A tale of two (Ducati) Monsters

jsudar

Well-Known Member
Location
Cedar Hills
Progress has slowed on this project, but it’s still moving forward. Had to take a little beak to build a couple custom bicycle frames. Some of my kids were feeling left out because they didn’t have a full custom frame that dad built in the garage.
Got a 48t rear sprocket (gold to match the rotors). Because of the extra travel the swingarm will see, I didn’t want to drop a tooth on the front sprocket, so I upsized the rear to help keep the chain off the swingarm.
Like Gravy said above, if I’m not planning on ripping around at warp speed all the time, low gearing makes it lots more fun. This was partially determined when I decided to see if my S4Rs would actually do the 155 MPH it’s supposed to do. Turns out, I can’t go that fast. I chickened out around 125 or 130 because I physically couldn’t hang on anymore. The wind load on a naked bike at that speed is incredible. Fairings are important. And 100 is plenty fast.

So the front end is basically finished, now I need to figure out how to get 200mm of suspension travel out of the rear. I toyed with the idea of ditching the linkage and using a matching KTM SMR PDS shock, but that was going to be major(er) frame and swingarm surgery. I scoured the Öhlins site for hours, since they have shock stroke and eye to eye data trying to find a factory shock that would give me the right travel and work with the existing linkage. The closest I could find was a Desert Sled shock at 81mm travel and 335mm eye to eye. But it only had an eyelet at one end and a yoke at the other. I needed eyelets on both ends. And it wouldn’t be valved for my application. It was looking like I needed a custom solution. I found a lot of European companies (a couple in Italy, one in Sweden) that could maybe build me a custom shock, but it was $$$ and a serious language barrier problem. Then I found RaceTech in Southern California. They make full custom shocks— any size, any ends, whatever valving I need. Super cool to work with and I didn’t have to learn Italian. And not as expensive as I thought. Still not cheap though. So, before I committed to having a custom shock built, I decided to verify it was going to work at all and I built my very own custom shock out of square tube. #mockshox46882E86-5F39-4814-98AF-6508EF31A014.jpeg1F44EF54-FC31-4678-9A71-FA22FAEB39D5.jpeg224F9672-4D2B-4D07-A20D-A5ECF649AAC6.jpeg
 

jsudar

Well-Known Member
Location
Cedar Hills
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Still need to do some mods to the swingarm to be fully operational, but I turned an adjustable pushrod on the lathe to match the custom shock. Currently getting 205 mm of travel out of the rear end of the Monster. Which matches the 200 mm fork nicely.
 

jsudar

Well-Known Member
Location
Cedar Hills
Well, lots has happened since my last post. Just not so much with the bike. I quit my cushy, secure government job of nearly sixteen years, but the new job has a full machine shop, welding shop and plastic fab shop. Almost makes up for the fact I could have retired in 14 years if I’d have stayed at the other place. Don’t know if I could have made it though.

Anyway, couple things have happened with the bike— I sectioned the the seat pan to narrow it up— ‘cause I have a plastic fab shop at work.
I really wanted gold bars on this bike, but I also really, really wanted the Renthal 827 Villopoto bend, which didn’t come in gold. Then Renthal did a limited edition run of gold ones. They sold out fast and I was sad. Fortunately, I scored an installed, but never ridden set on eBay. I threaded the ends for some plugs I made for hand guards.
The first time I made threaded bar end plugs for my dirt bike, I made them from mild steel. They worked great, but they are heavy and rusty. I had just enough 303L stainless to make another rust free set. Then I screwed up really bad on the threading and had to scrap them.
Since I had to purchase material, my aircraft mechanic buddy suggested 2024 aluminum. Light, cheap and pretty strong. It’s like 35k psi yield strength, which exceeds the stainless steel. He advised against 7075, which is nearly as strong as mild steel, but has corrosion problems.
The next major thing is I scored a Monster 696 motor off Facebook marketplace. The current 620 I have only has a five speed and it makes 55 HP and 40 ft/lb. The 696 is kind of a hot motor. It makes 80 HP and 50 ft/lb which is the most horsepower per cc of ANY air cooled Ducati motor ever. And it has a six speed. It needs a stator side engine cover and a stator. The seller actually had a brand new stator to go with it, but that motor had two options: 104.5mm and 107.5mm. He bought the 107.5 and of course it needed the smaller one. So, a new stator and eBay stator cover for a 796 (hope it fits) are on the way. The only downside is the exhaust ports are at a different angle than the 620, so my current exhaust won’t work. Now, I get to see how I do building custom exhaust.
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jsudar

Well-Known Member
Location
Cedar Hills
The plot continues to thicken…. I scored an amazing deal on a wrecked Monster 797. Not a bike I ever aspired to own, but it was so cheap I would have been an idiot to pass it up.
Now I have three engine options for this build:
1. 620- lowest HP and torque and a five speed, but I do have a wiring harness, ECU and exhaust for this motor.
2. 696- most HP, six speed, but requires adapting the wiring harness from the 620 (fairly easy) and a custom tune for the 620 ECU. Also requires custom head pipes.
3. 797- less HP than the 696, but more torque. Same bore, more stroke. I have the complete bike, so swapping should be straightforwardish, including the exhaust. Has a weird single throttle body with sub butterflies. Also has a cable operated clutch which is weird for a Duc. This doesn’t work with my other plans—

I started buying parts to convert the 696 to dry clutch, mostly because everyone on the interwebs said it can’t be done and because I like the rattle. It’s not a proper Duc if it doesn’t sound like your bike is shaking a bag of loose change. Kind of want to see that project through…
There’s a chance the 797 exhaust will fit the 696, so that may solve that problem.
I’m not sure what to do now. Too many options. And I’m running out of space, because there’s a non running Ducati ST3 on KSL right now for $1100 that needs a good home…
One thing is for sure— my wife thinks I’m like a sad cat lady, but for Ducatis.
 

jsudar

Well-Known Member
Location
Cedar Hills
Through some clever plumbing and machining a special nipple I was able to get the fuel tank and pump from my 2002 Monster to work with the returnless fuel system on the 2017. Surprisingly, they had the same electrical connector. Also stole the battery from the 02. The 797 is now a runner!
She fired right up after I finally got the air bled out. Makes me feel better about my purchase, hearing it purr like that.
 
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