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MadAss Mods

Discussion in 'Modifications and Projects' started by rossi1959, Nov 7, 2008.

  1. I have come across a few different forums asking about mods to the Sachs MadAss, I have done a few different mods on mine to try to find the right mix of getup & go and also be able to cruise on 100kmh. I searched the world for advice & parts and have come to a few conclusions. First is the history of the bike, it is designed by Sachs Germany and built in China by Guangzhou Panyu Huanan Motors Group.,LTD. The engine is a 120cc(not 125cc) Lifan built item(Chinese Honda copy) and is very good for it's intended purpose of zipping around town,the bike's handling is great and better with the normal mods to suit your weight & style, I have done a few different things and have come to two conclusions, 1- put a 141cc big bore kit with a 26mm Mikuni carb 105 main jet and a tuned length power pipe and change the gearing to 15/39, this is the best you can do with the standard motor apart from going to head work, I would not touch the cam because it is designed to give alround performance with that stroke but some mild head work to increase gas flow will help raise power very well. also fit an oil cooler . 2- put a bigbore pit bike motor in which has the cubes already in place, I have tried two kinds one a Lifan 150cc which lasted 65k's (expensive junk now) and the other a 140cc YX motor which is a performance Jialing motor , Jialing is a Chinese Honda ,lookup Jialing/Honda on the web and check out the big Honda factory in China, This motor is still in the bike doing a top job, The other thing I have seen on forums is about people putting the other brand motors in and finding that the battery is not charging or is not charging enough, the MadAss motor has a 3 phase 150 watt DC stator & regulator / Rectifier, I originaly modified the wiring in mine but have now put into the YX 140 a complete new 3 phase stator kit that plugs straight into the MadAss 3 pin plug(3 yellow wires), next motor will be the advertised 18 HP YX 160cc , yet to see if 18hp is real!! if it is then the thing should be a hoot,I have seen bore kits for these motors of 177cc and have heard on US sites of190cc but one must think of reliability ,if you need any info on these mods or parts pm me and I will try to help where I can.


  2. Cool to hear somebody else doing mods to their Madass :grin: :grin:

    I've only had mine a few weeks, so will wait till she's out of warranty before any major work.

    It'd be great if you could do a write-up of your mods - how you did it, problems faced and how you overcame them, etc.

    I think you have to have at least 10 posts??? before you can post pics, but links would be great.

    Keep up the good work.
  3. Hi AJ, yeah I have to do 5 posts to be able to post pictures, I have heaps of interesting stuff for all the MadAss mob. Search the web and look for the king of MadAss's it's on a stand at a bike show and look's to have a 500cc Royal Enfield motor in it, or somthing like that , if they built it I would buy one. anyway I will soon do some more posts and get some pictures on here.
  4. Thanks Spots , there's heaps of these MadAss's out there and after a while you get tired of lack of grunt but hey what do ya want for 3g's,The chassis can handle much more than what it's got so at some stage every body is gonna want to mod them, and I've done my share of doing this and that and buying big bore motor's to modding the standard motor and importing stuff from over seas (I shouda just got a GSX 1000 or somthin) And after being ripped and bullshitted to I have now found the right suppliers for whats needed as well as worked out what is needed and what is just crap, anyway cheers for now.
  5. OK this is me adding to the number of posts so we can see your pics Rossi. I'd really love it if you found the time to do a detailed post describing what suppliers, what parts, how much, how hard they were to fit, and what benefits you saw from each mod.

    I have been considering selling the MadAss and buying a brand new Yamaha WR250X SuperMotard, but at $10k plus ORC I am definitely open to spending another grand or so on the MadAss to see if it keeps me happy afterwards.

    I googled the MotoScoot guys in Milwaulke USA, who do a stubby little exhaust for the MadAss called the "AssPipe". It sits neatly under the footpeg and looks fantastic. But with the Aussie dollar suddenly worthless, I think this exhaust ($195 US) would end up costing well over $400 landed in Adelaide.

