Dellorto SS1 27 A or D ?

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mark3kb
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Joined: Sat Dec 07, 2013 3:29 pm

Dellorto SS1 27 A or D ?

Postby mark3kb » Tue Feb 28, 2017 8:10 pm

Hello, I was wondering if anyone in the community has come across this information before. I need to know the correct carb application for my US 1964 Diana Mark III (not Mark 3 250) resto which I am in the process of. I have a SS1 27 A and a SS1 27 D carb. Mick walkers book states that the carb that is specified on this bike is the SS1 27 D. I have a Berliner printed advertisement which states in paragraph " comes with a Dellorto SS1 27 A carb". I simply want to know which one is correct any ideas thank you

Rick
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Re: Dellorto SS1 27 A or D ?

Postby Rick » Wed Mar 01, 2017 3:33 am

The December 1963 Cycle World road test of a 4 speed Diana MK3 was uncrated and assembled by the testers, and they write that it came with a 30mm Dellorto- a photo shows it's an 'A' series SSI, with the riveted plate.
In November 1964 they tested a 5 speed, now calling it a 'Diana MK III', and they list it having a 27mm carburetor- again a photo shows it's an A series SSI, with the riveted plate.
I'm not a guy who bought one new and can say exactly what it came with, but with the period road tests, no one can tell you the A series is wrong, even though some of them may have come with the D series.
Rick

Bevel bob
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Re: Dellorto SS1 27 A or D ?

Postby Bevel bob » Wed Mar 01, 2017 5:49 pm

In order to get the best write up ,it was not unknown for the supplying dealer to "hot up" the bikes and fitting a bigger carb was one modification. It usually resulted in a poorer overall performance but they were looking for top speed to outdo the new jap bikes that were stealing their sales. 30 mm seems too large for that model ,even the later 5speed mark 3 were a bit overcarbed for best street use . I would go for the D carb. Think they were more usual.

double diamond
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Joined: Thu Apr 28, 2011 1:20 am

Re: Dellorto SS1 27 A or D ?

Postby double diamond » Wed Mar 01, 2017 9:25 pm

The SSI 27D was only original on later Scrambler models. Every image I’ve ever seen of what appear to be original examples of the Diana Mark III had an SSI 27A. The Cycle World article, which refers to the carb as a “TT Dellorto” lists the inch measurement as 1.06”, which equals about 27mm, yet they identify it as 30mm in the text. Although Del’Lorto did offer a 30mm A series SSI, I expect the carb on the road test bike is a 27A SSI. Mick Walker’s frame of reference was UK market models, with which he was quite familiar. His references to USA market models were second hand at best. The Diana Mark III was never sold in the UK, so I doubt Mr. Walker had ever seen one in the metal.

Hope you can post some pics and details on your restoration. Engine number? Frame tag? Wheel rim manufacturer? Cam color?

Matt

amartina75
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Location: Cincinnati, OH. USA

Re: Dellorto SS1 27 A or D ?

Postby amartina75 » Wed Mar 01, 2017 9:40 pm

no idea what is correct but the D models are much more common, the A models are sandcast and much nicer carbs. If it comes down to just preference Id use the SSI27A. Better metal, better casting, better looking.
1966 250 Scrambler
1970 450 Jupiter

thebossdj
Posts: 55
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Location: Vancouver Island

Re: Dellorto SS1 27 A or D ?

Postby thebossdj » Thu Mar 02, 2017 5:38 am

My 2 cents is go with the 27A. The green tag carbs look way sportier and trick plus nicer castings. Seems like all the early SSI carbs had green tags and as time went on the phased them out. Most later SS carbs under 30mm do not have green tags ie Ducati when the went to 5 speeds, Guzzi V7 etc. Use what you like but I agree with the amartina.

Rad you are are restoring the bike! Look forward to hearing and seeing pics

Vintmoto
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Re: Dellorto SS1 27 A or D ?

Postby Vintmoto » Mon Mar 20, 2017 12:50 am

I believe they changed the the D carb about the time Ducati changed to 5 speed bikes. For what it is worth, Tom Bailey says the early carbs look better, but wear quicker then the later castings. I don't think any of them were great metallurgically. Having said that, I have had no issues with mine. Certainly a D carb would be appropriate for a later bike.

mark3kb
Posts: 30
Joined: Sat Dec 07, 2013 3:29 pm

Re: Dellorto SS1 27 A or D ?

Postby mark3kb » Thu Mar 23, 2017 3:29 pm

Hello everyone and thank you for the feedback. After doing lots of research and getting the info back from yourselves, it seems there is no doubt that the SS1 27A is the correct carb. this is the carb that was in the box originally, but was in rough shape. I have found a nice example since.

ajleone
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Location: Pittsford, NY
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Re: Dellorto SS1 27 A or D ?

Postby ajleone » Sat Mar 25, 2017 3:11 pm

According to the parts book, SSD is the correct carb. But who knows?
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amartina75
Posts: 347
Joined: Tue Aug 21, 2012 1:13 am
Location: Cincinnati, OH. USA

Re: Dellorto SS1 27 A or D ?

Postby amartina75 » Sat Mar 25, 2017 4:20 pm

Tony,
His Mark 3 is a narrowcase bike
My parts book shows early mk3's having a SSI 27A then switching to a SSI 29A then after engine # 00350 switching to an SSI 29D
But does it really matter? I wouldn't care that much.
As long as there isn't a Mikuni on it... lol
IMG_1468.PNG
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1966 250 Scrambler
1970 450 Jupiter


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