FORK DIMENTIONS

FAQ tech questions, please check if the answer to your question is in here before posting elsewhere.
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RICSPEED
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Tue Jan 08, 2013 3:33 pm

LAMBRETTA FORK LENGTH INFO
FORK STEM LENGTHS - all measurements are approx and are taken with the lower bearing track removed
Italian Series 3+ GP - has speedo/front brake cable support as seperate piece - also has cut out for headset clamp at the side of the thread (in line with front wheel)

Chrome ring
From bearing track seat to centre line of steering stop = 361mm
From bearing track seat to bottom of thread = 413mm
From bearing track seat to top of fork stem = 467mm

Non chrome ring
From bearing track seat to centre line of steering stop = 355mm
From bearing track seat to bottom of thread = 405mm
From bearing track seat to top of fork stem = 458mm

TV 200 - Chrome ring
From bearing track seat to centre line of steering stop = 361mm
From bearing track seat to bottom of thread = 413mm
From bearing track seat to top of fork stem = 467mm

GP
From bearing track seat to centre line of steering stop = 330mm
From bearing track seat to bottom of thread = 380mm
From bearing track seat to top of fork stem = 438mm
Italian Series2 - has welded on "loop" for speedo cable/front brake support - also has the cut out for the headset clamp bolt at the rear of the thread (at 180 degree to front wheel)

TV175 S2
From bearing track seat to centre line of steering stop = 361mm
From bearing track seat to bottom of thread = 412mm
From bearing track seat to top of fork stem = 462mm

LI 150 S2
From bearing track seat to centre line of steering stop = 359mm
From bearing track seat to bottom of thread = 407
From bearing track seat to top of fork stem = 462

Spanish
JET 200 -Large damper type - have single damper stud of 9mm diameter welded to single plate at top of fork leg. Also has cut out for headset clamp at the side of the thread (in line with front wheel)
From bearing track seat to centre line of steering stop = 358
From bearing track seat to bottom of thread = 405mm
From bearing track seat to top of fork stem = 460mm

...........................................................................................................................................
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FATBLOKE
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Tue Jan 08, 2013 5:14 pm

hahaha we are here again....

No difference between series 3 Non Chrome ring and Chrome ring forks both 467 stem length.

The shorter ones were used by spanish who fitted a chrome ring headset without the chrome ring.

I bet several people have tried to fit spanish forks 458 stem in Non Chrome ring scooters and they dont fit I know I have....

New Stickys book page 215.... chrome ring and non chrome ring 467 stem length Spanish approx 460.

Think about it.... is there any difference between tube length on CR or NCR scooter? The difference is chrome ring and this is made up by the NCR versus CR headset dimension....

Ta Dah....

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RICSPEED
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Tue Jan 08, 2013 9:09 pm

simply made this a sticky in the faq section so that the information is to hand .. if there are any revisions or inaccuracies please add them
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FATBLOKE
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Tue Jan 08, 2013 9:28 pm

Its a great piece of information mate and its from Gem Booth so I believe, I started a discussion with him on this site or LCGB and he went away to think about it.

I stand by my belief that there is no difference between CR and NCR I actually bought some 460 long off eBay that I tried to fit to my 125 special and they wouldnt fit and that got me thinking.

Has anyone else had this problem? If so speak up.

Thanks

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Yanker
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Sat Feb 02, 2013 10:42 pm

FATBLOKE wrote:
I stand by my belief that there is no difference between CR and NCR I actually bought some 460 long off eBay that I tried to fit to my 125 special and they wouldnt fit and that got me thinking.

Has anyone else had this problem? If so speak up.

Thanks

Oh there is: especially if you ended up with Spanish NCR.

Jem's guide was 100 %. spot on when I tried to fit S2 TV forks to S2 Li frame, was also 100% accurate about my LI150S CR fork length and the incompatability with Jet forks for replacement.

EG1 needed a new slot filing for the pinch bolt. EG2 no way: thread height insufficient.

So far I have found Jem's guide totally accurate but have not tried out anything more than essential beyond 'keeping on the road'

Surely the person to ask is Frank Sanderson who has developed the range of PM/Scoaldi forks their measurements must be accurate or else they would not be wasting our time. Have a look on the PM Tuning site at their info supplied FOC!

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corrado
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Fri Feb 08, 2013 3:50 am

Yanker wrote:
Surely the person to ask is Frank Sanderson who has developed the range of PM/Scoaldi forks their measurements must be accurate or else they would not be wasting our time. Have a look on the PM Tuning site at their info supplied FOC!
Frank has made some amendments to the original list. Shame that I can't remember them.

shocky
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Fri Oct 09, 2015 4:07 pm

FATBLOKE wrote:Its a great piece of information mate and its from Gem Booth so I believe, I started a discussion with him on this site or LCGB and he went away to think about it.

I stand by my belief that there is no difference between CR and NCR I actually bought some 460 long off eBay that I tried to fit to my 125 special and they wouldnt fit and that got me thinking.

Has anyone else had this problem? If so speak up.

Thanks
Just a little update I have some late s3 forks in S4 blue which have the push in buffers and the innocenti emblem on the fork yoke ive examined them and there 100% original with no modifications and they have the same measurements as the chrome ring ones in the list above , but as has been confirmed to me the chrome ring ring was dropped in 65 ish and push in buffers didnt come in on S3, s till the late sx/s4 was produced in 68
incidently the fork I have were from a s4 that I bought compleate and assembled about 5 years ago and resold on 3 years ago the new owner bought forks with damper brackets on as he wanted dampers
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Wayne Miller
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Wed Oct 14, 2015 11:29 pm

Hi All,

Does anyone know what the OD of the fork tube is where the headset clamp attaches?

Edit : Lambretta S3 forks :)
Stay tuned..............

shocky
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Fri Oct 16, 2015 11:14 am

I just measured some indian gp ones
@ 27.30-27.50mm
late italian ones
@ 27.20-27.40mm
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garry inglis
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Sat Sep 02, 2017 7:31 pm

thanks for that

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