My first-born son (aka the first two-wheeled motorized vehicle I've ever owned) has returned back home



I picked up my 1988 Hercules Supra 3D moped (49cc 2 kW / 2.7 HP two-stroke 3-gear manual transmission Sachs engine, type 505/3 DK) last thursday. It's been hidden away behind a shed exposed to all elements this planet has to offer since 2003. I cleaned it today (almost no rust on a 22 year old moped is what I call real good quality!), changed the spark plug and gear oil, haven't found an air filter yet so had to clean the original 1988 air filter. Four kicks later the engine started and runs pretty well once it's warm. Terrible when cold though - when it dies it's really hard to start again, and it sounds like it suffers from a really terrible cough. It gets better after the first hundred meters or so, although I had to readjust the clutch and throttle cable. I'm having trouble with 2nd gear which makes a really horrible clunking sound - my guess is that the gear wheel is loose on the drive shaft. I can maintain speed in 2nd gear but as soon as I accelerate it makes that sounds and doesn't get any faster at all. First and third gear work perfectly fine.

Anybody ever had one of those and know what the problem with the gearbox could be? Also, any ideas how I could improve its cold run? I'll replace the almost ancient air filter ASAP, still looking for a replacement. Spares are a bit hard to find since the engine and moped were only built for a few months in 1988. Any ideas what else besides replacing the 1994 tires I should do?

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"Life is not a journey to the grave with the intention of arriving safely in one pretty and well preserved piece, but to skid across the line broadside, thoroughly used up, worn out, leaking oil, shouting GERONIMO!"

As for poor running - first replace the air filter - then if still bad, the carb will probably be gunked up - modern fuel goes off and varnishes up carb inners within months, let alone YEARS !!!!

I found some proper air filters on eBay and will replace the old one this week. Just need to make sure which one to get - there are air filters with 16, 22, and 27mm diameter for this engine. The carb looks pretty good, I was surprised myself. I kinda expected it to be all solid at this point. After some fine tuning the engine runs a bit better when cold, although I feel like there still might be room for improvement. Still looking for tires - anyone know what the difference between 2.50x17 and 2 1/2 x 17 is? The latter I need according to the operating license but it's really hard to find. I found tons of 2.50x17 tires though - is there a difference?

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"Life is not a journey to the grave with the intention of arriving safely in one pretty and well preserved piece, but to skid across the line broadside, thoroughly used up, worn out, leaking oil, shouting GERONIMO!"

I don't know this particular model, but a lot of mopeds had a choke lever directly on the carburetor.

There are clubs for people who restore old mopeds (and use as much time as it would take to restore a proper motorcycle ;-)), they might be able to help.

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Poul
May you enjoy peace and good health !

There's a choke lever sorta thing right next to the throttle. It sorta looks like a decompression lever but it's supposed to be the choke. Also, there's some sort of button on the carb but I was not yet able to find out what it's for. And I actually found a club for old Hercules motorcycles and mopeds and tried to join their forums, but they want my full name, address, and phone number before they let me in. Go figure

I've also made progress on the air filter front and have purchased the 22mm version. The original is 20mm and I had to chose between 16, 22, and 27mm with no 20mm air filters in sight. I've managed to get Heidenau on the phone and inquire about their tires, but the woman I was talking to didn't seem too competent. According to her the only difference between the 2 1/2 x 17 and 2.50-17 is the max speed. Didn't quite convince me so I'll keep my eyes and ears open.

I took it out for a spin today and was surprised how well it runs. I easily squeezed out 55 km/h and more without any engine modifications whatsoever. It's so light and small - the perfect city vehicle. I need to readjust the drum brakes though, they're terrible. And fix the gearbox because 2nd gear is completely gone.

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"Life is not a journey to the grave with the intention of arriving safely in one pretty and well preserved piece, but to skid across the line broadside, thoroughly used up, worn out, leaking oil, shouting GERONIMO!"

I wonder if the little button on the carb is a "prime", to tickle the carb & flood the carb to aid cold starting???? Like me old Triumph.