What is this!? 78 GS550 Accelerator Pump? Cannot find one anywhere!

[willywilliams]

I've been told its an accelerator pump, but I can't find one anywhere! This one is broken, as you can see its cracked and leaks bad.

Does anyone have a spare one lying around?

 

[tkent02]

'78 GS550s had no such pump. As far as I know none of them did. Some of the Kawasakis did, dunno about the 550s.

 

[roeme]

Take better pictures, showing more of the whole contraption.

 

[Agemax]

it is indeed an accelerator pump, so those are not the standard carbs for the bike.

 

[tkent02]

Probably easier to find a set of the correct carburetors for your 550.

 

[willywilliams]

I had them tuned perfectly, then this had to go and happen.

 

[willywilliams]

The pump is replaceable - I'd rather just see if I can find a replacement pump if possible. It was running so nicely as is.

Here are some more pictures, ignore the yellow tape, that was me attempting to fix it temporarily to get it over to someone to look at it. I need a truck...

 

[Nessism]

That pump looks like some aftermarket kit. I'd ditch that crap. And consider just picking up an unmolested set of carbs.

 

[Agemax]

those carbs have been seriously molested, what is the pipe fittings that have been tapped into the carbs on the inlet sides?

 

[willywilliams]

Agemax, the gas lines run from the accelerator pump into those fittings - I've read it's meant to help smooth out the ride?

 

[loud et]

From a 1981 vintage performance catalog I have.
There was also a version that came with carb bowls that directly piped to the carbs. This is more of the universal , general purpose version.

 

[loud et]

 

[willywilliams]

That's it!!! Your you solved the mystery loud et!

 

[loud et]

That's it!!! Your you solved the mystery loud et!

Well that may be it but being from 1981 ish, it'll be hard to replace.
A full teardown, cleaning and solder job may be your only repair for the crack in the body.
That will be a tough part to find to replace.

 

[tkent02]

Just curious, why would you want an accelerator pump on an engine that doesn't need one?

 

[willywilliams]

I'm thinking they aren't the original carbs? I have no idea - might try and pull it off and run it without it.

 

[tkent02]

550s run fine without it, with the possible exception of instantly whacking the throttle from closed to wide open at low RPM, it may stumble a split second. Since the 550s have zero torque at low RPM and can't even be ridden at low RPM anyway, it's not an issue.

Keep the RPM up where the engine is happy and it won't happen at all.

 

[willywilliams]

That's what I was trying to say, but I have hassled by a few people saying if I take the pump off it will stutter and not run right.

I have been on this site too much - now I am dreaming of the 650 top end swap, the top end needs rebuilding soon anyway ;/

Thanks again for your help!

 

[tkent02]

Well if you have to get in there anyway, the 675 conversion is a no brainer. No comparison between the two, it's like a whole new motorcycle.

You can still get in on this group buy for 700cc higher compression pistons too.

 

[allojohn]

That is some Heath Robinson kit right there!