Derbi Cross City 125 - No Spark

[niallac]

Folks,
I have just acquired a Derbi Cross City 125, which uses a venerable Honda 4T airhead single cylinder carburettor engine. I picked it up on Thursday and rode it home 150 miles without incident, including stopping and restarting the engine several times.

I tried to start it again yesterday, it fired a few times, but wouldn't run. On inspection, I saw that the plug was loose in its socket in the bore. I tried turning it over in the dark with the plug earthed on the cooling fins, and there was no spark. I got a new plug today, and still nothing. There is plenty of fresh fuel in the carb, the engine turns over strongly, but no spark. My next step will be replacing the plug lead and testing the coil against Honda resistance specs.

This bike was intended as a daily driver, and I don't have a viable alternative. Any ideas? I can't believe that the coil or cdi would have failed on a 6-month old bike.
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Ni!

[jaffa90]

Should have a 2 year warranty.

[niallac]

[Paulf]

If it fired a few times but would not run on, then you found the spark plug was not sparking. Sorry to ask did you push the lead on fully...just a thought. Because you must have had a spark. Then putting derbi cross city in Google suggest there is a problem with the fuel filler lid and causing a air lock. Is the plug getting wet and did you fill up during 150 miles. Things to look for before look at ignition coil and leads. Good luck
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

[niallac]

[iooi]

[niallac]

Yup, but nearest dealer is some distance away, I don't have a van, and I don't have much time.[/quote]

Well bang goes warranty then.... [/quote]

Yup, pretty much. Tried Piaggio Group customer service today, but closed due to public holiday. Will let you know how I get on.
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Ni!

[Paulf]

I honestly think there is not much wrong with it, the bike was firing, at most a plug cap. I looked at the internet to see what a derbi cross city looked like they look a nice bike. Are you kick starting the bike, if one fitted, or starter.
Anyhow a list to follow trouble shooting guide for the latter ones you will need a multimeter approx £10 ebay/Amazon and workshop manual.or haynes manual for the intricacies for your bike. I doubt it is 5,6 or 7
No spark
1. Battery voltage weak.
2. Spark plug fouled or defective.
3. Spark plug cap defective.
4. Spark plug not making contact.
5. Pulse generator coil defective.
6. Ignition coil defective.
7. Ecu defective.
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

[niallac]

[Paulf]

I agree sounds simple I work on spares and repair non runners and I have never come across 5,6 & 7. I listed everything in order I did not think it was battery.
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

[niallac]

[niallac]

Folks, thanks for all of your helpful suggestions.

The plug cap was a really nasty unbranded, hard plastic number. The screw-down connection to the lead was badly rusted, so I replaced plug cap and lead, and it now runs nicely.
____________________
Ni!

[Paulf]

Brilliant it had to be simple
____________________
Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims