kmac Posted July 31, 2009 Share Posted July 31, 2009 I upgraded the ignition on my 78 xs400 from points/condenser to electronic ignition using parts from 80 & 81 machines. Nice blue spark now dancing on each plug. Problem is, I don't know which coil plug goes to each coil. I have 3 different manuals (including yamaha) and all have same wiring diagram. None show which cylinder coil connects to which plug (one with orange lead, one with grey lead). I have a 50/50 chance, but before I fire it up, I thought I would ask if anyone could tell me which one is which. Does plug with Orange lead go to the left cylinder? Thanks & Cheers... Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 1, 2009 Moderator Share Posted August 1, 2009 I upgraded the ignition on my 78 xs400 from points/condenser to electronic ignition using parts from 80 & 81 machines. Nice blue spark now dancing on each plug. Problem is, I don't know which coil plug goes to each coil. I have 3 different manuals (including yamaha) and all have same wiring diagram. None show which cylinder coil connects to which plug (one with orange lead, one with grey lead). I have a 50/50 chance, but before I fire it up, I thought I would ask if anyone could tell me which one is which. Does plug with Orange lead go to the left cylinder? Thanks & Cheers... just connect and see, it won't do any harm as the sparks will still happen just at the wrong time. I do it all the time and never bother writing down which is which. Link to comment Share on other sites More sharing options...
kmac Posted August 3, 2009 Author Share Posted August 3, 2009 just connect and see, it won't do any harm as the sparks will still happen just at the wrong time. I do it all the time and never bother writing down which is which. Thanks! I did that and found out that orange goes to the left cylinder. I upgraded the exhaust with a 2 into 1 exhaust and didn't want to damage it. I probably couldn't hurt it if I wanted to. So it did fire up and works well...with the choke full on. I had the carbs cleaned and rebuilt by someone else. But I don't think that they did a thorough job. The bike had been sitting idle (indoors at least) for about 24 years and was gunked up pretty good. Between having a free-er flowing exhaust and some partially plugged jets, I still have some work to do. I've replaced all the rubber and most of the seals. Could be a leaky head gasket. But I don't think it could leak that much. I'm betting on a crappy carb rebuild and some rejetting to get her right. Its ok. Wanted to rebuild them myself anyway. Just didn't have time. Now...I will make the time. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 4, 2009 Moderator Share Posted August 4, 2009 where they ultrasonically cleaned? its amazing what comes out of "cleaned" carbs, we had a thread last year where the guy swore blind his carbs were clean ( till he saw the light) Link to comment Share on other sites More sharing options...
kmac Posted August 9, 2009 Author Share Posted August 9, 2009 where they ultrasonically cleaned? its amazing what comes out of "cleaned" carbs, we had a thread last year where the guy swore blind his carbs were clean ( till he saw the light) Not sure. They were cleaned in a solvent bath I know. Could smell solvent and exterior oxidation was removed and they looked quite good. But don't know beyond that (a long and disturbing tale of outsourcing carb repairs that you should do yourself). I think some 25 year old gunk is still in passageways. I am getting a used ultrasonic soon. Big enough to clean one carb at a time. Will give that a go. Also, I read in another thread that fishline works well for those hard to reach places. I had bought a xs400 engine from a guy off of craigslist a few months ago for cheap that included carbs. He had said that a high school student had rebuilt the carbs some years back. Tried not to roll my eyes as they didn't look like they had ever been off the bike. But...now...I decided to remove them from the spare engine, drop the float bowls and take a look. Clean. They had not been boiled out but at least they had not been sitting around for many years with old gas in them. Not sure what the kid did to rebuild them. After installing them on my bike's engine, and turning over...a few snorts and pops (old dust??), it fired up and ran pretty well after the engine warmed up. They too will need to be ultrasonic'ed. But at least I know that dirty carbs are my main problem. Link to comment Share on other sites More sharing options...