  6. Hi Nathan, I was just posting some pic's when you done your post, you will see the power pipe that I am currently in disscusions with 2 manufacturers and hope fully get them done a lot cheaper than that . and as for the stator I can get them. Check out OOracing in England just Google it and check out the MadAss mods, butdue to our low dollar everything imported is EXSPENSIVE even from China where they all deal in USD. Check out the pic of the oil pipes on the YX 160 feeding the head. The other pic's are in the other forum that we have been in, gotta try and find it now,

  7. Brian,

    All great pics thanks! Looking forward to hearing in a bit more detail what you've done or are planning to do and what you'd recommend I buy exactly to get started.

    I'm getting enthusiastic now, perhaps I won't go and buy that WR250X just yet...

    Oh, what do you think of the GPX 160 motor? Guy in Sydney sells them in his eBay store for $665 plus $30 shipping. Not sure if that comes with carb and CDI etc. Or would you go the YX 160?

  8. AJ,

    I'm not sure what kind of support you're gonna get from your dealer for warranty. They can't get parts at all, so I'm thinking you might be on your own anyway. I'd be going back to see them and asking some pretty tough questions - make sure they speak to the Australian distributor.

    This could be good news, you can get started modding right away!

  9. Nathan , sorry for the confusion but the GPX is a YX and is based on the KLX 110 barrel and head, and yes that is my pick of the engines, just check though you are getting the oil cooler and racing stator & cdi with it, if not check out a few other sites . don't forget you will need carby & filter as well and I did see one site with a complete kit I will go searching for you tomorrow, anyway I'm off for my nanny nap. I'll chat to you all tomorrow. CHEERS for now. Brian
  10. G'day all, Nathan there is a place in SA called east50's the owner is Brian and is an engineer he is helpfull with tuning and stuff and he has the YX/GPX 160 with every thing except carby for $675.00. I noted your from SA and seeming east50's is in your neck of the woods it might be easier to deal through them, plus if you buy from Brian his tuning tip's will be invaluable. I have got some photo's of the tools you will need to remove the stator from the YX/GPX when you get it, if you do get it from Brian he might even have the tool to purchase or even remove it for you then just contact me and I will give you the info on the new 3 phase stator and rotor , you will also need 1 small bottle of loctite 262 thread locker for the rotor nut and a small bottle of loctite 609 retaining compound to put onto the tapered key section of the rotor, remember only one drop is enough or else there's a mess if you don't have air tools Bunning's has those small set's with the air tools to make life easier to remove and redo the rotor/flywheel 14mm nut , the rotor /flywheel puller has two sections an outer section that screws into the rotor/flywheel by left hand thread(anti clockwise) it is a 27mm x1mm pitch LHT, it has a a normal RHT bolt that then screws into the other section (clockwise) and pushes onto the end of the crankshaft thus forcing the rotor/flywheel off it's tapered seat on the crankshaft end. I just use two shifters 1x 12 inch 1x 8 inch the 12 inch to hold the big nut of the puller and the 8 inch to turn the smaller inner bolt into the puller. (check photo's). If you can't find the tool try the tool store in Hallam VICTORIA. I will post about the 3 phase stator / rotor kit for the big bore YX/GPX to suit the MadAss. and also talk about the gearing. Cheers Brian.


  11. Great stuff! How much is this stator then? I think I'll take a lunch trip out to East 50's on tuesday.

  12. Hello all!
    First post!!!
    Very interested in this topic, because I own a Madass 50 that's just lunched its engine!
    Being a resident of Adelaide, I went down to east50's today and met Brian. Top bloke, heaps helpful, but he recalls a Queensland bloke that bought some parts to install a GPX motor into his Madass!
    Could that be you rossi1959?
    Anyway, looking to do the same, GPX 150 or 160 into a Madass. But I'm told the electrics need some work.
    Does yours work alright? Charge the battery and Power lights etc?
    Could you pm me a list of the parts I need please? And do you have any?

