Bol D'Or - New Project

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Lars
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Re: Bol D'Or - New Project

Post by Lars » Sat Aug 20, 2016 8:09 pm

hugomez wrote:Hi Lars and Lasse,

Just back from the test of the wire from ignition to coil. Result: right cylinder didn't start.

As Lars say, with this I think I have test all electric options, because swapping parts and replacing others there is no one component assigned to the right cylinder that I have not been tested. Nevertheless I will have another closer look to all wires to see if I am missing something that I still didn't test from there.

Lars, because was confirmed that the problem was not the carburetors, I have put again the twin 18mm on it. The 22mm drop some fuel after the test (maybe because the float bowl not been 100% straight), so I feel more comfortable doing the next test with the actual components I will have in the future on the bike.

The fuel tap (petcock) is fixed. At least this is what I think after adding two new fibre washers. Tomorrow morning I will know for sure. The problem with the "hard to turn" handle is now clear. The solution is to unscrew a bit two small screws that compress a piece of metal that is a bit curve. As more tight it is, the curve metal start to get flat and making pressure, and as more pressure, the harder is to turn the handle. I set in a way that was soft to turn, the handle, however fuel was coming out from there, so I tight it again. At the moment I do not mind anymore if the handle is hard, as long as there is no leak.

What to do next?, Going to the bar with some friends now. Tomorrow we will see.

Thanks.

OK, makes sense to use the correct carburetors. But now you know the problem is definitely not there, so you can turn your attention to other areas.

I agree with Arthur that the some sort of crankshaft seal problems is the most likely source of the problem. A problem with pistons or cylinders, for example, is very unlikely to improve when the cylinder finally starts to fire. But a crankshaft seal could leak in one direction (under vacuum for example) and start to seal better once the cylinder starts firing. It is conceivable at least.

If you want to test the crankcase for that type of leak under both pressure and vacuum conditions, I could lend you my test kit with the Mityvac pump which I wrote about in another thread. In that test you put the piston in the bottom position (transfer ports open), and block off the intake and exhaust ports on that cylinder. Then you connect the pump to the spark plug hole, pump up pressure and see if it holds. Then you switch to vacuum and pump up vacuum and see if that also holds over a period of time. I have the adapters and plugs needed to use the Mityvac kit on a Rumi engine.
I would be happy to send it to you if you think it would be useful to do such a test.

Lasse
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Re: Bol D'Or - New Project

Post by Lasse » Sun Aug 21, 2016 8:11 am

Good morning Hugo - here comes a wild idea...
This idea might in an quite easy way prove, if the seal has been mounted wrongly, or has been torn.

Overfill the gearbox with oil, to a level higher than the uppermost part of the seal.
If the seal is not working properly, you should have the right cylinder to fire at once - but at the same time have a lot of blue oil smoke in the exhaust.

Yes, this idea is way out - but what do you think?

arthur lewthwaite
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Re: Bol D'Or - New Project

Post by arthur lewthwaite » Sun Aug 21, 2016 12:22 pm

hugo pour a small amount of fuel into right hand cylineder through plug hole and se e if it starts on start up if fitted with single carb,orlittle drop of fuel down carburretor right hand side on twin carbs.just a sauce bottle cap full in each case.this gives a good idea as it richens fuel up enough to fire if to weak,may only fire for a few seconds or if revs reached could carry on running.

hugomez
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Re: Bol D'Or - New Project

Post by hugomez » Sun Aug 21, 2016 8:57 pm

Hi Arthur, Lars and Lasse.

You mentioned to add some fuel into the right cylinder, but we know it fire and works, not all the time, but it does, so I do not think is necessary to do that test. Maybe I did not understand the point of your suggestion test.

Lars and Lasse, in any moment during all the tests I did, I have seen an excess of smoke coming out the muffler box. I thought if I had a leak at the crankshaft seal, oil from the crankcase you be sucked and burned in the cylinder, producing that dreaded white/blueish smoke. Is not like that?, maybe I am wrong.

I understand from Lasse's test suggestion that if that leak is higher than the level of the oil, maybe is only sucking air and not oil?

