250 2C - various questions from new owner

[Richard_Carrigan]

Hi All,

I'm the, so far happy, new owner of a 1979 2C. I'm going through the process of reviving it as it has been stored at the back of the P.O.'s garage for about ten years. Unfortunately I can't ask him any questions about the bike as he's passed away - so I hope someone here can rectify my ignorance.

So far I've changed the timing belt & the oil, and have stripped and ultrasonically cleaned the carbs (VHBZ 22's), which along with the fuel taps, were full of sludge.

On both carbs, at the end of the passageway for the idle jet appears to be a tiny washer or 'o' ring. This doesn't appear in the Dellorto diagram I have, but the Mdinaitalia gasket set (on their website) shows 'o' rings other than those for the mixture screw and choke jet. Should there be one above the idle jet?

Lastly, in my copy of the Blue Book this model isn't listed so does anyone know if I can use the 350 settings for the valve and ignition timing?

Many thanks,
Richard

[Steve Brown]

Hi Richard, and welcome to the fold. I'm not aware of any washer or O ring where you describe. Are they removable for inspection? I'm sure if there had been anything other than the carb body the Dellorto manual would list them. On all the Dellorto carbs fitted to the air cooled V twins that I've seen the idle jet screws into the body till its head is seated against the body.
I can't remember anything about ignition on these but would expect timing marks to be on the flywheel. I.e. PMS 1 (TDC #1 cyl-Front) and ANT 1 for the ignition full advanced point
.

[Parker3865]

Hi Richard,
I am rebuilding one and found a handbook on the net. It was in Italian, but I have translated it, Both can be downloaded from
https://1drv.ms/f/s!AjEnhu6oX6Zpil01Lf6 ... O?e=FVOzAw
Hope it helps
p,s, apologies for any translation accuracies, you can blame Google

[mbmm350s]

Hi Richard

Thanks for the translation, your translation is way better than the official English translation (i have a copy of this) from the 80s


Richard,
Welcome to the forum,

The gasket set from Mdina, for Dell Orto, covers multiple carbs and potentially contains o-rings and seals not needed.

There is a tiny o-ring and washer fitted to the idle mixture screw (and also to the throttle stop screw), these are not shown in early parts books,
but are fitted to VHBZ carburettors, so there is no o-ring on the idle jet itself, I think you likely already know this.
Dont forget the fibre washer under the float valve seat though!

These carburettors are fitted with vacuum ports these are the brass tubes at the front engine side (to operate vacuum taps for example) these ports aren't used on 250s, what you need to do is either blank them off or connect them together. There may already be a connecting tube make sure it isn't perished.

One thing with these engines is the wet clutch might be stuck if its been stood for a long time, take care.

Mark

[72degrees]

Hi Richard

Thanks for the translation, your translation is way better than the official English translation (i have a copy of this) from the 80s

Seconded! I only need the 250 V book for everything else but the engine but it's jolly useful.

[Ming]

I have the owners manual and parts book if anyone wants a copy.

[Richard_Carrigan]

Thanks, everybody, for all the information. Especially Parker3865 for the great translation of the Instruction Book ( BTW I think 'candles' might be spark plugs).

I thought there was a tiny O ring up in the idle jet passageway on both carbs as after I'd cleared the blockages I wasn't seeing a nice disc of light when peering through, but an oval. Subsequent sessions in the ultrasound bath changed it to a disc, then back to an oval, back to a disc etc & my eyes just were not sharp enough to see what the blockage was. A guitar string and a few blasts with carb cleaner, from the throat side, finally shifted them.

While it's a nice looking little bike, it's the first restoration I've had where even the fuel taps have been solidly blocked! Damn stuff looked like clay & had to be scraped out in chunks.

I'll have tons of other questions for the Brains Trust, but I'll pop them into their own threads to make life easier for other seekers of knowledge!

Thanks again, All.

[RedVee]

I have the owners manual and parts book if anyone wants a copy.

Is that the Workshop Manual?
If so I could do with a copy please.

[Ming]

No, Owners Manual and Parts Book.