Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Moto Rumi technical problems or solutions
hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 2:18 pm

Hi,

Last time I rode the Formichino standard (the white one), after around 50 kilometers, the engine started to sound strange, too loud and not as nice as the usual Rumi engine sound, it sound rough.

At that time I thought that the reason could be the connection from the pipe to the muffler box, because once at home I notice the screw was loose. I tight it and thought the problem was solved, however I didn't start the engine since then.

I just start the engine testing something else, and the horrible sound is still there. :(

Looking around for some sign of problem, I can't see anything. I check if the muffler box has a crack, but so far I can't see any problem on it. I check if the manifold was a bit loose, but it is tight. The nuts from the pipes to the cylinders are also tight and the seals in place (I remove the nuts to check it)

It is possible if the ignition timing is a bit out of place, the engine doesn't sound nice and clean as it should?

Any idea is welcome :)
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should

Post by hugomez » Wed May 20, 2020 5:58 pm

OMG!!!!!!!!!!!!!!!!!!!! I just got a huge surprise (still not sure if good or bad).

I have this Formichino 14 years ago, and when I bought it I had no knowledges enough to restore it by myself, so somebody else did for me. Since the scooter was restored, always performed properly, no problems at the engine, so I never had to check anything about it.

Because of the strange engine sound I have now, I decided to check the ignition to see if maybe the break points were not 100% opening as they should or if the firing point was a bit out of place. So, I remove for the first time in 14 years the ignition side cover.

First surprise was to see that the condenser was not there, so I thought that maybe they put it hiding somewhere else.

Then is when I got the second surprise looking by the "holes" of the DANSI flywheel, noticing that there were not break points :shock:

So, I've removed the flywheel to have a look.

Then I remove the fairing to check the coils and noticed that there was a CDI little box that say "CDI 2164 IND ARG (Industria Argentina).

I've checked in Google and found who manufacture it, see link: http://www.pietcard.com.ar/Producto/Detalle/445
And the instructions to mount it (in Spanish), see link: http://www.pietcard.com.ar/Producto/MostrarPDF/445

When I was removing the flywheel, the nut that attach it to the crankshaft was extremely tight, difficult to remove, but eventually I have managed. Then I've notice that the little pin that keep the flywheel in position with the crankshaft was not there, so I thought that this explained the nut to be tight so hard, but not only that, I think the flywheel need to be in certain position and that position didn't match with the groove at the crankshaft, so that is why the pin is not there. (See last photo)

Wooow!!!!, What the f#ck should I do now?, I suspect that the strange engine sound was cause by the ignition not firing in the right moment, but I have no idea haw to work on this electronic ignition.

Any suggestion?

Maybe one of our Argentinian friends knows how to work with this electronic ignition?

Unfortunately when the flywheel was out, I kick the kickstarter lever with the hand to rotate the crankshaft to see the groove for the pin, so now I have no idea the position it was before. :oops:


Moto-Rumi-Formichino-Big-surprise-ignition-01.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-01.jpg (66.1 KiB) Viewed 2949 times
Moto-Rumi-Formichino-Big-surprise-ignition-02.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-02.jpg (102.73 KiB) Viewed 2949 times
Moto-Rumi-Formichino-Big-surprise-ignition-03.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-03.jpg (52.29 KiB) Viewed 2949 times
Moto-Rumi-Formichino-Big-surprise-ignition-04.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-04.jpg (71.95 KiB) Viewed 2949 times
Moto-Rumi-Formichino-Big-surprise-ignition-05.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-05.jpg (76.73 KiB) Viewed 2949 times
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 6:40 pm

There is one think for sure, this Formichino always start very easily, a little push even cold and it was working right away, but I always hear at the sparkplugs electric sounds, like if the ignition was producing more sparks that needed, but because the scooter was working fine, I didn't check if something was wrong.

Now those electric/sparks sounds at the sparkplugs maybe make sense with this electronic ignition installed.

By the way, that sound I am talking about right now has nothing to do with the bad rough engine sound that I talk at the first post of this thread.
My little Formichino here: http://www.formichino.com/pictures1.html

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Wed May 20, 2020 9:09 pm

Indeed Hugo, the scooter produces more sparks than it needs, since that electronic ignition is for single-cylinder engines and works in Rumi with "missing" spark, that is, both spark plugs produces spark on all crankshaft rotation, which is not a problem, I had used, and it works excellently well, even better than the break points.

Regards

Claudio

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Wed May 20, 2020 9:18 pm

This electronic ignicion don`t need "the little pin", it´s enought tightng very well the nut. Now, if you don`t know how the flywheel was installed, you have a problem, you should make a new ignition timing.

