Suzuki 2 Strokes

The pump arm has a dot and a line. Is the dot supposed to line up with the cast mark at idle? Is the line for WOT? OR do I need to open the carb window and line up the 2 dots? It is fully relaxed in this photo. I just noticed there is another dot way down there.

On the 380 and 550, remove the brass 10mm AF bolt in the RH carb and, looking through that hole, open the throttle. There is a dot stamped into the slide, and you set the oil pump so that the dot is right at the top of the window when the line on the oil pump lever lines up with the line in the indicator on the pump.
Cheers,
Mike

Dot to line? That's odd. I have seen dot to dot before but I think that was for earlier models. So the dots on the arm are pointless?

Hi,the lines should match each other ! What machine year/model are we talking about ? Early 750/550 or late 750/550 it would help to know
Cheers,
Roger

76 GT550 It's listed in every one of my posts.

The lines on the oil pump line up when the dot on carb slide is in the 'window' described above.

I think I read somewhere that the dots are calibration marks not used by the bike owner?
Mike

Thanks guys. With the slide dimple at the top edge of the window, I adjusted the pump cable so the lines matched. I wish everything was that easy. But that brings up another question.
Seems like all the pumps I have fooled with -- including this one, the pump arm hangs before fully returning. Doesn't take much to coax it along, then it snaps back where it belongs. I'm sure the arm will work correctly when the bike is running due to vibration. But I want to know what makes these arms have that little tight spot and is there a cure?. Like I said, all I've ever fooled with have the same hang before return.

I'm glad you asked that because many people seem to think it's wear or friction or something else. The answer is that as the pump rotates the center part has a cam on top that rubs on that actuating arm. If the motor stops when the pump is in the "up" position of the cam, the arm will not return to the rest position.

Rotate the engine a few turns without touching the throttle and you will see it pop back to rest. It's a feature of the design.

TZ is right, though its worth noting that back in the day, Suzuki did see really sticking oil pump levers, and prescribed an additional spring to help it return!
http://www.ozebook.com/compendium/techb ... 010-18.pdf" onclick="window.open(this.href);return false;
I think its the 3rd bulletin here.
Cheers,
Mike

Read service bulletin 14. My cap has no hole?

Oil tank cap? it should either be vented internally via a slot cut into the thread inside the cap, or perhaps the tank's filler neck, or have a hole. Mine had none of these so I drilled a hole!
If off base, ignore.
Mike

Never noticed but the filler neck is slotted. I still don't understand how it works though. The rubber 'blister' totally seals off the top edge of the filler neck. The 'blister' has a hole in the center and there is a plastic piece under that. I think the plastic piece is a key player.

The vented oil pump cap is really important. On Pinky, I had an unvented cap without the proper inserts, and I ran low on oil, and I swear, the pump sucked my oil tank flat! I was lucky there was no damage to the engine. I drilled a hole in the top and later found that it should have a couple of inserts in it for venting.


Lane

yeadon_m wrote:TZ is right, though its worth noting that back in the day, Suzuki did see really sticking oil pump levers, and prescribed an additional spring to help it return!
http://www.ozebook.com/compendium/techb ... 010-18.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
I think its the 3rd bulletin here.
Cheers,
Mike

I still wonder about that bulletin and what was really going on there. Part of me thinks it was a PR exercise rather than a design issue because they really didn't change the pump design - at least not at that time. Who knows what there were thinking.