Australian street legal petrol/gas build


New Member
Local time
9:20 PM
Nov 14, 2010
Darwin, NT, Australia
Ok this will be a bit lengthy but I thought I would try and get it over with in one post.

Australian street legal petrol MB why,where,what and so forth.

I was thinking of getting an MB about 4 or 5 months ago as It looked like I was going to be stuck without a vehicle. So anyway now I am and can't afford to get another one for a while as I will be studying working part time next year.

I live in Darwin, Australia. Its probably the most bicycle friendly place I've ever lived. Its nearly all flat and there is a really god network of bike lanes and dual use pathways you can get to and from just about anywhere in town or suburbs on it. In fact I still rode a fair bit when I did have a car. The bad thing is it's **** hot, even if your used to living here some days a 5klm ride feels like 20klm and you work up a sweat just looking at your bike :cry: .

Ok so we have a crazy 200w power limit on MB's in Australia and if you brake it you get done for unroadworthy, unregistered, uninsured, unlicensed if you don't have a motorbike license etc. My driving records not the best so I would probably end up sharing a cell with a big hairy guy who's bike is about 950cc bigger than mine :eek: .
So electric ?? - This will be my primary mode of transport so unless I want to fork out a fortune for kit with good high capacity batteries ( as much as a car would cost ) I will probably spend more time pushing a heavy piece of junk around instead of it pushing me. As a side thought I live in hot mostly sunny place I'm wondering how much the high temp would effect the battery efficiency. Also if I want to make an unexpected trip after I get home from work or something then I have to wait hours while the battery charges. So electric not really an option for me.
Petrol/Gas - As far as I know there are only two legal options here. Rotary Cycles sells a hub mounted kit based on the sachs motor that is as dear as a second hand car and Rock Solid Engines has a detuned HT kit for $425AU so this looks like my only option.
The RSE engine is expensive but they import the parts and do all the machining and assembly here and replace all the studs etc.. with high quality ones which I have seen several posts saying is a big improvement in reliability. They run the motor in and test it on a dyno give you the readouts with the engine and stick on a compliance plate stating that its 200w so nice and legal. In my ( inexperienced ) opinion paying the extra $200~$250 is a bargain. You get a better quality more reliable unit thats basically plug and play ( no run in, I think ?) thats machined and quality checked by someone who makes more than $5 dollars a week, and certification to keep the police happy.
Sick Bike Parts Shift Kit- Would these work as an effective pedal assist with such a low powered unit ? ie. 25~30kph from light or moderate pedalling instead of flogging myself. I sent a pm to screaming emu about fitting one of these with the RSE 200w. His opinion was that it would not be worth it as I would not get the use of the full range of gears. This makes perfect sense to me after all 200w is 200w ( **** you thermodynamics :mad: ) . So I might be wrong here but I assumed that having even some gearing would mean I could keep the revs up under higher loads ( going uphill ) and squeeze a bit more out of the engine if I do 20klm or more a day even squeezing another 20% out of it would be a big help. As I said I agree with what screaming emu said it was more me not giving enough info in my question.

Tweaks I might get away with - Besides better protection does using a high quality synthetic/racing oil boost the power output ? Honest officer I just use this oil cause its better for the engine.
I read a post saying that changing the plug lead can boost power a bit. Honest officer I only put the new lead on because I kept getting water in the boot ( It can rain so hard here that you have to pull over in the middle of the day cause you cant see past the front of your car with the wipers going full tilt )

Why not a scooter ? - In Australia a scooter is restricted to 50cc and 50kph top speed. Scooters are not aloud in bicycle lanes and have to stay in the traffic. You see a lot of these in Darwin and I rode one for about 3 months a couple of years ago, **** SCARY. Most drivers get more p#@#ed off with these than cyclist. Nearly all major roads in Darwin have bicycle lanes or completely separate bike paths so 95% of the time you are not in the way on a scooter you have to sit in the car lane doing 30kph less than the traffic and they get a lot closer to you than the cyclists. You spend most of your time with the feeling your about to become a hood ornament.

Final Thoughts - Even at a paltry 20~30kph I should be able to most of the places I need to go in under an hour. No worrying about public transport timetables I can go somewhere at 3 in the mourning if I want to. Weather is not an issue even when it rains its warm and half the time it rains that hard you get soaked getting to and from your car anyway.

Any corrections or suggestions would be greatly appreciated :D

Great forum. Heaps of great info and a good vibe not much flaming and b#$ching.
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I think the shift kit would give you better performance on this 200watt engine.
The reason is simple ! that 200watt output is equal to the average riders leg peddling power , so having extra gears is a no brainier :rolleyes:

If you were to remove the compression plate & carby restrictor that motor would have the same power as a normal 48cc engine , but that would be naughty :devilish:

Have Fun
Talking to a guy up the street the other day with a zbox 500cc. He was telling me he got pulled up the other night by the cops they reckoned it was over 50cc 200W.
Happened to have his laptop with him so pulled up the page for the RSE 200W and showed them. Looked like the same engine SO THEY LET HIM GO !

**** this dodgy internet connection !
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I second what Bobby said! Even if you don't de-restrict the engine, the shift kit would help a lot because you can keep the engine in it's power range when you want it.
or another thing for us aussies, is that the cops around probably wouldnt even see the engine, if you are worried get some sheet steel and make a cover around it ( make sure the engine gets airflow) and the cops would be like o yep just another normal bike...
What makes the cops look at you ? first they see a bike moving along without the rider peddling , so they look harder & then see the fuel tank on the top bar , then maybe hear the motor as they get closer .

Do this :
1. Ghost pedal on flats & when going up inclines .
2. Get a small gas tank & mount it behind the seat on a rack , if you can't find one , use the existing tank mounted sideways , cover this with some shade cloth .
3. Hit the engine cut off button the moment you see them .
4. Enjoy your ride & have fun :)

or another thing for us aussies, is that the cops around probably wouldnt even see the engine, if you are worried get some sheet steel and make a cover around it ( make sure the engine gets airflow) and the cops would be like o yep just another normal bike...

That would be about the only option in you neck of the woods. They only have too see the engine and your busted. Maybe you could make big stickers for the cover that said something like "Super Electro Bike"
lol a giant bill board on the back saying ' keep moving just another ordinary bike nothing to see here ' =)

Ha ha ha ha/ Just watched my DVD's of Star Wars with that episode. Had to laugh at your solution. May the Force be with you. :devilish:

Is it legal to carry a light saber *down under*. ;.)
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