The little Ducati Featherweight
- Thread starter jag767
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jag767
Over 1,000 Posts
I got a little creative, ordered some 35mm OD aluminum with a 60° bend, silicone coupler, and some nice stainless t bolt clamps, brings me back to when I ran turbos lol. It won't look the part, but it will function perfectly. Everything will match the vm28 carb diameter, and *should* clear. I didn't want to go with a 90° bend, didn't want to kink the air flow that badly if I could help it. Now whether it clears my leg or not is an entirely different issue :
jag767
Over 1,000 Posts
Before I tear this motor apart, I want to see it run, so since there is little to be gained til internal work is done, after some measuring the dellorto carb it came with is virtually the same as a mikuni vm20, which I have and was able to get on relatively pain free. Going to order the correct jets and once my ignition gets here try to run her.
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DesmoDog
Been Around the Block
Here's a 160 I put together a few years back.
There's a thread on it here, and a more complete one on advrider.com
http://www.dotheton.com/forum/index.php?topic=33195.0
http://advrider.com/index.php?threads/1966-ducati-160-monza-jr-rebuild.521288/
I just read all 9 pages here and will probably forget a few things but here are a few comments in no certain order:
My bike weighed in at just under 250lbs on the shipping scale at work. That was with maybe half a tank of gas and everything needed to ride on the street.
Chromoly isn't any lighter or stiffer than "regular" steel. The majority of garage builders who use it gain nothing other than a tube that's harder to dent. If you go to a thinner tube to save weight you have to go to a larger diameter to gain back stiffness. Moot point I guess since you went with a factory frame. Speaking of which... I'm curious if the stock Ducati frame is lighter than the one you used? No idea, I didn't weigh mine. I know they aren't impressively light though.
Engine mods. Buy Tom Bailey's "Ducati Singles" book. It has info on modifying a 160. The first bit of advice is, don't do it. From there he goes on to say that high compression pistons aren't available anymore so trim a bit off the bottom of the cylinder. Guys in Australia use some sort of Triumph piston. It's pretty well known the ports suck, but there is info out there on what to do to make the best of them. Serious guys do major work with lots of welding... Pretty much nothing from the larger singles fit with no mods, if at all. Cams from the larger singles can be modded to fit. The countershaft sprockets fit either engine. The 160 sprockets use a lighter chain but are harder to find and you haven't got a big choice in sizes.
Hmm.. what else...
That's about it I guess. Looks like a fun project but I wouldn't worry too much about brakes, you wont need them often. On an early ride the throttle on mine stuck wide open. Scary at first but humorous once I realized WOT on a 160 isn't exactly breathtaking. I had a kill switch but didn't use it, I figured out why it was sticking and dealt with it instead. Not the same response I would have had if I had been on my Monster 1200S...
There's a thread on it here, and a more complete one on advrider.com
http://www.dotheton.com/forum/index.php?topic=33195.0
http://advrider.com/index.php?threads/1966-ducati-160-monza-jr-rebuild.521288/
I just read all 9 pages here and will probably forget a few things but here are a few comments in no certain order:
My bike weighed in at just under 250lbs on the shipping scale at work. That was with maybe half a tank of gas and everything needed to ride on the street.
Chromoly isn't any lighter or stiffer than "regular" steel. The majority of garage builders who use it gain nothing other than a tube that's harder to dent. If you go to a thinner tube to save weight you have to go to a larger diameter to gain back stiffness. Moot point I guess since you went with a factory frame. Speaking of which... I'm curious if the stock Ducati frame is lighter than the one you used? No idea, I didn't weigh mine. I know they aren't impressively light though.
Engine mods. Buy Tom Bailey's "Ducati Singles" book. It has info on modifying a 160. The first bit of advice is, don't do it. From there he goes on to say that high compression pistons aren't available anymore so trim a bit off the bottom of the cylinder. Guys in Australia use some sort of Triumph piston. It's pretty well known the ports suck, but there is info out there on what to do to make the best of them. Serious guys do major work with lots of welding... Pretty much nothing from the larger singles fit with no mods, if at all. Cams from the larger singles can be modded to fit. The countershaft sprockets fit either engine. The 160 sprockets use a lighter chain but are harder to find and you haven't got a big choice in sizes.
