"R" flywheel

Charliem90 said:

Not with just a lightened flywheel.

RPM limits primarily based on reciprocating mass (i.e. TI rods, pin rods, pistons) and corresponding crank balance.

Flywheel acts as a power sink - storing energy on power stroke, releasing energy on compression stroke. As some noted, it will result in quicker engine spin up. But you'll notice increased engine braking effect on throttle roll-off (flywheel has less mass and so will release less energy).

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I understand what you are saying, but is the base or "S" at it's RPM limit already?

Only reason I ask is because I know on other bikes like the new zx10r when Don Guhl does the ECU flash he will raise the rev limit up by 500rpm for most folks. This is done with no modifications to the engine. So part of me wonders if the ducati is the same way....ie they roll off the factory line with a particular red line in place....but maybe they could have a higher RPM imposed? If the reciprocating mass plays a huge role, maybe the "R" model could co higher than the 500rpm redline it has over the base or s as well?

I'm not really going to do it....just speculating and wondering.

gnance said:

I understand what you are saying, but is the base or "S" at it's RPM limit already?

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No doubt there is some guard banding built in to the rev limits. Ducati would go broke dealing with warranty issues if the current limit were pushed right to the edge of upper limit.

My tz250 had a limiter at 14.5k which you could adjust yourself. And "everyone knew" that at 15k you were going to go shopping for a new motor. But that's race machinery (no warranties to worry about) and you essentially replaced the top end every weekend (and the cylinders and crank rebuilt every 750 miles) anyways.
Doubt the market would tolerate that thin a margin error for street use.

Great work Bolds!! To be honest, I would not have even thought about this. I didn't get a chance to read through the entire thread, but I would love to hear how it affected ridability. Lightened flywheels are both a blessing and a curse sometimes.

Years ago I over-reved a buddies BMW X5 (it was a manual) and blew the eingine. BMW knew that from the computer codes, and we had to fight to get the warranty - porbably even more true today.

Trauma said:

Years ago I over-reved a buddies BMW X5 (it was a manual) and blew the eingine. BMW knew that from the computer codes, and we had to fight to get the warranty - porbably even more true today.

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Yeah, we basically "black box" cars and if we deem you were using the car for racing based on shift patterns, time at revs, etc, we will refuse your warranty claim (even sports cars, lame I know). I don't know if ducati records data like this though, but changing the rev limit will instantly void your car warranty... so will changing a flywheel for that matter.

Trauma said:

Only $2K with known results, and no hit to the warranty. Seems like a simple choice.

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What wheels are lighter than the S wheels? I was calculating carbon.

May not take a hit to the warranty, but the flywheel, unlike a set of uber-light rims, won't be damaged by potholes....

gnance said:

I understand what you are saying, but is the base or "S" at it's RPM limit already?

Only reason I ask is because I know on other bikes like the new zx10r when Don Guhl does the ECU flash he will raise the rev limit up by 500rpm for most folks. This is done with no modifications to the engine. So part of me wonders if the ducati is the same way....ie they roll off the factory line with a particular red line in place....but maybe they could have a higher RPM imposed? If the reciprocating mass plays a huge role, maybe the "R" model could co higher than the 500rpm redline it has over the base or s as well?

I'm not really going to do it....just speculating and wondering.

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Kawasaki had to lower the RPM limit for the US to meet CO2 limits or something if I recall. So the engines were built to rev higher from the factory and only capped for administrative/legislative reasons.

I wouldn't raise the RPM limit of the Ducati. Probably not even if I was racing, unless upgrading to the Ti Conrods, too.

Anyone care to speculate on what fails first when the engine is subjected to overrevs? And if that was fixed what would be the second/third?

AntiHero said:

What wheels are lighter than the S wheels? I was calculating carbon.

May not take a hit to the warranty, but the flywheel, unlike a set of uber-light rims, won't be damaged by potholes....

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I was refering to my Mag wheels, but don't even want to touch that pot thing again

AntiHero said:

Kawasaki had to lower the RPM limit for the US to meet CO2 limits or something if I recall. So the engines were built to rev higher from the factory and only capped for administrative/legislative reasons.

I wouldn't raise the RPM limit of the Ducati. Probably not even if I was racing, unless upgrading to the Ti Conrods, too.

Anyone care to speculate on what fails first when the engine is subjected to overrevs? And if that was fixed what would be the second/third?

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If the engine is over-revved, your rod bearings will most likely fail first. If the rod bearing fails, the con rod goes out of sync. Being out of sync means that it is likely to bend valves or the rod bolt breaks, you now have a large piece of metal floating around that acts like a ping-pong ball and will cause serious damage. The result of this will be engine lock and on a bike this is not a good thing. If the rear wheel locks, then your third order effects will be dependent on speed and what your bike makes contact with until all inertia is lost and the bike comes to a stop on the pavement. Or could could just simply throw a rod.

