waynerobshaw Posted September 21, 2013 Report Share Posted September 21, 2013 Hi All, Anyone had this one? While riding today, bike lost power and intermittently now works. With the batteries fully charged and the throttle showing full power, the rear wheel won't spin. If I lift the rear wheel off the ground and spin it by manually it will start spinning albeit a lot slower than it should be. As soon as the throttle shut off, it won't spin up again unless I spin it manually again. It sounds like motor brushes to me, but can anyone confirm? Cheers all, Wayne. Quote Link to comment Share on other sites More sharing options...
gwhy Posted September 21, 2013 Report Share Posted September 21, 2013 yes sounds like brushes.. but worst case scenario it can be a open circuit winding in the motor :-( Quote Link to comment Share on other sites More sharing options...
juanroberts Posted September 23, 2013 Report Share Posted September 23, 2013 I have had to replace a few throttles as they tend to go quite predictably after a few hundred hours of use. You can test for this by short-circuiting the throttle wires and see if the rear wheel kicks in at 100% power (be prepared by setting the bike on a sturdy stand). Its also a very cheap replacement, and I have even used many aftermarket throttles. Unless you are a highly-qualified expert, I would highly recommend that taking the motor apart be the last option, and even then after diagnosing it. I thought I would "clean" mine (I later learned it was just tired out batteries) and then had no chance of putting it back together again as its very difficult, and ended up buying a new one. Other than my mistake, the motors have always been working very well. Let us know how it goes. Quote Link to comment Share on other sites More sharing options...
betarambo Posted September 23, 2013 Report Share Posted September 23, 2013 Sounds like a motor problem to me too, but Juan is on the money. Check the cheap/easy things first. Always start with the throttle. The throttle has two connectors (assuming it is fairly modern). Find the three pin one and disconnect it. You didn't mention which size it is, but I think that most of them now have decent color coding. If you see red, black and something else then use a piece of wire or paperclip to short red to the other color (not black) while the bike is truned on and sitting safely on a stand where the spinnign wheel will cause no mayhem. It should spin like full throttle. If you color coding does not match my description then just go through them trying each combination. Make sure you do this on the bike side (controller) not the throttle side. If the wheel spins then you need a new throttle. On 12" and 16" bikes the next easy/cheap thing to check is the potentiometer that controls power. When these fail it can intermittently stop the bike. Find the wire for this and just disconnect it. A disconnected pot is the same as setting it to full throttle. I know it sounds like a motor problem but I have seen (and often been the guy doing it) many people replace motors and controllers when they just needed a throttle. Quote Link to comment Share on other sites More sharing options...
waynerobshaw Posted September 23, 2013 Author Report Share Posted September 23, 2013 Hi Chaps, Before I read your posting, I had the motor off and the bike in bits only to find the motor spun fine when wired straight to the batteries (the motor connector took some removing - the connectors were properly seized!) So, I shorted out the potentiometer (now I see I should left it open circuit), still no better. Dismantled the throttle and sprayed it with WD40...wahlah....its working! So, you we're both spot on, it would appear that the throttle was the problem! Your postings provide a few good diagnostic pointers too, so many thanks to all! Cheers, Wayne. Quote Link to comment Share on other sites More sharing options...
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