250 Mk3 reborn - Exhaust Seal?

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smellybeard
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250 Mk3 reborn - Exhaust Seal?

Post by smellybeard »

Greetings.

My 1975 250 Mk.3 is going back together. I bought it around 2000 and it suffered big-end failure almost immediately. It was a really nice bike - very clean throughout - so I wasn't completely gutted. Twenty-two years later the engine is bolted in and I'm going out shortly for a new battery and fuel hose. The tires will do for now.

What oil should go in it? I'm not really looking for a big debate just now; just oil to put in it for the first few hundred miles.
IMG_0758.jpg
Many years ago, with my NF500.
DucandGuz.jpg
Last edited by smellybeard on Mon Dec 05, 2022 4:53 am, edited 1 time in total.
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BevHevSteve
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Re: 250 Mk3 reborn - but what oil?

Post by BevHevSteve »

congratulations on getting this thing back together! API or JASO ratings matter to get the high zinc content needed.

API "SG" rated
JASO MA or MA2 rated

I like MOTUL 3000 20w50 dino oil, no need to pay the extra for semi syn.................
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smellybeard
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by smellybeard »

What is a Ducati exhaust seal like? Do they do well with the modern style of collapsing copper thing or is a simple annealed copper ring good?
What's the original Ducati part like?
There was none in it when I took it asunder.

The only other thing delaying me is the breather hose. The original - I really think it was original - had turned into rigid plastic in the 50 years since it was fitted. There's no way it's going back in past the battery tray.
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Craig in France
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by Craig in France »

The Real Thing is a U-shaped ring of aluminium with an insulating filler. Plenty of pictures out there on Tinternet, for example at Ducati Vintage Store or Lacey Ducati. Here's one:

Exhaust gasket.jpg
But no reason not to use a hollow copper ring is you so wish. I see that's what Eurojamb offer:
Exhaust gasket 2.jpg
The breather tube is a simple replacement, just have to find one of the right diameter. If you can get one with some kind of ant-crush reinforcement, so much the better, e.g:

https://www.ducativintagestore.com/oil_ ... _wide_case
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by BevHevSteve »

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Steve Allen (925)798-BEVL[2385] Ride'm, Don't Hide'm
Ducati/Euro Spares -> https://Store.BevelHeaven.com
Facebook > http://facebook.com/Bevel.Heaven
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smellybeard
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by smellybeard »

I would if I wasn't on the wrong side of the planet and the EU hadn't started clamping down on collecting all VAT and duties on even the smallest consignments. The shipping companies are having a field day charging collection fees. $7.29 would become $30+.
smellybeard
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by smellybeard »

Craig in France wrote: Mon Dec 05, 2022 6:12 am I see that's what Eurojamb offer:
I might have a few of those somewhere. I'll pull the vernier out and measure them up.
Craig in France wrote: Mon Dec 05, 2022 6:12 am The breather tube is a simple replacement, just have to find one of the right diameter.
I'm going to nip down to the recycling centre to morrow and see what there is in the line of old washing machines and dishwashers. I might get a hose off one that will do me for testing. It might shrink with the heat but it's only going to be on it for a few hours running. The weather is turning wet and cold and with 20+ year old tires, I'm not going out much until next year.
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Craig in France
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by Craig in France »

BevHevSteve wrote: Mon Dec 05, 2022 10:57 am Please support This Place <snip>
smellybeard wrote: Mon Dec 05, 2022 11:31 am I would if I wasn't on the wrong side of the planet and the EU hadn't started clamping down on collecting all VAT and duties on even the smallest consignments. The shipping companies are having a field day charging collection fees. $7.29 would become $30+.
'Fraid this is true, Steve.

I DO normally point people in your direction, believing in the dictum, "Support those who support us".

But on this side of the Pond the enthusiasm with which shipping companies are pursuing the collection of paltry amounts of duty in return for a fee several times greater means that buying stuff ex-US (or Australia for that matter) is getting impossible.

And don't even get me started on eBay's Global Shipping Program ... :roll:
smellybeard
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by smellybeard »

The BMW R60/2 seals are 38mm. I have a pair.
Weather exceptionally miserable here today and for the next few days. I'll probably leave the recycling centre until next week.
I really don't feel like opening up the doors to start the engine anyway.
smellybeard
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Re: 250 Mk3 reborn - Running!

Post by smellybeard »

I'm very happy to report that the 250 Mk.3 is now running perfectly.
It initially wouldn't start but flipping the Lucas Rita doofor 180º allowed it to fire up on the very next kick.

In the end, I assembled it without an exhaust seal as the threads were a bit worn and wouldn't start with the thickness of seal I had available. I may cut out a thin copper gasket for it but am reluctant to overstress the threads.

Anyway, it's a nice afternoon and I'll give it a gentle ride out.
smellybeard
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Re: 250 Mk3 reborn - Exhaust Seal?

Post by smellybeard »

...and I saw my first swallow.
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