Problem Piaggio NRG MC3 DD Bogs down at start

Hi to all,

i have a piaggio nrg mc3 lc dd (hi per2 engine) which i have made a complete service, belt (811x18.5), transmision oil, sparkplug etc.... everything worked fine until i fited the engine with Giannelli Reverse.

The motor is stock 50cc, with the exhaust i got 5g roller weights, but i did not get any cltch springs. So i bought them spereatly in a set for 107mm clutch of 3 stifness(+25%, +35%, +45%). I think they are Chinese, not sure.

I installed the Giannelli Reverse with 5g roller weights, bigger main jet 65 (60 original, 62 deristricted) and hardest red springs +45% and the end result is not good.
The engine is really snappy it has little power till 7000rpm and than it explodes.

When i start the clutch starts to grab slowly at 4000 rpm but lets me till 6000 rpm, and here the engine is just not moving and bogs down .... this is until 15 km/h (aprox 10mph) then it revs us to 9500rpm like maad.
So the second part is ok and nice but the first starting part confuses me as i thought that this problem will be solved with harder springs .

At what rpm does your sccoter normally starts? Is the belt on my scooter the right size? Could be that the cutch springs are just crap and the scooter should rev higher at start?


I do not know what is the problem here ??? Could somebody please help with some advice?

 

Change the springs to the middle ones. It should allow the clutch to come in earlier.
With harder springs, the engine has to rev much harder to throw the clutch shoes out and bite before it will take off.
You will need to play with the jets in the carb to get it running spot on as well.
Jetting is not a quick job, have patience.

 

Hi,

maybe i wrote it wrong it does not bog down as there was something wrong with fueling.
But there is not enough rpm/power to start properly. If the engine over revs at the start that is fine with me.

This is simular as mine but mine is a little worse.

If you listnen to it at the begining there is a low rpm / slow area and after 2 sec it gets to real rpm.

I would like to have something like this or even more rpm at start



I was thinking if there was a problem with the belt, as i changed it and i compare it to the old piaggio belt(436864/6) it was a little wider and a bit smaller.
This might create a longer gearing from the start and higer rpm at the clutch (the clutch will engage faster). I did not put any washer to the vario to make it wider. What is the dimension of the washers for vario?


15 years ago i had yamaha spy with gianneli & polini alu sport 70cc, 21 carb, polini filter, polini transmision, malossi delta clutch ....... i never had such problems. Maybe this engine was a bit overreving at the start but this is fine with me.

 

Variator is stock just the weights changed, nothing else.

 

Hi, I have almost solved the problem. When I changed a belt I noticed that is a little bit wider than the old one. The problem was that a wider belt gets higher at the variator from the beginning. Which makes the clutch spinning faster and it engages faster not allowing more rpm. So I have added small spacer to variator and the belt positions lower than before, less rpm on clutch from begining and higher rpm on the engine...more power better clutch engagement.