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General Category => General Discussion => Topic started by: Groover on July 16, 2019, 09:38:15 AM
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Are the swingarms from the mid 70's tonti interchangeable with the newer models? I know there are the three lengths, but are the witdhs the same? Meaning, if I put say a T3 swingarm on a say a 98 EV (examples), would the shocks be vertically lined up, or will the shocks be spaced out wider on top in this case and narrower at the bottom when looking at the bike from the rear? like this \ 0 /
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Don't know buddy, you ask dumb questions..
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:laugh:
There are some variations , I think the later EV's have a slightly wider swingarm . The experts will weigh in shortly .
Dusty
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:laugh:
There are some variations , I think the later EV's have a slightly wider swingarm . The experts will weigh in shortly .
Dusty
When they changed from the Jackal to the Stone they were made wider for a bigger tire. Im assuming the EV's also changed at this time. Where the width increase was in the arm?. that I don't know.. might just be a bigger dimple in the drive shaft tube.
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Thanks guys, wondering if the frames on the EV, Jackal, etc are wider up where the shocks mount, or if they are the same width as say a T3. The later swingarms have bigger tube structure with the dimple for the wider tire, but the left side of the swingarm (brake side) also comes out a bit in a curve on the later models, vs the older short swingarms are straight, I guess that's what's confusing me.. does that curve mean wider frame above?
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Go to Greg Benders site thisoldtractor and look at the section with repair manuals. Many of the manuals have the frame dimensions and the swing arm dimensions.
I took a quick look yesterday at some manuals and from what I could tell the rear frame rails under the seat were about the same between a T and my EVT.
Tom
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The swingarms are all the same width at the pivot point, so yes, they are interchangeable. I believe the newer frames are wider, as are the shock mounts, not but much though and doable. The latest 03/04 style Tonti swingarm uses a different pivot pin ( different diameter threads and it`s not a direct swap without changing out bearings and modifying the pin length. The pin length is too long from an early tonti due to the shallower swingarm bearing recess on the right side of the swingarm. Recently modified pins to mount an 04 swingarm to fit my t3 type chassis to run a wider tire and rim. Also mounted the long Cal 3 / Jackal style swingarm to a Lemans 1000 , that was a more direct swap with the same bearings and pivot pin.
With either of these conversions, the shock will lay down at a much lower angle, dropping the rear height as well as changing the spring rate action.
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Great answers, that last one by 5154 was exactly what I needed to know. Thanks again to all, and have a great weekend!
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The swingarms are all the same width at the pivot point, so yes, they are interchangeable. I believe the newer frames are wider, as are the shock mounts, not but much though and doable. The latest 03/04 style Tonti swingarm uses a different pivot pin ( different diameter threads and it`s not a direct swap without changing out bearings and modifying the pin length. The pin length is too long from an early tonti due to the shallower swingarm bearing recess on the right side of the swingarm. Recently modified pins to mount an 04 swingarm to fit my t3 type chassis to run a wider tire and rim. Also mounted the long Cal 3 / Jackal style swingarm to a Lemans 1000 , that was a more direct swap with the same bearings and pivot pin.
With either of these conversions, the shock will lay down at a much lower angle, dropping the rear height as well as changing the spring rate action.
I have a follow-up question in regards to the jackal swingarm on the LeMans 1000. Is this for a custom job, or is the rest of the Le Mans the same, except for the swing arm swap? How does it ride, and how does it look (assuming the bike/fender/tail is stock otherwise)
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The swingarms are all the same width at the pivot point, so yes, they are interchangeable. I believe the newer frames are wider, as are the shock mounts, not but much though and doable. The latest 03/04 style Tonti swingarm uses a different pivot pin...
I'm looking into swingarms because I want a wider rear tire for my T3 with sidecar.
What are these 03/04 style swingarms refering to, 2003 and 2004, or something else?
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What everybody else has said however don't overlook the pivot point to the center of the axle especially on the right side the rear end length might be different maybe spacers Etc just an after thought
The lenght of the swing arm on a T3 convert G5 Etc is different than what's on a cal 11 and newer right side swing arm is longer where the one on the t3 to has a shorter right side piece but it's longer overall on both sides and may work out just they careful measurements from the pivot point to the axle and the rear end you're going to use
T3 wheelbase is approximately 58 in Cal 11 and newer the wheelbase is approximately 60-in apparently it's done all in the length of the swing arm and it may also be harder to put the bike up on the center stand however if you have a sidecar you shouldn't have a problem
TOMB
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There are medium lengths too ...Guzziology has the full SP on this. The width at the pivot point remains the same as far as I remember.
