Moderator Airhead Posted July 16, 2009 Moderator Share Posted July 16, 2009 nope, feck knows what is going on with that wiring diagram. basically where those 6 diodes are i have just one big zener diode sat in the middle of a heatsink EDIT: BWJ, maybe this will answer your question; Back in the 60s and 70s a lot of the little bikes had these single wave rectifiers. Now most bikes have full wave rectifiers that have four diodes rectifiers and zeners dont serve the same pupose though. Link to comment Share on other sites More sharing options...
wild foamy Posted July 16, 2009 Author Share Posted July 16, 2009 rectifiers and zeners dont serve the same pupose though. i know, as i understand it the zener is a regulator, turning the excess voltage into heat so that the battery is not overcharged. what the wiring diagram is showing me and what i see on the bike are whats confusing me. such as on the diagram you can see "Regulator", wheras on my bike im pretty sure that is the Rectifier, because the zener is my regulator. fekkin czechs ¬¬ Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 16, 2009 Moderator Share Posted July 16, 2009 i know, as i understand it the zener is a regulator, turning the excess voltage into heat so that the battery is not overcharged. what the wiring diagram is showing me and what i see on the bike are whats confusing me. such as on the diagram you can see "Regulator", wheras on my bike im pretty sure that is the Rectifier, because the zener is my regulator. fekkin czechs ¬¬ Your generating 3 phases so a 6 diode rectifier converts to DC and the zener controls the voltage, just do the usual checks on the rectifier, pass one way not the other etc and if thats ok get yourself another zener, maybe from RS or somewhere ...i dunno. with the right equipment you could even check the function of the zener i suppose, just need a bench DC power supply and at the most a multi meter Link to comment Share on other sites More sharing options...
blackhat250 Posted July 17, 2009 Share Posted July 17, 2009 Steve-o (Battery was charged for testing, should have been enough to excite the alternator?) aye steve problem sorted on rd400... ....broken wire on rotor (was just rewound 1 month ago ) wire rubbed through on 100 mile trip after fitting new rotor////// Link to comment Share on other sites More sharing options...
wild foamy Posted July 17, 2009 Author Share Posted July 17, 2009 aye steve problem sorted on rd400... ....broken wire on rotar (was just repaired ) wire rubbed through on 100 mile trip after fitting new rotar////// cheers for that BH, will give mine a check over just to make sure im still on the lookout for a topbox to put a car battery in... i feel that will be so much simpler Link to comment Share on other sites More sharing options...
wild foamy Posted July 20, 2009 Author Share Posted July 20, 2009 tested the diodes in the rectifier and they are fine, but unable to test the reg as it is a pcb based unit and not a zener diode as first thought. So its got to be either that or the alternator, and i cant get it out the shed until ive rebuilt the forks and got the front wheel back on Link to comment Share on other sites More sharing options...
JimR Posted July 22, 2009 Share Posted July 22, 2009 tested the diodes in the rectifier and they are fine, but unable to test the reg as it is a pcb based unit and not a zener diode as first thought. So its got to be either that or the alternator, and i cant get it out the shed until ive rebuilt the forks and got the front wheel back on Hi Steve, you are over complexing the problem .... did you do the base no load checks ? .... nine times out of ten the Jawa suffered from bad wiring ..... green earths etc .. to change the reg is the last resort ! Regards Jim Link to comment Share on other sites More sharing options...
wild foamy Posted July 22, 2009 Author Share Posted July 22, 2009 thanks for the input jim, im at a loss with the electrics now TBH, any chance someone could explain what no load checks i should be doing?, preferably with referance to the wiring diagram as i am just tieing myself up in knotts Link to comment Share on other sites More sharing options...
JimR Posted July 22, 2009 Share Posted July 22, 2009 thanks for the input jim, im at a loss with the electrics now TBH, any chance someone could explain what no load checks i should be doing?, preferably with referance to the wiring diagram as i am just tieing myself up in knotts Hi Steve, to do no load checks ... do the following :- disconect the genni from the loom, connect the volt meter to the genni (ac don't forget) and start the bike if you have shed loads of volts from this test the genni is sound if not it needs to be thrown away !!!! I have given u the process in previous posts so just do it ... unless you need help on it . if so i'll pick the tubes up & look at your wires Regards Jim Link to comment Share on other sites More sharing options...
wild foamy Posted July 22, 2009 Author Share Posted July 22, 2009 many thanks Jim, i think last time i tried plugging a multimeter inline with the genny i was getting about 2 volts, so if the genny needs to be changed that aint a big problem, there are/were two used ones on the Jawa/CZ owners club website for £8 a pop so i'll give the guy a ring tomorrow and see if he still has them Link to comment Share on other sites More sharing options...
