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DB2 motor build - 1034cc

 
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Speedmade



Joined: 27 Mar 2012
Posts: 76
Location: Minnesota, USA

PostPosted: Wed May 08, 2019 6:34 pm    Post subject: DB2 motor build - 1034cc Reply with quote

I will add to this thread as the build continues.

This is a big bore/stroker motor I am building for my friends DB2

Standard DB2 engine cases
Gio.Ca.Moto 96mm cylinders w/ JE pistons
Sport Classic 71.5mm stroke crankshaft
Custom length Carrillo rods
Dual plug heads, Lofgren porting
44mm intake valves
39mm exhaust valves
ST2 cams
41mm Keihin flatslides

I had to “notch” the half time shaft to make clearance for the rods and stroke







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brian



Joined: 22 Aug 2011
Posts: 3769
Location: Australia

PostPosted: Wed May 08, 2019 10:54 pm    Post subject: Reply with quote

Sounds like it be a very nice build. Does the Sport Classic crank shaft have a longer stroke? I’ll take one too thanks Laughing
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'99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851
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Speedmade



Joined: 27 Mar 2012
Posts: 76
Location: Minnesota, USA

PostPosted: Thu May 09, 2019 3:34 am    Post subject: Reply with quote

The Sport Classic, Hypermotard 1100, and the ST3 all have 71.5mm stroke vs the 900 has 68mm.

Because I wanted to use pistons meant for a 900, I had to have shorter rods made.

But another guy found that you can use the SC crank and rods along with the standard 94mm SC pistons into bored 900 cylinders, and everything fits in the deck. Makes a 900 into a 1000.
I'm building one like that for my Tesi
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vort28



Joined: 22 Mar 2010
Posts: 2194
Location: Northwest , UK

PostPosted: Thu May 09, 2019 6:32 am    Post subject: Reply with quote

Wow, that sounds like one hell of an engine.
Whats the expected BHP ?

Quick question on the crank , why ? Seems like a lot of effort when the SC one is a straight fit you say . Is it stronger etc , or is it simply for the extra cc /stoke benefits ?
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Speedmade



Joined: 27 Mar 2012
Posts: 76
Location: Minnesota, USA

PostPosted: Thu May 09, 2019 1:37 pm    Post subject: Reply with quote

Let me clarify. There are many details.

The 71.5 stroke crank (SC, HYM, ST3) is not a drop in to 900 cases. No matter what, there is work required.

The 71.5 and 68 stroke cranks use the same rods (130mm C-to-C). If you drop a SC crank into a 900 and use the 900 pistons, they will poke out the top of the cylinders 1.75mm.
On this project, I dealt with that by having Carrillo make rods 1.75mm shorter (128.25 C-to-C)

The other scenario I spoke of is using the SC crank, rods, and pistons. Those pistons have the pin height in a higher spot, so they will fit within the 900 cylinders.

71.5mm stroke and 96mm bore = 1034cc (900 cases, SC crank, special rods, big bore pistons/cyls)
71.5mm stroke and 94mm bore = 992cc (900 cases, SC crank, SC rods, SC pistons, 900 cyls bored to 94mm)

With all that, you still must deal with the rods interfering with the half time shaft. And there is some other case clearancing needed to deal with the larger crank counter weights.
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Speedmade



Joined: 27 Mar 2012
Posts: 76
Location: Minnesota, USA

PostPosted: Thu May 09, 2019 1:40 pm    Post subject: Reply with quote

And regarding HP

Once in the bike, I'm expecting that this will make maybe 95HP. That's because he is still going to run the standard DB2 header and run carbs.

If this motor got a big tube header and fuel injection (larger TB dia), It would probably make 10 more HP
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vort28



Joined: 22 Mar 2010
Posts: 2194
Location: Northwest , UK

PostPosted: Thu May 09, 2019 1:51 pm    Post subject: Reply with quote

Ah OK, thought from your earlier comment the SC crank was a simple drop in option, but clearly not.
Sorry , another question out of interest , why not use a 992 or 1078 2V motor or case's ? Are the mounting points different or is it to maintain the aesthetics / authenticity look of the DB2
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Speedmade



Joined: 27 Mar 2012
Posts: 76
Location: Minnesota, USA

PostPosted: Thu May 09, 2019 3:03 pm    Post subject: Reply with quote

I was originally building this motor for my DB2. I already had the piston set and the modified 900 heads.
One of the big reasons was that most everything bolted back up (intakes, exhaust, battery box, etc)

Once I realized that I was going to need to make a header (to get HP) I changed my mind.
So for my bike I started with a SC1000 motor and went nuts from there.
The newer motors have 12mm motor mount bolts. I could drill out my frame, but I decided to sleeve the cases down to 10mm
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Thu May 09, 2019 3:06 pm    Post subject: Reply with quote

I suppose he prefers Carbs rather than going Fuel Injection and I'd second that.....Ducati did make changes to the engine casings....bigger diameter for the rear swing arm pivot in the casing....so you'd have to take meat out of the side clamp parts on the front of the swingarm arms....or sleeve it down...…..I have no idea if the other 2 frame mount points are different on the later engines.....Space is tight under that frame to be fitting ECU's....and then theres messing with airboxs or fabbing up I suppose....Stick Keihin Flat slides on it and just drop some K&N cone filters on and ditch the old airbox and youre done.....Even the twin push/pull throttle cabling slides nicely under the tank....albeit you have to put a small bridge on the top cross rail so that the tank doesnt foul the cable lines....but its not like you need a special tank like the DB4 Corse version
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Thu May 09, 2019 3:12 pm    Post subject: Reply with quote

Speedmade wrote:
And regarding HP

Once in the bike, I'm expecting that this will make maybe 95HP. That's because he is still going to run the standard DB2 header and run carbs.