At Gnance,

It is very doubtful that the bike is factory programmed at anywhere near it's actual limit. You have to keep in mind that there is a lot of testing that goes into these bikes and the results of that testing is factored for reliability and set accordingly. The Duc is probably capable of much higher revs, perhaps even revving at 20k. The real question is how many times will it do it before it floats a valve, spins a rod bearing or throws a rod and the above happens? Going 500 RPMs more will probably do nothing in terms of reliability. Reliability of this mod will certainly play a role if you plan on riding this bike like you stole it all the time.

I do not know or understand where the idea stems that replacing the flywheel will increase the RPM limit or even match the R in what was called "revvability"? The flywheel would provide the rider slightly faster revs, but the ability to increase the revv limit lays in programming. Also, keep in mind that Ducati lightened the crank on the R, that is why Ti. con rods are being used. There is no way a base or s model would rev the same way without the inclusion of Ti. con rods and a lightened crank.

You tend to lose a lot of daily performance when switching to a lightened flywheel. I have had them on various performance cars of mine and they tend to be a real pain in the ass. Stop and go traffic sucks ass to include red lights (stalling is very normal when taking off). For race bikes however, this is critical as power bands are geared towards the higher RPM range. Race bikes have .... for torque and must maintain higher revvs to stay within their power bands.

I could be completely full of ...., but this is the way I understand it.

01a4man said:

floats a valve

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Technically impossible with the Desmodromic valve design - my .0002 cents!

Trauma said:

Technically impossible with the Desmodromic valve design - my .0002 cents!

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Sorry Trauma,

You are correct sir, I was speaking more generally and should have kept it to the Duc. My bad!

01a4man said:

Sorry Trauma,

You are correct sir, I was speaking more generally and should have kept it to the Duc. My bad!

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The rest of your statement was entirely accurate, IMHO

Trauma said:

Only $2K with known results, and no hit to the warranty. Seems like a simple choice.

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which wheels do you get for $2K??

well the parts are here and bike goes in tomorrow for the R flywheel swap, the revised R gearing, the new up map, rizoma rear sets cant wait to get it back, will be at the shop for the week, will let u know what i think when i get it back

peter

PS my r is ....... awesome

Besides my wonderful Pani Tri, I own a Porsche 997 GT3RS, and it has a light weight flywheel as part of the OEM RS modifications to the otherwise identical GT3 engine. Porsche advertises the RS as "made for the track, with the occasional street usage". The GT3 engine revs higher than other Porsche six-cylinder engines (8400 rpm) which is cool when you thrash it to redline, or want the coolest sounding downshifts this side of Michael Delaney, but, and this is significant, the light weight flywheel makes it a relative PITA to leave from a stop compared to other Porsches I have owned. It will stall if you are not VERY careful when pulling away from any stop - that is unless you want to rev the heck out of it and slip the clutch which will shorten your clutch component's lives significantly. Other than that, it is wonderful, but in the real world of stop and go driving, it gets real old, real fast. Sometimes made for the track is just that - for the track.

hi guys
got my bike back today

to answer a few questions
vibrations.... no worse than before
stall... with the shorter gearing , no probe, even taking of at a bee's dick over idle still doesnt stall
in neutral certainly revs a lot quicker
during riding seems to pick up a lot quicker(but i did get the revised spockets) so this could be because of the gearing change.
rizoma rearsets... puts ur feet where they should have been all along, will adjust them after i have acclimatised..
new map, yep fixed a lot of fueling issues, i do find the bike seems hotter now than before, not on the gauge, but my right leg is certainly feeling it.
did a few 3rd gear roll ons with a mate on a yami fz1, not so much that i smashed him, but every time i hit 8k, massive increase in power, certainly more noticable than before, and by 9k front wheel was in the air, tryied a 2nd gear roll on, same results , constantly backing of to keep the front down....

just throwing this out for everyones info
peter

raypeter said:

hi guys
got my bike back today

to answer a few questions
vibrations.... no worse than before
stall... with the shorter gearing , no probe, even taking of at a bee's dick over idle still doesnt stall
in neutral certainly revs a lot quicker
during riding seems to pick up a lot quicker(but i did get the revised spockets) so this could be because of the gearing change.
rizoma rearsets... puts ur feet where they should have been all along, will adjust them after i have acclimatised..
new map, yep fixed a lot of fueling issues, i do find the bike seems hotter now than before, not on the gauge, but my right leg is certainly feeling it.
did a few 3rd gear roll ons with a mate on a yami fz1, not so much that i smashed him, but every time i hit 8k, massive increase in power, certainly more noticable than before, and by 9k front wheel was in the air, tryied a 2nd gear roll on, same results , constantly backing of to keep the front down....

just throwing this out for everyones info
peter

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Thanks for updating us!

So the cost is 2k for the flywheel job? That's really not worth it. Or is that the cost for flywheel and sprockets? Honestly I'd shy away from a lightened flywheel. I've had them in cars and its nice but there is way less room for error on downshifting and blipping.

gatti man said:

So the cost is 2k for the flywheel job? That's really not worth it. Or is that the cost for flywheel and sprockets? Honestly I'd shy away from a lightened flywheel. I've had them in cars and its nice but there is way less room for error on downshifting and blipping.

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Nah, it was $770 for the flywheel job and maybe the 41T also. Back on page 2