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Popping from exhaust, just on idle, runs great,
- bloglos
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The popping from the exhaust started happening shortly after this. Very faint at first, to the point where I thought I was imagining it, then over the course of two weeks became louder and louder. Pop comes from the right exhaust (which flows from exhaust 1+4, not stock pipes, came from a different model KZ650)
I'm pretty militant about regular maintenance, so I check plugs, points, valve clearance, oil change very regularly.
Valve clearance was all well within spec in the spring with the exception of #1 intake being at the bottom of the spec. Plugs look good, points are good.
Regardless I'll be:
Checking for vacuum leaks on the carb boots
checking points again
valve clearance (I'm not really sure valve clearance would play a roll in the popping?)
Cleaning carbs again (If I have to)
I would appreciate any advice from the old pros around here if they have any hunches on what might be happening.
78 KZ650 C2 - Runner
77 KZ650 B1 - Project
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- Patton
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Fresh air filter, clean and unobstructed (gloves, shop rag, etc. stored under seat);
Clear tube test to assure fuel levels within spec;
Watch timing advancer under a timing light to assure rapid movement back and forth as rpm is varied by blipping the throttle (lube the pivot points);
Assure choke plungers are fully closing down.
Good Fortune!
1973 Z1
KZ900 LTD
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- Patton
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Good Fortune!
1973 Z1
KZ900 LTD
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- bloglos
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I will check the timing advancer with a timing light once I get my FSM back from a friend, but could you explain where I need to oil? Where are the pivot points?
Attachment PointsElec1.jpg not found
Patton wrote: If not already done, would address the following areas:
Fresh air filter, clean and unobstructed (gloves, shop rag, etc. stored under seat);
Clear tube test to assure fuel levels within spec;
Watch timing advancer under a timing light to assure rapid movement back and forth as rpm is varied by blipping the throttle (lube the pivot points);
Assure choke plungers are fully closing down.
Good Fortune!
78 KZ650 C2 - Runner
77 KZ650 B1 - Project
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- Patton
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Advancer weight arm pivot points should be accessible for lube through the timing inspection window.
If the advancer moves quickly back and forth while viewing the timing marks with a timing light and changing rpm by blipping the throttle, may rule out the possibility of a sticking advancer as the cause of the performance issue.
If the advancer is sticking in one position, it should be lubed, and probably both cleaned and lubed.
From the reported history, would most likely suspect that the bike began running richer for whatever reason.
Good Fortune!
1973 Z1
KZ900 LTD
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- bloglos
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So I guess the next course of actions would be:
1. check for a strong blue spark?
2. check points (I ordered new points and condensers as the old ones where getting pitted, I cleaned and filed and set the old ones so they work but they are so inexpensive I'd rather replace them with new
3. Replace coils and wires.
I had purchased a new set up EMGO coils for a previous KZ650 and took them off after a summer as they seemed to run very poor in comparison to the old coils (stalls, hard to start etc) Can someone recommend a better coil set? I don't mind spending some money if they are worth it for performance. I love my old KZ.
78 KZ650 C2 - Runner
77 KZ650 B1 - Project
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- Patton
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Given decent spark quality on #1, the dark plug would result from weak compression and/or an over-rich fuel mixture.
Ruling out weak compression leaves over-rich fuel mixture. Unless it's oil fouling due to a damaged oil ring.
If the clear-tube test shows fuel level within specs, the excessive richness might result from such things as a loose pilot jet (or the earlier mentioned possibility of a choke plunger issue), or perhaps an obstructed air passage in the pilot circuit, or a damaged needle on the pilot adjuster screw.
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1973 Z1
KZ900 LTD
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- bloglos
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I'll report back once I eliminate a few more things.
Patton wrote: #1/4 spark plugs are in the same secondary loop from the coil, whereby number 4 plug being nice and tan would indicate adequate high intensity voltage, and suggest some other reason for the dark #1 plug.
Given decent spark quality on #1, the dark plug would result from weak compression and/or an over-rich fuel mixture.
Ruling out weak compression leaves over-rich fuel mixture. Unless it's oil fouling due to a damaged oil ring.
If the clear-tube test shows fuel level within specs, the excessive richness might result from such things as a loose pilot jet (or the earlier mentioned possibility of a choke plunger issue), or perhaps an obstructed air passage in the pilot circuit, or a damaged needle on the pilot adjuster screw.
Good Fortune!
78 KZ650 C2 - Runner
77 KZ650 B1 - Project
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- mark1122
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- Keep twisting it
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also , it wouldn’t hurt to check that all exhaust bolts r tight. if they r ok, i might take the exhaust off. then examine the seals. u would be looking for signs of exhaust leakage, such as a dark soot path . the gasket should show no sign of soot escaping . exhaust leaks can cause exhaust popping sounds.
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.
~ ~ ~_@
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~ (k) / (z)
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- 650ed
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www.scribd.com/doc/48655900/Kawasaki-KZ-...B1-77-Service-Manual
What spark plugs are you using? The ones recommended in the original manual (including the electronic one above) are 1 heat range too cold. Later manuals corrected this error. Correct plugs are NGK B7ES or ND W22ES-U.
If possible, swap spark plug connections at the spark plugs between 1 & 4. If the problem stays with cylinder 1 the coil, wires, and cap are ok. If the problem moves to #4 you have isolated the problem. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- bloglos
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650ed wrote: While you're waiting for your manual to come back, here's an electronic copy:
www.scribd.com/doc/48655900/Kawasaki-KZ-...B1-77-Service-Manual
What spark plugs are you using? The ones recommended in the original manual (including the electronic one above) are 1 heat range too cold. Later manuals corrected this error. Correct plugs are NGK B7ES or ND W22ES-U.
If possible, swap spark plug connections at the spark plugs between 1 & 4. If the problem stays with cylinder 1 the coil, wires, and cap are ok. If the problem moves to #4 you have isolated the problem. Ed
78 KZ650 C2 - Runner
77 KZ650 B1 - Project
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- Patton
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Would consider these 4Ω coils from Z1E:
www.z1enterprises.com/ItemDetails.aspx?i...cap&item=IM01143-55S
www.z1enterprises.com/ItemDetails.aspx?i...aps&item=IM01143-55L
Good Fortune!
1973 Z1
KZ900 LTD
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