Author Topic: What's the realistic MPG for CB550?  (Read 17969 times)

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Offline TwoTired

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Re: What's the realistic MPG for CB550?
« Reply #50 on: September 03, 2010, 02:45:57 PM »
That plug does not look lean.
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

...And after 1000 miles at every throttle setting and power setting used during that time (including choke operation) the plug can only show an average.

IE., if the mains are too rich and the midrange too lean you can have plugs that read like that.
How will you differentiate what needs to be fine tuned?

Oh well.  Do what you want.  Best of luck to you.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Raef

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Re: What's the realistic MPG for CB550?
« Reply #51 on: September 03, 2010, 03:01:49 PM »
I think that plug looks pretty good, I know the picture sucks but what do you think?

I did a couple 1/4 throttle and 1/2 throttle checks to day in a school parking, and I only check # 4 saving time and plugs.

that is why I said lean between circuts, not basised on that plug
« Last Edit: September 03, 2010, 03:06:20 PM by raef »

Offline VigCS

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Re: What's the realistic MPG for CB550?
« Reply #52 on: September 03, 2010, 03:25:44 PM »
I usually get around 40 mpg with my 78 550k, but it has pod filters, 105 jets, and isn't very dialed in, so I'm sure it could be better.
'78 CB550K, 2004 KLR650

Offline Raef

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Re: What's the realistic MPG for CB550?
« Reply #53 on: September 05, 2010, 09:38:51 PM »
tried to get the bike on the dyno at the only local shop that has one, it is a Harley dealer, I was told they only did Harley's.

checking the air screws, they were all set at 1 turn, I backed them out another 1/2 turn to 1 1/2, checked the tune up stuff when I changed the fork oil. it's running to good to mess with so at this point 35mpg is what it will be.

 I may take it to the drag strip next week just to see where it's at, I think the grudge matches are on Tue, you can run anything for the price of admission.

Offline hoodellyhoo

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Re: What's the realistic MPG for CB550?
« Reply #54 on: March 04, 2011, 02:32:03 PM »
For those that are interested I just scanned an article about improving the mileage for the cb550. In the end he got it up over 60mpg without losing driveability. Look for it on the main sohc4 website in a few days.
1972 CB350F (Back from the Dead!)- http://forums.sohc4.net/index.php?topic=20822.0
1965? S65 - Coming Eventually!
1972 CB750K2 (father-son project)
1976 CB750K6- (sold) http://forums.sohc4.net/index.php?topic=96859.0
1976 CB750K6 (sold)- http://forums.sohc4.net/index.php?topic=62569.0