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Nirvana Rodeo Simonini Mini2plus NS50 Starter Motor Issue


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Hi guys,

I have a nirvana rodeo with a mini2plus engine in it that is also 16.8 volt electrical system.

The NS50 starter motor used by Nirvana (which is not a Simonini factory spec one) has failed.

My assumption is that Nirvana use a different starter because they have increased the battery to 16.8 Volt instead of the Simonini standard 12 volt electric start system.

After exhaustive trial and error and learning, i have managed to finally test it correctly and have determined that the resistance testing of adjacent poles on the comutator is the problem. When i test each adjacent pole, initially it shows a small resistance, however, with a few seconds, this value drops to zero.

My understanding is that if the resistance value drops after a short period of time, then there is a short.

The starter motor is also rapidly burning out the active brush after cleaning and reinstalling. Also, the starter barely even turns the motor over. The battery is brand new and is the 3rd new battery i have tried...so i think i can safely rule that out!

Does anyone know what make of starter motor the Nirvana NS50 actually is? (it is not the same as the one used on the Nirvana Instinct)

I would be open to an alternative starter, however, this system is 16.8Volts and I dont know if the starter motor is different to a 12 volt one because this is a 16.8 volt system. If it is different, in what way would that be the case? (ie windings, gauge wire???)


Images of starter attached.


Last 3 photos are after I machined the comutator, then reinstalled it into motor and tried to start (as you can see, its burning the active brush immediately)



















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I have had fun and games with an identical looking starter motor. Cleaned all the commutator as you have but it still stops in certain positions where it doesn't take any current and remains stationary.

From the burning and lack of starting I would guess you do have a short.

Sorry I don't know the make and model.

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I have removed the insulated windings and prepared the armature to rewind.

Apart from my time, its relatively inexpensive to purchase the wire to rewind this...so what the heck, i will have a crack at it.

After all, what could possibly go wrong that is worse then where i am at right now in that i need to purchase a new starter motor. 

If i can get the right wire...to be continued (never done this before, so i thought i would enrol in "Starter Motor Rewind" classes at the International Institute of Youtube)


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  • 1 month later...

Hi guys,

I have an update on this issue...

1. The nicads developed a memory and would take full charge.

2. The starter motor brushes packed it in

3. The simonini mini2plus decompression port had gotten blocked.


As you can imagine, i got completely confused as to what the heck was wrong in all of that. Suffice to say:

 1. 3 battery packs (i thought the nimh new one was a failure and therefore ended up buying a new nirvana nicad one as well),

2. 2 starter motors (which still didnt fix the problem),

3. and removal of head to clean out decompression port...and dinally the rodeo is singing along happily again.

4. Replaced fuel primer and new carby kit

You can imagine my shock when new battery and a second starter motor still wouldnt turn the engine over.

I didnt suspect the decompression port because i had checked it only a few hours before the final breakdown that grounded her months ago.


I have lost track of how much money this cost but im thinking roughly $600 AUD might cover it. An expensive exercise in frustration. Looking back i still cant see that i could have avoided all of the screwing around.

On a bright note, it turns out that:

1. the nimh batteries work brilliantly

2. I cant get replacement brushes for my starter...so after rewinding it, im still stuffed and had to get a complete replacement starter anyway (lucky i got a second hand one in good nick for $50...$400AUD for new one).


The nirvana has now done around 20 hours in the last month without any issues. Fingers crossed.


I wish it was possible to pull start it whilst on my back..

It develops so much compression its impossible. I can only just pull start it standing beside the unit (let alone with it on my back) Its no wonder the electric starter has so much trouble. These decompression ports on the bigger motors seem like a bit of a fail to me.


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