In my experience with the leak at the Bicarburatore crankcase halves, I had not just the smoke, but also drops of oil coming out from the small hole of the cap at the top of the upper crankcase half. That oil was coming out because of the vacuum effect, expelling it out from there. I do not see this happening in this engine.

Lars, I would be happy to do test with your vacuum machine. Thanks for your offer. We can talk by private about a few details regarding shipping and so on. My concern about this is that I do not want to apply too much "vacuum/pressure" to maybe open a leak where there is not. I would need to know how much is the top "vacuum" I have to apply for a correct and not dangerous test for this engine.

Lasse, your test is also easy to perform, I can also give a try.

In the meantime, I will change the way all the wirings are connected. Right now all the ends/heads/tips are crimped connectors, however to get a proper good connection, I will remove them and use tin soldering to connect the "tips" at the wires as I got suggested by private email.

Still I really hope to find the problem in something that do not require take the engine out and open it.

We will see.

Thanks :)
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arthur lewthwaite
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Re: Bol D'Or - New Project

Post by arthur lewthwaite » Sun Aug 21, 2016 10:30 pm

hugo, the point of adding extra fuel is that the right side fires but not easily and not very well,adding the fuel should richen up what the cylinder is receiving and should immediatly fire up straight away and strongly if only for a few seconds if only till the added fuel runs out,this will also prove your electrics are okay as it will run straight away on both cylinders,if this is the case then it shows a fuelling problem.i still think that with all you have tried unfortunately that the problem points to a seal problem. or again leaking in case halves on righthand side

hugomez
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Re: Bol D'Or - New Project

Post by hugomez » Sun Aug 21, 2016 10:47 pm

Hi Arthur,

But if there is a leak, should not be white smoke coming out from the muffler box because of the engine oil burned?, is not that the first sign of this type of leak?
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Lasse
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Re: Bol D'Or - New Project

Post by Lasse » Mon Aug 22, 2016 6:28 am

If you overfill the gearbox - you will see if its a seal-problem...

Lars
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Re: Bol D'Or - New Project

Post by Lars » Mon Aug 22, 2016 7:43 am

Hi Hugo,

About the vacuum/pressure test: It is not really a vacuum machine, it is just a simple hand pump. You use very low, completely harmless pressure: 6 or 7 psi and 5 to 7 inches of mercury (HG), then observe how much it loses over 5 or 6 minutes.

If you can wait a couple of days, I will try to do the test on one of my engines and take som photos of both the pump and the procedure while I am doing it. That way you will have some references to compare your readings to.

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Re: Bol D'Or - New Project

Post by hugomez » Mon Aug 22, 2016 9:24 am

Hi Lasse,

I will perform your suggested test and see what happen.

Lars, of course I can wait, thank you very much.

Have a great day everyone.
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arthur lewthwaite
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Re: Bol D'Or - New Project

Post by arthur lewthwaite » Mon Aug 22, 2016 5:39 pm

hugo its a difficult one,fuel mixture is very thin like agas when atomised akso air is very thin,also could be sucking in or blowing out and not neccesary pulling in oil,i have seen this a lot over the years on two strokes,the petrol test helps with eliminating theelectrics being the problem,after that its up to you which way to go.i hope you find an easy answer.

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Re: Bol D'Or - New Project

Post by hugomez » Mon Aug 22, 2016 8:13 pm

Hi,

I just found something that was wrong in the electrics. I was removing all the "climbed connectors" to instead tin soldered all of them. During the process I also took the resistor out, to have a closer look from the back part of it that is not visible when is attached to the bike. Then I saw the broken wire that you can see at the photo. (Sorry for the quality, I took it with the mobile phone)

To that resistor terminal are connected three wires: one from the CEV switch, one from the horn and one from the main power from IGNITION

Can this be the source of the problem?
Resistor-wire-broken.jpg
Resistor-wire-broken.jpg (176.36 KiB) Viewed 8996 times
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arthur lewthwaite
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Re: Bol D'Or - New Project

Post by arthur lewthwaite » Mon Aug 22, 2016 9:20 pm

hugo this is in the lighting circuit i believe,not ignition circuit,these circuits run of differant windings in magneto.

