1985 VT500C won't start when hot

8846 Views 48 Replies 10 Participants Last post by David C., Jul 10, 2015

David C.

Discussion Starter · May 7, 2015

I bought this bike back in Feb. of this year. It had a bad rod knock, so we tore it down and replaced the crankshaft, push rods, and push rod bearings. It is running fine. I can start it, drive it wherever I want to go, but if it's hot, it does not want to re-start. After a bunch of reading here, I decided that the fuel system might be creating a vacuum, so I started poking around. I noticed that the fuel shutoff valve has this vacuum line;

The new fuel shutoff valves do not have the vacuum line;

Honda Shadow Aero Sabre Spirit 1100 Ace Tourer Gas Fuel Tank Petcock Valve | eBay

Does anyone have experience with this problem, or should I be checking another part of the fuel system?

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David C.

Discussion Starter · #41 · Jun 3, 2015

swifty2014 said:
Which wire is getting hot?
If it is the red wire to the battery is warm that could be OK, if it is charging heavily. And the regulator will dump current to ground and so it can get hot also.
But check the wiring connections for all that as well as the 30 amp main fuse. Because if it is still the original strip of fuseable metal like mine was, They can crack and corrode and cause a resistance there.

It's the middle one in the picture...

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swifty2014

· #42 · Jun 4, 2015

That looks like HELL !!!
Those are the three famous yellow wires from the stater which charges the battery and can carry a heavy load while charging. They need to be clean and tight to work well and not get hot. Everybody cuts them and solders them together to eliminate bad connections. Start with those and all else may be good.

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Eagle7840

· #43 · Jun 4, 2015

David C. said:
It's the middle one in the picture...

Get rid of those make shift connectors and solder those connections. But before soldering make sure to slip a length of shrink tubing over the wires so you can pull them over the soldered connection and use a cig lighter to shrink the tubing for insulation to prevent shorting.

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David C.

Discussion Starter · #44 · Jul 7, 2015

Finally got this issue resolved, it was the coils. Cracks are circled in yellow paint marker.
I just wanted to thank everyone on here for all of the help that I have received. I'm riding this bike every day now and enjoying every minute.

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TorontoBoy

· #45 · Jul 7, 2015

David C. said:
It's the middle one in the picture...

While this is not your initial problem, as others have said, these 3 yellow wires that come from your stator/RR are a known issue. If these wires break all power from your stator will be cut off, your battery will no longer charge, once your battery wears down your bike will no longer run, leaving you stranded.

Originally these 3 wires were housed in a beige plastic connector, which probably melted from the heat. Your 3 wires look not only charred but black, which means they have heated up to the point of starting to burn. You will need to cut off those connectors, solder the wires together and shrink wrap them so that there is high enough throughput for your electrical system. This is a common electrical fix for old Hondas. Google the issue for yourself and see.
http://carmenbranje.blogspot.ca/2011/07/my-repair-for-infamous-3-yellow-wire.html

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David C.

Discussion Starter · #46 · Jul 7, 2015

TorontoBoy said:
While this is not your initial problem, as others have said, these 3 yellow wires that come from your stator/RR are a known issue. If these wires break all power from your stator will be cut off, your battery will no longer charge, once your battery wears down your bike will no longer run, leaving you stranded.

Originally these 3 wires were housed in a beige plastic connector, which probably melted from the heat. Your 3 wires look not only charred but black, which means they have heated up to the point of starting to burn. You will need to cut off those connectors, solder the wires together and shrink wrap them so that there is high enough throughput for your electrical system. This is a common electrical fix for old Hondas. Google the issue for yourself and see.

I did get the wires fixed a couple of weeks ago.
I actually started with the cheapest, easiest parts and worked my way up to the coils. I even replaced the voltage regulator, which it probably didn't need.

One day, I would like to rebuild the carb. (Probably in winter.) You wouldn't think that we actually get a winter here in Georgia, but it does cool down a bit in Jan.
Are the rebuild kits available? (1985 VT500C).

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Eagle7840

· #47 · Jul 8, 2015

David C. said:
Finally got this issue resolved, it was the coils. Cracks are circled in yellow paint marker.
I just wanted to thank everyone on here for all of the help that I have received. I'm riding this bike every day now and enjoying every minute.

Yup, them be the culprits and congrats.

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swifty2014

· #48 · Jul 8, 2015

Sure glad to hear you have it running good!~
Where did you buy the coils since I may need some in the future.

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David C.

Discussion Starter · #49 · Jul 10, 2015

swifty2014 said:
Sure glad to hear you have it running good!~
Where did you buy the coils since I may need some in the future.

WWW.hondadirectline.com

As recommended by several forum members, pricing was a few dollars less than other places, and I had them within a few days.

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