Topic: The little Ducati Featherweight

[jag767]

Here's  one i have of the piston, ill take more later.

[grcamna2]

Nice piston design Jag 

[jag767]

Lol that's original Borgo right there. Apparently they are bulletproof so i'm trying to leave it in there.

[grcamna2]

What bore and stroke is it ?

[jag767]

61x52

[jag767]

Damn these motors are easy to work on. Compared to a Honda 4 of course. I ground down both halves of the bevel drive to fit with the milled barrel, and filed it square. What's the saying, close enough for jazz? It all went together nicely. One part down. I will pop the head back off tomorrow to find out if I can get it ported in a day, or if I'll just do it myself.

[bill440cars]

  Sounding like this is gonna be quite a "Humdinger" of a ride, for sure. 

[grcamna2]

jag,
Does the bevel cam drive allow you to change the cam timing if wanted? or is it set-up w/ a key-way on the shaft ?

[jag767]

jag,
Does the bevel cam drive allow you to change the cam timing if wanted? or is it set-up w/ a key-way on the shaft ?

Technically you can, but i've been told it's a horrible idea.

[jag767]

Lots of boring things to report. Ordered new gaskets and orings from across the pond, and still waiting for parts from Australia. In the mean time, I had my machinist verify the cylinder was good to go, and there was no ridge from where the rings stopped travelling. The whole thing has a 1 thousandth v taper to it, but still all round, and will work just fine. Put it on and spun the motor around several times. I was happy to see the sleeve is clearing the con rod fine.

I spent some time on the bevel drive, trimmed 1.5mm out of each half shaft, and 1.5mm out of the housing. For those of you just checking out the build, this was to accomodate the 1.5mm removed from the base of the cylinder to bump up compression. At that point I removed the points side cover, verified the timing, and spun her over a bunch of times. Valves cleared just fine, as I was told they would. Now i'm down to boring stuff, removing 50 year old gaskets and the sort.  Once the new gaskets get here I will get them on asap. I know I've said it several times, but I love how simple this motor is to work on.

I will get a bunch of photos up soon, I know I've been lacking.

[754]

Its simple to pull the top end..
 Wait till you split the cases, or change a cam and have to shim bevel gears... Then you will miss the Honda 4..
 I split my Ducati case cases on my Mach 1 when I was 17 or so and got it back together..
 But i remember the special tools in the manual scared the crap out of me, and influenced my decision to sell.. That and the cracked head..

[jag767]

Its simple to pull the top end..
 Wait till you split the cases, or change a cam and have to shim bevel gears... Then you will miss the Honda 4..
 I split my Ducati case cases on my Mach 1 when I was 17 or so and got it back together..
 But i remember the special tools in the manual scared the crap out of me, and influenced my decision to sell.. That and the cracked head..

Yeah the special tool part is a pain, and so are the shims, all different sizes, and on everything. But being able to get the top end apart and back together in 20 mins is awesome!

[754]

 Yup, cab off..pipe off, take out 4 bolts..lft of head then cylinder.. I liked that..no headgasket..

[jag767]

Slight change of plans. With gaskets getting here Tuesday, ignition some time this week, and carb jets coming as well, rather than create more work, I'm going to start getting items checked off. This means for now the head will not be ported. It'll kind of wind up being a good thing, because now I will get to dyno it as a before and after. Stage 1 will be a mikuni 22mm carb, compression bumped up to 9.6 from 8.2, and free blowing exhaust. Stage 2 will be the ported head, and a 26 or 28mm carb. 

For Stage 1, the Mikuni 22mm will start with a 100 main jet and 35 pilot. Best I can tell, that's about 1 jet size richer on the pilot, and 2 sizes larger for the main. I'll know quickly with the air fuel gauge how far off I am. My guess is with this setup, the motor will run quite well with nice lower end grunt, but the top end won't be impressive. Based on the riding I will be doing, sounds like a good place to start.

[RAFster122s]

I hope you would hit any spots in the casting of the head that have debris or raised ridges Off and at least port match the intakes to the head and similar on exhaust side.  Really nothing like that little bit of work...

David

[jag767]

The ports are actually very clean castings, as yes I'll open the lip to 23.5mm to match the carb, just not going past that.

[bill440cars]

   I Know it has been said and I have even said it, But, This one Cool & Refreshing Build. 

[jag767]

Ok big update, just no photos, I will work on that. 12v conversion is done, will button up the clutch tonight. The top end is all finished, shold run like a champ. All the parts are at the powdercoater, will have them back end of the week. Hoping to do final assembly next weekend, very very eager to ride.

[grcamna2]

We may have an early Spring so it should be just in time. 

[jag767]

We may have an early Spring so it should be just in time. 

Haha, I still have to repaint the gas tank, but that may wait!

[jag767]

Motor is done, well other than the intake manifold

[CBGhia]

That's purdy!

[bill440cars]

Motor is done, well other than the intake manifold

That's purdy!

               I agree, That Is Purdy !! 
           

[RAFster122s]

What can you say differently, it is pretty indeed...
Nice work Jag.

[jag767]

Thanks guys, heres a bwtter shot. Still waiting on powdercoat..... never had to wait this long