Dellorto MD27F Choke

Derek Wardell

unread,

Mar 1, 2021, 3:21:55 PM3/1/21

to Guzzi Singles

I'm rebuilding a 1960 Falcone Turismo which is fitted with an MD27F carb. I can't find a parts diagram for this carb and I'm struggling to see how to fit the choke assembly. It has the usual drop down choke bar, which is held up by the cable in the normal running position. However it also has a brass sleeve which the choke fits into. There is nothing to secure the choke and the sleeve together, so when it's fitted in the slide, the sleeve just drops down.

Thing is, the bike was running fine when I dismantled it and I neglected to notice this strange choke system in the carb.

If anyone can enlighten me, or supply a diagram of the MD27F I'd appreciate it.

Cheers.

Gordon de la Mare

unread,

Mar 1, 2021, 6:00:32 PM3/1/21

to guzzi-...@googlegroups.com

Take a look at the MD in here it is a shared page with a MC variant:

:

https://www.mondoape.com/manuali/dell-orto-catalogo-1-carburatori-per-motoveicoli.pdf

Gordon

--
You received this message because you are subscribed to the Google Groups "Guzzi Singles" group.
To unsubscribe from this group and stop receiving emails from it, send an email to guzzi-single...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/guzzi-singles/b2231497-0efa-4a0b-a739-1d13bf15344bn%40googlegroups.com.

Alan Comfort

unread,

Mar 1, 2021, 9:49:22 PM3/1/21

to guzzi-...@googlegroups.com

Hello Derek,

I have never seen MD27F with parts like this. The MD27F does not have a choke per se, but rather an enrichener valve to assist with cold starts. I expect that the parts you show are a bodge to deal with a badly worn throttle body and/or slide. It looks like the brass sleeve is meant to fit over the throttle slide and is held in place with the throttle cable. If this was my bike, I would not ride it with this fix. Apart from the bike running like a bag of hammers, there is a strong likelihood that the throttle could stick in the open position with this arrangement.

New and used MD27F's are prohibitivly expensive to buy. It may be possible to bore your carb, fit a sleeve and fit a new slide. There are companies that provide this service for Amal carbs but I am not sure if anyone is doing this for Dell'Ortos. There is also a remote possibility that fitting a new slide will make the carb serviceable. Other alternatives include a more modern Dell'Orto. an Amal or a Mikuni. Not period correct, but will provide good service once fitted and dialed in.

Ciao, Alan in Roberts Creek

Ciao, Alan

--

Charles Mullendore

unread,

Mar 1, 2021, 10:11:13 PM3/1/21

to guzzi-...@googlegroups.com

The UB/MB has a choke slide like that (but not the sleeve).

https://www.dellorto.co.uk/product-category/dellorto-motorcycle-carburettors-parts/dellorto-vintage-carburettors-and-parts/ub-mb-parts/

Charlie

To view this discussion on the web visit https://groups.google.com/d/msgid/guzzi-singles/CAC8DhY1T12GW1WT%3D1w-T4%2Bgv7EfV0WQiayyZDua%2BbatHu1AOSg%40mail.gmail.com.

SED Sci

unread,

Mar 1, 2021, 11:04:27 PM3/1/21

to Guzzi Singles

MD27F - the spring fits between the sleeve and choke slide.

Derek Wardell

unread,

Mar 2, 2021, 4:09:18 AM3/2/21

to Guzzi Singles

Guys - many thanks for your replies and for the links to the correct diagram.

SED Sci - yes, the penny finally dropped. I was trying to assemble it with the part 1154 (Guide for the air tile) upside down....Your comment regarding the spring being between the 2 parts clarified it. I think the spring could be too long (probably out of a biro), but I'll see when I make up a new choke cable.