81 Honda CB650 C Introduction

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dr4
Posts: 11
Joined: Mon Jun 17, 2013 4:14 pm

81 Honda CB650 C Introduction

Postby dr4 » Sat Jun 14, 2014 6:44 pm

Image

This is my daily ride which I bought about a year ago. It barely ran when I first got it. It has a spitfire windshield and throw-over saddle bags now, and I've put almost 5,000 miles on it (started at 9,652 mi.).

I'm really grateful to all the experience that has been shared on this forum, or I probably still wouldn't have it running!

The most recent improvement is one I should have done a year ago--I finally took the advancer off and thoroughly cleaned and lubricated it. I learned the hard way (done it 3 times)--trying to get it freed up without taking it off does not work. I had been chasing a ghost for about a year, wondering if the sluggish throttle and low gas mileage was electrical or fuel, or just the nature of these bikes. All the time it was the advancer. Huge improvement in performance, smoother shifting, mpg, etc for a one-hour repair.

Many thanks again to the community.

FlipYa4Fake
Posts: 21
Joined: Sun May 04, 2014 10:37 am
Location: Ludlow,MA

Re: 81 Honda CB650 C Introduction

Postby FlipYa4Fake » Sat Jun 14, 2014 11:09 pm

Nice bike. I have a very similar one. I have been searching around and I am having a hard time figuring out what an "advancer" is. Can you please give me further details? Thanks,

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Folsoml
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Location: North Florida

Re: 81 Honda CB650 C Introduction

Postby Folsoml » Sun Jun 15, 2014 8:35 am

Nice bike! Congrats on solving your problem. Can you give a little more detail on how you cleaned the advancer?

FlipYa4Fake wrote:Nice bike. I have a very similar one. I have been searching around and I am having a hard time figuring out what an "advancer" is. Can you please give me further details? Thanks,


The advancer is in with the pulse generator. It adjusts the timing of the bike to account for acceleration.
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

dr4
Posts: 11
Joined: Mon Jun 17, 2013 4:14 pm

Re: 81 Honda CB650 C Introduction

Postby dr4 » Mon Jun 16, 2014 7:58 am

Thanks for the thumbs up. Now that its running better I can begin to concentrate on polishing chrome and cleaning it up more.

The Cosky manual referenced on this site has part of a page on the advancer. It's under "Electrics"--Ignition, p 17-5.

I took it off the bike after turning the crank to line up the timing marks and marking the exact position of the pulsar base against the casting.

Then I completely disassembled the springs, weights, and washers, and used 1000 grit emery cloth and a brass brush to clean it really well. The inside of the part that has the cam was corroded the worst. I used acetone to completely remove the various greases and oils I had tried over the past year.

I decided to use Syl-Glide grease in reassembly (Napa auto store, about $6 for a 4 oz. tube). I put it on all contact surfaces--on the sides of the washers facing the weights and the cam, in the holes holding the springs, on the posts the weights turn on, and on the shaft the cam rotates on.

The inside of the cam was what was really binding and sticking, I think. I didn't realize how the thing actually worked until I got to this point, where you can see how the weights actually move the cam in relation to the advancer unit while the whole thing is rotating. makes sense now.

When I put the advance back on the bike and tightened it down, I aligned the marks I had made on the pulsar base to the case, and double-checked the timing marks. No other timing adjustment was necessary. The first time I rode it, I used the same shifting patterns I was used to, except this time I lifted the front tire almost off the pavement when I let the clutch out in the first 4 gears!

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Folsoml
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Location: North Florida

Re: 81 Honda CB650 C Introduction

Postby Folsoml » Mon Jun 16, 2014 9:39 am

Sweet!
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

dr4
Posts: 11
Joined: Mon Jun 17, 2013 4:14 pm

Re: 81 Honda CB650 C Introduction

Postby dr4 » Mon Jun 16, 2014 7:48 pm

I know this is supposed to be an introduction topic, but while we're on the subject of the advancer--I noticed another side benefit today of getting it freed up. Before, my idle speed would be different at every stop light, anywhere from 1100-1500rpm. Now it settles right down to where it's supposed to be every time. Must have been the advancer stuck a little bit in the advanced position, even at low rpms.

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JorgenL
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Location: Helsingborg, Sweden

Re: 81 Honda CB650 C Introduction

Postby JorgenL » Wed Jun 18, 2014 3:32 am

dr4 wrote:I know this is supposed to be an introduction topic, but while we're on the subject of the advancer--I noticed another side benefit today of getting it freed up. Before, my idle speed would be different at every stop light, anywhere from 1100-1500rpm. Now it settles right down to where it's supposed to be every time. Must have been the advancer stuck a little bit in the advanced position, even at low rpms.


Good heads up on the advancer!
When I first got my bike it was idling all over the place. When I got the advancer off only one of the weights was stuck and the other one moved a little.
It's a pretty smart mechanism, easy to clean and service but often overlooked.


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