New 250 mk3 Owner

[machten]

Hi Derek,

As far as final drive gearing is concerned, I can confirm Craig's support of the 17/45 arrangement. I use that on my 68 250 Desmo and in my opinion it is an excellent compromise between urban streetability and higher speed freeway running.

One of the things you may have to aquire some comfort with with your reengagement with these lower powered, low capacity singles is the need to use the rev range to extract their joy. You do need to give them some revs to see them at their best. Whilst the 450's can supply you with some low end torque, the 250's deliver their best much higher up the rev range. If you're feeling it's too high geared, then you are possibly changing gear too soon. Give it some squirt. They like it, and so will you...and they will thank you for it. The worst thing you can do to them is to slog them on low revs.

Kev

[Bevel bob]

My 250 is now running 18/42 which although very high is lower than the stock 18/40. It is too high for any practical riding in average traffic , so i don't do that!.

[machten]

I can't vouch for the accuracy of this but I note that in Mick Walkers Ducati Singles book he states the stock issues as being 2.647 (17/45) for the Mk3 D 250 and 2.812 (16/45) for the Mk3 250. It suprises me a bit that they would be different, but that's what it says.

Kev

[Ventodue]

I note that in Mick Walkers Ducati Singles book he states the stock issues as being 2.647 (17/45) for the Mk3 D 250 and 2.812 (16/45) for the Mk3 250. It suprises me a bit that they would be different, but that's what it says.

Weird ... Here are the ratios given in the owner's handbook of May 1972. While the 250s are the same as each other, as are the 450s, it's the 350s that are different ...

* 250 Mark 3 AND Desmo - 1:2.647

* 350 Mark 3 - 1:2.812
* 350 Desmo - 1:2.625

* 450 Mark 3 AND Desmo - 1: 2.666

* 250 & 350 SCR - 1:3.214
* 450 SCR - 1:2.917

[Glawster]

Hi Guys,
Thanks for the good info on the gearing. I think the regular 45/17 will be right for the job. I'm hoping to call on Barry Jones this week to pick up some bits and I think he has the 17te in stock.

Just managed to find myself a new seat badge (the alloy one with the red lettering). It's just mad when you are in the UK and the only place you can find a part for a 40 year old Italian bike is in San Jose, California - but there it is! Anyway the refurbished seat is a really superb job at a very reasonable price (RK Leighton) so it deserves the finishing touch of a new badge.

Next question....I'm replacing the 150mm Aprilia headlamp rim as the chrome's shot and it's cheaper to replace than rechrome. What I can't locate is a new rubber or silicone seal for the headlight rim. the existing one is perished. Anybody got any ideas? I might head to my local washing machine parts shop as that seems like a good starting point for rubber seals - but I'm hoping someone on here has the right dodge to solve it?

Best regards,
Derek

[single]

Hi Derek...Spotted a headlight gasket at Guzzino.com (think thats in sunny California !) regards Paul aka single

[Glawster]

Thanks Paul - very helpful!

[Glawster]

Hi Guys - I'm back again for some more advice.
This time it's cable routing. I've just got the handlebars and brake mounts back from chrome plating so I'm reconnecting the cables. I've just let them adopt the position of least resistance as in the attached photo, but I'm sure it's not right....
- The clutch cable is hanging out of the left side of the engine and goes up alongside the frame downtube. Should it go vertically up and along the spine? The frame has some brazed on soft metal cable mounts on both sides of the spine tube. One the left side I've put in the wiring loom. Should I clip the clutch cable into the right side?
- The choke and throttle cables seem to want to just run up on top of the spine. Is this right?
- Where to place the fuel tank mounting pad? How far back? This pad had holes in it - should I run the clutch cable through one of the holes?

I should have taken a bit more interest when I was taking it apart but you know how it is.

Just waiting for the wheels to return and I hope to be up and running. I will get rid of that ghastly NGK plug cap as well.

Thanks for any info..
Derek

[Ventodue]

Your choke and throttle cable routing looks odd, Derek. Have a look at the routing on the photos I posted earlier. Starting from the handlebar, try going round underneath the right headlamp bracket (I see yours originally went over the bracket, btw), then pass inside the right fork leg, down between the tank and the headstock and then along the right side of the frame top tube - they seem to have got over to the left side of the top tube and be crossing over it.

The clutch cable doesn't want to go along the top/spine tube. Basically, it wants to hang loose, and follow the most easy and graceful curves you can find for it ... Try taking it over to the right side of the bike, then curve it back down under the tank and top tube to emerge this time on the left side before gracefully curving back round again to the lever. Aim for making a big 'S' shape. Don't clip it in. The clips you see can be used for holding the carb cables; but, even so, be careful not to pinch them. Do not run the clutch cable thru the tank pad (!)

The tank pad should support the rear edge of the tank, to stop it rattling against the frame.

HTH.

Craig

[Ventodue]

Derek,

Here's a photo from Mick Walker's, Singles Restoration that may help for the clutch cable. See how it appears, at the top left, from the right side of the bike ...



Note also all the bandaging to support the tank ...