Regarding the weird noise you were hearing, I doubt this is the problem.

Regards;
Claudio.

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 9:27 pm

Hi Claudio,

Thanks for your reply and clarifying about the pin.

I am reading the instructions of this system but I don't fully understand how is the process to make a new ignition timing.

Can you help me with this?

Greets,
Hugo
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 9:29 pm

By the way, there are some marks in the flywheel, and I think also in the crankcase. So maybe using those marks and putting the LEFT side piston 2mm BTDC, You think that may work?
My little Formichino here: http://www.formichino.com/pictures1.html

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Wed May 20, 2020 9:34 pm

Right! try in that way!!

greets

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 9:40 pm

Here you can see the photos of the marks.

In the crankcase there are two marks, one is a white dot painted, and I think that may be related with this ignition system. The other mark is from the rotor plate to the crankcase, but I think that may be from the old "break points" original system.

What do you think?

Beside that, you can also see two marks at the flywheel itself. One that say "D" from Derecha (Right side in English) and another that say "I" from Izquierda (Left side in English).

If I am correct, the system is set at the Left side (Izquierda).

Am I going to the correct direction?

Moto-Rumi-Formichino-Big-surprise-ignition-06.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-06.jpg (81.36 KiB) Viewed 2924 times
Moto-Rumi-Formichino-Big-surprise-ignition-07.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-07.jpg (82.5 KiB) Viewed 2924 times
Moto-Rumi-Formichino-Big-surprise-ignition-08.jpg
Moto-Rumi-Formichino-Big-surprise-ignition-08.jpg (78.6 KiB) Viewed 2924 times
My little Formichino here: http://www.formichino.com/pictures1.html

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Wed May 20, 2020 9:47 pm

Put the piston 1, 2mm BTDC, and place the flywheel, matching the "I" with the white dot on the crankcase and test if it works..

Good luck!

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 9:52 pm

RF125 wrote:
Wed May 20, 2020 9:47 pm
Put the piston 1, 2mm BTDC, and place the flywheel, matching the "I" with the white dot on the crankcase and test if it works..

Good luck!
Perfect, I will do that. Only one question. You said, "Put the piston 1,2mm BTDC", or "Put the Left piston 2mm BTDC". I think is the second option, but I just want to be 100% sure of what I am doing.
My little Formichino here: http://www.formichino.com/pictures1.html

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Wed May 20, 2020 9:54 pm

Piston left it's the number 1.

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 9:57 pm

RF125 wrote:
Wed May 20, 2020 9:54 pm
Piston left it's the number 1.
Perfect, I will do it and hope for the best :)
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 10:28 pm

Hi Claudio,

I just did it and is ready for test tomorrow morning, however when I was rotating the flywheel to put the piston 2mm BTDC, I noticed that some air was coming out from one of the cylinder heads. I am still not sure from where the air is exactly coming, but I think there is some air leak at the right side cylinder head.

Can this be the cause of the louder and rough engine sound?, I think so.

I will check if the seal from the cylinder to the cylinder head is still ok.
My little Formichino here: http://www.formichino.com/pictures1.html

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Wed May 20, 2020 10:39 pm

Surely! it's that ! you must change the head gasket...

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 10:44 pm

Great!!

It is for sure the right side cylinder, because if I remove the sparkplug at the right side cylinder (keeping the sparkplug at the left side, the air leak doesn't sound anymore)

I will remove the head and see what I find.

;)
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 11:01 pm

Here is it!!!!


Moto-Rumi-Formichino-cylinder-head-seal-broken-01.jpg
Moto-Rumi-Formichino-cylinder-head-seal-broken-01.jpg (116.46 KiB) Viewed 2909 times
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Wed May 20, 2020 11:50 pm

Hi,

The gasket is replaced by a new carbon one. Now when I rotate the flywheel I can't hear the air leak, so that problem was definitely that, however there is now another thing that worries me.

Without the screws of the cylinder head properly tight, the piston is already hitting the cylinder head. If I tight the screws to a reasonable torque, the piston get stuck.

Do you think I can start the engine with the piston touching a bit the cylinder head, and after some minutes tight slowly a little bit more the screws?

I am not sure if this is too dangerous for the con rod or maybe is something that can be done without too much risk. ?????

If that is not a safe solution, I afraid I will have to remove both cylinders and replace the gasket that is between the cylinders and the crankcase, maybe now is a bit too thin after tightening the cylinders several times. (I've put and remove the cylinder heads several times in the past)

Greets,
Hugo
My little Formichino here: http://www.formichino.com/pictures1.html

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Thu May 21, 2020 12:14 am

The piston dont touch the cylinder head, touch in the new gasket, surely...

