But the wheel is not modified in any way by adding weights, it is just balanced and yes the same can apply to a complete crankshaft assembly, in that you can mix and match rods pistons etc to balance a crank without having to modify the crankshaft.
But few people resort modifying by drilling or grinding their wheels to acheive balance.
So back to the rule, it says No modification of the Crankshaft, It does not say no balancing of the crankshaft asembly by selecting matchingcomponents

As for 916 wheels as far as I know a 916 front wheel is no different from a 620 front wheel and as the rule says
1.6.5 Wheels

Wheels including diameter and rim width must remain as originally produced by Ducati since 1992 for the 600/620 bikes.
Front wheel 17” X 3.5”, Rear Wheel 17” X 4.5”

There is no issue with using a 620 front or rear wheel in a 583 and if the 748/916 front wheel is the same part as a 620 it can also be used.
Did they fit any 620s with 5 spokes as found in the 996, if not then I doubt these would be allowed

Is that Druids? ;)

...there's a saying that goes along the lines of ".......won't be troubling the scorers!!" ;)

Nope, not even the Capirex as standard - I've already checked.

Mind you, there are mag wheels listed in the DP catalog as suitable for the 620s - surely that complies with "originally produced by Ducati since 1992 for the 600/620 bikes.
Front wheel 17” X 3.5” " ?? Then I figured the 500quid would be better spent on improving ability through tracktime or Magners. Guess what I chose?

No change there then :(

Think I'd better use the spare bike then - oh wait, its got a 999 fuse in it :lol:

Lighter Wheels you say......?
 

To quote Sir Falon's Monster and SS book:

1998 onwards

Frame and Cycle Parts

" With Brembo wheels..........from the 916 and ST2 having larger diam. (25mm) axles.........."

".....the wheels were also lighter than before at 225 grams on the front and 800 grams on the rear"

It's easy to spot which ones they are if you compare them side by side.
However, ther is only one sort that will slot straight into a Monnie or SS without palava with the rear wheel bearings and wheel bearing spacers.

(and I'm not gonna tell you which one that is.......;-) )
MarkO

Drinking Magners while riding around a track by any chance
Would explain a few things :)

Maybe the wording should be changed to "originally fiited by Ducati since 1992 for the 600/620 bikes

To a certain extent balancing, expecially on the Class B engines is not worth the expense as they do not rev that high anyway and are somewhat overengineered for 52bhp.

That is an opinion, nothing more. And at the end of the day there is a bhp limit anyway......

Just to add my own thoughts on this subject,

I dont see myself that David will have anything better than someone else will have.

The rules are designed to be fair to people and designed so that no one person can have an unfair advantage to somebody else.

David hasn't got anything in his engine that would not have come out of the factory in another bike on a different day of the week.
Its just that some engines are better than others as some will have fractionaly lighter parts, thats just the way it is. Its luck of the draw but all David has done is to turn his engine from a slower one with slightly heavier parts into one of the better engines.

I dont see the problem with that, as someone could go out tomorrow and buy an engine thats never been apart before that has a lighter crank than his but it would still be a standard engine.

So balancing actually reduces the chances of engine failure. You don't need to do it but once you open you engine it would be daft not to do it, as long as you keep within the factory weight tolerance limit. An alternative as somebody suggested would be to buy another engine atogether, play and pray...

I dont think its a case of that really Alex, these engines are about as agricultural as bike engines get and the chances of one flying apart because it didn't have a few grams added or removed here and there are pretty slim!

I guess it would reduce the chances of a failure but by a very very small margin, I think as far as reliability goes, we are probably racing in one of the series with the least mechanical failures on record.

I dont know what the answer is, but it is nice that people are so meticulous about the preperation of their bikes. I agree with Kev in a big way about it being time on the bike that makes the biggest difference, but knowing that what you have under you is good also helps confidence.