Cy Welch Posted August 9, 2009 Share Posted August 9, 2009 Not sure. They were cleaned in a solvent bath I know. Could smell solvent and exterior oxidation was removed and they looked quite good. But don't know beyond that (a long and disturbing tale of outsourcing carb repairs that you should do yourself). I think some 25 year old gunk is still in passageways. I am getting a used ultrasonic soon. Big enough to clean one carb at a time. Will give that a go. Also, I read in another thread that fishline works well for those hard to reach places. I had bought a xs400 engine from a guy off of craigslist a few months ago for cheap that included carbs. He had said that a high school student had rebuilt the carbs some years back. Tried not to roll my eyes as they didn't look like they had ever been off the bike. But...now...I decided to remove them from the spare engine, drop the float bowls and take a look. Clean. They had not been boiled out but at least they had not been sitting around for many years with old gas in them. Not sure what the kid did to rebuild them. After installing them on my bike's engine, and turning over...a few snorts and pops (old dust??), it fired up and ran pretty well after the engine warmed up. They too will need to be ultrasonic'ed. But at least I know that dirty carbs are my main problem. It also could be the butterfly seals since you say it was solvent cleaned. If the person doing the cleaning used carb cleaner and imersed the whole carb in the cleaner then the butterfly seals are probably ruined and need replaced. I believe MikesSX has the seals, you need to ones made for the 34 mm carbs which is what the 400 uses. If they are ruined that would cause the mixture to be so lean that it would only run on full choke quite easily. Link to comment Share on other sites More sharing options...
kmac Posted August 10, 2009 Author Share Posted August 10, 2009 It also could be the butterfly seals since you say it was solvent cleaned. If the person doing the cleaning used carb cleaner and imersed the whole carb in the cleaner then the butterfly seals are probably ruined and need replaced. I believe MikesSX has the seals, you need to ones made for the 34 mm carbs which is what the 400 uses. If they are ruined that would cause the mixture to be so lean that it would only run on full choke quite easily. Thanks, will check that out for sure! Very possibly the problem. Probably won't get to it until this winter. Love the MikesXS.com site. Bought a stainless brake caliper piston there that works in xs400. Nice. Link to comment Share on other sites More sharing options...
pezak Posted September 11, 2009 Share Posted September 11, 2009 I don't suppose you have the parts list for the ignition swap? Link to comment Share on other sites More sharing options...
kmac Posted September 11, 2009 Author Share Posted September 11, 2009 I don't suppose you have the parts list for the ignition swap? To upgrade my xs400e I used parts from 80 or 81 xs400 machines: o Pickup coil - 4R4-81671-10-00 o Rotor 3F9-81673-10-00 (will need longer bolt) o Ignitor assembly 4R4-82305-10-00 o Ignition coils 2F3-82310-60-00 (you could use aftermarket high energy too) o Ignition cover: 3F9-11157-00-00 (yep, your points cover is too shallow) You can get part numbers from: http://www.yamaha-motor.com/sport/parts/home.aspx If you want to make installation easier, get these too: o Battery box - Ignitor mounts on the bottom. Easier than adapting old one. o Wiring harness - untape an 80/81 xs400 wiring harness and lift out the wiring for the ignition coil plugs, ignitor plug and the pickup coil plug. One snip each for power and gound and you have all the wiring and plugs to add electronic ignition to your bike. o xs400G Wiring diagram. After you remove the points and condensor, there will be a red/white power connect left hanging. Use that to power your new circuit. It comes right off the kill switch. Add a connector to ground wire and find a place to bolt it onto the frame. Make sure you have a good battery. You're adding more load and you want to keep your voltage up when using electric start. Mikesxs has a maintenance free battery I have ordered but not gotten yet that has 170cc amps. Some ebay sellers say that the ignitor box from 82 works as well. But that is the year the xs400 went to DOHC. Don't know if that makes a difference, but I just kept looking if it came from an 82. There was very little or no retooling to the cylinder head from 79 through 81 so parts will fit nicely. Don't forget to set timing. Most parts are no longer available from Yamaha. But everything can be found on ebay with patience. I suggest getting spares if you go ahead with it. Have fun! Link to comment Share on other sites More sharing options...
Moderator drewpy Posted September 12, 2009 Moderator Share Posted September 12, 2009 good one, i'll copy and paste the info into the sticky for xs400's drewps Link to comment Share on other sites More sharing options...
