Merlin DOHC Progress (2018)

I remember this engine causing a lot of excitement with us back in the day, we went out Buxton way to a scramble because we had heard it was going to be there.

It was, and in an outfit, but we wanted it for a road bike. We are going back some years now but I don't think it finished the race.

Again the old memory might be playing up, but I think the head allowed the engine to rev, and in the 80s that wasn't a good thing, those bent rods and broken cranks may not be from the turbo engine.

I remember thinking how good it looked back then but now, nah, as a piece of engineering and history it would be nice for it to live again though.
 
Here's a pic of the 850 with the IHI turbo fitted, taken we believe at the Earl's Court show in the early 80s. Apologies for the poor quality, its a snap of a poster. After that are a few shots of the turbo itself which has been removed from the bike and could be for sale complete with its Keihin carb if anyone is interested.



 
Bsamat said:
And here's the same rolling chassis with the DOHC motor fitted, and another shot with I think Suzi Quattro is it? draped over it.

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Earls Court London Bike '81 21st to 31st August both pictures & yes Suzi Quatro
 
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merlin engine ran the cams of a beltdrive from left hand side via a blanc shaft in place of cam shaft but on testing the motor did not produce any more power then a tuned commando but the emmission were a bit cleaner was the only positive results to gain any more power with this you need to change the crankcase shape on the right side OR timing side so it will run direct from crank shaft to the cam shafts via a belt drive and tenion wheels and make a timing cover to fit the lot and the timing side will have be dry runnig for a cam belt, that one reason you need a design change on the timing side
 
Bsamat said:
Great pic. Is that a photo you took, or a brochure shot? I have found the Bike 81 programme online but can't see any mention of the bike in that.
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Hi Mat
I got if from

Rewind: Bike ’81 at Earls Court - Motorcycle Classics

I was dog-tired, but the tour of Meriden had left me curiously buoyant and even wired. The continuing heatwave and the capital's seething undercurrent of civil unrest weren't going to keep me away from Bike '81 at the famed Earls Court exhibition hall in West London.
www.motorcycleclassics.com
Regards
 
Bsamat said:
Here's a pic of the 850 with the IHI turbo fitted, taken we believe at the Earl's Court show in the early 80s. Apologies for the poor quality, its a snap of a poster. After that are a few shots of the turbo itself which has been removed from the bike and could be for sale complete with its Keihin carb if anyone is interested.



Click to expand...

The poster is done by SuperBike magazine (the Super above Bike has been cut off ?),They ran that style of logo/font from May 1982 until August 1983,So this dates the poster if it was at Earls Court as Bike'82 show 20th to 30th August 1982,May have been a show handout poster ?
 
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Wasp Wasp said:
The poster is done by SuperBike magazine (the Super above Bike has been cut off ?),They ran that style of logo/font from May 1982 until August 1983,So this dates the poster if it was at Earls Court as Bike'82 show 20th to 30th August 1982,May have been a show handout poster ?
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Thanks once again! I'll do some digging and see if I can find out more.
 
storm42 said:
I remember this engine causing a lot of excitement with us back in the day, we went out Buxton way to a scramble because we had heard it was going to be there.

It was, and in an outfit, but we wanted it for a road bike. We are going back some years now but I don't think it finished the race.

Again the old memory might be playing up, but I think the head allowed the engine to rev, and in the 80s that wasn't a good thing, those bent rods and broken cranks may not be from the turbo engine.

I remember thinking how good it looked back then but now, nah, as a piece of engineering and history it would be nice for it to live again though.
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storm42 May be that Day

Dropbox

www.dropbox.com www.dropbox.com
 
Wasp Wasp said:
storm42 May be that Day

Dropbox

www.dropbox.com www.dropbox.com
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Another really interestingly pic Phil, thanks. Staring at this photo it looks like the top couple of fins of the barrel are trimmed, presumably to allow exhaust clearance. The barrel currently fitted to the Merlin doesn't have this, but we have another barrel in the pile of bits that has this trimming. I wonder if its the same set fitted originally to this grass tracker? The fins on the drive side are also cut square to allow the belt drive to the OHCs to fit. There is very little wear in the bores. Maybe it was a spare? Here are a couple of pics;

 
Bsamat said:
Or is this barrel off something else altogether? Nortons. A mystery.
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Alan and John (who were Merlin) probably used 'used' spares to modify into the merlin format (trimming the fins on the drive side for the cam belt) and boring out to 920. I bet they had spare barrels that had broken fins so cleaned the break up and used them as well. The Previous owner in Wales could have done this as well. I know he bought Merlins first engine (presumably with the timing side 'trimmed fins') and then put a decent set of barrels on it for the Earls court show bike? Its all a bit of a mystery as all this happened 40 years ago.
What is the bore size on this set of barrels? 77mm is standard 828cc. 81mm will be 920 using a 89mm stroke crank.
 
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