Chupo Posted July 25, 2009 Share Posted July 25, 2009 First to say I didn't read any of those "replys" , as far as I know all the Jawa's hawe electronic problems. The engine is same as my TS Jawa. The best solution for electronics and charging on this bike is the next: find a used alternator from some old car, we used "Fiat", because it is smallest; place it under a seat or right behind the carb, Take off rotor and stator from engine, put the small belt drive on its place,we welded it on, it easy, drill two holes on the side cover for the belt. it would solve all yours Jawa electronic problems, I can provide you some pictures in couple next days if you are willing to do this. Contact: [email protected] Link to comment Share on other sites More sharing options...
wild foamy Posted July 26, 2009 Author Share Posted July 26, 2009 thanks for the reply mate, but i would rather not drill holes in my engine cover to run an external alternator, plus my alternator also has the contactless ignition sysem bolted onto the arse end, so removing the alternator would require me to fabricate an adapter to allow the ignition system to drive from the crankshaft in place of the alternator itself... however, if i can find an alternator with the same mounting pattern as my existing one that will fit inside the cover without needing to cut it up and i am able to drill the end of the shaft, tap it and use that to run my ignition system that would be ideal. maybe a trip down the scrapyard is in order, maybe rob one off the rideon mower... any chance i could use the rotor out of another alternator?, im assuming that is the faulty part as the stator windings are intact and have the correct resistance reading but thankyou for your reply nonetheless Link to comment Share on other sites More sharing options...
wild foamy Posted July 28, 2009 Author Share Posted July 28, 2009 okay, gave the bloke from the jawa owners club a ring and both the alternators have already gone ... I found the PART i need on the MZ-B website, submitted an enquiry form so im just waiting to hear back from them, alternatively i'll be on the lookout the owners club and ebay for a 640/639/638 engine to rob for spares... can't understand why my alternator has (supposedly) failed though... was getting 1ohm readings off the stator coils and 1.5miliohms off the rotor... (that's a good reading, right?) Link to comment Share on other sites More sharing options...
ShoKz Posted July 28, 2009 Share Posted July 28, 2009 when you going to be able to ride this on the road? you got a licence? Link to comment Share on other sites More sharing options...
wild foamy Posted July 28, 2009 Author Share Posted July 28, 2009 im taking my full test when im 17 (26th October) and will be able to ride that under the ">33bhp" rule. ive got my eye on a nice XJ600 though, so who knows... BTW the Jawa will no longer be known as the blue dragon, it is now to be known as "Agro" ¬¬ Link to comment Share on other sites More sharing options...
blackhat250 Posted July 28, 2009 Share Posted July 28, 2009 BTW the Jawa will no longer be known as the blue dragon, ¬¬ Now known as the blue Lagoon [ Deep bottomless money swallowing hole ] Link to comment Share on other sites More sharing options...
barkwindjammer Posted July 28, 2009 Share Posted July 28, 2009 im taking my full test when im 17 (26th October) and will be able to ride that under the ">33bhp" rule. ive got my eye on a nice XJ600 though, so who knows... BTW the Jawa will no longer be known as the blue dragon, it is now to be known as "Agro" ¬¬ I like that name, its kind of cultural Link to comment Share on other sites More sharing options...
wild foamy Posted July 28, 2009 Author Share Posted July 28, 2009 I like that name, its kind of cultural ah i get it... Agro Cultural Agricultural... ahaha... good one... Link to comment Share on other sites More sharing options...
wild foamy Posted July 28, 2009 Author Share Posted July 28, 2009 Hot diggity feckin dam! got a reply from a bloke from the jawa owners club who is selling a load of Jawa 350 parts and he has a Magneton rotor for a 640 and is going to get back to me on thursday! watch this space... Link to comment Share on other sites More sharing options...
wild foamy Posted July 29, 2009 Author Share Posted July 29, 2009 MZ-B have quoted me £296 Euros for a rotor including P&P and tax its gonna have to be a second hand unit i suppose... Link to comment Share on other sites More sharing options...
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