Hmm.. what else...
That's about it I guess. Looks like a fun project but I wouldn't worry too much about brakes, you wont need them often.
On an early ride the throttle on mine stuck wide open. Scary at first but humorous once I realized WOT on a 160 isn't exactly breathtaking. I had a kill switch but didn't use it, I figured out why it was sticking and dealt with it instead. Not the same response I would have had if I had been on my Monster 1200S...
jag767
Over 1,000 Posts
DesmoDog said:Here's a 160 I put together a few years back.
There's a thread on it here, and a more complete one on advrider.com
http://www.dotheton.com/forum/index.php?topic=33195.0
http://advrider.com/index.php?threads/1966-ducati-160-monza-jr-rebuild.521288/
I just read all 9 pages here and will probably forget a few things but here are a few comments in no certain order:
My bike weighed in at just under 250lbs on the shipping scale at work. That was with maybe half a tank of gas and everything needed to ride on the street.
Chromoly isn't any lighter or stiffer than "regular" steel. The majority of garage builders who use it gain nothing other than a tube that's harder to dent. If you go to a thinner tube to save weight you have to go to a larger diameter to gain back stiffness. Moot point I guess since you went with a factory frame. Speaking of which... I'm curious if the stock Ducati frame isn't lighter than the one you used? No idea, I didn't weigh mine either. I know they aren't impressively light though.
Engine mods. Buy Tom Bailey's "Ducati Singles" book. It has info on modifying a 160. The first bit of advice is, don't do it. From there he goes on to say that high compression pistons aren't avaialable anymore so most guys trim a bit off the bottom of the cylinder. Guys in Australia use some sort of Triumph piston. It's pretty well know the ports suck, but there is info out there on what to do to make the best of them. Serious guys do major work with lots of welding... Pretty much nothing from the larger singles fits with no mods, if at all. Cams from the larger singles can be modded to fit. The countershaft sprockets fit either engine. The 160 sprockets use a lighter chain but are harder to find and you haven't got a big choice in sizes.
Hmm.. what else...
That's about it I guess. Looks like a fun project but I wouldn't worry too much about brakes, you wont need them often.
Desmodog I read your build in detail, great stuff! I may have to pick you brain when I set the timing on the cdi as I don't know exactly how the points are set on these. Once I ran into the tiny ports I realized I may have hit the greatest limiting factor. I can get high compression pistons made easy enough, but unless flow in and out of the motor is improved it is likely a losing proposition. Weight wise the 200 number will be easy enough. I've been paying attention to the weight of each component, I'd say I'm in no danger of exceeding it. Also I'm back to rearsets, lost the hand shift for now. Makes for more exhaust work but it's for the best. I may just try to stick wiht keeping the low end torque as high as I can, maybe get a little extra out of it, and enjoy it. It seems to have more of the characteristics of the 125 it was bored from than a 160.
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jag767
Over 1,000 Posts
After talking at length with a ducato guru, apparently the best bet is to mill the head down to increase the compression. The shaft driving the cam is easily shortened, and 11:1 compression is very doable. It seems the motor can make significantly more power with other tweaks, but as this will only be for joyriding, i think simple is best. I was also told from the factory the motor has more than 10hp, likely around 13-14. Just with making it breathe better and higher compression, 20hp is very doable. Seems like im on the right track. I was also told as there is no major improvement having a long exhaust for this motor, short would be just fine.
jag767
Over 1,000 Posts
Through some Good luck, it turns out Tom Bailey, who is an expert on ducati singles, lives a stones throw from me. He happens to have a head he modified from the factory 21.5mm intake track to its now 26mm, with the combustion chamber reshaped, available. He also has a milled barrell kicking around which will raise me up from 8.2 to about 10:1 compression. According to Tom, that's not nearly as high as one can go, but will still have tons of reliability, as is more for street that race use; exactly what I am looking for. Needless to say, I will be driving to pick all this up on saturday. According to Tom, this with a 26mm carb and free blowing exhaust, will give me a major performance boost. As I have a vm28 on a shelf, I will be seeing how that works first.
