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Author Topic: throttle problem??  (Read 1197 times)

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Offline samfig

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throttle problem??
« on: March 27, 2007, 07:50:03 pm »
Hey Guys,  here is another newbie question ...

When I accelerate my bike while it is idling it seems to take a long time to unwind.  I played around with the thumb screw on the throttle (loosened the hell out of it) and the problem is still persisting.  When the bike is off I play with the throttle and it pretty much snaps back.  I think it might be a carb issue with the needles sticking but I'm not sure since I am new to bikes in general. 

Also, Not sure if this is a related issue or just another thing wrong, but when I'm riding in pretty much any gear and accelerate the hell out of the bike it just bogs down and goes slower!!!!  This seems to happen most in 2 gear and up ...  I played with the choke while riding (opening it up a little bit) and it helps ... but then the bike costs on its own, which is something I don't like. 

Any help on either of these problems would be a great help.

Thanks in advance guys  ;)
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-1973 CB750

Offline medic09

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Re: throttle problem??
« Reply #1 on: March 27, 2007, 07:56:40 pm »
What model bike are we talking about?
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Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline TwoTired

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Re: throttle problem??
« Reply #2 on: March 27, 2007, 11:26:32 pm »
I agree, the problem may be that your bike just doesn't know who or what it is.
Perhaps it doesn't know if it is in stock configuration or has modifications, either.

A mechanical psychiatrist might be able to help.

Cheers,

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Lloyd... (SOHC4 #11 Original Mail List)
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Offline samfig

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Re: throttle problem??
« Reply #3 on: March 28, 2007, 03:09:23 am »
sorry guys.  It is a 1974 CB 750 with stock carbs and air filter, but an after market exhaust.  I hope that helps.
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Offline TwoTired

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Re: throttle problem??
« Reply #4 on: March 28, 2007, 11:39:31 am »
Okay, your carbs have mechanical slides and no accelerator pump.  This design will not accept massive twist grip changes for acceleration without making the mixtures severely lean and the engine losing power.

It *should* accept twist grip changes of up to 1/2 throttle movement and respond properly and vigorously.
If this is you're complaint, learn to live with it.  If the throttle is more sensitive than this, turning in the idle air bleed screws a small amount could help.

Quote
When I accelerate my bike while it is idling it seems to take a long time to unwind. 

I need a translator.  You mean it doesn't return to idle quickly or gain RPM?  When's the last time the carbs were syncronized?  Could you have an air leak(s) between the carb and cylinder head?

???
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline DammitDan

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Re: throttle problem??
« Reply #5 on: March 28, 2007, 11:53:55 am »
If it doesn't return to idle RPMs quickly (takes a while to wind down) then you may very well have a vacuum leak in your carb boots.

Of course it may just be an idle adjuster knob that is turned up too high.  I'm just throwing ideas out there, though.  ;)
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