If this motor got a big tube header and fuel injection (larger TB dia), It would probably make 10 more HP


Maybe a little pessimistic there....My Db2 is a 944 big bore kit with Keihin FCR41 flatslides....K&N cone filters....ST2 cams and HiComp V2 billet crowned pistons....Its running standard Bimota Db2 headers but with straight thru MotoCorse titanium end cans....Dyno sheet is 90bhp from recollection (I'll dig out and check)...Gas flowed and polished head...lightened balanced crank/flywheel...….It can eat clutches for breakfast so I upgraded to Ducati Corse billet clutch basket and Barnett HD billet clutch pack. I still run the standard front oil cooler but added a thermistor in the nylon gauze Oil sump filter housing and fitted Ducati 851 triple clocks to have an Oil temp gauge...as it does run hotter than any other 0f my Duc engine bims....Another on here with same spec engine...has larger bore headers...but also a secondary Oil cooler plumbed in high up in addition to the standard one lower down....runs cooler than mine

Loving the sound of this project by the way...keep up the good work and posting
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Thu May 09, 2019 3:15 pm    Post subject: Reply with quote

Speedmade wrote:
I was originally building this motor for my DB2. I already had the piston set and the modified 900 heads.
One of the big reasons was that most everything bolted back up (intakes, exhaust, battery box, etc)

Once I realized that I was going to need to make a header (to get HP) I changed my mind.
So for my bike I started with a SC1000 motor and went nuts from there.
The newer motors have 12mm motor mount bolts. I could drill out my frame, but I decided to sleeve the cases down to 10mm


Oh yeh...the battery box....as Bimota chose to fit the vertical cylinder front valve cover with the same valve cover as the horizontal one on the DB2...which has a built in bracket for the Oil cooler...and they use that bracket to hold the battery box on the vertical...which houses it neatly under the tank...and every friggin electrical piece clips to it here ther and everywhere....aside from the Reg/Rec....If it aint broke...dont fix it
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Thu May 09, 2019 3:16 pm    Post subject: Reply with quote

double

Last edited by 2bims on Sat May 11, 2019 6:53 pm; edited 2 times in total
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Thu May 09, 2019 3:16 pm    Post subject: Reply with quote

Speedmade wrote:
And regarding HP

Once in the bike, I'm expecting that this will make maybe 95HP. That's because he is still going to run the standard DB2 header and run carbs.

If this motor got a big tube header and fuel injection (larger TB dia), It would probably make 10 more HP


Maybe a little pessimistic there....My Db2 is a 944 big bore kit with Keihin FCR41 flatslides....K&N cone filters....ST2 cams and HiComp V2 billet crowned pistons....Its running standard Bimota Db2 headers but with straight thru MotoCorse titanium end cans....Dyno sheet is 90bhp from recollection (I'll dig out and check)...Gas flowed and polished head...lightened balanced crank/flywheel...….It can eat clutches for breakfast so I upgraded to Ducati Corse billet clutch basket and Barnett HD billet clutch pack. I still run the standard front oil cooler but added a thermistor in the nylon gauze Oil sump filter housing and fitted Ducati 851 triple clocks to have an Oil temp gauge...as it does run hotter than any other 0f my Duc engine bims....Another on here with same spec engine...has larger bore headers...but also a secondary Oil cooler plumbed in high up in addition to the standard one lower down....runs cooler than mine

Loving the sound of this project by the way...keep up the good work and posting
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2bims



Joined: 03 Apr 2010
Posts: 7289

PostPosted: Thu May 09, 2019 3:16 pm    Post subject: Reply with quote

I suppose he prefers Carbs rather than going Fuel Injection and I'd second that.....Ducati did make changes to the engine casings....bigger diameter for the rear swing arm pivot in the casing....so you'd have to take meat out of the side clamp parts on the front of the swingarm arms....or sleeve it down...…..I have no idea if the other 2 frame mount points are different on the later engines.....Space is tight under that frame to be fitting ECU's....and then theres messing with airboxs or fabbing up I suppose....Stick Keihin Flat slides on it and just drop some K&N cone filters on and ditch the old airbox and youre done.....Even the twin push/pull throttle cabling slides nicely under the tank....albeit you have to put a small bridge on the top cross rail so that the tank doesnt foul the cable lines....but its not like you need a special tank like the DB4 Corse version
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quikduk



Joined: 13 Aug 2016
Posts: 287
Location: Southern California, USA

PostPosted: Fri May 10, 2019 9:16 pm    Post subject: Reply with quote

Every once in a while I wish I had FCR's on my DB6, however the work and parts change-out would likely be very pricey.

The typ. Pegaso FI glitch isn't too bad when it rears its ugly head but enough that it reminds me to slow down and pay more attention to what I am doing. It also isn't too bad when it is warmed up properly.

That looks like a nice project. I thought it would be good to do a BB conversion on my DB6 but somewhere on here I read that the 1000 cases and barrels are too thin when overbored and I'd have to switch to the 1100 version if I wanted the engine to last.

I think I'll spend some $$$ on the suspension via Matris eventually.

Looking forward to the results of this project though.
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