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Discussion Starter #1
My motor is completely apart, I was going to be balancing the stock 996 crank anyway. Then I remembered that a 900ss crank can be used for a little extra capacity..
Are there any drawbacks to doing this? What if any are the necessary accommodations that must be made to other parts of the system if this is done?
I have Pistal pistons, not the r2000s sadly, the regular 98mm drop in ones. (along with sps cams, stock valves, if that matters)
I guess it might rev a little slower due to the increased stroke, but I've lightened most of the engine internals (light clutch including hub, primary gear, flywheel) so she spins up pretty quick as is
Just throwing around possibilities in my head seeings how everything is apart anyways
 

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Discussion Starter #3
thank you for your input belter
So no drawbacks in your opinion?
I've got one of Brad's chips, bb239, does the increased capacity screw things up with the chip, or could it be compensated for during tuning on the dyno?
 

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Discussion Starter #5
A '99 900ss crank is on it's way from somewhere in the U.S up here to Vancouver
Supposedly some Pistals are also on their way from Italy. Hopefully they were sent before the whole place got shut down..., hmm, never mind, seems rather petty now that I've said it!
The crank will be lightened and balanced with the Carillos and Pistals. Fresh bearings all around.
A bit of extra power with the capacity increase along with the peace of mind of knowing that the whole motor is as fresh as possible from bottom to top will somewhat make up for the sprag disaster of last year
 

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I did a 900 crank in a 996 last year and it was a decent gain but only if the engine is in pieces IMHO. The cost to do just a 900 crank would not be worth the effort (IMHO) if that's all you were going in for. sps cams would give similar gains with similar costs but much less labor.

The balance of the 996 and 900 were off enough we needed to change rods (Carrillo also) as part of the balance. We kept the stock pistons for cost reasons but if cams are planned you will want/need pistons with deeper pockets.

If I had a 996 motor that needed a crank I would probably consider the swap, why not. I would also plan on hi comp pistons ( as much for the pockets) and rods because why not? stock rods would be fine if the package balances out but it was not close enough with stock pistons. Gain was about 10% on HP and 6-8% on torque.
 

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Discussion Starter #8
Hello ducvet, thank you for your reply
Due to the "sprag disaster" I referenced in my previous post my engine was already completely apart which was the only reason I considered doing the SS crank.
I was going to lighten and balance my 996 crank anyways so the 900SS option definitely seemed worth considering. After positive feedback from the forum and a big thumbs up from one of the Ducati tuning gurus down in the US that my mechanic communicates with, it seemed like a no brainer
My engine already has Carillos and SPS cams so that part is covered
Like I said in my last post, I have Pistals on their way in the mail. Just the regular 98mm Pistals, not the r2000s. I'm a little worried that I'm missing a critical piece of the ideal puzzle with that fact, but we couldn't track down any r2000s. Tbh, I'm not sure how much of a difference there is between the two pistons, or what accounts for that difference, but in these pages whenever 996 tuning is the topic of conversation the r2000 is always referenced as THE piston to have...
 

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Discussion Starter #9
That;s going to be tasty
I really hope so Namor, I really hope so! Actually, I'm pretty confident that it will be..
I had about 1000km last season on the previous version of my engine before the sprag went south, and it felt absolutely glorious.., loose and raw, so free revving and responsive to the throttle. The perfect level of shove for myself, the kind that makes you shout in giddy excitement in your helmet without scaring the shite out of you.
When it all comes together by mid May (fingers and toes firmly crossed) it's just going to be all of that with a slightly larger cherry on top. Along with peace of mind that comes from fresh bearings, ideal tolarences, etc
 

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Discussion Starter #11
It's funny because I did read that report ( for the umpteenth time, along with all your other Desmo tuning reports ) while deliberating about going for the 900ss crank. I translated that report as sounding fairly lukewarm about the whole thing, which was making me somewhat hesitant as well. My heads are more or less standard as well, same as the bike in the report. They've been "cleaned up" but are still standard valve size..
Anyways, will see how this all comes together
Even though i may not have the absolutely ideal combo of ingredients ( regular Pistals instead of r2000, 45/60mm Akro exhaust with standard heads that may not really allow that exhaust to breath to it's top end potential..), like I said to Namor in my previous post, I have that feeling that when it's all together it will be a very very entertaining motor to ride and I'll forget all about these "ideal" combination of components.
We'll see, and I'll certainly let you all know how it all turns out
 

