wheelbase 1977 3CL

See my comment about chain length. Some chain adjustment systems can allow a wheelbase change and some can even change rear ride hight or swingarm angle, those with a ring eccentrics at the wheel axal or swingarm. Not so much on std Laverdas. I don't think there is a full link in the swingarm adjuster length.
https://www.laverdaforum.com/forum/index.php/topic,100134.msg443816.html#new
 
maurice turner said:
Thanks for all the replies just for the exercise bike resting on centre stand rear wheel fully forward standard offset Ceriani triple clamps standard Ceriani 38mm front forks and standard Ceriani rear shocks.
I am getting a dimension on one of my bikes at 1510mm axle centre to axle centre.
Click to expand...

Maybe a swing arm length plus distance between bottom engine mount and front axle (unloaded) might give a clue where that extra inch and a half has come from?
 
Surely you just measure from axle to axle, with the fr wheel as true to the rr as poss? I personally use the mid-point in the axle slot when considering wheelbase, but that doesn't help for general reference - so fully fwd seems a good idea. Of course, forks have to be level with the top triple clamp, not dropped through as some bikes with clipons have.
 
Food for thought, how many of you really believe that every frame that came out of the factory was identical down to the millimeter/s when measured. If you reference back to old motorcycle magazines from the Laverda triple era you will find differences in the reports of rake, trail and wheelbase. The frames were not put together like a Bimota it was a jig and a welder with tolerance to work with. I had my frame checked by a repair shop using a  Scheibner Mega-M.A.X. analysis! Basically a big jig that holds the bike and uses a laser to measure shit, it can also twist, pull, bend your machine back to stock or to any :o custom spec (with limitations). It had preprogrammed factory measurements of just about every bike ever made. Laverda has a +/- tolerance 1.3degrees on the steering head angle, not much but it does change wheelbase measurements. And no it is not recommended to adjust your steering head angle from 29 to 27 degrees without other modifications even though the Scheibner Mega M.A.X. can do it easily.  :o
 
When I was a uni student I was using my 3c as a commuter until I just couldn't afford it any more, but there was a period when it was still a runner but maintenance got deferred. I managed to get 26,000 miles out of the original chain, although it was and truly buggared long before I actually replaced it. I did take one link out because I ran out of adjustment. But I was amazed ate the difference in handling with the new chain and shortened wheelbase. It went from really ponderous and needing to be forced into corners to pretty much squirting where I was looking.
Miss that bike.

Ken
 
If it were 40mm shorter than the norm, you'd be a lot more worried than 40mm longer. Short would make you look for previous collision damage.

But 28 degrees at the headstock, converts to the forks to "somewhere" between 26 and 30  ???

index.php
 
Hey Maurice, I'd have thought you'd have another 3CL framed bike to use as a reference.

My Jota started out as a Ceriani forked 3CL, but somewhere in its history it got a set of Marzocchi forks and triple clamps. I can measure it if you like, but the Marzo front end will probably make a difference.
 
Gday Cam I have compared it to one of my other 3CL's and its longer and I now know why the front down tubes are bent forward pulling the base of the steering head, dont ask me how that could ever be achieved????
 
chrisk said:
If it were 40mm shorter than the norm, you'd be a lot more worried than 40mm longer. Short would make you look for previous collision damage.

But 28 degrees at the headstock, converts to the forks to "somewhere" between 26 and 30  ???

index.php
Click to expand...

Just be aware that this drawing shows the headstock angle as 28o but has the fork tubes as 26.5o, so must have the early non-parallel triple trees which give an increased trail (please correct me if I'm wrong).

I was once told that replacing these triple clamps with the later parallel type improved the steering, presumably quickening it by reducing the trail. However it might not be so straightforward, as I think the Marzocchi clamps have a different offset between steerer tube axis and fork stanchion axis compared to Cerianis.

Grant modified his Ceriani clamps to parallel on POP.

Cheers,

bazzee
 
bazzee said:
Just be aware that this drawing shows the headstock angle as 28o but has the fork tubes as 26.5o, so must have the early non-parallel triple trees which give an increased trail (please correct me if I'm wrong).
Click to expand...

You're not wrong Bazee. That drawing shows an early 3C frame.


maurice turner said:
the front down tubes are bent forward pulling the base of the steering head, dont ask me how that could ever be achieved????
Click to expand...

I reckon they probably got bent backwards in the normal way, then someone rotated both fork tubes 180? in the clamps.

They must only be bent a couple of degrees, so should straighten out easy enough.
 
maurice turner said:
Gday Cam I have compared it to one of my other 3CL's and its longer and I now know why the front down tubes are bent forward pulling the base of the steering head, dont ask me how that could ever be achieved????
Click to expand...

Was probably used to pull Monos Mo  :P. With a not so gentle landing !
 
Dellortoman said:
You're not wrong Bazee. That drawing shows an early 3C frame.


I reckon they probably got bent backwards in the normal way, then someone rotated both fork tubes 180? in the clamps.

They must only be bent a couple of degrees, so should straighten out easy enough.
No not the fork tubes Cam the frame down tubes
Click to expand...
 
I had my 3c measured at the only working in Oz Computrack set up a few years back and thankfully it came out straight and correct. It was expensive at $500oz. Who knows what has happened over 40 years of use.
http://gmd-computrack.com/network.html
 
Dellortoman said:
You're not wrong Bazee. That drawing shows an early 3C frame.


I reckon they probably got bent backwards in the normal way, then someone rotated both fork tubes 180? in the clamps.

They must only be bent a couple of degrees, so should straighten out easy enough.
Click to expand...

But it's the front DOWN tubes that are bent fwd, Cam, not the fork tubes. Maybe it went over a jump ... or a railway line ... a la the Kel Wearne CBX!!
 
Wouldn't any bend in the downtubes reduce their overall length thereby trying to pull back the bottom of the steering head? I would think that the angle they meet it would make that nigh on impossible. It must be a Monday frame, the day after a big soccer (football, footer....) loss for the local team.
 
Tippie said:
Wouldn't any bend in the downtubes reduce their overall length thereby trying to pull back the bottom of the steering head?
Click to expand...

Makes sense. Whether bent forward or backwards the result would be the same. Short wheelbase. Bent spine however, that's another story.
 
What about the old cut the frame backbone to remove the tension and add a bit, that went around the forum a long time back. But that again would shorten the wheelbase?
 
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