iconic558 Posted February 9, 2015 Report Share Posted February 9, 2015 (edited) 1980 320TL std: Typical having a great trial yesterday dropping but 4 on two rounds and on the 1st section of the last lap, just entering the section bike stops dead, as if I'd pulled the lanyard off....she had lost her spark After the lunchbreak when I started her she was running a bit rough, almost 4 stroking, turned her off, restarted and she was fine. Also the last few times I've jet washed her down she ran a little rough until I WD-40'd the ht lead...hmmm that was going thru my head as I started sweated cobs kicking her over. Did a few checks on the section before pushing her back in embarrassment... plug OK, points opening, took lead off cap and earthed, still no joy. Been out this morning to have a look. Just popped a new HT lead on her, disconnected kill system still no joy, no obvious broken wires, check the coil resistances and found the following: coil terminal + to HT lead 4.7k ohms coil terminal - to HT lead 4.7k ohms coil terminals + to - continuity ....not being up on magneto points ignition with AC external secondary coil, using AC voltage to generate a spark any thoughts on those readings? If I set my Fluke to AC I'm getting a voltage of some sort from the live feed from the source coil (primary) to the secondary (ignition) coil, hard to measure being AC but something is there...points not burnt either. What sort of coil do I buy?...any suggestions. any help welcome Edited March 4, 2015 by iconic558 Quote Link to comment Share on other sites More sharing options...
blocky Posted February 9, 2015 Report Share Posted February 9, 2015 Condenser 1 Quote Link to comment Share on other sites More sharing options...
lbhbul Posted February 9, 2015 Report Share Posted February 9, 2015 You probably already have added an automotive condenser under the tank and have good ground, the malady you describe screams condenser as above by Blocky. Good luck Larry Quote Link to comment Share on other sites More sharing options...
b40rt Posted February 9, 2015 Report Share Posted February 9, 2015 What they said ^^^ 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted February 9, 2015 Report Share Posted February 9, 2015 http://www.ebay.co.uk/itm/Ignition-condensor-VW-Beetle-Bus-t1-t2-1964-72-round-connector-/111309966731?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item19ea974d8b 1 Quote Link to comment Share on other sites More sharing options...
iconic558 Posted February 9, 2015 Author Report Share Posted February 9, 2015 wow, thanks guys, I'll give that a go... ...in 40 years of working around engines I've never had one go down so I'll be pleased if it is, I can join the 'bad condenser' club after all these years I always used to change the condenser when I changed points on my old cars, it was always the rule of thumb. next question....I need a puller for the flywheel...any recommendations, I see different sizes listed for Rotax lumps? 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted February 9, 2015 Report Share Posted February 9, 2015 Something like https://www.machinemart.co.uk/shop/product/details/clarke-cht698-46-piece-harmonic-balance-puller?da=1&TC=SRC-puller Quote Link to comment Share on other sites More sharing options...
dadof2 Posted February 9, 2015 Report Share Posted February 9, 2015 (edited) Originally posted that points not burnt. Burnt points are a common sign of condenser failure. If you can rig up spinning the engine with a power drill (plug out and a bit of oil squirted into bore) I would expect to see between 20 and 30 Volts AC from the source coil in flywheel. Primary on HT coil to ground / Earth should be about 1 ohm. I would expect earth on HT coil to secondary to be about 3,000 ohms so your 4,700 ohms looks as if there may be excess resistance. 4 stroking and poor starting are often signs of HT coil failure. Bit of a guess here but I would suspect source coil if resistance a long way off 200 or 250 ohm. I would think any similar single terminal HT coil of a TY, Bulto or Mont would do. EDIT - figures based on general knowledge of points systems on bikes of that era, no specifically SWM. Edited February 9, 2015 by dadof2 1 Quote Link to comment Share on other sites More sharing options...
iconic558 Posted February 10, 2015 Author Report Share Posted February 10, 2015 Cheers for that Quote Link to comment Share on other sites More sharing options...
lbhbul Posted February 10, 2015 Report Share Posted February 10, 2015 Nice bit of running around the pump looking for the handle. Please at least try, we have all been there. Have a nice day Larry Quote Link to comment Share on other sites More sharing options...
iconic558 Posted February 10, 2015 Author Report Share Posted February 10, 2015 Nice bit of running around the pump looking for the handle. Please at least try, we have all been there. Have a nice day Larry ya so right....fixed that Quote Link to comment Share on other sites More sharing options...
lbhbul Posted February 10, 2015 Report Share Posted February 10, 2015 Iconic, Hope no bad, long day. Best Larry Quote Link to comment Share on other sites More sharing options...
iconic558 Posted February 12, 2015 Author Report Share Posted February 12, 2015 (edited) Well that's just my luck, fitted my new coil after testing its resistances and all was well, the old coil had a very high resistance on the primary side and a little high on the secondary. So full of joy I looked for a spark, no joy So I checked the AC output from the magneto (alternator) and nothing at all now. Condenser as well....? Checked for broken wires and bad engine to frame earth all is well. Checked the condenser using two methods: 1/ resistance, checking on ohms for a around 20 seconds using the meter to inject volts (current), then checked for a DC voltage...nothing... 2/ 12 volt battery on the condenser terminals for 20 seconds, then connected condenser earth to positive to check for a spark, nothing... I tried to run without the condenser fitted and still nothing....I've run car engines with 12 volt DC without a condenser, big sparks across the points but get you home, but my understanding is that the AC alternator magneto will not run at all without a condenser in the circuit. So, VW condenser ordered. more to follow....if nothing else I've learnt that I thought I understood 'magneto ignitions' but didn't after all cheers guys Edited February 12, 2015 by iconic558 Quote Link to comment Share on other sites More sharing options...
lbhbul Posted February 12, 2015 Report Share Posted February 12, 2015 (edited) Iconic, We recently had the wire from the mag (Femsa) with broken insulation show up causing no end of problems,there are only a hot and a ground on a Femsa mag that are required. Did you source a flywheel puller? Aprilia & early Scorpa used Rotax engines & others I am sure. Looks like we were posting at the same time. Larry Edited February 12, 2015 by lbhbul Quote Link to comment Share on other sites More sharing options...
iconic558 Posted February 12, 2015 Author Report Share Posted February 12, 2015 Just bought a puller kit, will come in handy for other things! not my ignition week....wifes Beemer's done 2 coil packs today! They are ganging up on me! Quote Link to comment Share on other sites More sharing options...
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