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All's good-fouled plugs

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versuspop
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Location: columbus, ohio

All's good-fouled plugs

Post by versuspop » Fri Apr 30, 2010 4:28 pm

To start, thanks all for he help over the past year. My CA77 runs great! Like most on this forum my bike's butt is owed to LM.
Here is the situation:
Bike is running well. Carbs et al set to ed's recipe. Accelerates through throttle without hesitation. Fouls plugs black as midnight on a moonless night. This is after 2 20 minute runs on brand new D6HA's. The carbon build up is dry and carbony. Compression at 100/90 on electric start (kick start no workie). I am in no way confident in those readings, as the compression tester was not screwed in, but used one of those rubber tipped thingies. does x+y=top end job?

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davomoto
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Post by davomoto » Fri Apr 30, 2010 5:24 pm

Are the jets and needle factory or aftermarket items? I'm not sure on the dreams, but the CB/CLs use D8 plugs, hotter I think. Perhaps smaller jets will help, sounds like it's running rich.
davomoto
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teazer
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Post by teazer » Fri Apr 30, 2010 5:54 pm

D6 plugs run hotter than D8 and should be able to burn off surplus carbon under normal running conditions. 90/100 sound rather low even for a push on gauge - assuming the throttles were wide open.

Try that test again and repeat after squirting a small amount of oil down the plug holes. If the "wet" reading is much higher, the rings are not sealing properly. Remember, both plugs out and throttle wide open. Watch the needle rise and stop after 5 or six revolutions when it stops rising.

If the compression is actually OK, then it's running too rich.

versuspop
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Location: columbus, ohio

Post by versuspop » Fri Apr 30, 2010 7:07 pm

sorry, but by throttle wide open-you mean have the control cranked all the way?

Goodysnap
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Post by Goodysnap » Fri Apr 30, 2010 7:35 pm

You will have abnormally low compression readings w/ the throttle slide or slides closed. Not enough air to give accurate readings.
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65' CB160

versuspop
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Location: columbus, ohio

Post by versuspop » Fri Apr 30, 2010 7:47 pm

original needle and needle jet. cant't remember if it has original main jet or not, but it is 120. idle jet is 40, and not original equipment. i do have a 35 jet that I think is original.

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davomoto
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Post by davomoto » Fri Apr 30, 2010 10:32 pm

You may want o try that 35 pilot, and chech position of clip on needle. Teazer, thanks for correcting my heat range mistake!
davomoto
64 CB77
63-7 CB77 Cafe'
67 CL77
64 CL72
66 CL77 big bore flat tracker
Many others!

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