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Backfiring Issues
- KZYoungBlood
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I have the air filter case off right now. And most of the backfire seems just misty gas but sometimes it spits out some smoke.
I don't think its gunk from the tank cause I just cleaned it with muratic acid. Are the carbs tuned wrong?
Could you guys help me figure out what's wrong? I'm new to motorcycles & KZ's. Sorry if I can't offer more technical data
1981 KZ1000-J1
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- Patton
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A too tight intake valve may allow combustion inside the cylinder to backfire out through the carb.
Good Luck!
1973 Z1
KZ900 LTD
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- KZYoungBlood
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1981 KZ1000-J1
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- MFolks
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I don't like the Clymer or Haynes versions, but if they have the valve clearance specs and they are easy to follow, I don't see why not in buying one of them.
The valve clearances are checked with a cold engine.Precision shims are used to adjust the space between the valve stem buckets and the cams. The buckets are a large diameter metal shim holders that will need a hold down tool,feeler gauges, and possibly a micrometer or vernier caliper to measure shim thicknesses.
A small magnet,machinist's scribe and plenty of patience and this chore can be accomplished.
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- KZYoungBlood
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you guys sure think its the valve clearance too? its an aweful lot of work and i'd hate to try and fix the valves only to realize that's not the issue :S
www.z1enterprises.com/catalog.aspx?pid=KZ1000-J1-1981-EN1 so i get my shims there. k. but i'll have to buy the $100 shim set cause I don't know which shims I need? :blink:
i found a feeler gauge on z1 but where can i find the valve lifter/hold-down tool?
1981 KZ1000-J1
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- KZYoungBlood
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and i don't think the engine was backfiring when my dad ran it 10 years ago but it is now. what would happen to the valves to cause them to do this?
1981 KZ1000-J1
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- MFolks
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1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- Patton
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But won't know until measuring with a feeler gauge.
Measuring is the easy part.
Changing the shims is a little more involved, but not necessary if the clearances are within specs (i.e., don't need adjusting).
Incorrect ignition timing may also cause backfiring.
Good Luck!
1973 Z1
KZ900 LTD
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- KZYoungBlood
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And I'll do a Point Gap Adjustment and Static (w/ Ohmmeter) Timing Adjustment to readjust the ignition timing.
hopefully this will stop the backfiring
thanks for all the help
1981 KZ1000-J1
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- Patton
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...And I'll do a Point Gap Adjustment and Static (w/ Ohmmeter) Timing Adjustment to readjust the ignition timing....
'81 J model has electronic ignition without points.
Good to verify timing and proper functioning of the advancer by using a strobe-type timing light with engine running.
Am thinking the wrong manual is being consulted.
Good Luck!
1973 Z1
KZ900 LTD
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- KZYoungBlood
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i'll buy the right one soon enough. i feel cheap right now
this manual has details on how to do a strobe-light timing test. it will do no?
1981 KZ1000-J1
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- taildragger1197
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i don't think the engine was backfiring when my dad ran it 10 years ago but it is now.
Sounds like a lean condition to me. Have you cleaned the carbs? At what RPM/speed does it backfire?
Union City, Tennessee
1979 KZ1000 LTD B3
1979 KZ1000(1260)LTD S/G Pro ET
1993 ZX11 D1 Ninja
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