1982 cb750c problems

Posted: Sun Apr 26, 2015 9:02 am

I know the title is kind of vague, but where do I start? I bought my first dohc cb750c. Non running off craigslist. It started off as someone's project and they decided to convert it to a chopper Then lost interest. I had to ask, "how did the bike run?" Then my favorite answer. "It was running great before I took it apart." First they told me it had a crack oil pump, which it did, do I replaced that. The carbs were all jacked up. And I was told there was a jet kit installed. Wonderful. So long story short, I fixed the issues the previous owner had stated. I rewired it, got the bike cranking, attached carbs and only two of the float bowls filled up with any fuel, levels were way off. I disconnected the carbs and saw he had installed the float needles upside down, and wedged the rubber tips of the needles into the floats themselves. I corrected them, went over everything else in the carbs and reinstalled them. And carbs were still getting no fuel, spark plugs were also dry. So I took carbs back off and waiting for my new floats and needles to arrive in the mail. So I decided to get a compression tester and without carbs installed I tested the first cylinder which gave me a 40psi reading, I know that's low, like crazy low. Not sure if that's an accurate number being that the carbs were not attached. Not really sure where to go from here. Any input on what I should look for in the engine as of now, more tests I can perform. Actually aanybody's two cents would be appreciated...in the meantime I gotta find out why my virago xv1100 front cylinder in only firing when I am cranking the throttle. Thank you.

Posted: Sun Apr 26, 2015 11:22 am

Welcome to the forum. Read the NMT for the forum rules and how to put your bike model in your sig. Lots of other bike and forum info in the NMT like where we have the Honda Shop Manuals....

40 PSI of compression isn't going to run at all, much less great. You need over 100 psi just to get it started, and it should be more like 175psi to be right.

You get your most accurate compression readings without the carbs on to block in intakes. If the carbs have stuck slides, they'll cause bad compression readings, better off without them to test compression.

Posted: Sun Apr 26, 2015 12:44 pm

Welcome to the site sebastian6880 ... Smile

Posted: Sun Apr 26, 2015 5:30 pm

hello