solway19 Posted July 26, 2015 Report Share Posted July 26, 2015 Hi, In the final stages of rebuilding my MAR and need some advice on magneto's. It is road registered however it only has the 3 wire ignition only magneto. Previously there was just a battery for the lights mounted on a homemade side panel. I am wanting to keep it original so had to do away with the battery. I have been looking for a magneto/alternator all over for a few weeks now with no success. Can anyone help and point me in the right direction? Pic attached to share Thanks Mark Quote Link to comment Share on other sites More sharing options...
woody Posted July 26, 2015 Report Share Posted July 26, 2015 The stator that is ignition only has only two wires, blue and black. The stator that includes wiring for lights and horn etc has more than three wires ( five, maybe six, can't remember as never had lights wired up) So if yours has three it's more probable that it does have lighting but the wires have been cut right back behind the stator. Your bike looks like a MK2 (with MK1 forks) and from the MK2 I think they generally had lighting stators fitted. If you're thinking of buying another stator you need to ensure it is compatible with your flywheel as they changed the timing point somewhere around '74 and with the piston at TDC some stators have the timing point at around 8 (on a clock face) and later ones at around 4. By timing point I mean the hole in the stator and flywheel that have to line up with a timing pin which indicates the firing point.Use the wrong combination and your timing will be way out. Stators and complete ignitions come up on ebay from time to time. There may even be a modern full replacement ignition which Steve Sell may have (search forum for contact details) but I don't know if it would include lighting. Also worth rerouting the wires out through the front of the crankcase if not already done. The reason a lot of wires have been chopped back is that the loom is quite thick with all five wires and where it exits under the engine it was common for the bashplate to get hammered out of shape by rocks which caused it to bend upwards and squash and break the wires. It was also a 90 degree bend which didn't help and as the wires became brittle with aging they could crack and short out. Rerouting through the front of the case solves all of those problems. Search the Ossa or twinshock forums and you'll find info and maybe pictures on the mod. Bike looks nice but if you're going to use it, those mudguards are really fragile. I had two of the front mudguard stays break on mine first time out. Look great for an original build but maybe not so good to ride with. 1 Quote Link to comment Share on other sites More sharing options...
solway19 Posted July 26, 2015 Author Report Share Posted July 26, 2015 Thanks woody. Sorry I made s typo, it only has 2 wires. From what I can find no other bike stators fit, is this correct? I have tried calling Steve but can't get through so left a message late last week. Yes I hear your point regarding the mudguards, I have kept the brackets for plastics that came on it. It is a mk2 1975, out of interest what is the difference with forks? Thanks again Quote Link to comment Share on other sites More sharing options...
solway19 Posted July 26, 2015 Author Report Share Posted July 26, 2015 Just looking at pictures of forks, looks like mk2's should have double pinch bolts where mine are single which I guess are mk1's like you say woody. Wish i had known before spending hours rubbing and polishing Quote Link to comment Share on other sites More sharing options...
woody Posted July 26, 2015 Report Share Posted July 26, 2015 Have a look at the catalogue pictures here http://www.ataq.qc.ca/galerie/index.php?folder=/Mus%E9e/Ossa/ Yours has the 1972 MK1 forks, the '74 bike has the MK2 forks. Only difference really is the legs, the way they are shaped around the spindle. MK1 forks take a longer spindle too. The action is the same on both although by '74/75 the damper rod piston had a fibre seal around it to help control oil flow, earlier betor forks didn't (Bultaco was the same) The earlier piston, once worn will let oil past whereas on the later piston you can install a new fibre ring made from PTFE card. As far as I remember a Bultaco stator will fit as will the flywheel You could always send your stator to Motoplat UK for a refurb which would include new wiring. He's been doing them for years. I had two done years ago - no issues, work perfectly. http://www.uk-motoplat.com/home.html If you leave Steve Sell a message make sure you don't have your number blocked as he won't respond to incoming calls / messages with unknown numbers. He's also busy with his day job as the Ossa work is a hobby, not a job. 2 Quote Link to comment Share on other sites More sharing options...
woody Posted July 26, 2015 Report Share Posted July 26, 2015 (edited) Just looking at pictures of forks, looks like mk2's should have double pinch bolts where mine are single which I guess are mk1's like you say woody. Wish i had known before spending hours rubbing and polishing Nothing wrong with the MK1 forks - see above. When they moved from the MK1 to the MK2 it wasn't unusual for some early MK2 bikes to still have a few MK1 parts like cylinder head and / or cylinder. Yours may even have come with those forks if it's an early model. You only have to change the legs if you feel the need, MK2 legs will go straight onto your stanchions. Just need the right spindle and MK2 only has one spacer on opposite side to brake Edited July 26, 2015 by woody Quote Link to comment Share on other sites More sharing options...
twinshock giles Posted July 27, 2015 Report Share Posted July 27, 2015 Just a quick question for Woody, was a decompressor factory fit? I've had bikes with them, but also have some with a blanking bung or an undrilled space where the decompressor usually fits. Not that it makes any difference to anything I was just curious. Quote Link to comment Share on other sites More sharing options...
woody Posted July 28, 2015 Report Share Posted July 28, 2015 Don't know for sure, I don't think so as I never saw a new one with one fitted. We used to pile into a shop called Bruce's Motorcycles every Saturday morning. It was only a small place on the opposite side of the road from the famous Vale Onslow emporium and we'd just gawp at the selection of beautiful shiny new MARs lined up in the showroom. Never actually saw one in Onslow's but they had just about everything else you could name. Happy days Back on topic, every cylinder head I've seen has two plug holes so I guess they came like that from the factory with the second hole fitted with a blanking plug Quote Link to comment Share on other sites More sharing options...
solway19 Posted July 28, 2015 Author Report Share Posted July 28, 2015 Thanks a lot for your help woody, I will contact motoplat UK. Quote Link to comment Share on other sites More sharing options...
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