Author Topic: Newb with a serious dream!!!  (Read 548 times)

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Offline ProjectThor

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Newb with a serious dream!!!
« on: July 24, 2017, 01:19:59 AM »
Hello! First off my name is Ty and I am from AZ, I am new to this forum and to motorcycles in general. Although I may be new to this, I had purchased a 1978 cb550k from the second owner a few months back. It was a bit beat up honestly and had not run in the past 6 years. The owner could not figure out what was wrong with it and sold it to me for cheap. After a good carb clean and rebuild later and replacing of broken and missing parts, I got the bike fired right up! It only took me about a week to learn how to get it back from the dead but due to financials, it really took me two months.... But none the less, it is alive!!! It does have some problems though that I hope to find the solutions to through this forum. I'm going big on this bike and need to get it to run perfectly (at least close to perfect) before I make this bike into one of the main attractions for this cb550 model. If have questions or comments about my plans, I would gladly share all of my thoughts out loud. The current problem with the bike is that it DOES NOT WANT TO IDLE. I turn it over and it will occasionally rev up to 3rpm and stay there. I can only ride the bike when the CHOKE IS ON. If the choke even slips a little off it dies. Also, for whatever reason when I put the bike into first gear, it stalls out REPEATEDLY. I have noticed though that when I prop up the rear tire off of the ground, I can shift through the gears very easily without any stalling, could that be because of the lack of my body weight on the rear tire?? I have no idea but I hope that I can find out. And the last thing that I have noticed is that when I lean the bike to my right, the rpm lowers until it decides to die where as if I lean to the left, the rpm stays the same and nothing happens. Not sure why it is acting that way and I cannot seem to find a forum that addresses that problem for the pd46c carbs on this cb550k. If anyone may know what could lead to these poor performance conditions, advice would be extremely appreciated. Thank you.

Offline calj737

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Re: Newb with a serious dream!!!
« Reply #1 on: July 24, 2017, 05:18:01 AM »
Welcome. Your issues with idling and surging sounds simply like improper fuel levels in the carbs. Use the "Clear Tube" method for accurately setting the fuel.

The high idle can be either a vacuum leak around the carbs (spray some aerosol around the carbs, boots, manifolds) to see if the RPMs change. If they do, there's your issue. Does the bike still have the stock airbox?

The "dies when shifting into 1st" can be stuck clutch plates (common for a bike that hasn't run in years) or an improperly adjusted clutch cable. Do you have the Shop Manual? It can be downloaded from this site-
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline jaynatola

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Re: Newb with a serious dream!!!
« Reply #2 on: July 24, 2017, 10:05:51 AM »
Greetings from Vermont.....welcome

Offline ProjectThor

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Re: Newb with a serious dream!!!
« Reply #3 on: July 24, 2017, 01:47:22 PM »
Sounds great!!! I'll work on the bike and do my best to get those problems fixed, there more than likely is a vacuum leak considering the last owner gave me boots with these long cuts on the side of two of them so that more than likely is one of the issues, I just tried to fix it with duck tape as a temporary fix until I buy some new ones. I thought there was something wrong with the fuel height too on the carbs so I will work on that, as for the clutch.... hey how tough can it be right? I will adjust the wire first and then take a look at the disks. Thank you for the help and contributing to this masterpiece waiting to be built. And greetings to you too jaynatola! I will have pics up of the progress as soon as possible.

Offline jgger

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Re: Newb with a serious dream!!!
« Reply #4 on: July 24, 2017, 05:49:28 PM »
Before you adjust anything on the clutch, check to see if it is disengageing. Put it in gear with the motor not running and see if you can roll the bike around with the lever pulled in. If you can't  then put it in 3rd or 4th gear and pull in the lever and rock the bike foward and backwards. This may break the plates loose for you.

If it breaks free then try it running to see if it needs further adjustment  or has solved the issue. The clutches on these bikes can lock up from sitting/sleeping for extended periods of time.
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Offline ProjectThor

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Re: Newb with a serious dream!!!
« Reply #5 on: July 24, 2017, 09:01:58 PM »
Thank you jgger!! sounds like a plan and I will do