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Tweaking flat acceleration louder not faster. 29 Nov 2015 10:58 #701102

  • Newton
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Ok - so I am not a mechanic - but I try. 81 KZ750e. I got a needle and jet kit. The last step says to turn the fuel mixtue. "3 - 1/2 turns". Do you think that means 3 and a half turns or 3 half turns.? Normal setting is to back it out two full turns - right?

So i did 3.5 turns. Smelled rich no power.
Did 1.5 turns. No power off the line without reving and in second additional throttle means louder - not faster. Decelleration has backfiring once he is hot.

While in the process of dicking around pretending that I know whatI am doing, i bought a 4 carb sync gauge set. Took me a while to figure out that with three adjustment screws and 4 carbs that the idle speed screw counts as the adjuster for the number 2 carb. Tok me another while to figure out that I should use the vacuum nipples and i could stop looking for screw ports. Anyway - when I had him all connected he would show 2 lbs pressure and would only get out of the red (on the littlegauge) when i rev'd to about 2..5 k.

I read about using carb cleaner to locate a vacuum lean on that part that connects carbs to motor - no leak.
Eventually i just was satisified to have all carbs acting the same - though they registered low.

Did i check the float level? Nope i guess i will get on that.
Did my kit include pilot jets? Nope just needles and main jets - is that a problem? I did remove soak and clean them.
Are the little rubber plugs over my pilot jets compromised? Yep sure are. Is this a problem?
Am i sick to fricking death of pulling the carbs off? Yes i sure am. Its a pain i want to get pods.

Currently bike is at 1.5 turns backed off air fuel mix. Louder doesnt mean faster. I am thinking i have this totally wrong but 1.5 turns. And 3.5 turns is a huge difference, i am surprised it even runs at both.

Is it hard to check the valve clearances and does anyone have a youtube channel thar shows this?

How do i go from 'bike is complete but runs like ass' to ' thats a nice little bike'?
Should i be worried or replace the cam chain tensioner?
Newton

1981 KZ750E
2007 HD Softail Springer Classic
2012 Super Tenere 1200

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Tweaking flat acceleration louder not faster. 29 Nov 2015 12:19 #701116

  • SWest
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Adjust your valves first, then do the carbs.
Steve

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Tweaking flat acceleration louder not faster. 29 Nov 2015 12:35 #701121

  • jertho
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There is a lot of good information on this site, but a service manual for your model is a very good investment if you are doing any work on your bike.
Jerry
1978 kz750 twin

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Tweaking flat acceleration louder not faster. 29 Nov 2015 12:54 #701127

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B)

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Tweaking flat acceleration louder not faster. 29 Nov 2015 16:05 #701159

  • TexasKZ
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Yup, the factory service manual will be the best tool you ever buy.

The valves need to be checked before messing with carb adjustments. If some of the valves are way out of spec, the carbs will need to be readjusted after the valve lash is corrected.

Fuel level needs to be checked next.

Pilot screws should be set to 3.5 out as a starting place. There is no point in jacking with them before taking care of these other matters.

Synchronizing comes last.

Blindly picking thins at random will likely make you want to be an ax murderer.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

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Tweaking flat acceleration louder not faster. 29 Nov 2015 22:28 #701186

  • bountyhunter
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Newton wrote: Decelleration has backfiring once he is hot.

That part usually means lean pilot jets, but can also mean insufficient valve clearance.

I would:

check valve clearance

check timing advancer

set float levels BEFORE doing any carb tuning since the fuel level changes everything.

Definitely need FSM, might find one on Fleabay for $5 (I did).


Is this bike stock or has it been modded?
1979 KZ-750 Twin

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Tweaking flat acceleration louder not faster. 30 Nov 2015 02:20 #701189

  • undiablo
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I have the same engine.
Fuel mixture screw should be set individually to achieve maximun RPMs at idle. My bike has each fuel screw open at different turns. Bike has never run better from idle.

I just donĀ“t trust the "x turns" method.
Kawasaki KZ 750/4 LTD 1981
Kawasaki KLR 650 2011
Argentina - Buenos Aires

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Tweaking flat acceleration louder not faster. 30 Nov 2015 05:11 #701198

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You're learning.... :woohoo:
Steve
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Tweaking flat acceleration louder not faster. 31 Jan 2016 21:00 #708825

  • Newton
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Ok - got the manual.

Valves are all within tolerance. .13 to .18.

I seem to have something going on with cylinder 1. When i pull the spark plug cap off there he makes no different noise or running. Any other plug will kill the bike. There is spark going there though.

I spotted a nasty crack in the carb mount on that cylinder - so I ordered a replacement

When i too the carbs apart and cleaned them - there was the needle and main jet - then another jet (assuming pilot) then a plastic plug with a rubber gasket over what looks like a third jet. I could not find this plug thing mentioned anywhere and i cant figure out if it will allow me to put in a new o ring as the one that was there disintegrated in my hands. I also backed out the main jet to spec and set the needle to spec for the jet kit i bought but left the others alone.

Could i have screwed up the order of the coils going to the plug? Maybe i am sending spark at the wrong time.? Is that even possible?
Newton

1981 KZ750E
2007 HD Softail Springer Classic
2012 Super Tenere 1200

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Tweaking flat acceleration louder not faster. 01 Feb 2016 04:21 #708842

  • JR
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I

seem to have something going on with cylinder 1. When i pull the spark plug cap off there he makes no different noise or running. Any other plug will kill the bike. There is spark going there though.


#1 may not be running. Spray water on #1 exhaust header and it should sizzle right off.

I spotted a nasty crack in the carb mount on that cylinder - so I ordered a replacement

They usually some as a set so better to replace all 4

When i too the carbs apart and cleaned them - there was the needle and main jet - then another jet (assuming pilot) then a plastic plug with a rubber gasket over what looks like a third jet. I could not find this plug thing mentioned anywhere and i cant figure out if it will allow me to put in a new o ring as the one that was there disintegrated in my hands



You have a secondary main jet, a primary main jet and the plastic cap covers the pilot jet which gets its fuel off one of the other two - cant remember which. You need to replace that disintegrated O ring. Bike will not run right or not at all without that cap and O ring seal

Could i have screwed up the order of the coils going to the plug? Maybe i am sending spark at the wrong time.? Is that even possible?



One coil fires cylinder 1 and 4 and the other fires 2 and 3. Each coil will have a red wire and then either a green or a black wire. I cant remember if green goes to the 1 and 4 coil or the 2 and 3 coil but you could try swapping the balck and green/

From your earlier post I would guess that your pilot circuits are still not clean. Soaking in cleaner is not enough. You need to poke through with a bristle or guitar string and use compressed air. If you have the factory manual this will have a section on the pilot circuit a(as well as the other carb circuits) and will also show or mention the cap.

Good luck
1980 kz750E1, Delkevic exhaust
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