Engine inspiration thread!

WNTITAL

New Member
tprader said:
WNTITAL, I have to say, that is about the most beautifully done engine I have ever seen. I am using it as a template for my own cl360 build. Thank you for the eye candy!
Trader, thanks for the kudos. It was a lot of work to get it like that but well worth it. Please feel free to ask me any questions as you get started on yours. I feel honored that you want to use my motor as a template for yours. More updates to come in my build thread. Motor is finally into the frame and things are moving fast. Thanks again! Good luck with yours.
 

DesmoDog

Member
So if you've got an old "barn find" Ducati, this is probably what the engine will look like.


FWIW this is a 1974 750GT. This is their first production V-twin engine, all the Ducati streetbikes were singles before this came out in 1972. This is from the "bevel" era of Ducatis. Specifically this is a roundcase, so called because of the rounded sidecovers. In 1975 they introduced an engine which had more squared off sidecovers. It came to be known as, surprise surprise, a squarecase. BTW - not all Ducatis are desmos. This one isn't. Up until... 1980(?) they were still making bikes with springer heads. In 1974 the only desmo twin available was the 750SS, the lowly GT and the midrange Sport both used valve springs.

Why they came to be known as bevels:


Cleaned up a bit. The central shaft runs the ignition. The outer two turn the cams, the lower gear spins the oil pump:


Long story short, after a bunch of hours and a few dollars, you can turn the barn find engine into something that looks more like this.


 

WNTITAL

New Member
Desmodog - Very cool and interesting motor! How long did that take you? Either way a lot of work and looks awesome!
 

DesmoDog

Member
WNTITAL said:
Desmodog - Very cool and interesting motor! How long did that take you? Either way a lot of work and looks awesome!
Thanks. The entire bike took a little over three years to get back on the road. The engine itself took over a year if I remember right? There were a few months here and there when nothing got done on it.
 

WNTITAL

New Member
We have all had those times where nothing get's done. Summer mainly for me. To much other stuff to do around the house. Either way well worth it. Bike looks good!

I am curious, in the first pic you posted, where does the intake to the carb go? The pipe looks like it goes into nothing. Maybe I'm not seeing something that I should be seeing on the other side but the other side looks like the exhaust port. Maybe I'm just not getting it.?>?>
 

DesmoDog

Member
WNTITAL said:
I am curious, in the first pic you posted, where does the intake to the carb go? The pipe looks like it goes into nothing. Maybe I'm not seeing something that I should be seeing on the other side but the other side looks like the exhaust port. Maybe I'm just not getting it.?>?>
There are a couple air filters on the stock bike that aren't shown. Here's the rear one, it hides behind the sidecover. The front one hides under the tank, I don't have any pics of it.



The hoses weren't connected to anything when I bought he bike. Here's what that rear filter housing looked like inside! (the top of it is broken away in this shot)


Here's what that spot looks like now;


The pink filter is the breather, that line used to run to the filter housing under the tank.
 

tprader

Know Thyself
I noticed that the ducat's engine acts as a fully stressed member. That is really innovative. I can't imagine many bikes in that era had such engineering.
 

teazer

Active Member
DTT BOTM WINNER
TP, so was a 1961 Honda CB72.



See. No down tubes. That was the bike that Laverda copied for the 750 twin.
 

DesmoDog

Member
teazer said:
TP, so was a 1961 Honda CB72.
I don't think it was all that uncommon. I know the Ducati singles were set up basically the same way too. Here's one from the early 50s


I don't know who did it first, or when. Vincent did it back in the '40s with the Rapide and it wouldn't surprise me if you could find examples of this back into the '20s. It seems somebody tried just about everything back in the '20s!

Vincent Rapide (1946?) No downtube.
 

teazer

Active Member
DTT BOTM WINNER
Vincent = no frame. Just a tube on top to hold the forks on. Innovative design and thanks for reminding us about some of those older designs.
 

crazypj

Split personality, I fake being smart
teazer said:
TP, so was a 1961 Honda CB72.



See. No down tubes. That was the bike that Laverda copied for the 750 twin.
First 'real' bike I fell off properly ::)
I have a set of Koni's just like those 8)
 

teazer

Active Member
DTT BOTM WINNER
And are those Konis solid now? The oil goes to a wax and clogs the orifices. I had to completely strip and rebuild that pair. Messy, but not too difficult. That one's my old race bike.
 

crazypj

Split personality, I fake being smart
tprader said:
I noticed that the ducat's engine acts as a fully stressed member. That is really innovative. I can't imagine many bikes in that era had such engineering.
Phelon & Moore (Panther) used engine as stressed member, not sure when they started using engine like that
By 1936 it was well known 'feature', seems model 100 was first designed for launch in 1932
http://classic-motorbikes.net/gallery~panther-classic-motorcycles
 
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