But someone elses could have come out of the factory with poorer flowing heads due to factory tolerances, which wll cause the engine to run out of balance
So where does this line of acceptance get drawn ? is it when everybody can pay out to have there engine Blue printed to factory spec

As for reliability One blow up in 4 seasons under the No modification rule would suggest that as they come from the factory they are pretty reliable

for me personally the bottom line is that this year I just want concentrate on my riding and forget about mechanical issues and if balancing aids it I welcome it!

What engine rules are in place for Superstock racing?

Surely what we have is a similar kind of thing to that?

1.6.21 Crankshaft

No modifications are allowed (including polishing and lightening).


Thats what the rules say quite clearly. Where does it say that balancing is disallowed?

With regard to the crankshaft rule that we have had in the rule book for the 4 previous years, no doubt there are some out there that have already ignored that rule and had work done and got away with it. sadly thats human nature

BUT what is it that is now wrong with that rule.
Its very clear, its in black and white, easy to understand.
So why would we now need to change it.

Excuse 1 = Improve reliability = evidence already says they are reliable
Excuse 2 = Somebody may have a better one than me = and some probably haven't
Excuse 3 = Its good practice = only if the factory balancing is along way out and it costs just to find out
Excuse 4 = No Modification doesn't mean I can't modify it = says who
I'm sure if I read back through the topic I will come across a few more excuses

just here

1.6 Machine Specifications

All items not mentioned in the following articles must remain as originally produced by Ducati on a 600 or 620 aircooled 2 valve model.

It ISNT modified......not in any way, how many more times Kev? And who are you or anyone else to determine someones right to do something within the rules that costs anything if they so choose? If someone wants to spend the money to make sure the engine is as well put together as it can be why cant they? It doesnt say ANYWHERE in the rules that there is a ceiling or a limit on what may/may not be spent on any one area of the bike build? if someone wants to spend £500 on a Nitron shock would you tell them it goes agains the spirit of DD ? Why not have a set of rules that says you can do NOTHING to a Class B bike save remove lights, stand etc, if you really are on a crusade to save other people's money for them? What happened to freedom of choice WITHIN THE RULES?

It doesnt mention wheel balancing either. Is that also disallowed under the same blanket?

try reading the rules rather than making your own up

1.7.1 The following items MAY be altered or replaced from those fitted to the homologated motorcycle:

Any type of lubrication, brake or suspension fluid may be used.

Any type of spark plug.

Any inner tube (if fitted) or inflation valves may be used.

Wheel balance weights may be discarded, changed or added to.

If used Wheel balance weights must be suitably taped.

Gaskets and gasket materials.

Instrument and instrument bracket and associated cables.

Painted external surface finishes and decals.

An interesting discussion and one I that I've enjoyed reading (even if I am in anorak mode for a while).

A question:

If someone has a big end failure and NEEDS to rebuild and finds the crank is scored:

Does this then mean that for DD racing (using our rules) it means a replacement crank straight away???

Also -
My basic impression of 'balancing' is that it matches components (or, yes - alters them) to reduce vibration and hence increase reliability....

But perhaps someone might like to explain further

Cheers - Frank

Then go through EVERY DD bike and make sure NOTHING on any of them is modified beyond your interpretation of the rules Kev. Thats the only fair thing to do...or adopt a common sense approach and accept that balancing does NOT involve modification or polishing or lightening, and neither does it give any performance advantage whatsoever.

Nog, how was your crank balanced?
If it involved removing material in any way then the rules say it's not allowed.
Factory tolerances? Was the item found to be outside these tolerances to start with? If not then your arguement for reliability falls down, it's good enough as it is and doesn't NEED balancing.

For what it's worth, (assuming material has been removed in order to balance it) I don't see what you've done is giving any noticable performance advantage, so personally wouldn't have a problem with it.
BUT... it's subjective to opinion isn't it? So what must be done is simply follow the rule book and not have an entrant try arguing that his/her opinion is of higher importance than the written rules we've all subscribed to.

Ok, that seems fair enough.....


...but now you rather shoot down your own argument. If it makes it smoother/more reliable then is that not giving you an advantage over someone who does not balance their crank?

too much sense in this post....


if its just had parts mixed and matched, but not modified and standard parts from standard ebngines, surely thats fine isnt it? only if its actually been changed to bring in to whatever tolarance and has it therefore been modified. Thats how I read and interprit the rules, seems simple?!?!

