Carburator and ugly sound

Moto Rumi technical problems or solutions
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hugomez
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Carburator and ugly sound

Post by hugomez » Mon Sep 16, 2019 6:10 pm

Hi All,

Yesterday I planned to have a ride in the Formichino Normale/Standard, so I decided to put all the settings in the UA15S carburetor as the factory recommend, because until that moment I had a different configuration on it.

The reason why I decided to change it is because even if in the first three gears it rides well, in 4rd it doesn’t fully goes all the way up, it get stable but not goes into high revs like the others three lower gears, so I thought that maybe playing with the carburetor settings could improve that.

However ….. during the 80 kilometers ride I found out that is was too rich, the sparkplugs look a bit oily and black, but there is something else that worries me, it was the sound of the engine. In some point I thought that I was driving a tractor instead of a Rumi. I even stop two times to check if the pipes were properly attached, because I had the feeling that there was an air leak somewhere of the exhaust system, however with the engine working and looking the area, I could not see any leak or problem at the exhaust system, but the sound was not the usual nice Rumi one, neither like the sound that it has when riding with the other carburetor "specification"

IT IS POSSIBLE THAT THE UGLY TRACTOR/BROKEN EXHAUST SOUND WAS CAUSED BECAUSE A TOO RICH CONFIGURATION?

I was riding with a mixture fuel/oil at 3%

Previous: Slide 55
Now: Slide 55

Previous: Atomiser 260
Now: Atomiser 262

Previous: Needle C7
Now: Needle C7

Previous: Main jet 58
Now: Main jet 60

Previous: Idle jet 45
Now: Idle jet 45

Previous: Float needle length 58
Now: Float needle length 58

Previous: Float weigh 6.5
Now: Float weigh 7.5

I’ve highlighted in blue the parts that were not correct if we follow the Rumi factory specifications and replaced to the once that the factory say, however the result was not good.

What do you think?

Beside that, here a few photos of the ride :)

Moto-Rumi-Formichino-Puch-MV50-Ride-summer-2019-1.jpg
Moto-Rumi-Formichino-Puch-MV50-Ride-summer-2019-1.jpg (155.15 KiB) Viewed 2407 times
Moto-Rumi-Formichino-Puch-MV50-Ride-summer-2019-2.jpg
Moto-Rumi-Formichino-Puch-MV50-Ride-summer-2019-2.jpg (142.94 KiB) Viewed 2407 times
Moto-Rumi-Formichino-Puch-MV50-Ride-summer-2019-3.jpg
Moto-Rumi-Formichino-Puch-MV50-Ride-summer-2019-3.jpg (102.92 KiB) Viewed 2407 times
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
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Re: Carburator and ugly sound

Post by hugomez » Mon Sep 16, 2019 6:36 pm

Hi again,

I just check the bolts and nuts that tight the pipes to the muffler box, and one of the was much more loose that the other. however I would not say it was loose enough to let air coming out (and consequently a sound as a broken exhaust), however maybe I am wrong and that was the only silly cause of the bad sound.

Now is strongly tight.
My little Formichino here: http://www.formichino.com/pictures1.html

greasy-fingers
Posts: 531
Joined: Thu Jan 07, 2010 11:36 pm

Re: Carburator and ugly sound

Post by greasy-fingers » Tue Sep 17, 2019 7:14 am

Hi Hugo, the first thing I would check is that the atomizer you have changed is a 2 stroke one, both the 2 and 4 stroke atomizers fit but your formi will not run correctly with the 4 stroke version, the 2 stroke ones are plain - the 4 stroke ones have some small holes drilled along the tube section. Graham.

greasy-fingers
Posts: 531
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Re: Carburator and ugly sound

Post by greasy-fingers » Tue Sep 17, 2019 7:25 am

oh yes - and what was so fascinating about that tree :lol: :lol:

hugomez
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Re: Carburator and ugly sound

Post by hugomez » Tue Sep 17, 2019 11:47 am

greasy-fingers wrote:
Tue Sep 17, 2019 7:14 am
Hi Hugo, the first thing I would check is that the atomizer you have changed is a 2 stroke one, both the 2 and 4 stroke atomizers fit but your formi will not run correctly with the 4 stroke version, the 2 stroke ones are plain - the 4 stroke ones have some small holes drilled along the tube section. Graham.
Hi Graham, it is definitely a 2 stroke atomizer, that is not the the problem.
greasy-fingers wrote:
Tue Sep 17, 2019 7:25 am
oh yes - and what was so fascinating about that tree :lol: :lol:
I could not stop looking at it :lol: :lol: :lol: :lol: :lol:
My little Formichino here: http://www.formichino.com/pictures1.html

greasy-fingers
Posts: 531
Joined: Thu Jan 07, 2010 11:36 pm

Re: Carburator and ugly sound

Post by greasy-fingers » Tue Sep 17, 2019 4:38 pm

I have found that the older I get the more interest I have in similarly positioned trees :D

Ian Skinner
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Location: South Wales UK

Re: Carburator and ugly sound

Post by Ian Skinner » Tue Sep 17, 2019 7:18 pm

Hi Graham, don't say that, the surgery is most uncomfortable!!

Ian

hugomez
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Re: Carburator and ugly sound

Post by hugomez » Tue Sep 17, 2019 8:46 pm

greasy-fingers wrote:
Tue Sep 17, 2019 4:38 pm
I have found that the older I get the more interest I have in similarly positioned trees :D
Hahahahaha :lol:
Ian Skinner wrote:
Tue Sep 17, 2019 7:18 pm
Hi Graham, don't say that, the surgery is most uncomfortable!!
Ian
Ouch!!! that sound painful :cry:
My little Formichino here: http://www.formichino.com/pictures1.html

arthur lewthwaite
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Joined: Fri Dec 28, 2012 7:03 pm

Re: Carburator and ugly sound

Post by arthur lewthwaite » Thu Sep 19, 2019 6:52 pm

Surgery uncomfortable, my health issues over the last couple of years has got bad, culminating in me waiting for an urgent operation on my neck taking out a piece of bone grinding it and putting back, or i wind up in a wheelchair, did rumi make one, not looking forward to it, one of my systems is i need hugs tree urgently or it to late, its another wet day. all down to a trapped spinal cord, old age :cry:

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