1979 Jota front end

J

jota6297

New member
Good evening, I have been having an issue with the front end on my 1979 Jota. I rebuilt it a little while ago, new stanchions 630 mm long, and on reassembly it appeared to me they were longer than they should have been. I say this because the front tyre sat on the ground when on the centre-stand and it handled "funny" i.e. it didn't want to change direction as quick as it used to. I pulled the forks apart again and sent all the bits to a Ducati mechanic, (someone who understands Marzocci front ends), who reassembled them. I re-fitted them and they still appear a bit long but I haven't ridden it yet so I don't know how it handles.

To put this to rest once and for all can someone tell me what the correct distance is from the centre of the axle to the top of the forks with the wheel fitted and the bike on the stand. I've measured mine at 820 millimeters give or take a couple of millimeters.

thanks in advance.

Ian
 
I am pretty sure that 630mm fork stantions are for the RGS series,I cant put my finger on a factory sheet that I possess giving details (it was out a month or so ago, to supply info to a mate, now I have temprarilly mislaid it, but I think (memory again) that the Jota (180) had 595 mm stantion lengths.

Not much of a problem to drop the legs through the yolks a bit, but your handlbars might prevent this, not very hard to cut down the forks to the correct length,. although this is specilaist machine shop work, at least its not trying to make them longer, which can be done, but is never satisfactory.

Somone will chime in with correct lengths unless I find my sheet in the meantime.

CLEM
 
Std 38mm Marzo tubes were 630mm for the 180's and Jota 120 and 660mm for the RG series - the extra 30mm to suit the clip ons going above the top yoke - Regards - Phil
 
So, what else is different between 180 and RGS forks?
Is it only the length of preload spacer for the springs to take up the 30mm change, or are there bigger differences?
 
Hi Grant - the only other difference I know is that the non RG models used a dual rate spring and the rg series a single rate - may be other way round though?? - Regards - Phil
 
On my 79 Jota, with the bike on centre stand with front tire just touching the ground the distance from centre of axle to top of fork caps is 80.8mm.
Dennis
 
Dennis said:
On my 79 Jota, with the bike on centre stand with front tire just touching the ground the distance from centre of axle to top of fork caps is 80.8mm.
Dennis
Click to expand...
That's quite a difference from the previous post @ 812mm  :D standard Laverda tolerance...?
 
The 808 vs 812mm difference may have to do with how the centre stand is adjusted.

After repainting my frame, when I fitted the motor, wheels & suspension, the front and rear wheels were too close to the ground.  I could not turn the wheels by hand and it was very difficult to roll the bike off the stand.    Adjusting the centre stand bolts fixed both problems.  In effect, it raised the frame from the ground and, in so doing, also extended the front suspension.    Actually, it is now too easy to roll the bike off the stand, and I?ll need to adjust the stand down a little. 
 
OK, on more accurate inspection/measuring my 820 give or take comes back at 815 mm. How can the centrestand be adjusted, I have never done it, I have had it off but not adjusted it.How critical is 815 mm compared to 810 mm?

Thanks
Ian
 
Hey Ian ,

Dont think centre stand adjustments gunna change the
length of ya shocks  ;)

You did say earlier that whilst bike on centre stand the front wheel
just cleared ground surface ??

Take it for a fangin and scrubb those new tyres in, then report
back on handling  8)

If it is just a tyre to ground clearance issue whilst on stand ??
you probably pick that  5mm up thru the yokes.
 
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