No Modifications - what does it mean
 

I have read recently on another website about a DD bike having its crankshaft balanced.

From previous experience of this type of work it usually include one of the following
Grinding Metal away
Drilling or Milling away metal
Weldiing to add metal

Now with the DD rules concerning Crankshafts having remained unchanged in this area since the very first set of rule for the 2005 Season V1.01 up to the latest set of rules, they have always stated NO MODIFICATIONS TO THE CRANKSHAFT ARE ALLOWED.

Current rule reads
1.6.21 Crankshaft
No modifications are allowed (including polishing and lightening).

So how the hell do you get them balanced, even by normal methods which would be in breach of the rules its about £160 to balance a Ducati Crankshaft

I thought we were trying to keep the racing cheap especially class B and as such we don't need costs like this creeping in, after all if you can't split and rebuild your engine yourself the overall bill is going to add up to quite a bit more than I have paid for a spare engine

Don't know how you would police that! as the cranks are balanced from the factory to a certain degree, I've not done anything below the barrels on my bikes but if I did I would certainly balance the crank! it would be daft to go to the expense of a rebuild without.

And there in lies the problem
Policing it. A standard factory crank may or may not be distinguishable from a balanced or modified crank, I may have to investigate futher to see just how distinguishable they are

It would be hard to tell a balanced crank from a slightly lightened one without stripping the crank from the engine and removing the rods etc and then weighing to see how it compares to a crank that hasn't been modified in anyway after leaving the factory and allowaning a small tolerance

Now if its easy to tell a unmodified crank from a modified one be it balanced or lightened, possibly by just removing the front cylinder and rotating the crank, policing it becomes easy
eg.
Unmodified = legal
modified = illegal
which makes the rule as it exists suitable for the series

If this rule has to be modified to allow for grinding, drilling or welding then it becomes very unclear where balancing a crankshaft then becomes a performance advantage by removing a little extra.

To date DD bikes have proved fairly reliable with very few blow ups and little debris being left on the track for others to hit.
So if the rule can't be policed then it becomes meaningless and may as well be dropped which then leaves the way open to those that want to push the limits of crankshaft reliability vs weight.

Is it a gray area or is no Mods Clear enough
personally I don't see the need to modify the crankshaft on a DD bike as they do come with a certain degree of balancing from the factory and like the rule in its current state, as it should make the series easier to police.

I have owned bikes even back in the 80's such as my CB900F taken out to 1065, Carillo rods, Drysump, lightened, balanced and knife-edged crank so do know why its done and the benifits to be gained against the reliability factor.
But I certainly don't want to see DD heading down this route.

I couldn't even tell you what a crankshaft looked like, let alone the benefits of balancing or lightening it :confused:

Mine is balanced.... On the paint tins in the garage, Reminds me I really should start my prep...

Differences in crankshaft weight, which as Chaz says have been factory balanced are normal so not a discriminant.

And, lets put that somebody protests you because thinks you have your crank balanced: pays 250 to strip the engine, balancing would be undetectable unless a reputable qualified Ducati engineer ceritifies the modification, and you will be left with an engine in pieces which will cost 500 pounds to reassemble. It will be cheaper to pay the 150 fee..

Moreover, lets put the case somebody has to change one or two pistons in a 583, which currently are out of production, he/she will be forced to use non OEM pistons which again is against the rules.
Curently the only OEM pistons available from Ducati dealers come with barrels at ~600pounds/pair....cheap
Replacing the pistons with used standard will need re-balancing for a good result and increased engine reliability. However I am not technician and I don't pretend to be. I agree with Chaz though.

Why not limit the rules' policing within weight/bhp?

We are back to the subject of second hand bikes! I know for a fact that engines have been stripped by the likes of JHP/Louigi Moto & found to be illegal & the present owner had no idea! so you buy a bike in good faith what do you do? pay out a load of cash to have it checked! or trust the honesty of the seller?
There are quite a lot of bikes out there that have changed hands.

Yet you can buy a standard 583cc engine from a breakers for £250 stick new belts on it, give it a oil and filter change Put it in a chassis and then stick it on the podium.

So why spend so much money on all these engine rebuilds, new pistons etc.
I've see engine bills from £900 to £1350 for rebuilds without any crankshaft balancing and if you really think the balancing is going to improve your results, I doubt it.
Where as a bit of lightening for quicker acceleration (still the same bhp and weight, bit like fitting a lightweight flywheel) may help with the results as that would be cheating and I along with others would rather not have cheating going on in DD.

Now if the easy way to police it is to ban Cranksharft modifications of any sort then I'm all for it and thats how the rules have been for the last 4 seasons.
Currently modifying the crankshaft in any way is breaking the rules, is that rule not Clear enough.

Saying it is better for the bike to have the crank balanced isn't much different from saying its better for the bike to run Ohlins forks, Mag wheels or Diablo Corsas and just ignore the rules so long as it meets the BHP and weight limits.
Or is it the risk of getting caught out that determines what rules people follow and which they choose to ignore.

Here is a bit from the Sigma Performance website, they are on about the 944cc Monster but I bet the same applies to the 600

" it would be nice to rebalance the crankshaft to make sure the engine is smooth…….experience has taught us however that the 900 twin is quite resilient in terms of crankshaft balance (an alternative explanation is that its not very sophisticated engine as standard and a mere 75gram change in piston weight isn't going to make a big difference!!)."

I agree with you about getting motors from a breaker that is what I would do, not to many 620/6speed around though & later 583's are getting harder to find.

..as if I have not looked for one...No chance. Let me know if you find one please.

because the front piston is grooved and I cannot find a replacement. A dealer
has a HC pistons but no OEM which are unavailable even in Bologna unless you buy the barrel.

I am not looking for increased performance, just peace of mind that my engine will not blow up. There is no point in giving out obviously not pertinent comment on forks and tyres.

Thanks