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Sputtering Under Hard Acceleration
- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
If you have full advance at 4K RPM, and the problem is 6-7K, the advancer should be ruled out. Capacitors usually will make it crap out all of the time, not just at a certain RPM range. But another thing to consider on you Points set up would be Dwell Angle, which is point gap. This can change drastically under RPM do to point "Bounce". This is from a weak spring on the Point assy. Does you DVOM have a Dwell measurement capability? If so check your dwell angle, set the point gap so the Dwell is correct, then rev the motor watching for a big change. The Dwell should remain constant with just a couple of degrees. This Dwell Angle is the Time of Charge for the Ignition Coils, so is quite important.
1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- Topper
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bluej58 wrote: Because of all I have read about problems with inline fuel filters screwing with gravity fed systems,
I abandoned the idea and am putting all my trust into the petcock filter because the screen is very fine and I figure anything that passes it through will make it past the jets and get burned up.
Interesting. My petcock screen has a small hole in it. I'd need to replace that if I were going to run without inline filters. I'll take it for a ride without the filters just to see if the problem goes away.
Motor Head, I do have an air compressor, but the filters are brand new. So I don't think they're clogged.
I do not have a dwell angle tester, but I might know a buddy who does. Maybe I'll swing it by his place.
Permanent and perpetual noob.
1979 KZ750 Twin
2009 Kawasaki Versys
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- baldy110
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- Topper
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I replaced the coils with new Emgo ones shortly after buying the bike.
Permanent and perpetual noob.
1979 KZ750 Twin
2009 Kawasaki Versys
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- Rainman
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and have not had any problems (with this) since.
Good luck,
Jim
80 KZ750 H1 - the Kaw calf
79 KZ750 Twin - Miss Nov 2008 KZR calander
79 KZ750 Twin parts bike
78 KZ650 C2 Parts Bike
75 KZ400 Wife's old bike sold
81 KZ440 A2 LTD Wife's new bike
84 Honda 450 Rebel Wife's newest bike
Jim
Quincy,IL
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- Patton
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If any doubt whatever, would charge overnight and have it load-tested.
If not already done, would assure good ground connection where the negative battery cable attaches to the engine.
With engine off and ignition switched on, what voltage is actually being received at the coil primary terminal?
With ignition switched off, what is voltage between the battery posts?
Is the air filter fresh and clean?
And nothing blocking the intake (such as shop rag, gloves, etc.)?
Good Fortune!
1973 Z1
KZ900 LTD
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- Motor Head
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Motor Head, I do have an air compressor, but the filters are brand new. So I don't think they're clogged.
I do not have a dwell angle tester, but I might know a buddy who does. Maybe I'll swing it by his place.[/quote]
Unless you still have a bunch of junk in your tank, running without an in-line filter to see if it is the cause shouldn't be an issue. Good Idea to run one, i run one, but you don't want a restriction. I run an Automotive filter, metal not plastic, no restriction, it can feed a 500 cid motor under 6 psi of pressure. So a gravity flow is ok. I had one of those other Motorcycle filters and it would starve it under hard running.
1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- Topper
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I'm leaning towards it being the timing advancer, but I've got some other issues to work out before I come back to this. I'll keep you posted.
Permanent and perpetual noob.
1979 KZ750 Twin
2009 Kawasaki Versys
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- martin_csr
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- Patton
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If not already done, would install brand new spark plugs (not-R type), and solid metal core plug wires; and eliminate resistor caps (if being used); all toward minimizing resistance in the secondary loop.
Would also perform ohm check on secondary loop.
And would measure voltage being actually received at the ignition coil primary terminal, which should ideally match voltage measured across the battery terminal posts. As it's critical that the battery is good, fully charged, and holding its charge, and that the full charge is being received at the coil.
Good Fortune!
1973 Z1
KZ900 LTD
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- Topper
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Battery is about a year old and has been recently tested.
Permanent and perpetual noob.
1979 KZ750 Twin
2009 Kawasaki Versys
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- Patton
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Topper wrote: I haven't checked the voltage recently, but the ignition coil (and wires) were replaced with a new Emgo coil last year. At the time I remember having good voltage at the coils, but I should test again. Battery is about a year old and has been recently tested.
Are suppressor type plug wires fitted (as opposed to solid metal core)?
Are resistor spark plug caps fitted (which can go bad and create excessive resistance)?
Resistance in the secondary loop should be measured to determine whether it's within the specs as provided in the FSM.
Excessive resistance in the secondary loop may result in stumbling while under high speed acceleration, caused by a weaker than needed spark under that condition.
(Sorry to sound like a broken record.)
Good Fortune!
1973 Z1
KZ900 LTD
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