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Discussion Starter #1
Can it, has it been done?

I know that the 1100 crank has a tapered primary but can it be used in a 1198 sbk engine?

Using hi comp pistons. Would it need really shorter rods, due to the throw?

I have heard about machining the timing layshaft.

Can the cylinders cope for the extra stroke?

Prob more questions than answers really.
 

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The 1198 already has shorter rods than the 1098 and all the previous superbikes. I think running an even shorter rod would be a step in the wrong direction regarding thrust loading and such. Maybe some custom pistons can be made to increase piston pin height in the piston and move the ring pack up a little bit. Running the 71.5mm stroke would only result in an additional 60cc or so. Probably isn't worth the trouble, especially seeing as the 1198 limitations are really from swingarm length/chassis layout not power.

That being said, if you decide to do it, please document and share! Sounds like an awesome project.
 

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Discussion Starter #4
How about multi 1260 (71.5mm) crank in 1198 sbk?

Is that a direct fit, or is the crank longer in overall length?
 

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My view for what it’s worth. Always think hard when doing these types of mods. Ask yourself what you you are trying to achieve and why. Is it only big numbers your after? Is it you want to to change the power delivery? Or do you just like to mess around and learn? With what you want to do the cost benefit would be quite small. The extra capacity will give you more mid but little in the top. A set of multi cams will give you heaps of mid if that’s what you’re after, of course at the expense of top end. One of the last things I would do to an 11 is shorter rods.
 

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Hi

To fit 1100 cranchaft in a 1198 as Herman Jolink did for dragster races :)

the cranschaft mass must be remachined, because they collide with the timing lay schaft.
place 1.8mm shims under the cylinders (stocke difference= 71.5-67.9=3.6 & 3.6/2=1.8mm)
you have to supply the1100 right primary cranckshaft gear (conical bore) to fit on the 1100 crankschaft
your main problem will be to fit the throttle bodies in place , because of the 1.6mm undercylinders spacers , the distance between the 2 trottle bodies will need to be increase. so they won't fit in your airbox anymore.



I'm working on this engine project to...with a X diavel (1260) crankschaft


You have to know thet the 1260 crankschaft has the same stroke as the 1100 ,
No collision between this crankschaft mass and the timing lay schaft
but the the grooved primary gear as the 1198... but on this engine the LH timing lay gear on the crankschaft has a
bigger bore and much more teeth. that's means you have to supply a 1198 one , rebore it , and the remachine the groove.


on the 1260 connectings rods are much more longer than on the 1198 (126.1mm instead of 122.5mm) and barrels (cylinders) are 5.1mm longer.
of course you can fit 122.5mm (1198) rods on this crankschaft, to obtain the same dimension that your solution with the 1100 crankschaft, the problem for the gear to remachine and the airbox fitting will remain...



perhaps the best way would be use 122.5mm conrod (the 1198/1200 ones) + to surface the top of your pistons , remachined the valves clearance.... and to rebalance the naw crankschaft (new piston weight). you will be aible to fit corectly the throttlebodies on the airbox.
 

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Hi

To fit 1100 cranchaft in a 1198 as Herman Jolink did for dragster races :)

the cranschaft mass must be remachined, because they collide with the timing lay schaft.
place 1.8mm shims under the cylinders (stocke difference= 71.5-67.9=3.6 & 3.6/2=1.8mm)
you have to supply the1100 right primary cranckshaft gear (conical bore) to fit on the 1100 crankschaft
your main problem will be to fit the throttle bodies in place , because of the 1.6mm undercylinders spacers , the distance between the 2 trottle bodies will need to be increase. so they won't fit in your airbox anymore.



I'm working on this engine project to...with a X diavel (1260) crankschaft


You have to know thet the 1260 crankschaft has the same stroke as the 1100 ,
No collision between this crankschaft mass and the timing lay schaft
but the the grooved primary gear as the 1198... but on this engine the LH timing lay gear on the crankschaft has a
bigger bore and much more teeth. that's means you have to supply a 1198 one , rebore it , and the remachine the groove.


on the 1260 connectings rods are much more longer than on the 1198 (126.1mm instead of 122.5mm) and barrels (cylinders) are 5.1mm longer.
of course you can fit 122.5mm (1198) rods on this crankschaft, to obtain the same dimension that your solution with the 1100 crankschaft, the problem for the gear to remachine and the airbox fitting will remain...



perhaps the best way would be use 122.5mm conrod (the 1198/1200 ones) + to surface the top of your pistons , remachined the valves clearance.... and to rebalance the naw crankschaft (new piston weight). you will be aible to fit corectly the throttlebodies on the airbox.
Morning Fab. Any performance specs for that motor? HP, max rpm, cams ,valves, throttle bodies etc. how often between rebuilds. And have parts failed?
 

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Hi,
no sorry.

I read that it was a 1098RS engine , with a 71.5mm stroke... the only crankschaft that existed was the 1100 one, with the conical RH pulley end (for conical bore primary gear)

he was sponsored by Ducati Corse dpt... so maybe he had a special manufacturing crankschaft., in a full factory engine...

I wrote him few @mails, he never answered.


on this movie, you can see the presence of a spacer under the cylinder , and that the crankcases are 1098RS


I'm pretty sure he used a 71.5mm stroke 1100 crankschaft with a 122.5mm conrods 1198 conrods
 
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