engine cranking slowly

[mikey909]

i have a gilera dna 125. the bike is starting to crank really slowly under load, but when i take the spark plug out the engine will crank normally. the battery is brand new and fully charged. my guess is that the starter solenoid has, or is starting to go?

[CestrianX]

Check all the connections that carry plenty of current, clean with a wire brush as any debris can cause resistance to current flow, you may find a dirty connection will warm up more than the others. Also, get a multimeter on the battery and check the voltage whilst the starter is turning, I know you said it's a new battery but you should check all possibilities.

[Clutchy]

Sure its fully charged? As stated get readings for battery when not in use and then when cranking.
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[G]

Does it even have a starter solenoid?
Some bikes probably do have them (never looked at a scooter one), but it's pretty rare if they do and I've never seen one.
Usually just have a normal relay and a clutch arrangement on to the flywheel or similar.

Also, what they said above .

[mikey909]

[G]

But are you sure it has a solenoid?

The only items listed under that for your bike I can easily see on the internet are normal bike style relays.

As above - I'd check the voltage as you turn it over and check connections etc.

Also; do you have a battery tester?
It may be you've got a duff battery.
Even one showing full voltage may not do so well with a proper battery tester that puts it under load.

[mikey909]

[G]

I'd also try connecting up a car battery with jump leads; that way you can be absolutely sure it isn't a case of battery cranking amps that's the issue.
However, it might be worth checking for shorts first - if it was a short circuit causing low amps to get through, giving it even more may not be ideal!