Dreer 880 barrels

On the Dreer 880 currently under discussion in the for sale section see:

things-seen-craigslist-ebay-t7204-2265.html

What barrels are they? Dreers own? Painted Maney barrels? Or something completely different?

Looks to me like Dreer new how to nail a bike together!

Kenny had his own cylinders made. Some of them had iron liners and some of them had Nicasil (or other similar treatment) on alloy bores. The ones I bought from him also had his own design for a one-piece lifter retainer block. I think I still have three of them left, with untreated alloy bores, but only one of the lifter retainers. I plan to eventually make lifter retainers for them, and sleeve them with iron liners. Project number 999....

He may have used a Maney cylinder for an early bike, but he wasn't able to get Steve to sell him enough for the number of bikes he expected to build, so I don't think he used many of them. I loaned him one of the Robertson alloy cylinders I used to import so he could put together a non-running display bike to meet a deadline, when he hadn't yet received his own cylinders.

Ken

Thanks Ken.

I should have also mentioned that Kenny also built some 880 engines using the stock iron 850 cylinders bored out to take the larger pistons. Not all 850 cylinders will take boring that large, but many will.

Ken

lcrken said:

I should have also mentioned that Kenny also built some 880 engines using the stock iron 850 cylinders bored out to take the larger pistons. Not all 850 cylinders will take boring that large, but many will.

Click to expand...

I have 3 of those from Kenny. Worked fine for me.

lcrken said:

I should have also mentioned that Kenny also built some 880 engines using the stock iron 850 cylinders bored out to take the larger pistons. Not all 850 cylinders will take boring that large, but many will.

Ken

Click to expand...

Would that be a 79.5mm bore Ken? Is there any way of telling which barrels can take this and which can't?

Fast Eddie said:

Is there any way of telling which barrels can take this and which can't?

Click to expand...

Bore them, and if you can see daylight through them,
or you see the fins jumping up and down, thats a no ? !!

Interesting question....

Carefully measuring the thicknesses pre-bore, and calculating the prospective finished overbore dimensions should give you a fair idea.

Of the non-sleeved barrels I bored for 880 kits about 1/3 of them eventually cracked.

I ran a barrel with 920 pistons and no sleeves for a couple years too. Then I developed a small oil leak. I could look between the fins and see the flashes of combustion. Jim

Fast Eddie said:

lcrken said:

I should have also mentioned that Kenny also built some 880 engines using the stock iron 850 cylinders bored out to take the larger pistons. Not all 850 cylinders will take boring that large, but many will.

Ken

Click to expand...

Would that be a 79.5mm bore Ken? Is there any way of telling which barrels can take this and which can't?

Click to expand...

I believe they were 79 (872 cc), and rounded up to "880", but I'm not positive. The alloy cylinders I got from Kenny are all 79 mm bore, so I'm guessing that's also what he used for the iron ones. There are some reviews of Kenny's 880 Commandos somewhere on-line, and they might have more reliable info on the bore size.

Jim and Paul's answers about how to tell if the barrels can take it are pretty much the same as I'd have said, if I'd got to it in time. If I were doing it, I'd put liners in. I've never tried to bore for a 920 displacement without using liners. Jim was braver than I to try that.

Ken

lcrken said:

I've never tried to bore for a 920 displacement without using liners. Jim was braver than I to try that.

Ken

Click to expand...

Actually the first year with the 920 pistons with no liners was the best it ever worked. Then it started using oil and the hole developed.
Then I got a set of slightly used sleeved barrels from TC. He gave them to me and said "good luck" They looked perfect but they wouldn't stay round when hot and the bike used oil at about 200 miles to the quart.
Then I had my original barrels sleeved by a shop in town using LA sleeves. Within a few hundred miles they were just like the barrels I got from TC. You could look in the bores and see where the rings were not making contact.
I have built a couple 920s with sleeved iron barrels since then that worked a little better. Modern, thinner rings helped. I still wouldn't do it for a long distance runner. Jim

I know alloy barrels are desirable for weight saving, but alloy is weaker than iron, and the holes need to be much larger to allow for liners to be fitted, weakning things further still.

