Author Topic: Bogs under load  (Read 1323 times)

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Offline Bigbondo007

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Bogs under load
« on: December 20, 2018, 04:13:55 PM »
Hey guys, I recently acquired a 76 cb750a
 The bike sat for quite a while as the previous owner died. Just had the carbs cleaned as the idle jets were clogged. The bike idles great,and revs fine on the stand, however even after warmup the bike will bog or have low power while under load traveling down the road. If I pull the choke out the bike will speed up and run better/accelerate better. I'm in south GA, the bike is from Missouri and the elevation difference is only 100 feet. The bike is equipped with pd carbs and kv products dyna s electronic ignition, factory air box. I set the initial air/fuel mixture to 1 1/2 turns out. When I first pulled the carbs I noticed the choke cable was adjusted as to have the butterflies 1/2 closed, now they are fully opened.

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Offline bear

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Re: Bogs under load
« Reply #1 on: December 20, 2018, 05:35:07 PM »
The rubber manifolds between the carburetors and the head may not be sealed.
They can go hard over time and allow air to enter into the fuel mixture.
If the bike will idle cold try squirting a little fuel over the rubbers with a mist bottle or something similar.
If the motor increases rev's you've found your problem.
Just be carful and have an extinguisher handy if possible.  ;)
The older I get the faster I was.

Offline Bigbondo007

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Re: Bogs under load
« Reply #2 on: December 20, 2018, 05:42:59 PM »
Next question is where can I find boots for the smaller 750a carb bank?

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Offline Bigbondo007

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Re: Bogs under load
« Reply #3 on: December 20, 2018, 08:41:02 PM »
The rubber manifolds between the carburetors and the head may not be sealed.
They can go hard over time and allow air to enter into the fuel mixture.
If the bike will idle cold try squirting a little fuel over the rubbers with a mist bottle or something similar.
If the motor increases rev's you've found your problem.
Just be carful and have an extinguisher handy if possible.  ;)
Tried propane around all boots and could not get a change in engine rpm. Would adjusting the pilot screw help the bike riding properly or is just an idle mixture adjustment?

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Offline Bigbondo007

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Re: Bogs under load
« Reply #4 on: December 21, 2018, 04:45:35 AM »
There is no coughing or popping from the carbs, I'm starting to think that someone Messer with the needle adjustment.

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