Doppler Engine Spring Gas Coil-Over Overhaul

Doppler Engine Spring Gas Coil-Over Complete Overhaul- Peugeot 103

Doppler Engine Spring Gas Coil-Over Overhaul - 103

$159.49

qty:

here's what ya get in this PARTYYY!:

1 of Add-a-Fitting 212mm M6 Threaded Gas Strut - 15lb ($27.99 value!)
1 of flat washers - M6 ($.27) ($0.27 value!)
1 of m6 blk corrosion resistant fender washer ($1.79 value!)
2 of metric nylon lock nuts - M6 - 1.0 ($.25) ($0.50 value!)
1 of peugeot 103 moped doppler engine tension spring ($99.99 value!)
1 of Two-Piece Clamping Shaft Collar - 19mm ID ($18.99 value!)
1 of Two-Piece Clamping Shaft Collar - 8mm ID ($17.99 value!)

this is the version that comes with the stuff to overhaul your doppler spring into gas coil over mode and DOES include the doppler spring itself

wow wow wow! people have long known the advantages of using a gas spring in addition to your regular engine tension spring on french bikes. it eliminates the "goating" phenomenon, where if your engine tension spring is too light, the motor will bounce off the line, meaning you'll hear the characteristic "bah bah bah" of the goat, robbing your acceleration unless your foot is heavily planted on the launch lever/your pipe/a giant case bolt you left sticking out because you're too cheap to buy a launch lever. but it's always been up to you to figure out how such a shock would mount from your motor to your frame. no longer!

this pack will drop right in place of the M8 stud in the peugeot 103 doppler engine tension spring! The only permanent modification you'll need to make is to cut down the nylon spring guide in order to slide the smaller shaft collar more forward, or else your engine won't be able to swing back and you can't fully variate. this is an easy process, and if you decide to go back to your old doppler spring setup without the gas shock, it's still totally usable! in order to tighten the nylock nuts on either end of the shock, simply tighten the shaft collar to the respective side and keep the hex key inserted to one of the heads on the shaft collar allen screws. while you're at it, might not be the worst idea to put some blue or orange loctite on the shaft collar screws as well!

to adjust preload, loosen the larger shaft collar, and either slide it forward to stiffen or slide it back to lessen the preload, and tighten when preload is at the desired setting. seems to work well with the yellow spring and very little preload, but the doppler springs all fit, so feel free to try another we carry if you like!

***NOTE FOR MBK AND SPX DUDERS***
this setup has only been extensively tested on peugeot 103 motors, so while it should fit on the mbk or spx doppler engine springs, we do not know if they require stiffer gas springs to work well.

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Best of both worlds	October 19, 2023
taco eater : Anonymous Person from planet french

Once you run a strut on a single variated engine it’s hard to go back to spring alone.

With a mechanical spring, the resistance is progressive. The more load that’s put on it, the more it will resist that force. This is good at hi-RPMs, but to avoid goating off the line, you have to put more preload on the spring to have it resist bouncing the engine.

With this, you still get the extra resistance of a mechanical spring at hi-RPMs, but you can set the spring tension of it much lighter overall since the strut resists force uniformly. Ask any French guru and they’ll tell you: you want the lightest spring tension possible without goating at takeoff.

I’ve been running this setup on three frenchies for a few years now, and I’ll probs continue to do so on any other I get my hands on.

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