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If you keep currant fender/shock set up the LM4/5 has the widest clearance for rim width. Think about shock angle if using longer.
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I installed a Jackel swingarm on my Le Mans 2 a few years ago . First off it 's more than 2" longer , which is
what I wanted , because I was stretching the seating space . I made rear fender struts to relocate the seat and fender
and to move the shocks back so they maintained the same angle ( and ride height as the Le Mans ) . The wider swingarm and
rim allowed a 130 rear tire . You'll also need the original drive shaft for which ever swingarm you chose . The
handling was not as good as the original . I made a longer brake hose also , the pivot points were the same . Peter
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This Old Tractor site has many resources. Including drawings with dimensions. A good resource when interchanging parts.
If you change to a shorter swingarm you will need to move the top shock mount forward. There is a boss welded in the frame that can be drilled through and tappeded. I did this on my bike when I changed to a Magni swingarm.
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The swingarms are all the same width at the pivot point, so yes, they are interchangeable. I believe the newer frames are wider, as are the shock mounts, not but much though and doable. The latest 03/04 style Tonti swingarm uses a different pivot pin ( different diameter threads and it`s not a direct swap without changing out bearings and modifying the pin length. The pin length is too long from an early tonti due to the shallower swingarm bearing recess on the right side of the swingarm. Recently modified pins to mount an 04 swingarm to fit my t3 type chassis to run a wider tire and rim. Also mounted the long Cal 3 / Jackal style swingarm to a Lemans 1000 , that was a more direct swap with the same bearings and pivot pin.
With either of these conversions, the shock will lay down at a much lower angle, dropping the rear height as well as changing the spring rate action.
what 5154 said, and please for gods sake do not try and move an upper shock mount. Buy a shock of the proper length to give you the geometry you want.
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what 5154 said, and please for gods sake do not try and move an upper shock mount. Buy a shock of the proper length to give you the geometry you want.
i recall back-in-the day... i would cut off the top shock or sometimes the lower mount on the old dirt bike. It was a trend back in the early 70's. had to have the "lay-down" shocks ! Id did make landing jumps a bit softer, unless you blew through the travel ! good times !
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Thanks to all for the replies.
It was nice to practice some English as well :laugh:
I would prefer to keep the same arm length, given the consequences for the various mounting points and stuff around.
I’ll check out Guzziology once I got my copy back from my friend.
So far I’ve checked Greg’s sources and indeed the factory manuals pretty well show the dimensions of the swingarms.
At first glance I can’t find an arm with the same length that has a recess for the tire.
Using an angle grinder to take a bite out of the T3 swingarm and weld a sheet onto the hole would work but will to a certain extend weaken the construction.
Later swingarms with recess have larger diameter legs.
I have no clue about the wall thickness of the tubes for the different swingarm types.
The current tire is a Michelin Collection X 125/80 15 but that’s a summer tire, and I would like to have a winter tire.
Unfortunately they don’t exist with these dimensions.
I can have 135/70 15 but at the moment there is barely 8 mm between the current tire and the right leg of the swingarm.
With the 135 wide tires the rubber would be very close to the shaft tunnel (3 mm in theory).
The best trade-off seems the LM1000 swingarm.
It has a recess, larger diameter legs and fits my T3 frame, at least on paper.
Disadvantages are it is 20 mm longer and the left doglegged side might complicate the upper shock attachment.
A LM1000 swingarm is on its way to me and I will test-mount it in an empty frame I have laying around.
I will post the result of my findings.
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Notching the short swingarm used to be commonly done back in the 80's . If it's done competently there should be zero loss of strength.
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LM IV swing arm is a good choice. The only thing you will have to do is stack shock eyelet washers on the inside up top. Better hope your shocks have a narrow enough eyelet (in and out, ID must be right of course). I have done the LM IV swinger on an old short swing arm frame with many different shock brands, ohlins, koni, marz, works. Some of the long konis for LM IVs have the shock eyelet welded offset. Eyeball the shock and using washers or reversal of the shock (if eyelet offset), get the shock most close to vertical that you can. It will be good enough.