Author Topic: 40mm Fork Tubes  (Read 244 times)

Online Groover

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40mm Fork Tubes
« on: September 08, 2021, 09:47:38 AM »
Considering using the 40mm Triples and fork lowers off a LM1000, but on an older Tonti frame with the shorter steering tube and don't want them to stick out on top so much. What are my options in this case, considering the cartridges inside would also need to be different as well, correct?
« Last Edit: September 08, 2021, 10:47:19 AM by Groover »
1981 Moto Guzzi V1000G5
1987 Moto Guzzi LM1000SE, a
1987 Moto Guzzi LM1000SE, b
1980 Piaggio Vespa P200E
1980 Piaggio Vespa P125X
1980 Vespa Grande Moped
1980 Vespa SI Moped
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Offline Stevex

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Re: 40mm Fork Tubes
« Reply #1 on: September 08, 2021, 11:08:31 AM »
Have you thought about fitting Showa cartridges to the oem forks?
Steve
1980 Le Mans II
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Online Groover

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Re: 40mm Fork Tubes
« Reply #2 on: September 08, 2021, 12:16:49 PM »
Thanks for the response Stevex. I am open to suggestions. Where can you get the showa cartridges'? Was thinking of reaching out to Franks Forks in regards to the 40mm question, but still confused on how the cartridge would be handled even if the tubes could be shortened. Hopeful to hear some answers here as I'm not quite yet ready for this project so these are just thoughts I'm working through.
1981 Moto Guzzi V1000G5
1987 Moto Guzzi LM1000SE, a
1987 Moto Guzzi LM1000SE, b
1980 Piaggio Vespa P200E
1980 Piaggio Vespa P125X
1980 Vespa Grande Moped
1980 Vespa SI Moped
http://scooteropolis.com/

Online guzzista

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Re: 40mm Fork Tubes
« Reply #3 on: September 09, 2021, 12:03:31 AM »
Years ago I had a  LM 40MM fork I wanted to adapt to a short neck Tonti so my plan  was to swap the steering stem from a short neck triple  onto the 40mm lower triple , assemble everything and then measure what if any length would be  needed to shorten off the tubes.
As for cartridges, if I am not mistaken a 39 mm damper assembly from a 1990's Honda VFR ( showa?) could be made to work ( lots of those around cheap). You might need bespoke springs, but Sonic Springs would have that covered.  Hope this is some more food for thought.

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1975 750S Tribute bike, 1994 Cali 1100, 2007 Ducati GT1000, 1983 SP1000 1967 Vespa 180 SS, 1976 Vespa Rally 200

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Re: 40mm Fork Tubes
« Reply #3 on: September 09, 2021, 12:03:31 AM »

Online Groover

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Re: 40mm Fork Tubes
« Reply #4 on: September 09, 2021, 08:29:03 AM »
Great info Guzzista, this gives me a direction. Very much appreciated. Thanks!
1981 Moto Guzzi V1000G5
1987 Moto Guzzi LM1000SE, a
1987 Moto Guzzi LM1000SE, b
1980 Piaggio Vespa P200E
1980 Piaggio Vespa P125X
1980 Vespa Grande Moped
1980 Vespa SI Moped
http://scooteropolis.com/

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Re: 40mm Fork Tubes
« Reply #5 on: September 09, 2021, 11:52:35 AM »
One more thing to keep in mind are the fork legs. Both 270mm and 300 mm rotors can be used on the LM  40 mm forks. So either matching the rotors to the type you have  or make adaptor plates for the calipers ( for 300mm rotors) may be required
« Last Edit: September 09, 2021, 09:05:17 PM by guzzista »
1975 750S Tribute bike, 1994 Cali 1100, 2007 Ducati GT1000, 1983 SP1000 1967 Vespa 180 SS, 1976 Vespa Rally 200

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Re: 40mm Fork Tubes
« Reply #6 on: September 09, 2021, 12:29:33 PM »
Is the rotor mounting bolt pattern the same between an LM3 front rotor and the LM4 (I say LM3 because of the 180mm fork spacing)? I understand the caliper will need the adapter to push it out for the 300mm.
1981 Moto Guzzi V1000G5
1987 Moto Guzzi LM1000SE, a
1987 Moto Guzzi LM1000SE, b
1980 Piaggio Vespa P200E
1980 Piaggio Vespa P125X
1980 Vespa Grande Moped
1980 Vespa SI Moped
http://scooteropolis.com/

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Re: 40mm Fork Tubes
« Reply #7 on: September 09, 2021, 06:47:05 PM »
LM 850/LM2/CX100 LM3 as well as T, T3.T4, G5, Vert all have a 6 hole rotor  bolt pattern, LM4  and  later others, 5 hole bolt pattern. The fork spacing is 180mm on  LM3/ 4,5, 1000  so axle / spacing will only be affected by which  wheel you decide to use
1975 750S Tribute bike, 1994 Cali 1100, 2007 Ducati GT1000, 1983 SP1000 1967 Vespa 180 SS, 1976 Vespa Rally 200

Online Groover

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Re: 40mm Fork Tubes
« Reply #8 on: September 09, 2021, 09:02:53 PM »
Ok thanks again. I should have known that (bolt pattern).
1981 Moto Guzzi V1000G5
1987 Moto Guzzi LM1000SE, a
1987 Moto Guzzi LM1000SE, b
1980 Piaggio Vespa P200E
1980 Piaggio Vespa P125X
1980 Vespa Grande Moped
1980 Vespa SI Moped
http://scooteropolis.com/


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