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

[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!

[bobgroger]

The accelerator pump looks like a standard Holley part

https://www.holley.com/products/fuel_systems/carburetor_components/accelerator_pump_parts/