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Discussion Starter #12
That being said, now that I probably have two pieces of the puzzle, both the 1026cc capacity and the 45/60mm Akro exhaust, being somewhat hindered by the standard valves, I'll probably upgrade to larger valves at some point down the road.
I envision putting it all together with what I currently have, enjoying the hell out of it for the next couple of riding seasons ( while absorbing the significant financial outlay of the last few years), then taking the heads off and sending them to Guy for some 38/32mm ss valves. And that will be that! Nothing left to do...
Well, other than the longer Mag swinger and altered front geometry to suit..;)
 

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if i had a 996 apart i'd be reluctant to put it back together without a 900 crank. i have tried to talk a couple of people into it when the option has presented itself. 900 crank availability is usually the hold up. the good comp with std parts and no belt tension issues are what i like.
 

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My engine already has Carillos and SPS cams so that part is covered
Like I said in my last post, I have Pistals on their way in the mail. Just the regular 98mm Pistals, not the r2000s. I'm a little worried that I'm missing a critical piece of the ideal puzzle with that fact, but we couldn't track down any r2000s. Tbh, I'm not sure how much of a difference there is between the two pistons, or what accounts for that difference, but in these pages whenever 996 tuning is the topic of conversation the r2000 is always referenced as THE piston to have...
You might check with Ben Fox. He had a few sets of CP high compression pistons. That's what I'm using in my 851/996, which seems to go OK. He may have a set left.
 

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You might check with Ben Fox. He had a few sets of CP high compression pistons. That's what I'm using in my 851/996, which seems to go OK. He may have a set left.
Belter has already sad the normal pistons will give about 12.7:1 so where do high comps take it, will it still live on street gas?
 

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Discussion Starter #16
This is a street/ trackday bike that will live on street gas, yes
A knowledgeable birdy just told me that the regular 98mm Pistals don't actually give much more compression than stock ?!!
Static compression, squish, gasket sizes and other finer details of putting all this stuff together and how they all relate is well beyond my expertise and where I have to trust my mechanic/engine builder and the knowledge of the forum
 

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Belter has already sad the normal pistons will give about 12.7:1 so where do high comps take it, will it still live on street gas?
Yes, I run pump premium and have a similar spec with no detonation or issues at all. ST4S (996) cases, 996RS crank, Carillo rods, Ben's CP pistons, cleaned up 996 heads with stock valves, SPS cams.
982020
 

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Discussion Starter #18
Yes, I run pump premium and have a similar spec with no detonation or issues at all. ST4S (996) cases, 996RS crank, Carillo rods, Ben's CP pistons, cleaned up 996 heads with stock valves, SPS cams. View attachment 982020
For some reason I thought you were running larger valves in your motor..
Wow, you got very impressive numbers with stock valves, didn't you get in the low 140s hp wise and low 80s tq wise?
 

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Yeah, 147, but that's on Chris Boy's dyno which is generous (although Boelo said that was more than his 888 AHRMA bike with the 996RS heads made on the same dyno). On Ducshop's or something similar I would expect the "real" number to be around 140.

After Ben provided the whole balanced bottom end, TJ Schultze did the heads and motor assembly (that photo was at Ducati Milwaukee when he was still there). I know he did something with the heads, but didn't elaborate and all I could see once it was built was the nicely matched ports.
 

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Discussion Starter #20
Yeah, 147, but that's on Chris Boy's dyno which is generous (although Boelo said that was more than his 888 AHRMA bike with the 996RS heads made on the same dyno). On Ducshop's or something similar I would expect the "real" number to be around 140.

After Ben provided the whole balanced bottom end, TJ Schultze did the heads and motor assembly (that photo was at Ducati Milwaukee when he was still there). I know he did something with the heads, but didn't elaborate and all I could see once it was built was the nicely matched ports.
Obviously the components, even all the right ones, only get you so far and it's the knowledgeable person or people putting it all together in the most effective manner that makes for a rideable, powerful, and hopefully somewhat reliable motor. You definitely had those right people!
I've got all the parts now it's in the hands of my engine builder.
Now if this pesky little bug would just go away so I can get back to work so I can pay for the damn thing!
 
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