Exactly, a 40hp 'panting' (heavily)Originally Posted by jellywrestler
No8 Wire Extraordinaire
Exactly, a 40hp 'panting' (heavily)
Don't you look at my accountant.
He's the only one I've got.
Me Like Cafe
It's the chugga motor. Making it into a cafe racer style would just be making it uncomfortable, it would still be a chugga.
Blast From The Past Axis of Oil
No8 Wire Extraordinaire
S'alright, looks only count. Wouldn't be ridden far.
Don't you look at my accountant.
He's the only one I've got.
Anorak
While I am sure they might have recycled some parts, the life expectancy of an early 851 crankcase bored to full oversize and having its nuts revved off is far less than 300 km. Lots of early engines never even lasted a race. I know at least some Corse cases were sandcast; they went back to this again with later R engines.
This does not in itself not make them stronger ,but is cheaper method of making heavier designs and faster changers.
Later 888 models (1990 SP2) and onward are stronger but still not strong enough. The 916 is better, and the 996 is better again. Later deep sumps are better still. From memory, Cathcart was at times using one case per meeting on the tricolor kit bike, which is why it was almost brand new when he sold it. As even with his special relationship with the factory he could get all the cases he needed.
Every iteration was ever so slightly different, according to Rankin, with webbing and changes as the factory tried to make them work within the confines of the limitations of the molds and tooling they had. Also, the design, although better than the non-Mille bevels, still resembles a significant compromise, as it has outer roller bearings under preload, which places loads on the case. The Supermono had plain bearings all around as an attempt to show what could be done with the next engine; Bordi had hoped to make the 916 like this, but they couldn't afford the new tooling. The rollers also limit the material and space they have to add material compared to plain main bearings. Remember the ducks have the two small outer outrigger bearings as well to stop the crankflap. if you look at the Ducati or even a old pommy parallel twin you can see why they need outrigger bearings.
COntrast this with Slight on the works RC45Two years ago, Superbike Ducatis regularly broke the main bearings out of their cases, making one-race-percase the rule if 11,000 rpm was used often. The cases were later reinforced.
actory Ducatis employ relatively heavy, Austrian-made Pankl con> rods in steel. There have been occasional failures of the very heavily loaded rod bolts, for the Austrians don’t yet make use of the multi-phase steels pioneered by the U.S. firm SPS. Multi-phase steels not only have extremely high tensile strengths, but they also have high elongation before failure-they stretch before they break. This means it takes a lot of extra energy to break them. Eraldo Ferracci uses American-made steel Carrillo rods and bolts in the engines he builds for Doug Polen, and has never had a rod or a bolt fail-even in cases of piston break-up.
Kevin Cameron Daytona 1992
People think in a factory team you just bolt stuff in and out but we didn’t. Everything had a life. We didn’t just bolt engines in and out. You might pull down an engine and even re-use the same rods and pistons, just put new rings and valves in. We never used a whole new engine all at once. It had an optimum running time and was changed accordingly. It amazed me. I used to think well, you’ve got the engine apart, you might as well use new parts in it. There was no rule against it. But they didn’t. They were like, well, it’s run in now, might as well keep using it. Leave it alone. But because we were using a different gearbox every weekend, and that meant the cases had to be split, the engine was apart all the time. You could’ve put anything in it you wanted to.
While it's true the crankcase design goes back to the pantah. The gearbox centers were moved after the first pre 851 748ie as the 748 had to have a rather weak 6 speed to fit in the extra ratios I think they keep these centers and widths with some later bikes, Maybe the 350/400 six speeds. (edit seems to be 600/750's these were reused in the 800 series too according to BradB)I have never questioned why, but I know The belt 750 cases at least up to the mid 90's don't fit the std 900/851/916 6 speed. (edit you can used the 6 speed from the 696/796/800.in the 600/750 5 speed cases)
looking into it The gearbox it seems was moved for to reasons the swing of the crank being one.
This kind of reuse old shit designs is not restricted to old pommy twins and shitty Ducati's have a look at almost any MF tractor up to the 1980 an you can see TEA ferguson DNA.
Not to mention the venerable VW, 350 chev 6 cylinder and 308 Holden etc etc.
The Desmoquattro engine itself, with the valve spacing originally designed as a 748ie, (which evolved to the 851 that won the Daytona Bott around 86?87?) designed by bordi and migoni (sp)
places the valves too close together which limits the valve size able to be used when used in a bigger bore engine, leading to the engines having to use almost two-valve timing. Plus, greater revs are needed to make enough power. It is said that later 996 works bikes had wider-spaced valves and special rockers, but I have never seen photographic proof.
My SP2 has the AA spec cams the are rather too much for the road even for a lot of tracks. Unless you are a works class rider. You can spend $$$$ chasing that last few HP.
If you have a look at the 748SPS you can see why the top ends were so short lasting
Kinky is using a feather. Perverted is using the whole chicken
No8 Wire Extraordinaire
My information is heresay, ((heresy says correction) but came from Chris who used to work for Dallas) so same same
Don't you look at my accountant.
He's the only one I've got.
Rasta Ratskins
Hearsay is gossip, heresy used to carry the death penalty.
Only a Rat can win a Rat Race!
No8 Wire Extraordinaire
Sorry autocorrect got me twice!
Don't you look at my accountant.
He's the only one I've got.
Forum whore
The Duke of Wellington story mentions crankcase issues and how every set they got from the factory seemed to be different in some way
https://www.classicracer.com/dukes-wellington/
it's not a bad thing till you throw a KLR into the mix.
those cheap ass bitches can do anything with ductape.
(PostalDave on ADVrider)
Anorak
One of jelly's bikes is pictured in that article...
There was one article only about fast-n-fragile writen years before for streetbike mag.
He's also mentioned previously he was one of those that cajoled Dallas into putting the speedway headed version back together.
That said I never picked up they deleted the flywheel and used the cover as a form of Brace??)
This makes sense now as F&F ran a ignition trigger on the clutch hub and a 900SS ignition this is possible as early Ducatis have a 2:1 primary later ones are 1.8:1
They removed the alternator, cut off the end of the crankshaft and made a replacement outer cover-plate to strengthen the most stressed side of the crankcases.
Kinky is using a feather. Perverted is using the whole chicken
"channellling the Pleideans"
https://www.trademe.co.nz/a/motors/m...ing/5334768365
not optimistic. I need this, right?
I thought elections were decided by angry posts on social media. - F5 Dave
Anorak
It's Greg's old bike
Kinky is using a feather. Perverted is using the whole chicken
In the riders seat
You do, if I had money I'd already be bidding on it
I can remember him coming into work with it in the back of a CF Bedford van back in the day
"If you can make black marks on a straight from the time you turn out of a corner until the braking point of the next turn, then you have enough power."
Una Storia Italiana
KBer Grumph... seen the bike at the track last weekend, i duno what class it go in but hey...
cheers DD
(Definately Dodgy)
Making James May look quick...
Pre ‘89 F3
Sometimes you wish it was easier, but if it was, everyone else would do it, then you remember you don't want to be like everybody else!
Anorak
This is the thread about Greg refreshing the Bike.
https://www.kiwibiker.co.nz/forums/s...evival-Mission
Kinky is using a feather. Perverted is using the whole chicken
There are currently 2 users browsing this thread. (0 members and 2 guests)
Posting Permissions
Reply With Quote
Bookmarks