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Re: Bol D'Or - New Project

Post by hugomez » Mon Aug 22, 2016 9:29 pm

Hi Arthur,

From ignition came out three wires. One is going to the right coil, the other to the left coil, and the third one is the main power that goes to the resistor, exactly to the terminal in the resistor that has the wire broken (just soldered).

Is that third wire provide electricity just to the lighting?

No idea if this broken wire in the resistor can be a major problem.

By the way, lights works, as well as horn.

Maybe with that broken wire at the resistor the only problem I could get is that bulbs could blow/break easily?
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arthur lewthwaite
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Re: Bol D'Or - New Project

Post by arthur lewthwaite » Mon Aug 22, 2016 10:29 pm

hugo look at diagram on rumi club tecnical page,the part with broken wire regulates voltage to lights and horn circuit onl,not linked to ignition.

Lars
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Re: Bol D'Or - New Project

Post by Lars » Tue Aug 23, 2016 5:49 am

Hugo, the current path through the voltage dropping coil (resistor) is active only in position 1 (Pilot light/Parking light) of the lighting switch.
The break in the coil meant that you had no power to the pilot light and tail light in that switch position. You mentioned earlier that the pilot light did not work. You just found the cause!

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Re: Bol D'Or - New Project

Post by hugomez » Tue Aug 23, 2016 8:28 am

Hi Arthur and Lars,

Pity that this is not something that could cause the major problem the bike has, but at least now I know why the pilot light didn't work.

At least I am learning a lot about the electric system, before I knew nothing about it, now I know almost nothing, so it is an improvement :lol:

Thanks.
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Re: Bol D'Or - New Project

Post by hugomez » Tue Aug 23, 2016 6:05 pm

Hi,

Just test the bike after checking and tin soldering all ends of the wires.

Same result.

Next Lasse's test.

How much "extra" oil should I add at the crankcase? Right now it has 1 little.

Please let me know.

Cheers
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Lasse
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Re: Bol D'Or - New Project

Post by Lasse » Tue Aug 23, 2016 8:36 pm

leave the surface of (new) oil, approx. 10-15mm under the hole on top of gearbox.
After the test, you can easily use the oil for other purposes.

hugomez
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Re: Bol D'Or - New Project

Post by hugomez » Tue Aug 23, 2016 8:51 pm

Thanks Lasse, I will fill oil until that level.

After the test I will put the oil again in the metal can to use it at the gearbox of any of the Rumi once I need it.

Unfortunately is possible that I won't be able to do this test until next week.

Thanks.
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Ian Skinner
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Re: Crankcase pressure and vacuum testing on two Rumi engine

Post by Ian Skinner » Tue Aug 30, 2016 11:57 pm

Hi Lars, I agree this test should be done, to check out any leeks.

LINK: http://www.formichino.com/forum/viewtop ... =17&t=1380

However, I have referred the problem to a colleague. His opinion on seals is, when the cylinder was firing without grey smoke, indicates that crankshaft seals are not the cause of the problem.

His view, as all the electrical options have been bottomed out, there is only one other possibility. He asked if the cylinders were freshly re-plated and ground. I affirmed this.

He has encountered similar problems when working with racing Yamaha TZs. If there was an issue of this nature, it occurred immediately after cylinder refurbishment. The cause is ‘belling’, an area of the cylinder below the transfer ports being larger than the nominal bore diameter. This prevents gas tight piston ring sealing when the piston is attempting to pressurise the crankcase to affect mixture transfer to the combustion chamber and also the primary induction from the carburettor. Of course, this sort of fault should have shown up during the process provider's inspection activity, which may concentrate on the top of the bores only.

Well, Hugo, if the pressure test fails to confirm a seal or joint issue, then I'm afraid it is a head-off and cylinder removal to get the bore checked out.

Ian

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Re: Bol D'Or - New Project

Post by hugomez » Sat Sep 03, 2016 4:34 pm

Hi,

Lars, thank you once again for sending me your pressure/vacuum tester, it work great.

Today I did the test. I did it several times in two conditions, at BDC and also at TDC.

The reason why I did the tests several times is because first I just focus on the test, doing it as more precise as possible, and then later I did it again recording videos at the same time with the mobile phone in my hand (sorry for the camera shaking), so in those once I was not very accurate positioning the needle.