Runningdog Posted October 14, 2009 Share Posted October 14, 2009 Good topic...I just picked up a '78 XS400E, and was thinking that electronic ignition would be one of the first improvements I would attempt. I spent far too much time fartin' around with the timing and ignition on my '77 DT250, and swore that all future project bikes would be breakerless. Question #1 was if the CDI from a newer 400 would work...well, you've answered that for me. Thanks again for stepping in front of the (mis)firing squad for the rest of us..... Link to comment Share on other sites More sharing options...
(Graham) Posted May 13, 2010 Share Posted May 13, 2010 just connect and see, it won't do any harm as the sparks will still happen just at the wrong time. I do it all the time and never bother writing down which is which. Hey drewpy, I've been having issues starting after reassembling the bike. I am getting spark and gas.. it never occurred to me that the the coils could be wrong. That would mean spark at the opposite time which makes sense because my bike isn't even thinking about starting just getting occasional backfires after running the starter a while. I thought I had read somewhere the HT wires cross over but that is not how I currently have it rigged. I'm gonna switch them and see what happens - nothing to lose! Link to comment Share on other sites More sharing options...
Moderator drewpy Posted May 13, 2010 Moderator Share Posted May 13, 2010 Hey drewpy, I've been having issues starting after reassembling the bike. I am getting spark and gas.. it never occurred to me that the the coils could be wrong. That would mean spark at the opposite time which makes sense because my bike isn't even thinking about starting just getting occasional backfires after running the starter a while. I thought I had read somewhere the HT wires cross over but that is not how I currently have it rigged. I'm gonna switch them and see what happens - nothing to lose! I did it again last week, it backfires when its wrong way round. go for it.... Link to comment Share on other sites More sharing options...
armyofda12mnkeys Posted May 14, 2010 Share Posted May 14, 2010 Coincidentally i got this email today replying about a xs400 electronic ignition kit I asked about a month ago: Dear Sir, The (1978) XS400E needs the CKT-YAM4 Newtronic kit. At the moment this kit is not in manufacture but should be available later in the year. Please check our website for product updates or visit our eBay shop for product availability. Your sincerely, Autocar Sales Support www.autocar-electrical.com just in case someone wants to try a prebuilt ignition vs using other parts as noted above Link to comment Share on other sites More sharing options...
(Graham) Posted May 20, 2010 Share Posted May 20, 2010 I did it again last week, it backfires when its wrong way round. go for it.... Just an update, cleaned the carbs out some more, reassembled, switched the wires over, and it started up like a champ!! Just took it out for a 200km scoot, everything seems good. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted May 20, 2010 Moderator Share Posted May 20, 2010 ride on G Link to comment Share on other sites More sharing options...
Guest harhar Posted May 23, 2010 Share Posted May 23, 2010 I upgraded the ignition on my 78 xs400 from points/condenser to electronic ignition using parts from 80 & 81 machines. Nice blue spark now dancing on each plug. Problem is, I don't know which coil plug goes to each coil. I have 3 different manuals (including yamaha) and all have same wiring diagram. None show which cylinder coil connects to which plug (one with orange lead, one with grey lead). I have a 50/50 chance, but before I fire it up, I thought I would ask if anyone could tell me which one is which. Does plug with Orange lead go to the left cylinder? Thanks & Cheers... Hi there, I was wanting to change over my 79' yamaha 400xs to electronic ignition but I couldn't find out how anywhere. Could you please e-mail me at "levi.megenbir @ gmail.com" and let me know how you did it, with what parts etc? Thanks so much. Link to comment Share on other sites More sharing options...
kmac Posted May 23, 2010 Author Share Posted May 23, 2010 Hi there, I was wanting to change over my 79' yamaha 400xs to electronic ignition but I couldn't find out how anywhere. Could you please e-mail me at "levi.megenbir @ gmail.com" and let me know how you did it, with what parts etc? Thanks so much. I think drewpy pinned the instructions and parts list in 'xs400 links'. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted May 24, 2010 Moderator Share Posted May 24, 2010 I think drewpy pinned the instructions and parts list in 'xs400 links'. i did, but peeps CBA looking Link to comment Share on other sites More sharing options...
kmac Posted May 24, 2010 Author Share Posted May 24, 2010 Sorry! Got it and responded. Must have had the wrong goggles on. Link to comment Share on other sites More sharing options...
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