Ok, I know that there has been much posted about carb issues on this forum. I have looked at most of them at least twice. My Ca77 was ridden by me one time. That was the day that I bought it. I had it on my trailer and my Blazer quite running about five miles from home. So, I untrailered the Dream hoping that it would start and run. I was grateful and surprised when it did. I got about two miles from home when the rear tire blew. So, I had my Blazer, trailer and now my Dream sitting by the road side within five miles of home. Not to concerned about trailer and Blazer open to the publics view. The Dream I was concerned about. Wife rescued my with the Dream being top priority. Not to concerned about the Dream sitting idly in the garage waiting its turn. I had another identical Ca77 except it was white instead of blue with the red seat. The blue Dream's number came up about a month ago. Surprised at the condition of the carb as it ran quite well when parked. New needle valve and seat, gaskets and replaced float that had pinholes. Checked the oil and added a little fuel. Didn't buy a battery so borrowed one from another ride. It was time for a long delayed test ride. Since I had gone through the carb, I needed to make a few adjustments first. While making the adjustments the RPMs sky rocketed which made my priorities change from adjustments to switching the Dream off. I went through the usual suspects first, FIRST cleaned and lubed the cable and made sure that it moved freely, 2nd resurfaced the mounting flange, 3rdslide was a little sticky so I smoothed it up where it would fall in and with a very little tap in the hand the slide would fall out of the carb, 4th
dismantled the throttle tube and replaced the old grease remnants with new lubricant and made sure that it operated smoothly, 5th replaced the carb slide spring with one from Lowe's as suggested on this forum. None of these efforts helped. I took the throttle assy off and operated the cable by hand so as to eliminate any throttle tube issues. No change, RPMS still maxed out. Finally, I realized I had the same carb on my white Dream so I pulled it and mounted it on the blue Dream. Worked like a champ. I don't like to mechanic by switching out parts but I am out of solutions. I took the slide and needle from the carb that worked (white Dream) and put them in the (blue Dream) carb body. Still revved to the max. I did check for air leaks by spraying carb cleaner around the mounting area of the carb. I had to do this quickly as the RPM's would top out quickly after a few seconds of idling. Spray didn't detect any air leaks. The RPM problem is reminescent
of a two stroke with an air leak. I know another carb would fix the problem, however, I am interested in knowing what is going on here. That is why I posted this problem. I realize this is pretty lengthy but I also know that the background of what has been done cuts down on a lot of posts and help resolve the problem more quickly.[/list]
Malfunctionng Carb
From your detailed account it seems that
a) the carb was fine until you touched it b) the bike ran fine when you rode it (almost) home c) the other carb you have also works fine The effect you describe often happens when people install the slide back to front. The cutaway at the bottom goes to the back. I think you just need to re-check the adjustments that you made and closely compare the two carbs. G '60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F From your detailed account it seems that
a) the carb was fine until you touched it b) the bike ran fine when you rode it (almost) home c) the other carb you have also works fine The effect you describe often happens when people install the slide back to front. The cutaway at the bottom goes to the back. I think you just need to re-check the adjustments that you made and closely compare the two carbs. G '60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
Hello G-Man, sorry it has taken me so long to respond. I had a lengthy reply ready to go and lost it because I wasn't logged in. I did get another carb body from ebay. A couple of hours cleaning it and even put a little clear coat on. It was missing the float bowl and other stuff. No big deal, I would transfer my parts to the ebay carb body. It was time to put the float bowl on and much to my disappointment my float bowl would not fit. The sides of the carb body where the bowl snaps in is slightly concave. Whereas my original carb body is slightly bulging on the sides parallel to the engine. I would not have expected the carb body to warp due to not having the float bowl in place. Have you had any experience like this? Here is another effort at replying. I could tell several stories of witnessing the aftermath of slides installed backwards. The slide in backwards usually creates a situation where the bike is difficult to start. The slide in backwards victim then resorts to having a buddy help "bump" start the motorcycle by placing it in 2nd or 3rd gear and pushing it fast as possible and then dumping the clutch. Persistence pays off and it will start but at full throttle in 2nd or 3rd is considerably faster than us human beings were meant to run and hold to handlebars. The excitement usually does not last long, although the consequences may last a life time. What I am about to say next is not for your benefit as you already know the things I will mention. The next few comments are for the benefit of readers that will come along in the future searching for answers and hopefully learning from our mistakes. It is much more difficult to put the slide in backwards than to install it correctly. The return spring stacks up because the slide is not in the slide bore as far as it should be. Twisting the throttle feels different because of the excess slack in the cable due to the slide not pulling the cable to its full length. Always verify that the slide is returning by listening for an audible "thunk" that is made when the slide bottoms out on the idle speed screw. In some cases one can visually verify that the slide is returning with a mirror and flashlight looking into the air intake side of the carb. The easiest way to check that your throttle cable has sufficient slack and not binding is to be at idle speed and turn the handlebars full lock both directions. There should not be any change in engine rpm. If there is then you have a little more work to do. You do not want to discover in a full lock turn that your motorcycle is going to accelerate on its own. If throttle response is erratic, sometimes hard to turn throttle or throttle not returning properly, one should be very afraid that the throttle cable is beginning to fray. Usually at the twist grip or at the carb.
Please send a pic of the carb you are comparing this with. Early carbs had convex sides to the float bowl.
G E
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
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