  13. Hi 2incam,

    Welcome to the home of MadAss mods in Australia! Well, welcome to a thread that helps anyway.

    I still haven't been out to see Brian at East 50s. I've racked up 7500 kilometres on my original 120cc motor, and while it's still starting easily and not burning oil, I can feel that it's lost a bit of power and feels looser, and is vibrating more at the top of the rev range.

    Will a MadAss 50 take the same YX160 engine as a MadAss 125? Do they have 4 speed manual gearbox or a CVT auto trans like a scooter? Obviously if you fit a larger motor, you'll need a motorbike license to ride it.

    My biggest problem now, covering around 45 kays every day on my commute, is the seat. My butt goes numb within 15 minutes and by the time I get home, I've got pins and needles in both legs. The seat is angled down towards the front and you slide forwards. Plus, with no petrol tank to grip between your knees and the footpegs so far forward and the handlebars so close, you take all your weight on your coccyx. I'm thinking of putting a block of wood spacer under the front seat mount to try and lift the front, but I don't know how well this might work.

  14. hey nathan

    what are your options if you feel the motor is a bit tired?
    a freshen up rebuild?
    new engine?
    different engine?
    any mods?


  15. Well, for me it's to put a YX160 in from East 50s. At $675 plus carby, I doubt I could get the factory 120cc motor rebuilt.
    Doubling the horsepower would let me run a larger front gear and be able to cruise at 100kph comfortably as well as keeping up with faster traffic away from the lights.

  16. Mine's a 2007 model Madass 50. it's done 3500 kays, but is having problems. 2 speed Auto, but they did come in a 4 speed Manual.
    It'll do 60km/h most of the way from my place in the North Eastern Burbs to the city, little slower on the way home though.
    I changed to a thinner oil and that livened it up a bit, accelerating through the revs a little quicker.
    Does yours have the older style seat, or the newer one? Maybe get flatter/lower handlebars, that'll put more weight on your hands but less on your butt?

    At the moment though it's got problems, it's hard to start and then it will run for 2mins or so and conk out, then it's back to the hard starting and a further 2mins running time. It now hates hills and conks out almost as soon as it faces a hill. Top speed now only 45km/h.
    Does anyone have any ideas as to what it might be?
  17. I have recently picked up a Madass 125 from FX Powersports in Brunswick.
    They have put a better intake and carby on for me, however I was wondering if there is any way of easily putting in a fuel gauge.
    I noticed that when the bike is first powered on that there is a gauge LCD display on the left. Is it possible to get this activated?
  18. Just use the odometer.
    My 50cc will do 150-160km on the 4.5l tank.
    Your 125 will probably do the same or more on the 5.1l tank you have because you have a 4 speed gearbox.
    Fill it up, reset the ODO and ride it till you have to go on reserve, then make a note and make sure to fill up on time!
    It'll be too hard to install a gauge, you'll have to mount a float etc. and make room for wiring. Even a warning light would be too hard because you couldn't use any form of switch apart from a float.
  19. Guys, the MadAss, like most genuine motorbikes, is equipped with a reserve fuel feature. There's a fuel tap on the lower left of the frame, you simply ride with this in the down position for normal riding (arrow pointing up but main tab of the handle facing down). When you feel the bike starting to run out of fuel (hesitant pickup, followed by no power) flick the fuel tap all the way around to up, keep the throttle open and she'll go for another 20 kilometres on the remaining fuel. This is the time honoured method on a motorcycle, coupled with using the odometer to record general distance.

    My 125 goes for around 160-175 kilometres before hitting reserve, which includes half of that distance running at 80-85 kph (using more fuel than at 60kph due to higher revs)

    It's also a good idea to get into the habit of turning the fuel tap off when parking the bike for any length of time, because a gravity fed fuel system like the MadAss employs can leak when the tap is left on, flooding the motor and making starting very difficult. Perhaps this is your whole problem with the 50?