Oil Pump Bleed - 75 GT250

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Dammen
Still in the Driveway
Posts: 2
Joined: Thu May 28, 2009 8:20 pm
Location: Minnesota, USA

Oil Pump Bleed - 75 GT250

Post by Dammen »

Hello All,

This is my first post. As I read through the forum, I was impressed and excited to find all this expertise on Suzuki 2-strokes.

I have a 75 GT250 that's ready to go, save one last detail. The bike was sitting for 15+ years, so in addition to a bunch of other things, I cleaned out the oil tank. I don't have a manual. The only place I could find that had one, has put me on perma-backorder. The manual I have is for post 77 and, besides being on the other side, my pump looks a lot different than the one in the book.

I can't find a dedicated screw, and can't figure out how to bleed the oil pump to ensure the motor gets lubrication as soon as it starts.

Does anyone out there in Sundial-land have info on this?

Thanks in advance.

Dammen
"It sounded like a good idea at the time."
bighole
To the on ramp
Posts: 204
Joined: Sun Oct 19, 2008 8:20 pm
Location: Dansville, MI

Post by bighole »

Dammen,
Welcome to the group! Lots of great resources and tons of knowledge here, you came to the right place.
I don't have much experience with the 250s but the basic oil pump operation is the same. If you are unable to locate the bleed screw I would try removing the pump from the spider lines keeping the tank supply line attatched. Take a syringe of oil and gently force into the lines at the spider inlet where the pump used to sit. Draw back (again, gently) to assure checkvalve operation.
Mount the pump shft in a drill to spin the pump to check that it is functioning properly and to draw oil thru. Remount as soon as possible and this should remove most of any air in the system. Any bubbles in the line above the pump will bleed themseves naturally by rising up the line. Idealy you want to use the bleed screw on the pump but I couldn't tell you where it is either. :?
Also check your oil tank cap to make sure that the vent is in good condition. A long ride can create a vacuum in the oil system and run your motor dry if not venting properly.
If I am incorrect on this please let me know as this is how I have been going thru my oil system! :)
Hope this helps, good luck!

-John
My bike is a "bighole" I keep throwing money into, so I had to get another!

09 Aprilia RSV1000
73 gt750
77 gt750 cafe
73 gt550
74 RE5
elbert
On the main road
Posts: 133
Joined: Tue Oct 21, 2008 8:11 am
Location: Stavanger, Norway

Post by elbert »

You can bleed the oil pump by loosening the union bolt at the front of the oil pump and let the oil drain out until all the air bubbles in the feed line has disapeared (engine not running).
To get the air out of the oil lines going to the cyllinders, start the engine and manually push the oilpump lever forward while the engine runs at aprox 1500 rpm, you should see the air bubbles move every second or so.

I mix oil directly in the fuel tank on the first tank after a rebuild just to make sure that the cyllinders gets some oil while I adjust/bleed the oil pump, ignition and carbs.
Dammen
Still in the Driveway
Posts: 2
Joined: Thu May 28, 2009 8:20 pm
Location: Minnesota, USA

Post by Dammen »

Thanks for the info. I'm glad it's sort of complicated - that means I wasn't missing something obvious.

Cheers!
"It sounded like a good idea at the time."
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