Urban Express no spark all of a sudden

Hi all, I just finished up doing many good things to my Urban Express over the past two months. Tires, tubes, cables, brakes, battery, gaskets, exhaust rebuild, etc.

This machine has been slumbering for decades indoors. On the first or second kick it roared to life. Hooray. Today I finished up the brakes, and muffler and kicked it again. Started right up. Ran for about ten minutes and died. Will not start. Have confirmed with new plug and spark tester tool, there is no spark at the plug wire.

Battery is full charged and new, fuse is not blown, tests good with multimeter. I do not have a wire diagram for the ignition system.

Any advice? Thanks.

Re: Urban Express no spark all of a sudden

look in the wiki for wiring diagram. proceed to check every connection.

Re: Urban Express no spark all of a sudden

I have no idea how to search within the wiki. None at all.

Re: Urban Express no spark all of a sudden

Got it now. Page 13-7 of the Honda service manual. That clears up quite a bit. Thanks. Should have this nailed down soon.

Re: Urban Express no spark all of a sudden

Interesting. After sitting in the cold NH air for a few hours, the spark came back. It ran great for about 10 minutes and then died. No spark.

I am going to say it's a bad coil. Heats up expands shorts out.

Any suggestions for coils? Will the 15 dollar orange eBay coil work? Something from Treats or Lucky 2 Strokes?

Re: Urban Express no spark all of a sudden

Consider the condenser , if it has one .

Re: Urban Express no spark all of a sudden

Jack Rutherford /

no condenser on the urban

Re: Urban Express no spark all of a sudden

Captain Janeway /

If you can't figure it out troubleshooting, there are always people selling misc parts and I bet you could find one cheap. Depending on bike condition, maybe you just need a new wire/boot.

Had one that looked like it had spark and could run intermittently, but it turned out to be compression and broken rings. Go figure.

Re: Urban Express no spark all of a sudden

> Jack Rutherford Wrote:

> -------------------------------------------------------

> no condenser on the urban

In that case , clip a 1/4" off each end of the plug wire , check that each contact is clean of any corrosion and reattach the wire . You might also remove the resistor from the cap , if it has one , and replace the spring and resistor with a section of solid copper wire .

Check that ALL involved connections are scratch clean , grounds included .

Do all that prior to replacing the HT coil .

Re: Urban Express no spark all of a sudden

Did all of that already. Cutting off the stretched out ends of the spark plug cable. That's automatic. Replaced the spark plug cap with a new NGK (at only a few bucks each I have several kinds on hand), compression is very good.

Using my spark tester, I'll show spark when it is bone cold. And it runs great. Then it stumbles and dies. Tester shows no spark at all when the coil is warm. and the engine won't run I've seen this many times on old electromechanical ignition cars and on motorcycles both with electromechanical and CDI ignitions. 40 year old coils don't do well when they heat up.

I'll have the answer for sure next week. Lot of not-wrenching going on until then.

Thanks for chiming in.

Re: Urban Express no spark all of a sudden

Good you have it narrowed .

And , it's not so much the age as the materials used in construction . Particularly , the 'insulation' used to coat the winding .

I have the original dual fire coil from my '57 Simplex that performs as intended , without missing a beat . ;)

Re: Urban Express no spark all of a sudden

Some coils continue to work over amazing amounts of time. Some do not. My 1972 Honda SL350K2 has an original coil, one of the two anyhow is from the factory.

My next door neighbor's brand-new 1975 AMC Pacer had a failed coil and a cracked distributor cap at just 49 miles on the odometer. Boy we built some quality American cars in the 1970s.

Talk about parts that last? The tiny high beam indicator bulb on my 1972 SL350 is original. Works perfectly.

Re: Urban Express no spark all of a sudden

It seems that the folks that built some of these mopeds may well have been the same ones that built the AMC Pacer . LOL

Re: Urban Express no spark all of a sudden

I think you're right. Let's just blame AMC and then go have a beer. 8-)

Re: Urban Express no spark all of a sudden

Captain Janeway /

When you figure it out come back and tell us what it was.

Re: Urban Express no spark all of a sudden

Hi all. Been offline for a while, up in extreme northern NH where there is no cell coverage worth mentioning.

Good news. The $12.95 eBay ignition coil fixed the Urban Express right up. It's running really well. After almost 2 months of tinkering, I think it's done. I registered it for road use yesterday and am having a blast riding it.

Thank you all for your assistance. I've put almost $400 worth of parts and a lot of time into this Urban Express and I am pleased with the results. I've resurrected many an old Honda however they were all in the 350cc and up four-stroke category. This little bike is very cool. Everywhere I go, people want to ask about it. It is a true conversation starter. I can't wait to rip around Market Square in Portsmouth, NH. There's quite a moped renaissance happening there.

Now that the NU50 is on the road, here are my two red Hondas at home in the garage. Thanks again for all your help.

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Re: Urban Express no spark all of a sudden

Captain Janeway /

She's in beautiful condition! Bulletproof bikes if you leave them stock. Had one 20 years and it only needed basic maintenance. Loved it until it was stolen.

Re: Urban Express no spark all of a sudden

Great looking ped.

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