Stark Varg 80HP to Duke 125 2017 conversion (engine)

[Simon Tkac]

Hey, I found a stark varg Alpha for quite cheap and I‘m wondering if i could fit the engine into my duke 125. Sort of an engine swap. Now, I ain’t no engineer, I’m just 18yo, so I don’t even know where to begin to see if this would work, so I came here for help

 

[Erwin P]

If it's 18 year old budget i'm willing to pay you double to save the bike

By all means if you really want it you could. You need to rebuild the frame around the motor and need a frame to hang the battery in. Also you would need to upgrade the swingarm to handle the torque and respring the fork and shock to hold the extra weight.

I would suggest using a Starg Varg frame as a shortcut to make things easy on yourself. Might use the swingarm and suspension as well.

 

[Philip]

I would download high-resolution side-view images of both bikes. Scale the images in MS Paint to be proportional to their real-life wheelbase numbers. Cut out the motor+battery from the Varg, drag it over to the Duke image, and see if it fits the side view of the bike.

Then would measure the width of the real Varg's battery and see it fits between the Duke's trellis frame tubes.

Identity where the Varg's powertrain is bolted to the frame and see if you can add the same attachments/brackets to the Duke's frame.

It's could be a fun project, ot it could be a hacksaw massacre of both bikes.

 

[Chadx]

Hey, I found a stark varg Alpha for quite cheap and I‘m wondering if i could fit the engine into my duke 125. Sort of an engine swap. Now, I ain’t no engineer, I’m just 18yo, so I don’t even know where to begin to see if this would work, so I came here for help

Would be an interesting project but require a fair bit of fabrication. Fitting the Varg's motor (it's electric, so use the term "Motor" and not "Engine") wouldn't be too big of an issue, but fitting the battery is where I'd expect you to run out of room fast. Or would you be building a custom sized/shaped battery for the Duke? Also curious if there is anything wrong with the Duke 125 engine or do you simply have the bug to try your hand at an electric conversion? If the latter, you might keep your Duke as is, find some other suitable donor bike on the cheap (that has a blown engine) and try your hand one that bike instead of your Duke.

Curious what your use case would be since this sounds like a fun project. Playing on a low speed track with lots of tight turns? Low speed around town type riding? Medium to high speed highway riding? (highway speeds drain battery fast)

As others imply, pushing 60hp through a chassis built for 15hp could lead to catastrophic failure. You might be safe running 25hp through it, but would avoid pushing the full 60hp or 80hp through that chassis without mods to handle the power.

 

[leeo45]

Some good advice above, especially the part about the Duke 125 being far from the ideal bike to use as a recipient for the Varg power plant. I understand that you have the Varg donor parts, however, if you want to convert your Duke to electric there are numerous excellent kits available (battery, motor, controller, etc) that would be much more appropriate for that bike and a much simpler conversion. There are also a number of people on this forum with a lot of experience making those conversions who are always ready to provide help and guidance.