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Author Topic: What's with my #1??  (Read 1200 times)

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Offline Burke

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What's with my #1??
« on: April 11, 2008, 06:24:06 PM »
1977 CB750K
Valve adjusted: Check
Cam Chain adj: Check
New Plugs : Check
Compression on #1: 150 lbs
Timing: Check (At idle and the 2500 rmp per manual)
Carb Sync: Check (About 8.5 inch)

Number 1 is still mis-firing.
Carb problem?
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Offline 750goes

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Re: What's with my #1??
« Reply #1 on: April 11, 2008, 06:36:07 PM »
Check your plug cap for resistance ... and maybe trim a bit of the lead back.. check the length of the lead for cracks in the insulation as well...
is the exhaust pipe running as hot as the other three ??
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Offline Burke

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Re: What's with my #1??
« Reply #2 on: April 11, 2008, 07:20:03 PM »
no. the pipe is cooler than the others.
If I rev it it will fire more often. but still not as it should.

I will check the wire.
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Offline 750goes

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Re: What's with my #1??
« Reply #3 on: April 11, 2008, 08:50:37 PM »
sounds possibly fuel related if it is not getting as hot as the others...

is it only while the bike is idling that it backifires or idles rough, then when you increase throttle to say 3000rpm it all smooths out... I would say you have a plugged idle jet....or a clogged up circuit in the carburretor...
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Offline KB02

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Re: What's with my #1??
« Reply #4 on: April 12, 2008, 06:10:53 AM »
I agree. It sounds like a carb problem.
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Offline Burke

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Re: What's with my #1??
« Reply #5 on: April 12, 2008, 09:00:28 AM »
Quote from: 750goes on April 11, 2008, 08:50:37 PM
sounds possibly fuel related if it is not getting as hot as the others...

is it only while the bike is idling that it backifires or idles rough, then when you increase throttle to say 3000rpm it all smooths out... I would say you have a plugged idle jet....or a clogged up circuit in the carburretor...

Yeah, thats the conclusion I have came to as well. I did some seaches on the forum and  found others that had a simliar problem seem to resolve it by going back through thier carbs again.
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