Carburettors

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Paz2112
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Re: Carburettors

Post by Paz2112 »

Mark, I made a mistake I meant to say that my Main Jets are indeed 115 and the Float valves were 200. Would the E24 needle make the carb too lean?

Also does this look like the correct 260BD Atomiser, apart from its length?
https://www.dellorto.co.uk/shop/dellort ... z-20-26mm/

I have not received ATG for over a year now, I cancelled my subscription due to illness and never renewed. I have searched for any guide on this but was not able to find anything showing how to modify the 260K. Any help is greatly appreciated.
My Other Italian V-Twin is an Italian V-Twin
3potjohn
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Re: Carburettors

Post by 3potjohn »

You can always swap the needles and recheck with the colourtune to see if the fault moves as well. I tried reducing my Sport’s pilot jets from 50 to 43 but it ran best at 45. If you have standard air filter, exhaust etc then the needles seem unusual.
Let us know what you find.
John
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Re: Carburettors

Post by EVguru »

Paz2112 wrote:MAlso does this look like the correct 260BD Atomiser, apart from its length?
https://www.dellorto.co.uk/shop/dellort ... z-20-26mm/
Wrong length? It's the wrong bore size.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
mbmm350s
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Re: Carburettors

Post by mbmm350s »

Hi,

could I possibly persuade you to rejoin the club? as membership secretary I can process your renewal!

The only difference between E24 and E17 is the E24 comes onto the taper 1.5mm later (about one notch or so )
E17 Length 65, main diameter 2.45, final diameter 1.70, start of taper from tip of needle 21.5
E24 length 65, main diameter 2.45, final diameter 1.70, start of taper from tip of needle 20.0

PM me and I send details of the 260BD, sadly the one you found is 2.69mm bore not 2.60.
I don't think Eurocarb have stocked the 260BD for years. ( part number 9994)
However its not necessarily the case that the BD would make any difference,
there are too many variables.

The 260K is drilled starting from the bottom and going upwards diameter 0.8mm
2,4,2,0,0
The 260BD drill diameter 0.8mm
2,4,2,4,0
The post 1979 K engines with HS carbs 260D again 0.8mm
0,4,2,2,0

Obviously you have checked the ignition is spot on for both cylinders?

Mark
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Paz2112
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Re: Carburettors

Post by Paz2112 »

Mark,

As with all old bikes, I have no way of knowing what the previous owner(s) were trying to achieve by using the E24 Needle in the front carb. Did they think it was too lean? I actually want to go back to the start and check both my carbs again, fit them, balance them and then see what the colour tune is showing me. In practical terms, when I out the choke on the front carb the revs pick up a lot which would lead me to think that it is too lean. I was previously not able to get a bunson blue from the front carb but I forget if it was too yellow or possible more white so I need to run that check again before commenting too much further.

I am not so worried yet about finding the BD Atomiser, the 260K that is in the rear carb is managing a good bunson blue burn so it cannot be that far off. I am running a 50 idle jet and everyone seems to suggest that a 48 or 45 is a better idea but I don't understand the logic of this so any help would be appreciated.

P.S. I would not be against a paid membership again, how much is it these days?
My Other Italian V-Twin is an Italian V-Twin
EVguru
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Re: Carburettors

Post by EVguru »

Morinis often suffer from a stumble through progression due to running rich with modern fuel (with its higher percentage of aromatic fractions).

The Idle jet in combination with the mixture screw controls idle mixture.

The Idle jet in combination with the slide cutaway controls progression mixture.

A leaner idle jet is easy, cheap and often effective, but not always. On my 125H I had to increase the slide cutaway, but fortunately this was from 40 to 50 and a spare 350 slide was used. The slide change is probably a better solution, but slides are quite expensive and there is a very limited selection still available. I just machined a pair for someone.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
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Paz2112
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Re: Carburettors

Post by Paz2112 »

Update.

I have ordered replacement pads for the choke plunger as these were not replaced when I rebuilt the carbs the last time. I also plan to replace both the Needles with new E17 and not have the mix of the E17 and E24. I also plan on ordering two sets of idle jets, a pair of 48 and a pair of 45, so that I can experiment with this modification as recommended by Paul and a few others.

Can I ask for any advice on any other parts that I should now order while I am at it?
My Other Italian V-Twin is an Italian V-Twin
mbmm350s
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Re: Carburettors

Post by mbmm350s »

Hi,
you could take a look at the float needles, if they look worn on the sides or tip, then replace with the modern viton tipped version.
I think these are readily available.

