help needed with testing accelerator pump

If it's broken or just needs tweaked

Moderators: Volker_P, tidd650

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

help needed with testing accelerator pump

Postby juntjoo » Thu Jan 18, 2018 4:59 pm

https://youtu.be/74ihrKel3n8

so I've found no leaks in my carbs, floats hold the fuel, but the accelerator pump isn't working right and I don't know why. As you can see it's squishy. I guess that means with air. And would this be because the rod's boot isn't on to seal it there around the rod shaft where I noticed air and gas bubbling through? Could there be something wrong with the diaphragm that I just can't see? Seems to fit perfect all the way around it's edge, no tears or holes.
82" cb650 Nighthawk

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Thu Jan 18, 2018 6:31 pm

someone at sohc4. net tipped me off to the possibility it's the "check valves" in the cover.

https://imgur.com/a/p94ix

that one I'm pointing to, goes to the bowl, should block flow TO the bowl while rod action pushes fuel to fuel rail, I'm guessing, so I applied suction to that hole to see if it would hold/not allow fuel to push back from the other side in the diaphragm area, and it doesn't hold it. So would this be a faulty cover?
82" cb650 Nighthawk

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Thu Jan 18, 2018 8:16 pm

olay, now I understand it better. So both my check valves part of the fuel pump arent working. I can suck/blow air/fluid through both in the wrong direction, that being into the square plugs, hence my faulty squishy squirt test. I saw this test on a similar carb on youtube and they were squirting it like a squirt gun so mine def isn't workimg right.

But I've never seen a thread on dirty or faulty check valves, and I've read a lot of threads on some bikes way dirtier than mine. Please if possible ease me of my confusion. Do I need a new #2 bowl with accelerator pump cover or a better method of cleaning these check valves out or is there some other secret I'm missing here? Ill be soaking these parts... Thanks!
82" cb650 Nighthawk

User avatar
GeorgeSweety
Posts: 323
Joined: Tue Aug 08, 2017 11:47 am
Location: UK.

Re: help needed with testing accelerator pump

Postby GeorgeSweety » Fri Jan 19, 2018 2:57 am

I think that I would try the carbs on the bike and stop looking for problems until they actually happen. You only assume that the accelerator pump isn't working but you haven't taken into account the pressure created inside the carbs by the engine. If you are getting fuel through the little brass tubes in the carb throats then they are clear, it is only a tiny little squirt that comes out of them, not a constant stream. Get the carbs on and fire the beast up, then see what's not bloody working :lol:

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Fri Jan 19, 2018 5:29 am

GeorgeSweety wrote:I think that I would try the carbs on the bike and stop looking for problems until they actually happen. You only assume that the accelerator pump isn't working but you haven't taken into account the pressure created inside the carbs by the engine. If you are getting fuel through the little brass tubes in the carb throats then they are clear, it is only a tiny little squirt that comes out of them, not a constant stream. Get the carbs on and fire the beast up, then see what's not bloody working :lol:


no no, they're def not ready. these plugs need to be cleaned. I've seen how those nozzles are supposed to squirt. and I'm not getting fuel at the brass tube, just the #2 one and I checked both check valves and neither are one way. so gotta clear them. I'll report back....
82" cb650 Nighthawk

User avatar
Folsoml
Posts: 1621
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: help needed with testing accelerator pump

Postby Folsoml » Fri Jan 19, 2018 9:02 am

Did you check page 20 of the MacGregor manual? It has information on cleaning the accelerator pump, and how to make sure it is working as it should.

Edit: Additional information on page 27.
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Fri Jan 19, 2018 9:17 am

Folsoml wrote:Did you check page 20 of the MacGregor manual? It has information on cleaning the accelerator pump, and how to make sure it is working as it should.

Edit: Additional information on page 27.


yes thanks, but it's not thorough enough. This is tho:

http://www.hondachopper.com/garage/carb ... page1.html

and if I can't free up the balls with easier methods I'll be trying this guide
82" cb650 Nighthawk

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Fri Jan 19, 2018 9:34 am

actually it won't work as my plugs are brass. Well I suppose it could work but I messed up a spare cap I have with the drill bit and that guide obviously is for a cap with a nylon plug. idk. I'll keep reading...
82" cb650 Nighthawk

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Fri Jan 19, 2018 12:16 pm

fuel pump check valve ball stuck https://imgur.com/a/cXz5C

i can insert it about 4mm all four sides. an blow/suck air in both directions. anyone with carbs out able to check their working pumps?

or if someone can confirm for sure this set of carbs can't do the spray test off the bike, otherwise so far I've seen a few vids with squirting pump nozzles either #2 carb by itself or all bolted up with the rails off the bikez so I'll assume i need to pass this test first
82" cb650 Nighthawk

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Fri Jan 19, 2018 12:30 pm

i wonder if i could drill a tiny hole at any of the sides of the square plug just so I can make space to push a pick through to free up this alleged ball. I'm starting to get suspicious there's some malicious little creature in there playing tricks on me rather than a rusty bb. I mean, I have yet to actually even see a picture of this supposed ball.
82" cb650 Nighthawk

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Fri Jan 19, 2018 12:58 pm

so I decided to volunteer/sacrifice my extra cover to r&d drilled out the plug to uncover the mystery beneath and I'll be danged:

https://imgur.com/a/UAIeR

I can actually save this if I didn't destroy my other cover if I can somehow furnish another metal plug somehow. I suppose I could sand a piece to fit. geez what a PITA maybe Ill check ebay first if it wont cost me an arm
82" cb650 Nighthawk

MEHall
Posts: 403
Joined: Mon Nov 15, 2010 8:25 am
Location: Sweden

Re: help needed with testing accelerator pump

Postby MEHall » Sat Jan 20, 2018 8:50 am

In my opinion it seems to work properly and as someone said it only need a small squirt. :wink:

So long there is fuel coming out it will work i think. :wink:
Riding bikes? I ride where ever i want and whenever i want. :wink:

Online manual: http://cosky0.tripod.com/

juntjoo
Posts: 247
Joined: Fri Nov 10, 2017 6:19 pm

Re: help needed with testing accelerator pump

Postby juntjoo » Sun Jan 21, 2018 2:51 pm

MEHall wrote:In my opinion it seems to work properly and as someone said it only need a small squirt. :wink:

So long there is fuel coming out it will work i think. :wink:


seems?
this is where I am

https://youtu.be/oca15-dnBnE

I hope you're right but everywhere I looked about this indicated these pumps need to work like squirt guns, and I couldn't get much more than squishy action out of the cap itself or the nozzles in the carb throats, So got one clean used one. After checking all I try again and if it's still behaving like this off the bike I may throw them on and see what happens.
82" cb650 Nighthawk


Return to “Technical Discussion”

Who is online

Users browsing this forum: No registered users and 20 guests