Regards

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Thu May 21, 2020 12:27 am

RF125 wrote:
Thu May 21, 2020 12:14 am
The piston dont touch the cylinder head, touch in the new gasket, surely...

Regards
So, it is safe in this case to start the engine and once the new gasket start "molding" with the piston, tight the screws a little bit more until they get a reasonable torque?
My little Formichino here: http://www.formichino.com/pictures1.html

Lars
Posts: 306
Joined: Fri Nov 02, 2012 3:09 pm
Location: Sweden

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by Lars » Thu May 21, 2020 8:38 am

What a surprise. You have had a Rumi with elctronic CDI ignition all along, without knowing it!

I would never try to start an engine if I heard and felt the piston hitting. Find out where it hits and do whatever it takes to get the necessary clearance first.

The cracking or sizzling sound you hear from the ignition is probably not just caused by the firing of both spark plugs at the same time. Many early CDI systems were designed to produce much higher voltage than needed - just because they could! Nothing you can do about it. Just try to keep the ignition wires in good shape, otherwise they will arc. And keep you hands away from the ignition wires when the engine is running. We don´t want you electrocuted, Hugo!

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Thu May 21, 2020 9:35 am

Hi Lars,

Yes, it is crazy that all this time I didn't know it. I made many things on this scooter along the years, but never remove that side cover because it was not needed. When the seller sold me the bike, he sent me a photo without the cover and there is visible the Dansi flywheel, so all these years I thought it was using the original system. Now make sense how easily this scooter start.

About the piston hitting the head, following Claudio's advise by Whatsapp, I just identify the exact point where the piston was touching the new carbon seal, so carefully with the dremel I've cleaned that area of the gasket seal. Everything is now ready for the test, however I will wait a bit longer to don't upset the neighbours, here is van holidays today, so the neighbourhood is pretty quiet right now.

Thanks for the advise about not touching the ignition wires when the engine is running, I also don't want to feel the electric power in my body :D

Finger crossed!!!
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Thu May 21, 2020 12:03 pm

Hi,

Bad news but maybe also good news.

I tried to start the engine but the timing is not correct. :(

Then I remembered that I took one photos of the flywheel before removing it the first time, and there I can see some marks at the crankshaft axle, and also at the flywheel itself.

I replicate that position and remove the LEFT sparkplugs rotating it until 2mm BTDC.
Then I check if at the point where the mark at the flywheel with the letter I (Izquierda (Left in Spanish)) match with any other mark at the crankcase, and seem to match with one mark. So, maybe the white dot was a previous mark before the restoration and the new mark is the one you see at the last photo.

I will take it out and test again to see what happen.

Ignition-flywheel-for-second-test.jpg
Ignition-flywheel-for-second-test.jpg (85.5 KiB) Viewed 2876 times
Ignition-flywheel-for-second-test-02.jpg
Ignition-flywheel-for-second-test-02.jpg (50.19 KiB) Viewed 2876 times
My little Formichino here: http://www.formichino.com/pictures1.html

hugomez
Site Admin
Posts: 3792
Joined: Thu Jun 11, 2009 10:05 am
Location: Amsterdam
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by hugomez » Thu May 21, 2020 12:50 pm

IT WORKS!!!!!!!!!! :D

Ignition timing is now as it was before. I will remove the white dot mark to avoid confusion in the future.

Unfortunately the piston is still hitting the new gasket seal. I was loosing the screws with the engine one to see if I managed to loose the head enough, but with the 4 screws pretty loose, I can still hear the clicking of the piston hitting it, so I will take the head out, hope to see an clear mark on the gasket, and retouch it again with the Dremel.

Thank for your help Claudio ;)
Hugo
My little Formichino here: http://www.formichino.com/pictures1.html

RF125
Posts: 248
Joined: Fri Jun 12, 2009 7:50 pm
Contact:

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by RF125 » Thu May 21, 2020 1:07 pm

;) :D

Congrats!

greasy-fingers
Posts: 540
Joined: Thu Jan 07, 2010 11:36 pm

Re: Engine doesn't sound as it should ... (BIG SURPRISE INSIDE)

Post by greasy-fingers » Fri May 22, 2020 12:38 pm

Always good when you find the definite cause to a problem :wink: . Reading this reminds me to ask - I do not like the idea of the split pin on the flywheel nut, if you cannot reach the position to match the slots in the nut with the hole in the crankshaft without overtightening it requires you to back the nut off !!. I have always tightened the nut to around 50ft lbs and not fitted the split pin, I would be interested to hear what others do ?

Post Reply