Need Help Troubleshooting

If it's broken or just needs tweaked

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weasnerb
Posts: 3
Joined: Sun Jul 22, 2018 12:09 am

Need Help Troubleshooting

Postby weasnerb » Sun Jul 22, 2018 3:39 pm

Hello All!

I just want to note that I am new to this forum and rather new to motorcycling so sorry in advance if I am breaking any forum etiquette.

I bought a 1982 Honda CB 650 SC about a month ago. It was riding fine until last week when it broke down on me.
The bike will start up if in neutral and as soon as I change gears (even before I release the clutch) the motor dies.
In neutral the bike revs easily to 6000 rpm, however after I rev it for a while and try to bring it back to idle, it dies.
Before this started happening, I had some issues the day it broke down where I would be in gear and it would take the bike a while (a couple of seconds) to "recognize" that I was giving it throttle, making all the cars behind me really pissed at how slow I would accelerate.
After a while of this slow "recognition of throttle" any time I gave my bike any throttle that would rev the engine above about 3000 rpm, it would die.

I have been looking around and some forums have said that the issue with the motor dying when put into gear could either be due to a kickstand switch (which I don't believe my bike has) or a sticky clutch, which I don't believe is the case as I can easily switch between gears with the engine off. I am not sure what could be causing this as I said it was running fine for quite some time.

Thanks in advance for your help!

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Folsoml
Posts: 1621
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Need Help Troubleshooting

Postby Folsoml » Tue Jul 24, 2018 4:22 pm

Welcome to the forum!

You are correct in that your bike does not have a kickstand switch. When the bike dies when you put it in gear, does it feel like it wants to lurch forward at all? If so, the issue could be that your clutch is not disengaging. I know you say it shifts fine when the bike is off, but the clutch would have little effect on that.

Have you cleaned the carburetors since you've had the bike? What about the fuel tank? Do you have any kind of fuel filter on the fuel line? Check inside the tank and see if there is any rust visible. A chunk of crud could have worked it's way loose in the tank and made it into your carbs, and is now plugging something up.
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,

weasnerb
Posts: 3
Joined: Sun Jul 22, 2018 12:09 am

Re: Need Help Troubleshooting

Postby weasnerb » Tue Jul 24, 2018 11:23 pm

I tried getting it to run today and now it won't start. I sometimes hear a click, but it won't turn over at all.

As far as changing gears, even with the bike turned off it seems that I am having some difficulty changing gears. I think you are correct that I am having an issue with my clutch disengaging, or at least sticking

I talked with the previous owner and he said that he cleaned the carbs a month or so before I bought it. As far as the fuel tank goes, it looks alright just looking in, and I have been adding some seafoam to it the few times that I have gassed up. I have not yet checked to see if I have a fuel filter and whether or not it is clogged. I'll do that tomorrow and update this thread.

Thanks for the help/pointers!

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Folsoml
Posts: 1621
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Need Help Troubleshooting

Postby Folsoml » Wed Jul 25, 2018 12:02 pm

The first thing is: Never believe anything a previous owner told you. :lol: If he said he cleaned them a month ago, he may have done it last year sometime.

Seafoam IS one of the things that can cause something in the tank to come loose. There is a fuel filter built into the petcock, but over the years, these have often disintegrated. So if there is not an aftermarket filter in the line, there's nothing to keep the crud from going straight to the carbs.
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,

weasnerb
Posts: 3
Joined: Sun Jul 22, 2018 12:09 am

Re: Need Help Troubleshooting

Postby weasnerb » Wed Jul 25, 2018 12:13 pm

So it looks like I will be draining the tank, checking the petcock, and cleaning the carbs this weekend!
I am also going to be looking at how to fix a non disengaging/ sticky clutch and try to figure out what is causing my bike not to start (from the sounds it's making it's probably the relay and/or the solenoid)

Thanks!

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Folsoml
Posts: 1621
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Need Help Troubleshooting

Postby Folsoml » Wed Jul 25, 2018 5:15 pm

There is a free manual here in the general discussion forum. It contains information on how to adjust the clutch.

If your battery is fully charged, but it is still not starting, try bridging the gap between the two bolts on the solenoid. If the engine turns over, its a pretty good indicator that your solenoid is bad.
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,


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