Running great one night, died the second

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Bater55
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Joined: Wed Aug 16, 2017 10:19 pm

Running great one night, died the second

Postby Bater55 » Sun Sep 24, 2017 7:22 pm

Hello all,
I have been working on my 1982 nighthawk cb650sc and finally got it running! It ran great, rode it around all night probably went around 10-15 miles and it seemed to be running great. I then got on it to ride yesterday and it was a little slow to start but it did start. I rode it for all of 30 seconds and it lost power and died. I started it up again thinking I just didn't let it warm up long enough and then it did it again. I then had to walk it back to my house where it is sitting now. I had replaced most of the electrical on it including the starter solonoid, spark units, ignition coils/plugs/wires, battery and set the timing and thought itd be running great but since then I haven't gotten it to start at all. I recharged the battery and still nothing. There's gas in the carb bowls but I think I'm getting a weak spark (it was orange when I tested it with the screwdriver trick) any advice from here? I've been working on it for 4 months now and thought I had it going (it was a very happy day) now it's back to sitting! Any help would be great.

Thanks!

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Folsoml
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Location: North Florida

Re: Running great one night, died the second

Postby Folsoml » Mon Sep 25, 2017 5:36 am

When you say "lost power," I'm presuming you mean engine power and not electrical power. That being said, did you clean out the fuel tank when you got it? If not, there is the potential that some crud broke loose during your ride and has now gone into your carbs and gunked things up. Also, I did not see in your description that you did anything do the carbs. Have they been cleaned?
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Bater55
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Joined: Wed Aug 16, 2017 10:19 pm

Re: Running great one night, died the second

Postby Bater55 » Mon Sep 25, 2017 7:19 am

Sorry for the confusion, yes I meant engine power. And I have gone through the carbs multiple times and they seemed to be working fine, they've been synched and everything. But it is quite possible that they could have gotten gunked up. I'll check that today!

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GeorgeSweety
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Location: UK.

Re: Running great one night, died the second

Postby GeorgeSweety » Mon Sep 25, 2017 8:13 am

Hi Bater, I recall that you repaired a broken wire from one of your pick ups, have you checked it since the repair? I agree with Folsoml about crud in the tank, well worth checking out. Did you adjust your valves when you worked on the bike?

Bater55
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Joined: Wed Aug 16, 2017 10:19 pm

Re: Running great one night, died the second

Postby Bater55 » Mon Sep 25, 2017 10:35 am

Yes, I checked those wires and both are still putting out right around 530ohms so that didn't disconnect! And no I did not do that as I do not know how. I'll check those carbs tonight!

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GeorgeSweety
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Location: UK.

Re: Running great one night, died the second

Postby GeorgeSweety » Mon Sep 25, 2017 11:39 am

Can you also check the fuel filter in your tank by removing your fuel tap? When you unbolt your tap and gently pull it out of the tank your filter will most likely stay inside your tank. If you can find a spare bolt that is slightly wider than the filter opening and carefully thread it inside the filter by about a quarter inch, you should be able to remove the filter by gently pulling on the bolt. It would be a good idea to check your tap operation by blowing through the outlet while turning the tap between on, off and reserve, you may also want to slide a clean, spare piece of pipe over the outlet to avoid a mouth full of petrol :lol: BTW, what colour are your plugs?

Bater55
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Joined: Wed Aug 16, 2017 10:19 pm

Re: Running great one night, died the second

Postby Bater55 » Mon Sep 25, 2017 3:17 pm

I have been able to get the filter out pretty easily so I will check that to make sure. And by plugs I'm guessing you're meaning spark plugs, and when I pulled those they were black most likely due to an overrich mixture.

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GeorgeSweety
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Location: UK.

Re: Running great one night, died the second

Postby GeorgeSweety » Tue Sep 26, 2017 1:27 am

Can you put some fresh spark plugs in (in UK we just call them plugs, sorry about that) and see if she'll start? If she does then try turning your mixture screws in half a turn. You should be able to spot straight away if your fuel tap filter is clogged. Have you checked your fuel cap vent is clear? Is your fuel tap vacuum shut off still connected? as I've heard that these can cause huge problems with fuel delivery when they start to fail.

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Folsoml
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Location: North Florida

Re: Running great one night, died the second

Postby Folsoml » Tue Sep 26, 2017 4:52 am

GeorgeSweety wrote: Is your fuel tap vacuum shut off still connected? as I've heard that these can cause huge problems with fuel delivery when they start to fail.


Yes they do!
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GeorgeSweety
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Location: UK.

Re: Running great one night, died the second

Postby GeorgeSweety » Tue Sep 26, 2017 5:03 am

Folsoml, you sound like you have encountered that problem before :lol: Isn't it referred to as the "Spawn of Satan"? :)

Bater55
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Re: Running great one night, died the second

Postby Bater55 » Tue Sep 26, 2017 11:27 am

Thanks for the help guys I think I figured it out. The rubber gaskets in the carb bowls broke apart and clogged up the jets. I was having trouble getting them in so I used a bit of gasket maker to hold them in place and that solidified and broke loose clogging up the carbs.

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GeorgeSweety
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Location: UK.

Re: Running great one night, died the second

Postby GeorgeSweety » Tue Sep 26, 2017 11:31 am

It's all good then, Happy Riding :D

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Folsoml
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Location: North Florida

Re: Running great one night, died the second

Postby Folsoml » Tue Sep 26, 2017 11:53 am

GeorgeSweety wrote:Folsoml, you sound like you have encountered that problem before :lol: Isn't it referred to as the "Spawn of Satan"? :)



Absolutely! It's the first thing I throw away when I get a new old bike.

Bater55 wrote:Thanks for the help guys I think I figured it out. The rubber gaskets in the carb bowls broke apart and clogged up the jets. I was having trouble getting them in so I used a bit of gasket maker to hold them in place and that solidified and broke loose clogging up the carbs.


You learned the lesson the relatively easy way to not use silicone or RTV gasket maker. When used in the engine, it does the exact same thing--and clogs up important oil passageways. If you must use something, use something like Hondabond.
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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