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ZIA revs hanging when throttle is blipped

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garybrez
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Re: ZIA revs hanging when throttle is blipped

#16 PostAuthor: garybrez » Sun May 19, 2019 2:21 pm

Sorry … dropped the needles a notch to reduce mid range lean running

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Pigford
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Re: ZIA revs hanging when throttle is blipped

#17 PostAuthor: Pigford » Sun May 19, 2019 2:28 pm

garybrez wrote:Sorry … dropped the needles a notch to reduce mid range lean running

Raised the needles by lowering clip on needle to lift it & make richer is what you’re saying :wink
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garybrez
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Re: ZIA revs hanging when throttle is blipped

#18 PostAuthor: garybrez » Sun May 19, 2019 4:05 pm

That's the one … cheers

needaz1100r
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Re: ZIA revs hanging when throttle is blipped

#19 PostAuthor: needaz1100r » Mon May 20, 2019 6:47 pm

garybrez wrote:Latest … pilot & main jets increased to 120 / 20 and lifted the needles a notch …. running better but still hanging on blip …. while the carbs were off I put my hand over each inlet rubber then turned the motor over, all kept a good vacuum until I removed my hand except, cyl 3.... I removed the inlet rubber on cyl 3 and still no vacuum ….. could this be the problem


It won't help anything. Did you do a compression test?

Valve clearances is next to check I think.

Something I have learnt is that these bikes are 40ish years old, they can have lots of little things that give the symptom of one thing or another and lead to you chasing your tail as you find one or other of the small problems and it doesn't sort it.

Valve clearances, cam timing (you'd be surptised how often the inlet cam is got one tooth out), inlet rubbers good and sealed and making vacuum, compresion check, new plugs, clean carbs especially pilot circuits and blowing through or carb cleaner or ultrasonic is often still not enough, clean air filter, good coil voltage is all a must, just for starters.
Cheers,

Mark.

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Ultim8pc
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Re: ZIA revs hanging when throttle is blipped

#20 PostAuthor: Ultim8pc » Thu May 30, 2019 8:01 am

Got to agree with Needaz1100r here.
Unless you know everything else is OK, you could be wasting your time thinking it's the carbs.
Many bad running issues can be carb related, but as has been said, a problem in some other system can exacerbate things or appear to be a carb issue.
Last edited by Ultim8pc on Thu May 30, 2019 2:27 pm, edited 1 time in total.
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Richard L
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Re: ZIA revs hanging when throttle is blipped

#21 PostAuthor: Richard L » Thu May 30, 2019 8:30 am

Hi ,
Been there and got the post card , spent weeks mucking about with the carbs on my 1100 because revs were hanging on in the mid range and eventually turned out that the so called expert that had done some top end work had managed to set up the valve timing 1 tooth out . I never realised that the bike would start and run ok in this state but hanging revs was the most obvious symptom . Saying that other problems give similar results so do not assume anything . Good luck and lots of patience ! My breakthrough was borrowing a set of carbs that were running well and discovering the symptoms remained .

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Re: ZIA revs hanging when throttle is blipped

#22 PostAuthor: needaz1100r » Thu May 30, 2019 8:59 am

Richard L wrote:Hi ,
Been there and got the post card , spent weeks mucking about with the carbs on my 1100 because revs were hanging on in the mid range and eventually turned out that the so called expert that had done some top end work had managed to set up the valve timing 1 tooth out . I never realised that the bike would start and run ok in this state but hanging revs was the most obvious symptom . Saying that other problems give similar results so do not assume anything . Good luck and lots of patience ! My breakthrough was borrowing a set of carbs that were running well and discovering the symptoms remained .


It will start like that (one tooth out) as you can testify, and run, but will be down on compression and give all of the symptoms of that.
Cheers,



Mark.

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garybrez
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Re: ZIA revs hanging when throttle is blipped

#23 PostAuthor: garybrez » Sun Jun 02, 2019 12:17 pm

thanks again for your advice …. did compression test on all cylinders … #3 had no compression all others erratic around 90psi ….. checking valve clearances #3 inlet is zero so is not closing … all others are out of spec … so I have some shimming to do … need a tool now


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