I'm obviosly missing something here

The rules clearly state that the Crankshft can not be modified and also state it must remain as originally produced by Ducati,

It does not say as designed by Ducati

If your Crankshaft has not been modified during the balancing procedure it is within the rules, if it has been machined (modified) to balance it then it is in breach of the rules.

I have no problem with people doing anything within the rules and don't care how much they pay to have it done providing they then don't bitch about the cost of racing.
But with the rules as they are which includes phrases such as No modification or must remain as originally produced by Ducati, there is only so much that can be done and that in itself helps stop costs spiralling out of control to the sort of levels seen in SoT racing.

Having a crankshaft machined to balance it is Modifying it to improve its performance, otherwise why would anybody bother or is what the Ducati Factory put out just cr4p

I agree balancing alone gives no real noticeable power or acceleration increase so why bother spending the money, breaking the rules and having it done. Over the years many have abided by these rules so why would we need to change them now

The point is the rules on crankshafts say No Modifications, yet you have your own interpretaion of the wording taking it to mean altering the balance of the crankshaft to meet a better spec than that delivered by Ducati.

Now if the rule included wording like that it would be taken by some as anything goes.
Finding suitable wording to allow a crankshaft to be balanced to a tighter factory toleance should't be to hard, but then it comes back to how to distinguish the difference between a crankshaft as supplied by the factory, one modified to balance it to meet a tighter factory tolerance and one that has been modified to give improved engine performance, without having to resort to full engine strips and crank removal for weighing something I would rather not see.

I started this post to gather views on what may well be a gray area as covered by the 3rd post on page 1.

and as this years rule book was ammended to try and clarify some issues and cut out gray areas this maybe one issue that slipped through the net.
I have said before if a rule can not be policed it has no value so either needs ammending or throwing out.

Now if a technical inspector could not tell if a crankshaft has been balanced by looking at it then the rule as it stands has little value.

This wasn't meant as a personal attack its just that your post stating that you had got your Crank balanced showed it was a subject that needs debating and a conclusion arrived at and I tend to gather as much information as possible to arrive at my own conclusions.
The thing is all evidence could point to leaving the rules as they are and altering a crankshaft to balance it be classed as a modification and deemed to be breaking the rules.
On the other hand it could point to the fact that unless someone states there crank is balanced by means of modifying it a technical inspector would never be able to tell (as weighing would only show a lightened crank) then the rule may have to be ammended.

My view is that if by looking at a crank you can tell it has been altered/modified even if only for balancing reasons then the current rules are good enough for policing the series, but if you cant tell by looking then ammend the rule.

Just have a random dyno check at 1 or 2 rounds next year. If anyone has an unlawful amount of power we can worry about how they got it then.

Just a note one of the most powerful 583 engines seen was a lump bought off ebay with no history at all, it was checked and put in the bike. The dyno centre said it was the most worn loosest engine they had seen with the most piston slap ever when cold :(, it went on to produce the most power they have ever seen from a 583 and more than one or two 620's, it wouldn't last half a season they said.....2 years later it was still going :)

So don't waste time/money with new components buy an old shitter and enjoy the power ;)

Thats pretty much the same story of my old 583, 52 BHP and it sounds like a bag of ****.

worked for me (well it worked, i didn't!) - just balancing the carbs and plastic welding a crack in the airbox gave me an extra 2 bhp :eek:

my bike had been stood outside for 7 years before i (or rather my kind local dealer) got their hands on it.

Oh, so it could have been an ex-race engine, with fully modified bottom-end, balanced, lighthened and optimised -;) - it all makes sense now :eek:

You'd never spot a crank that has been balanced tbh. It's nothing more than "perfecting" the spec'. Blueprinting if you like. No different to taking a pot of pistons and picking 2 that are the same weight, if you like.
Lightening is a different ball game and not cheap. If you were going to the expense of lightening a crank, you'd move some metal which would be obvious. A balance could be no more than taking another mm out of the holes that the factory drill in the first place.
There's very little, if any, performance advantage to be had. Reliabilty is main/only benefit. You'd get more by shimming the crank a little on the light side to get less drag on the mains.....