MRC subs are on the website, when you buy now you get membership until 31/11/2021 i.e one year plus 4 months
If you wait until 1st August there will be a price drop.
http://www.morini-riders-club.com/produ ... Membership

Mark
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Re: Carburettors

Post by MickeyMoto »

mbmm350s wrote:
MRC subs are on the website, when you buy now you get membership until 31/11/2021 i.e one year plus 4 months
If you wait until 1st August there will be a price drop.
http://www.morini-riders-club.com/produ ... Membership

Mark
I presume you do not work in Sales, Mark? :)
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Paz2112
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Re: Carburettors

Post by Paz2112 »

He does now.
My Other Italian V-Twin is an Italian V-Twin
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themoudie
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Re: Carburettors

Post by themoudie »

This 1986 K2 350cc is a vexatious bit of kit! :evil: This is the first twin, other than a 1988 Honda Bros 400 that I have worked on in 53 years of motorcycling and now I know why couriers used the Honda Bros and not a Morini Tre e mezzo!

Having rebuilt the carbs with rebuild kits from Eurocarbs and adjusted the cable adjusters, throttle stop screws and mixture screws to the settings when they were removed from the machine, I finally tried to start the engine tonight.

Petrol 'ON', both enrichment levers raised and on the third kick the wee beastie ROARED into life! :shock: I quickly shut both of the enrichment levers and the revs dropped to a steady 3,200rpm. :twisted: I cannot get the revs down from this despite 'blipping' the throttle. :evil:

So, where to next? :x I suspect I need to go back to base settings for these 'standard' carbs and the 'Blue book' is as useful as a chocolate teapot! If they were Amal carbs I might have a chance?

Please may I ask if anybody has initial settings for the mixture screw (Does this adjust air or fuel?) and the throttle stop? Number of turns from seated would be gratefully received. Also the amount of slack in the cable, with the throttle slide sitting at the bottom of it's travel and with the throttle stop screw resting against it, but not raising it? I think that it it is 1.5mm?

Or am I barking up the wrong tree altogether and should I be checking the ignition timing having replaced the timing belt and disturbed the stator and rotor? The stator I marked before removal and reinstalled, with those marks aligned, as was the dot on the camshaft pulley with the nick in the crankcase. Whilst the keyway and punch mark on the crankshaft were aligned with the punch mark on the crankcase at approximately 02:00 on a clock face.

Thank you for your time and patience.

My regards, BillR
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Ming
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Re: Carburettors

Post by Ming »

You may find carb settings on the Dutch Morini Club site. I don't think position of the rotor or stator have any effect on timing as they only produce power for the battery and ignition units - as long as the cambelt sprockets have not moved relative to each other. Are you sure the slides are the right way round and the throttle cables not trapped above the adjusters?
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Paz2112
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Re: Carburettors

Post by Paz2112 »

It could be an air leek. Are the slides worn or in good condition? Check that the idle screws have seals on them when fitting them. Another thing to check is that the rubber bung/seal on the bottom of the choke/enhancement lever are intact and in good condition. If they do not seal correctly, you will always be 'choked' even when closed or down. Are the rubber grommets holding the carb onto the cylinder in good condition with no holes or cracks?

Other than that, make sure that the cables are not too tight, there should be some slack, about 2-3mm in my opinion before they start to lift the slide.
My Other Italian V-Twin is an Italian V-Twin
3potjohn
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Re: Carburettors

Post by 3potjohn »

If we eliminate other issues like incorrect ignition timing, and leaking chokes, backward slides ( not sure if you can get them in backwards on a K2) are you able to reduce tick over by undoing the slide screws right out ?
On my K1 I have the idle screws about 1 & 3/4 out. This bike has always run properly carbs wise yet I only discovered yesterday I had omitted the little o rings on them ......after 10 years.
My slide screws are about the same out. The tubing is all new including the balance pipe between the carbs.
Can you hear and feel the slides touching bottom when you move the throttle. I am running 45 pilot jets
I do not think the pilot jet can cause this no matter what position the idle screws are, well not in my experience.
Have you watched the YouTube carb stuff Paul Compton did it May jog your mind?
Keep at it. I cannot eliminate rough running at approx 4500 rpm on another Morini ( this with with PHBH carbs ) so feel your pain.
John
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themoudie
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Re: Carburettors

Post by themoudie »

Good morning and thank you All for your insightful replies.
As it is raining 'cats and dogs' I am going to sit and read from cover to cover this Dellorto carb tuning manual: Dellorto_Tuning_Manual
Then go and make a LARGE Aeropress coffee and open the garage door! I'll keep you posted! :wink: I wonder why this bike was nearly broken for spares, before I 'saved' it? :twisted:
Good health, BillR
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