It seems a shame to me that no one has made specific 920 iron barrels. It would only require mild modification of stock patterns to allow extra material in the key places.

They could then be bored without having any liners. This would seem an ideal, robust, solution for road bikes, especially high mileage bikes.

They'd also look stock.

If anyone fancies making a batch, put me down for a set, or perhaps two!

comnoz said:

lcrken said:

I've never tried to bore for a 920 displacement without using liners. Jim was braver than I to try that.

Ken

Click to expand...

Actually the first year with the 920 pistons with no liners was the best it ever worked. Then it started using oil and the hole developed.
Then I got a set of slightly used sleeved barrels from TC. He gave them to me and said "good luck" They looked perfect but they wouldn't stay round when hot and the bike used oil at about 200 miles to the quart.
Then I had my original barrels sleeved by a shop in town using LA sleeves. Within a few hundred miles they were just like the barrels I got from TC. You could look in the bores and see where the rings were not making contact.
I have built a couple 920s with sleeved iron barrels since then that worked a little better. Modern, thinner rings helped. I still wouldn't do it for a long distance runner. Jim

Click to expand...

I had similar results with the sleeved 920 cylinders back in the late '70s, primarily with the sleeves distorting around the counterbores for the through bolts. I made up a set of top and bottom torque plates, and used them to bore and hone the cylinders, and they were much better. No more dark spots on the bore, and no excess blowby and oil loss through the breather. I'm still using one of them on the bike I ran at Bonneville, and the bore looked really good last time I had it apart. To be fair, I only ever ran one iron 920 in a street bike, and it didn't get all that many miles on it, so I have no idea how well it would hold up for your sort of mileage. I'm debating that right now for a MK III I'm building for the street. Should I go with the 920 or stick to a 78 mm overbore? Decisions, decisions!

I like Fast Eddie's idea of a new 920 casting, but I'd be surprised if anyone put the time and money into it. You'd still have the issue of a very thin wall around the counterbores, unless you eliminated them, and left the bolt heads above the deck, which would require counterboring the head for them, as well as custom gaskets. Not all that impossible to do, but I'm not holding my breath for it.

Ken

I thought Jim might 'take the bait' and make a batch Ken... don't tell him though...

Funnily enough I've just returned from Melbourne recently where I had extensive meetings with my engineers at Harrop Engineering where we finalised the design of my Fullauto Technologies aluminium barrels. They will be made of 6061-T6 the same as the heads with iron liners (in 850 only at first). The casting has been modified so that the liner is completely enclosed by the casting with no bits of liner hanging out in the breeze. Apart from a bit of extra bulk, they will look like a standard set of cast iron barrels, with the finish matching my heads. They will be bored and honed using torque plates to give everything the best chance of remaining round. Torque plates will be available seperately for those who want them. They are going to be expensive with bore coatings being optional at extra cost. Brace yourselves because they're not going to be cheap. However, don't hold your breath. I'm not expecting the first batch until towards the end of next year due simply to money, or, more correctly, a lack of it. I've already sunk some money into it and have to find another 25 grand or so before I even get to the point of producing any barrels.

Now, the good news out there for all you big bore fans. You will be able to bore the barrels out to 920 with no other changes.

Fullauto said:

Now, the good news out there for all you big bore fans. You will be able to bore the barrels out to 920 with no other changes.

Click to expand...

What do you call not cheap ?

So are you going to be supplying them already bored out to 920 ?
Makes sense so no double boring.....

The best part of a couple of grand in AU$.

I haven't got THAT far in the thinking process yet. But then I would need a crystal ball to figure out how many I would need. But it makes sense.l

Thanx in advance for sticking your neck (and wallet) out there for us Commandophiles.

No worries GrandPaul. I sit outside the train station on Saturday afternoons with a tin cup, rattling it to pay for these things. My children have rope burns on their necks from towing coal carts in those little mine shafts.

Don't even ask what I make my wife do.........