TESTS at BDC (Bottom Death Centre)
Time: 3 minutes

01 LEFT cylinder:
Pressure: 6 p.s.i.
Lost after 3 minutes: 0.6 p.s.i.

02 LEFT cylinder:
Vacuum: 6 inHG
Lost after 3 minutes: 0 inHG

03 RIGHT cylinder:
Vacuum: 6 inHG
Lost after 3 minutes: 0 inHG

04 RIGHT cylinder:
Pressure: 6 p.s.i.
Lost after 3 minutes: 0 p.s.i.


TESTS at TDC (Top Death Centre)
At TDC I didn’t wait the three minutes as I did at BDC, just 1 minute and a half.

05 RIGHT cylinder:
Pressure: 6 p.s.i.
Lost after 1.30 minutes: 0 p.s.i.

06 RIGHT cylinder:
Vacuum: 6 inHG
Lost after 1.30 minutes: 0 inHG

07 & 08 LEFT cylinder
Vacuum & Pressure similar results as RIGHT cylinders.

As you will see at the video, at the tests in TDC, the pressure/vacuum drop in every pump. I understand this happen because the pressure/vacuum is “leaking” by the piston rings, until the complete cavity behind the pistons get pressurise/vacuumise (does this word exist?), then it remain completely stable, not loosing pressure/vacuum. Is that correct?

I consider these tests very successful because the pressure/vacuum remain strong in both cylinders, but of course I would like to know what you guys think about it.

Ian, do you think this test is good to dismiss the re-plated cylinders problem theory?, should I do some more test?

Greets,
Hugo

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Lars
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Re: Bol D'Or - New Project

Post by Lars » Sat Sep 03, 2016 5:52 pm

Hi Hugo,

Great video, very clear. There is nothing like seeing the test being performed, and seeing the movements of the needle.

A good idea to also do the test at TDC. It then becomes a leak-down cylinder test plus a crankcase test, just as you suggest.

What is clear from this test is that your engine is perfectly tight and that you have absolutely no problems with crankshaft seals or crankcase sealing. You could not ask for a better test result. I only wish my own engines were that good!

Lars

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Re: Bol D'Or - New Project

Post by hugomez » Sat Sep 03, 2016 8:02 pm

Hi Lars,

I am very happy of the result, the problem now is that I do not know what to do next to try to find the source of the problem at the right cylinder.

Any suggestion?

Greets,
Hugo
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Lars
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Re: Bol D'Or - New Project

Post by Lars » Sun Sep 04, 2016 7:13 am

Hi Hugo,

The only thing I can think of now, is to remove the heads and cylinders and inspect them carefully. Look for any difference between the right and left cylinders. Have the cylinder bores checked for possible problems as suggested by Ian. Also check and measure the pistons and look for any left/right differences. Piston rings too.

A mysterious problem to be sure, but there must be a reason, somewhere...

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Re: Bol D'Or - New Project

Post by hugomez » Sun Sep 04, 2016 9:55 am

Hi Lars,

I thought this test would help to proof that cylinders (and re-plated) are ok, not needed to remove them of the engine. With the small area to work in this bike, removing the cylinders would be really painful. Is this completely necessary at this point?

We see there is same compression in both cylinders at BDC and at TDC. I could test also with the piston at the middle position inside the cylinder, to see how the pressure react. If there is any problem with the re-plated, I guess I would notice in the needle at the pressure machine. Would this be a solution to avoid remove them?

My main concern is not remove them, is to put it back. Even with the engine on the table is not very easy to manage the pistons rings when assembling, I can not imagine doing it with the engine on in this scooter.

I did it in the Bicarburatore and was more or less ok, because there are a lot more space to work, but in the scooter .....

Any advise is welcome regarding this.
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Lasse
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Re: Bol D'Or - New Project

Post by Lasse » Sun Sep 04, 2016 10:54 am

Hey, Hugo - I believe you now have "peace of mind" regarding the motor (cylinders)'
To put it simple, everything seems to be in order.
But why does the right cylinder then not fire instantly?

It could simply be "lack of use - lack of kilometres"!
What if you drove a couple of 100 kilometres?
Wouldnt you think, that carburation, & ignition then might "settle"?

Frankly, it could well be so i think - so why not try to use the scooter, and then see what happens...

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