Author Topic: First Bike, Summer Project - 1981 CB650  (Read 1564 times)

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Offline iDorsey

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First Bike, Summer Project - 1981 CB650
« on: June 22, 2013, 04:51:42 PM »
Hi everyone! I've been lurking for a while, trying to learn as much as I possibly can about these Hondas. Today I finally picked mine up, a 1981 cb650. I got it for 500$ from a good friend of mine.

The friend whom I bought it from bought it in 2008 as a project. He was only 18 at the time but he worked with a 'mentor' who was a motorcycle mechanic. He brought it from the dead, got new grips, replaced seals and gaskets, new tires, changed the lines, got a new tank, and a lot more. He ultimately got it running pretty well. A few months down the road he left the choke on while doing a bit of riding and the bike died on him. He later got it running a couple of times but it got worse and worse, stalled a bit, and eventually just stopped starting up. The engine still turns but does not start up.

I am a college student and I have about 60 days to get her running again. I have a ton of time on my hands and am willing to spend 4-6 hours a day on this. I plan on utilizing this forum quite a bit as I do not have much mechanical experience, just time and dedication.

 My first goal is to take apart, clean, and rebuild the carbs. I have two sets of carbs - he replaced the 1981 CV carbs with the 1980 mechanical ones. For the sake of ease and simplicity it seems like a good idea to use the CV carbs. I have them out, and I am reading through my clymer manual in order to figure out where to start with the rebuild. After I finish this I will sell the unused carbs, so if you are interested, keep an eye out for that. I am also considering selling it once I get it running in order to attain something more beginner friendly, specifically a gl500. This is premature as I haven't ridden the cb650 yet, ill make that decision down the road.

I have a question - on my journey home I was an idiot and I did a terrible job with the ratchet straps, which led to a gas tank dent. I don't mind it at this point (it's pretty small), and I would like to wait until the bike is running to address it. Does this seem like a good idea? Is there any issue with a dented tank once it is running?

If you have any ideas, thoughts or suggestions I would like to hear it. Thanks SOHC4, you guys are a great help.


Edit: I should add that ultimately I plan on making the bike look stock, except with a gunmetal grey color. My style is kind of clean and minimalist. Right now I am focused on learning as much as I can about the bike and making her reliable. I want to be confident i won't end up at the side of the road, but if I do I want to be confident that I will be able to figure out the issue. After that I will deal with the looks.
« Last Edit: June 22, 2013, 09:21:41 PM by iDorsey »

Offline rb550four

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Re: First Bike, Summer Project - 1981 CB650
« Reply #1 on: June 24, 2013, 04:21:27 PM »
Change the plugs, rebuild/or clean the carbs depending on condition, then try it out.
Some times dents can be dealt with with a hairdryer and some dry ice depending if it's a very shallow no kink ding kind of dent, that won't effect if it runs either way.
Main thing is to get her up and running. Play safe and have fun.
A few Honda 500's, a few Honda 550's, a few Honda 650's, '72 cb 450, a couple 500/550/650 hybrids, and 2001 750. 
  550 Snowbike -Somebody had to do it.
  http://forums.sohc4.net/index.php/topic,101678.0.html             
http://forums.sohc4.net/index.php/topic,137317.msg1550907.html#msg1550907

Offline 750cafe

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Re: First Bike, Summer Project - 1981 CB650
« Reply #2 on: June 24, 2013, 05:53:27 PM »
It certainly looks like a great starting point to me.
Mine, usually start out in boxes.  ;)

As mentioned prior, get those carbs squeaky clean, change the oil and filter, put some fresh gas in the tank with an entire 15 ounce can of Berryman's B-12,
new plugs and adjust the valves. She WILL run!

Eric
Is there anything more fun than riding? They are between your legs and are quiet when you turn them off.

Offline iDorsey

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Re: First Bike, Summer Project - 1981 CB650
« Reply #3 on: June 26, 2013, 02:53:39 AM »
The carbs are all cleaned up! The extra set of carbs that I have is actually another set of cv carbs, so I just had a ton of extra parts and was able to use the best ones. They really weren't as bad as I was expecting, i thought it was a pretty easy job.

Tomorrow I'm going to remove the battery and start charging it, change the plugs and air filter and put the carbs back in. Should be able to try starting her up on thursday or friday.

Offline 750cafe

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Re: First Bike, Summer Project - 1981 CB650
« Reply #4 on: June 30, 2013, 09:09:10 PM »
Extremely important to change the O-rings around the fuel seats and make certain to poke/clean the enrichment tube orifice with a tiny torch tip cleaner or tiny metric drill.
If you don't replace those O-rings, it will always run rich or dump fuel into the crankcase oil or both.
If you don't clean out that tiny little orifice, it will not get the extra fuel needed to start when cold. (no choke)

Eric
Is there anything more fun than riding? They are between your legs and are quiet when you turn them off.