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Engine started to sputter in gear
- Bunty27
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Background: When I was setting the fuel level on the carbs, I noticed one of the brass overflow tubes had a crack. I used epoxy to seal it up and verified that the leak stopped and also that the overflow mechanism itself was working and the tube wasn't blocked or anything.. I then reset the fuel level correctly.
This morning, before the test ride, I noticed that one of the overflow carbs(not the one with the crack) was leaking full on PRIME. I hit the carb bowl with a screwdriver suspecting a stuck float and that stopped the leak. Not sure if I'm still having problems with the float on this carb. Just surprised that everything was fine for a while before things slowly went bad.
1982 KZ550 LTD
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- 650ed
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1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- Bunty27
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1982 KZ550 LTD
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- 650ed
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Bunty27 wrote: Any suggestions on where I start and what I look for?
I would start with the oil pressure switch. Make sure the connector and wiring are in good shape and not grounding against anything when the engine vibrates. Also make sure your oil level is correct. If that is all good you may need to hook up an oil pressure gauge to test the pressure. If the pressure is good but the light still flickers the oil pressure switch may need to be replaced (no biggy). If the pressure is not good you may have a clogged screen on the oil pump, or worse case but less likely a bad pump. Ed
Attachment 00000_2012-10-15.jpg not found
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- Bunty27
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It was bit chilly this morning but the bike did start up with the choke enabled. However, I noticed that it was struggling to idle and I had to help by giving some throttle. But when I tried to get it moving in gear, I noticed that there was very little power and it was struggling to go. After a couple of seconds and going a few meters, it completely stalled. I pushed it back in the garage and now it won't even start though the engine turns fine. The fuel switch was on prime and I verified again that the fuel is flowing out of the petcock.
I quickly did a compression check and the numbers haven't changed since I checked them last (150 - 170 psi). I then did a spark check and though everything seemed to look good, I'm concerned about the spark on plug #2. I did install new plugs and recently cut a 1/4" off the ignition cable.
I did not see the oil light come on this morning during the test. The bike went from riding just fine to sputtering and power loss to more power loss to complete death. I was soo excited that I was ready to ride just in time for the fall weather but it looks bad this time. What should I be looking for? Thanks for all your help.
1982 KZ550 LTD
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- Patton
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Has an in-line fuel filter been fitted continuously since the carbs were reassembled?
Advancer --
Has correct operation of the ignition timing advancer been verified by observing it with a strobe type timing light to see it quickly moving back and forth as rpm is varied by blipping the throttle?
If the engine won't crank and run, would lube the advancer pivot points anyway, and attempt to manually move the weight arms in an effort to assure they aren't stuck. Access may be gained through the timing inspection window.
If the advancer looks rusted or seems tight, would remove it for clean-up and lubing.
Spark --
What's the apparent issue with spark on plug #2?
Good Fortune!
1973 Z1
KZ900 LTD
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- Bunty27
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Yes, I did install a in-line fuel filter since the carbs were re-assembled.
I did lube the advancer and verified that the springs were good (by moving it by hand). I have a transistorised ignition so timing shouldn't be the issue. The engine does crank just fine but doesn't fire up and run anymore.
Not sure about the Spark plug but I don't see a nice big blue spark but a mixed blue and yellow spark on each of the plugs that kinds looks weak. I will try and test the coils as explained in the manual later this evening but could this be the issue?
1982 KZ550 LTD
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- Patton
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Bunty27 wrote: ...The engine does crank just fine but doesn't fire up and run anymore.
Not sure about the Spark plug but I don't see a nice big blue spark but a mixed blue and yellow spark on each of the plugs that kinds looks weak. I will try and test the coils as explained in the manual later this evening but could this be the issue?
Where the starter motor spins over the engine just fine, it indicates that the battery is okay and sufficiently charged.
Less than perfect spark at the plugs is sometimes due to inadequate voltage at the ignition coils' primary terminals, often due to corroded wiring connections somewhere along the line between the battery and the coil.
Ideally, voltage actually received at the coil primary terminal should match battery voltage measured across the battery posts. Look for 12+ volts at each coil primary terminal with the ignition ON and engine not running.
If voltage at the coils is lower than battery voltage, here are some places to check for voltage loss:
Ohm checking the primary and secondary coil windings is okay, but usually both coils don't fail simultaneously. Would ohm-check the secondary loop both ways, being from plug cap to plug cap, and also with the plug caps removed (from core to core).
Are the original spark plug wires still in service?
Good Fortune!
1973 Z1
KZ900 LTD
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- Bunty27
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Thinking more about this, the sparks that I noticed earlier this morning didn't look way different from when I checked them just recently before I put the carbs back on. The fuel seems to be moving through the carbs fine since I loosened the overflow screw on the carbs and noticed the fuel flow freely when the fuel switch was on prime. Also, with the overflow screw turned in, I don't see any overflow which would suggest that the float valves are working well too (the float valves are brand new).
So if the sparks are ok and the fuel is flowing through the carbs and the cylinder compression is fine, what else could slowly kill power and turn off idle start? I could easily start the engine with the choke engaged without any problems for many months until this morning when it stalled. Hmmm......
1982 KZ550 LTD
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- Patton
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One possible reason could be too tight valve clearances.Bunty27 wrote: ...So if the sparks are ok and the fuel is flowing through the carbs and the cylinder compression is fine, what else could slowly kill power and turn off idle start?....
Good Fortune!
1973 Z1
KZ900 LTD
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- Bunty27
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My model has air suction system and I was reading in the manual that problems with this valve could result in sudden power loss. I'll take a look at it this evening and see how it's doing.
I'm stumped!!
1982 KZ550 LTD
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- Bunty27
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Any more ideas on what may be happening? Thanks for all your help as always.
1982 KZ550 LTD
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