SecaBoy400 Posted August 25, 2008 Share Posted August 25, 2008 I recently purchased a 1982 XS 400 SECA. Ran ok for a couple weeks, then started to have the following problem. Jumped on it one morning to head for work, got about 3 blocks and seemed to have trouble keeping it running below 2500rpm. It finally stalled out and wouldn't restart. Pushed it home. After about 1 hour it started up fine, took it for a ride,, it did the same thing. I runs ok at first, but then starts having trouble running at low rpm and will bog down and eventually die, then wont restart till you let it set an hour. Seemed like a carb problem, So I pulled the carbs off, tore them completely down, they were full of rusty looking crud that had made its way into the carbs from the gastank. I cleaned everything with carb cleaner, got all the crud out. Reassembled the carbs and reinstalled. Well the bike runs better than when I first got it, especially when your getting on it hard, it runs great. But like before, it runs fine when you first start it, ride a little ways, and it starts having trouble running at low rpm, starts bogging down like its really rich, then will die. Just a note, when I first started to tear into it, I noticed that the air cleaner was soaked in gasoline. Any way, i've changed out the spark plugs, I've pulled the carbs off a second time and went completely through them again, everything was clean and looked ok, I cleaned out the gas tank, checked out the vacumme thingy in the petcock, and replaced the fuel filter. So, take it for a ride !,,, Does the same thing, not quite as quickly, but it will still start bogging down when you stop for a light or stopsign, and it will start to bog down unless you keep it revved up above 2000 to 2500 rpm. I'm stumped ? Any ideas ? Any idea where I could get some tuning information for the Mikuni carbs ? Or a service manual for this bike ? I really need to get this thing running, I bought it to commute to work so I could save gas, instead of driving my truck. Thanks Scott Link to comment Share on other sites More sharing options...
billa65t Posted August 25, 2008 Share Posted August 25, 2008 Hi there, Sounds more like an electrical problem,more likely one of your coils is breaking down when it gets hot then when it cools down will work again. Take it for a ride then when it stops put a spare plug in the HT lead earth it out and turn the motor over and see if you have a spark, then you will know ? Hope this helps Regards Bill Link to comment Share on other sites More sharing options...
SecaBoy400 Posted August 25, 2008 Author Share Posted August 25, 2008 Thanks Bill, I'll give that a try ! I was wondering if there wasn't some kind of electrical thing going on, since i've cleaned the carbs twice, and because this problem started all of a sudden. The dirt in the carbs i'm sure took some time to accumulate. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 25, 2008 Moderator Share Posted August 25, 2008 I answered another post earlier like this, so i'll repeat it for this Well were all coming up with different ideas Ive got three for the mix 1 ) You are developing vacuum in your tank as the fuel is used up, maybe a trapped vent line. To check for this run the bike with the fuel cap loose and if its ok check for trapped vent line. 2 ) Faulty vacuum diaphragm in fuel tap (Petcock), Try running in Prime position, if its ok sort out vacuum diaphragm, dont continue to use prime position as a fix though! 3 ) If the above dont fix it, maybe ypou fuel filter is blocked, To check remove the fuel line to the carbs, switch to prime position, there should be a good flow of fuel. (Definitely a no smoking operation) Good Luck Link to comment Share on other sites More sharing options...
mikemanray Posted October 8, 2008 Share Posted October 8, 2008 hey dude, I have the same exact bike, and the same exact problem. It's been annoying the crap outta me and I still haven't resolved it. However, I do think I have an issue with my left spark becoming weak once the bike warms up (and the dirty plug doesn't help). The two combined make it so I stall at every stop sign, and have trouble restarting. The funny thing is...it stalls much worse under hard braking. if I coast down it isn't nearly as bad; and I know that the brake light isn't stealing current from the coils because I've tried it with the brake light disconnected. Have you noticed if this happens to you? Oh, also, I have the service manual as a PDF; but it's 80MB so if you'd like to do a direct file transfer over AIM or something similar then I'd be happy to. Let me know Link to comment Share on other sites More sharing options...
buckshotbob Posted June 27, 2009 Share Posted June 27, 2009 I bought a 82 seca, 400 xs400RJ for my son and am having ignition probelms. Can't find a manual, bought a Haynes only to find out is does not cover this bike. Can I get a copy of your PDF or does anyone have the electrical diagram on this bike? Link to comment Share on other sites More sharing options...
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