As I am now equipped with far more knowledge on these motors, the goal will be around 20hp from the little guy. For those of you who'd like a little history lesson, the problems with the 160 motor, well A) were put there on purpose, and B), aren't it's own fault. The 160 started life at 100cc, and quickly went to 125. It only went to 156cc when the American importers asked for something to put in their showroom to go against the honda 160's, and a 125 would not do. So without any additional engineering, the motor was simply bored, and larger valves fitted. Exhaust diameter didn't change, nor did the intake diameter. So, the end result became a 160 breathing through a straw. The compression was kept low intentionally, and the very restricted exhaust was meant to keep it quite silent. The end result was an underpowered 160, that was overbuilt, and very reliable. The two things I found immensely interesting are, the 160 is the most original design of ducati's original ohc bevel drive engine. The design, even when introduced, was by no means revolutionary. By contrast, things used by other manufacturers were far more innovative. So even though it's a 1960's motor, the technology being worked with is quite a bit older.
Secondly, I had no idea the initial ducati's sold in the US, we're essentially gran prix endurance racers. These bikes were used for 6, 12, even 24 hours endurance racing, ergo a race bike with an electrical system just strong enough to support a headlight. Since that kind of racing was non existant in the US, people thought since it was equipped with a tailligt and headlight, it must have been built for the street. Just something I found interesting.
According to Tom, at the dealer he was a mechanic at, they couldn't keep them in stock. The 160 sold more than any other model during its short life. Once he was afforded the opportunity to dig into one, it became clear simply doing the work ducati didn't take the time to would easily grab for more output from these little guys, and felt like at totally different bike. I feel like this is quickly turning into a "gateway drug" to the ducati world, and I'll have a 450 around here in no time haha.
As I am now equipped with far more knowledge on these motors, the goal will be around 20hp from the little guy. For those of you who'd like a little history lesson, the problems with the 160 motor, well A) were put there on purpose, and B), aren't it's own fault. The 160 started life at 100cc, and quickly went to 125. It only went to 156cc when the American importers asked for something to put in their showroom to go against the honda 160's, and a 125 would not do. So without any additional engineering, the motor was simply bored, and larger valves fitted. Exhaust diameter didn't change, nor did the intake diameter. So, the end result became a 160 breathing through a straw. The compression was kept low intentionally, and the very restricted exhaust was meant to keep it quite silent. The end result was an underpowered 160, that was overbuilt, and very reliable. The two things I found immensely interesting are, the 160 is the most original design of ducati's original ohc bevel drive engine. The design, even when introduced, was by no means revolutionary. By contrast, things used by other manufacturers were far more innovative. So even though it's a 1960's motor, the technology being worked with is quite a bit older.
Secondly, I had no idea the initial ducati's sold in the US, we're essentially gran prix endurance racers. These bikes were used for 6, 12, even 24 hours endurance racing, ergo a race bike with an electrical system just strong enough to support a headlight. Since that kind of racing was non existant in the US, people thought since it was equipped with a tailligt and headlight, it must have been built for the street. Just something I found interesting.
According to Tom, at the dealer he was a mechanic at, they couldn't keep them in stock. The 160 sold more than any other model during its short life. Once he was afforded the opportunity to dig into one, it became clear simply doing the work ducati didn't take the time to would easily grab for more output from these little guys, and felt like at totally different bike. I feel like this is quickly turning into a "gateway drug" to the ducati world, and I'll have a 450 around here in no time haha.
stroker crazy
crazy as a fox
Things have moved up a giant step!
Crazy
Crazy
