MadAss 500

MadAss Mods

Hi All, I have been modding my MadAss 125 to get the best performance out of it and have found two way's to go about it. The way to do it depends on what you want and the pro's & con's of either way. The first way is to keep the original 120cc Lifan engine(it is not a 125)and put a 141cc big bore kit and 26mm Mikuni carb with angled inlet manifold and pod filter, then a power pipe and front&rear sprockets of 15 & 39 respectively. You can mod the head & cam if you want but that then starts to move the power up higher in the range and becoming cantankerous it is best to keep head and cam standard as the head is the 23/27 BVH(big valve head) and the cam is suited to the stroke and every day riding. The bore is taken out to the maximum of 57mm which is up from the standard bore of 52.4mm, and the stroke is 55.5mm which then makes the motor slightly over square and gives a near perfect rod/stroke ratio of 1.02. I went one step further with the bore and had it electroplated($440.00) and put a high quality Japanese high compression piston in as well (150.00) as you can see it can get expensive. The pro's are , same engine number,same stator/rotor and electric start. cons EXPENSIVE. I then put in a YX140cc which is a performance Jialing(HONDA) and had to mod the wiring to suit the single phase stator/rotor and DC regulator/rectifier of the MadAss and then removed the 4 pin cdi and wired in a 5 pin racing cdi and an always off relay . ( I am now getting a replacement 3 phase stator/rotor to suit the YX 140 and all other horizontal Chinese Honda clones. This will then just plug straight into the MadAss wiring loom and negate any need to change any of the wiring (including the cdi) all up costs approx $600.00. pro's are simple drop in and already built to be 140cc + con's different engine number,no electric start,EXPENSIVE. I then put in a Lifan 150cc racing motor (same setup as YX140) I must mention that the YX & Lifan 150 need the engine mount bosses drilled out to 10.5mm to fit the MadAss chassis mount, The Lifan lasted 65k's and is now junk end of story (an EXPENSIVE story) I am now going to fit the advertised 18 HP YX160 with my other mods and this should be the ultimate mod as these motors are being taken out to 177cc + I have even heard of 190cc, I will have to wait to see if the Aussie dollar goes up first. Any way Cheers for now and if you want to contact me my email is brianpross1@bigpond.com