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wally34

Joined:

Dec 11

Posts: 68

wally34 says:

poor running at low speeds

Ihave a zzr1100c1 and recently cleaned carbs and replaced air filter.Last month the bike started o.k. and pulled o.k. but on deceleration it started to sound as if it was missing a cylinder and the revs fell when coming to a standstill.It all cleared up on return journey home from work but after 10 miles it started to backfire on deceleration.Could anyone offer any ideas please.

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  • Posted 2 years ago (19 January 2013 20:29)

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jaffa90

Joined:

Mar 09

Posts: 8790

jaffa90 says:

backfire

Very difficult this one,the spark plugs will tell all but a ball ache to check,are you talking exhaust noises or spitting back through the carbs? Is there a smell of fuel around the carbs/end of exhausts? Is the exhaust system airtight and are the down pipes the same temp (don`t burn yourself).Did the carb slides lift all together  and return slowly? When were the valve clearances last checked? What colour is your fridge? (that`s a smidget joke):lol:

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kcmc

Joined:

Jan 08

Posts: 7082

kcmc says:

Kawasaki ZZR 11OO C1

Hi Wally34

At this moment with the info given it sounds like its fouling a plug,this could be due to one carb being out of whack ie to rich,to weak,or an electrical fault like say H.T.lead plug cap,or maybe a split vacuum pipe to a carb?Good Luck

KCMC:tongue: 

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wally34

Joined:

Dec 11

Posts: 68

wally34 says:

poor running

Jaffa the noise is definately coming out of rear and i would be almost certain it is the left exhaust.No unusual smells carbs were all balanced.What about carb float bowls,brother in law suggested draining them in case there is any water in there .Have not checked spark plugs yet Kcmc ,what should i be looking for?:doubt:Valve clearences not checked but would this lead to the backfiring and lowering of the revs? 

[This Reply has been modified by the Author]

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jaffa90

Joined:

Mar 09

Posts: 8790

jaffa90 says:

carb

Water? You`ve cleaned the carbs,no harm having a look.

Does/did all the carb slides return slowly after lifting them up slowly?

It`s possible you have one carb overfilling (needle valve) and giving a rich mixture and excess unburned fuel firing in the exhaust system.(spark plug will tell all).

It`s possible your valve clearances can tighten up when the engine warms/heats up.

Have you checked the colour/level of your engine oil and coolant?

Going back to the water is your overflow pipe working/blocked just in case water is getting into the tank cap?

For now.     

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smidget

Joined:

Nov 07

Posts: 2387

smidget says:

Hi wally34

I have to ask why you decided to originally remove and clean the carbs?

What if anything was replaced whilst the carbs were off the engine?

How did the jets get cleaned (was wire used to clear / clean them).

What settings were adjusted if any?

When was the last service done on the bike?

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wally34

Joined:

Dec 11

Posts: 68

wally34 says:

poor running

Carbs were removed as i bought bike without any service history and the same problem was occurring with revs dropping etc .Will check all the above and post an analysis when iget her into the garage.Another theory is when i checked the overflow pipe on fuel cap i found it was bunged at both ends with black sealant,tried to remove it from overflow but i know there is some left in there,what would this do to the running of the bike.

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jaffa90

Joined:

Mar 09

Posts: 8790

jaffa90 says:

poor running

Overflow as my last post,your tank should have a breather pipe as well so fuel can get out of the tank.

Have you run the bike in a dark garage to see if there`s any sparks flying about above the engine?

I hope that your header/down pipes are sealed.

 

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smidget

Joined:

Nov 07

Posts: 2387

smidget says:

Hi wally34

blocked overflow pipe will mean that any spilt fuel will vacate the area anyway it can, it should not effect the engines running.

As you are not aware of the bikes past service history then your best course of action is to carry out a full service. Whilst doing this you will have the chance to inspect all pipes leads wiring connections earth points, etc.

This will eliminate all the basic engine settings from the equation.

Do this first and then see what happens.

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wally34

Joined:

Dec 11

Posts: 68

wally34 says:

poor running

:smilethat s the best advice and the most sensible thanks for everybodys input will keep you all posted

[This Reply has been modified by the Author]

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