Only added after reading the first page, but now read it all :)
Frank brings up an interesting point....
If the big ends failed, would a crank regrind and oversize shells be illegal?? The rules, if followed to the letter, would indicate so. Surely common sense would prevail??
There's a distinct line between balancing and lightening.
I think the point made about "good practice" in building a good motor is well made. There's no performance benefit and policing it is nigh impossible.

That sort of talk won't be tolerated here !

:rolleye:

Woohoo, if that was the case I've been breaking the rules for 2 years then, except when I was on the ex-Geoff Spencer bike.;)

I'll hand back all the trophies I won as a result :lol:

Anyone else bored of this thread yet?

Tut tut Paul ;)

With regard to possibly regrinding a crank after a blow up (how much would this cost against sourcing another crank) then surely the course of action would be to email the RC and seek permission to get it done.
Not unlike Paynep emailing and asking about using a different frame.

I agree that balancing a engine is good practice and to some extent this is carried out at the factory, but as the Desmo Due rules not only state no Modifications to the crankshaft but also that it should remain as it left the factory there are quite a few entrants out there that have followed the rules.

For example Senna3 had his engine rebuilt at Baines Racing last year including the fitting of two new pistons, Now I wouldn't dare suggest Geoff or John don't know how to assemble a Ducati engine be it air-cooled or water-cooled but they did not adjust/alter/modify the crank as they were asked to make sure it complied with the rules.

Surely it is one rule for all

Nelly I'm not sure how many Desmo Due engines you have built from the crankcases upwards, maybe none. But if you have, have you always applied best practice or have you left the crank well alone inline with the rules

A regrind and shells would most likely work out cheaper than sourcing another crank. You'd re-shell it anyway as a matter of course.

I've built several motors from the cases upwards, and yes, i always apply "best practices" so as to build a good, reliable motor.
If i was asked about balancing as part of a DD build, then i wouldn't have a problem having it done. I don't interpret it as being outside the rules.
The cranks are balanced at the factory. Further checking/balancing is merely checking that it's as close to optimium as possible. No different to setting the squish, filing the piston rings to make sure the gap is spot on, setting valve clearances, setting the air gaps on the pick ups........ There's more benefit to be had adjusting those than checking/having the crank balanced.
Who's to say that nog's crank went away, was checked and nothing needed doing? More than possible.
If i was asked to have the crank webs machined away and knife edged, then i'd suggest they take it somewhere else, if i was asked about balancing then i don't see the problem.

May well get asked a lot more now than in the last few years after this rivetting read :)

But the thread wasn't meant to be just about Nogs crank, although the thread where it was mentioned was the catalyst for the initial question "No Modifications - what does it mean"

To me and many others No modification means leave well alone, if it doesn't and relates to meeting factory specifications I'm wondering if I can afford this little lot


one of my con rods is slightly heavier than the other and both are heavier than the minimum weight quoted by the factory, I know what I will do I will balance them so that the meet the factory minimum weight. After all the engine will be smoother and less likely to shake apart

Same as above goes for the new pistons

Also my rear cylinder head has a lower flow rate than the front cylinder head and I know someone elses flows more than that, so I think I'll get someone to alter them so they both match the higher flow rate of somebody elses engine, so long as I don't exceed the class bhp limit

Just been comparing camshafts and found mine have a fraction less lift than my mates and are even different to each other, I'll have to get them ground to the factory tolerance that will give the best performance. I'm not modifyong them as thats probably how some left the factory.

After checking the combustion chambers one is marginally smaller than the other so what I will do is match the other one to it, a quick skim will sufice after all its not really removing material as thats how it should have left the factory it just good practice to balance them out.

Just found out so and sos flywheel weighs a tad less than mine but is still within factory tolerance, I'll have to adjust mine to suit.

Crikey how much :o
be better off racing in CB5s