on the 175/200 pump for those of you that may be interested.
http://bridgestonemotorcycleparts.com/index.php?topic=3640.0

[bsforever]

Thank you Karl for the info and possible solutions. I will check things out further and will post later on when i find out what the problem is exactly.

[CL-100]

I've used Graham's posting to disassemble a 350 oil pump that I have, clean it out, retime it, and it now works beautifully.  One of the things I've learned is that the black plastic pin that moves with the main gear will get stuck.  I've been told by another site member that they usually get stuck in the wide open position, pumping oil as if the throttle is wide open.  This may be the cause of many 350 owner complaints of excessive smoking.  Anyway, I suppose it's possible for that pin to be stuck in the closed position too, metering out a small amount of oil.  Since your pump hasn't been run in a while, it may just want a good cleaning and lubing!

For me the time spent following Graham's instructions were invaluable.  Easy to understand and I came away with a great understanding of how the pump works. 

Best of luck.

[disc_valve]

Hi,

THat's a good thought about the plastic plunger pin stickingh. I'd not come across that , but it makes perfect sense. I reckon the pin could only stick "fully open", though, because it is positively lifted by the cam on the back of the pump pulley as the throttle is opened, but it relies on the spring in the center of the plunger gear to return it. The right wrist is a lot stronger than a teensy spring!

Graham