# Aprilia 125 / Lynch DC / VARIO



## RIPPERTON (Jan 26, 2010)

Im doing the motor mounts ect for a friends Aprilia 125 conversion.
I know I trash DC motors all the time but hes had this Lynch lying around for ages and needs to put it in a project.
So Im experimenting with a vario transmission off a TGB 125 Express scooter I got for $70 and the front clutch seems to run ok.
I think I need to keep the same direction of rotation for the trans because there is a cork screw device in the rear tensioner pully.

Sorry about the smelly 2 stroke photos








Heres the double reduction I designed to get the 80kmh top speed.
Don't really like double reductions because the primary chain makes a lot of noise and deteriorates quickly.


YouTube vid of vario centrifuging as motor spins on 12v
https://www.youtube.com/watch?v=NfRtTntM24k&list=UUoOd7A2JVRmeuaEfGbO7f_g


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## kingr (Dec 5, 2014)

Good work.

What's the power rating on the motor ?

Planned battery setup ?


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## RIPPERTON (Jan 26, 2010)

kingr said:


> Good work.
> What's the power rating on the motor ?
> Planned battery setup ?


Thanks the label say its a Lynch 127 and has a staggering 13kW.
A big stack of A123's 24s 3p should do.


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## RIPPERTON (Jan 26, 2010)

Looks like its all going fit pretty nicely.
I flipped the front clutch around so the belt pull was closer to the Lynch bearing, less chance of bending the shaft. Just have to figure out how to lock the clutch to the shaft.
The bearings were removed from the rear clutch which will be attached to a solid jack shaft that has a 16t sprocket on the end of it.


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## RIPPERTON (Jan 26, 2010)

New alu spring cap to replace the centrifugal clutch.


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## RIPPERTON (Jan 26, 2010)

A bit like a shear pin on an outboard prop I drilled 5mm hole through the main shaft and rounded off 2 short pieces of 4,5mm key stock and bashed them into the holes. Then cnc'd 2 keyways in the fixed sheave.



Then to lock the bolt socket I sliced a piece of 6mm keystock in half and ran it from the original keyway in the main shaft up into a cnc'd keyway in the bolt socket underneath the outer sheave slide tube.



Might have heat problems with the fixed sheave because Ive machined all its cooling blades off to get it closer to the motor.


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## RIPPERTON (Jan 26, 2010)

The acetal turns into aluminium.
captured main bearing for the rear clutch.
Taper lock 14t 520 sprocket with 30mm bore goes on here



Frames havnt been welded on yet.



Adjustable split perch for the off side bearing so I don't have to rely on precision welding to get the bearings aligned.


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## kingr (Dec 5, 2014)

Nice progress.

Are you going to run a bms with those cells ?


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## RIPPERTON (Jan 26, 2010)

Got all the welding done and spun the Lynch up on an old lead acid with 8v.

https://www.youtube.com/watch?v=7heqNp-qlQc


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## RIPPERTON (Jan 26, 2010)

The Vario didn't work for some reason, the belt just slipped a lot and didn't drive or upshift so ripped it all out and canned it.
Went to a T belt primary and works well.

A question for DC controller experts
The problem is the difference between full throttle rpm through the Alltrax AXE 7245 controller and direct battery voltage rpm.
80v direct from the battery gets about 4300 rpm free spin.
Motor rpm with the Alltrax on full throttle gets about 3800 rpm free spin.
The controller is configed at 100% output.
Question is how to fix this.
Can I put a "boost" contactor in the motor cables feeding direct full battery voltage to the motor with out blowing up the Alltrax ?


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## barron (Dec 10, 2011)

RIPPERTON said:


> Can I put a "boost" contactor in the motor cables feeding direct full battery voltage to the motor with out blowing up the Alltrax ?


Issues I see with the boost contactor are:

1. How would you limit current through the boost contactor?
2. If Voltage is X thru the boost contactor and Y at the Alltrax output then X-Y volts are being dropped somewhere, and if current from either the Alltrax or boost contactor are high enough then something, somewhere, is likely to burn up.

Would be preferable to find the root cause of the lower Alltrax RPM before going down the boost contactor route, although I've no idea what that cause is!
When you measure the output voltage from the Alltrax do you indeed see a voltage difference that corresponds to the reduced RPM?


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