early triples & 750's forks

Lothar if my memory is straight, the braking at Mallory was filmed on a cine camera with a roll of film in it (remember them or are you too young?) and later the same day played on a projector (same again) in the (old) clubhouse, I asked for some footage at the time but didn't get it, haven't seen or heard from Adrian O'meara, the long term and long ago chairman of ILOC for years and years.
CLEM
 
Hi Clem, I do remember them, not much younger than you (at least don't feel much younger... :-[ ). Wonder how he did slow-motion though with that and also developed the film the same day, cut it and showed it? Amazing what some people do...

This would really be an incredibly nice video to watch... I felt the bending of the fork of my SF(0), too, several times. The bike was so lovely, but the combination of the fork (with new stanchions, new seals and everything), the Ceriani shocks and the drum brake was just nothing I wanted to trust my live to anymore and so I sold it heartbreakingly only roughly 1.700km after the restoration... I could just not make myself change it to other components, I wanted someone else to appreciate it as it was.

Summary: although the experts like Piet and Marnix have seen it only on one bike (3C with 35mm forks and disks) or on bikes with a bent frame, other confirm they have seen the fork bending much and touching even the header on bikes with 38mm forks or even SF's with Drumbrakes and 35mm with the balancer pipe. Funny, too, that Roger from OCT has made me aware of the fork-flexing when I changed to 4-pot calipers almost 20 years ago. So - even the experts are not all on the same page - how can we?

seems it remains a mystery. I would have accepted Piet's and Marnix words as I trust them and their experience very much and believe what they say. how ever, there are others, that experienced it, too, and that makes me think that no matter how long you work on bikes or other points, we should always accept the fact there are exceptions from the rules.

Still - if someone has a proof to show of a straight frame bike with such indents, please let it be coming. The more replies with facts we get, the more we can maybe find a rule on which bikes it happens under which conditions.
 
Be aware that the new Tarozzi stanchions that you buy for Ceriani 35mm drum forks these days are much more prone to bending under braking because they don't have the thick wall section.

If that's what you fitted, I'm not surprised that you saw them bend

When you fit the origininal springs in these stanchions, you can hear them rattle inside.

Nothing beats the good old Ceriani stanchions.

Marnix
 
Hello Marnix,

the dent in the 750 SF balance pipe of mine seem to having happened with original Ceriani forks and stanchions (I still have the caps here, as I had to change to new stanchions with new caps from OCT due to massive rust on the original ones. They were still straight though..). The bike was put off the Road in 1974 (I had all the original Papers of it) and stored for over 30 years untouched until I bought it from the original first owner and restored it.

I hear what you are saying and it makes a lot of sense, Marnix, just like Piet and others. I know that you know what you are talking about. I am just trying to find out why mine had it or under which circumstances it happens or can happen. Bent frames are one reason, I agree. But some frames are straight and bikes have original forks, and it still seem to be happening on some. Weird.  ::)
 
Is it a given that the factory tested every variant by removing fork caps and sliding wheel/guard assemblies to the limit of travel to determine whether adequate clearance existed ... or not?

As for triple forks flexing, as I noted in the Motodd thread with Scrumpy's pics of the Mk1, there is huge potential inherent in the length. But wouldn't this length then limit or negate the potential for guards to hit centre headers?

For those who wonder why USD forks have become the norm, have a look at the rigidity of the assembly held in the triple clamps, combined with the significant strength advantage of the large OD alloy uppers where conventionals have steel staunchions. Manufacturers went from 35mm to 38mm, to 41mm to 43mm and finally (I think) 46mm ... and then realised that USDs were the way to go.
 
I have 46mm conventional forks on mine, off an SV1000, SV1000 riders swap these with GSXR USD forks, because "they flex too much" which I think is code for, "like the look of USD forks".
My forks are rock solid. Even under front wheel lock-ups they perform brilliantly, just a tad harsh ATM. 
 
chrisk said:
I have 46mm conventional forks on mine, off an SV1000, SV1000 riders swap these with GSXR USD forks, because "they flex too much" which I think is code for, "like the look of USD forks".
My forks are rock solid. Even under front wheel lock-ups they perform brilliantly, just a tad harsh ATM.
Click to expand...

I have a 2001 Caponord with probably the same forks... conventional and huge in comparisson with 35/38 Ceriani as fitted in the day. Despite owning April for 2 or more years now I've only done 2,000 or so miles on him/her, and still on 'untraceable' Isle of Man number plate. :D The forks work great, no flex or anything; "You can ide me much harder, if you wish". :D
 
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