Topic: bike stalls once clutch is released

[cafe2be]

So the bike in question is my 77 750f. Only mods. Supertrapp muffler and pods. I had pods and a yoshi pipe last year and the bike ran, not great but ran.
The carbs have 125 jets. Cleaned and rebuilt within 200 miles ago.
Synced the carbs and they are within 1-2 cfm of eachother. Pretty straight line. Valves, points and new oil are all done. Plugs are good.

So the bike has a great idle when not in gear. Revs fine. Slam on the throttle and it bogs HARD!

When in gear and trying to ride, idle is still good. Release the clutch and stall outs. Sounds like its gasping for air.

Adjusted the air/fuel knobs everywhere from 1/4 turn all the way to 2 1/2 turns and still the same problem

Fresh gas.

Really confused. Are the main jets too big?

[TwoTired]

Is your accelerator pump working?

[cafe2be]

I replaced it with a new one, when I bought the carb kit.

[TwoTired]

I replaced it with a new one, when I bought the carb kit.

Doesn't really answer the question.
Did you verify that it actually squirts fuel into the carb bores?   There is more to the pump than just the diaphragm.  Two check valves and tiny orifices at the exit jets.

Cheers,

[cafe2be]

gotcha TT, thought it was just the diapram. How can I tell if it squirts? Take off the pods and pull the throttle? 1 carb, 4 carbs? Thanks for your expertise! Always appreciated.

[TwoTired]

Yes, remove all the pods.  (and give them back to the devil.  )
 Anyway, if you close the choke plates, you'll see a small hole in them that aligns with the top of a post at each carb bore entrance.  The post should squirt a pretty solid stream into the carb bore each time you twist the throttle.

Cheers,

[cafe2be]

TT, if indeed it is the accel pump, what is the fix? Change the diapram again or more complicated?

[TwoTired]

There is a check valve in the pump base that needs to be free to move and seal in the seat, and another check valve in the #2 carb bowl that houses the pump.  Then then are the 4 "post" orifices that need to be clear.

The diaphragm has "mickey mouse" ears.  And, those holes must be clear, too.

Cheers,

[Inigo Montoya]

Certain diaphragms only have 1 open ear though. I have seen a few like this. If you have the stock honda pump, then I think it is 2. Regardless, there should be fuel squirting anyways even if there is only 1 hole.

[cafe2be]

I thought about something. I removed the silicon diode and the bike never has a nuetral saftey switch. Would this be a reason for not being able to ride?
I am going to pull the carbs and check them out.

[Inigo Montoya]

Well maybe but usually not having that safety switch would just cause the bike to lurch if you tried to start it without pulling the clutch while in gear.

[cafe2be]

I have learned that lesson, compliments of the PO. Always engage the clutch on start now. So we are still leaning towards a carb issue I assume?

[Spanner 1]

+ me on the acc. pump...one more thing..there is an O-ring between lower and upper carb body on carb #2 only that seals the pump passage up to the 'squirter' rail that feeds each carb...need to check its there. It comes with a carb rebuild kit and is 'left over' on carb #1, #3,#4 so you should have spares !!  These PD carbs are completely dependent on the acc. pump above idle to get the bike enough rpm/vacuum for the slow jet to come on stream....

[cafe2be]

Spanner, I will definately check out the carbs. I will look for that oring. Have a pic of location by any chance?
Thanks
Andrew

[Spanner 1]

Sorry, I don't have a pic., it's pretty easy to see the passage and its match in the upper carb body when you drop #2 float bowl....

[cafe2be]

I am definately going to pull them tomorrow and check them out. This is the only thing preventing me from riding the bike!