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Vroom's 79 Build Thread- scrambler/brat?

Discussion in 'The Garage' started by Vroom4, Dec 8, 2012.

  1. Vroom4

    Vroom4 XS400 Addict

    I know it's been a while since I last posted here, but the XS left me stranded on i95 this morning and I figured I would share. I had a fully charged battery, she started up from cold. I was even able to use the electric start. No problems there.

    I get her warmed up and take off. All is well and I hop on the freeway for my short commute. About 4 miles in I notice the power fading... I've felt this before and knew what was going on. Battery was drained:doh: Even riding at 60mph at 5.5k she still drained... I get on the gas and make my way over to the exit. She's dead and coasting before I can get down the off-ramp.

    Luckily I have a short commute and my office is close to i95. I walked her to the parking garage at my work and there she sits...

    I gotta get that reg/rec combo unit in asap... if that doesn't do it, idk where that leaves me:shrug:

    Sorry for the rant... this all just happened.
  2. volcomskater77

    volcomskater77 XS400 Chopophile Top Contributor

    i replace my voltage regulator and battery as a pair. about every 5 months of riding or so. im pretty sure my stator is the culprit. reg/rec is more of a band-aid for mine. idk if youve done the diagnostic check, but i would test your stator before, and after you replace the reg/rec. your stator might be masked by failing reg/rec as well. worth a shot.
  3. Vroom4

    Vroom4 XS400 Addict

    So I have a reg/rec combo unit I plan on wiring in this weekend. When I last tested the system, it was generating 13-14 volts, so I thought I was good with the stator? I'll need to check over everything again and see how it goes from there.

    Getting it home should be interesting. I'm thinking about recharging my battery tonight and doing a mad dash home tomorrow morning with all the lights off...
  4. Vroom4

    Vroom4 XS400 Addict

    Okay, so here goes...

    Finally hooked up the new reg/rec combo unit. I used the oem plugs & soldered to the reg plug wires and rec plug wires separately.

    Soldered everything and it hooked up as follows:

    Rec plug:
    3 whites to 3 whites
    1 red to 1 red
    1 black to 1 black(combined with reg black)

    Reg plug:
    1 green to 1 green
    1 brown to 1 brown
    1 black to 1 black(combined with rec black)


    I also put a small razor on a string right up against the stator case.

    Still not charging...:banghead:

    So i do preliminary tests again:
    - Stator: 0.7 ohms across all 3 white wires at both the direct stator plug as well as the harness plug to the rec. - Check
    - Field Coil: .4 ohms between the green and black wire at both the direct field coil plug as well as the harness plug to the reg. - Check
    - When i turn the key to the on position, the razor bounces a lil the sticks to the case. Also if i jump the green and black from the field coil directly to the battery with clips it does the same only stronger(i only did it for a quick second btw). So there is magnetism
    there. - Check

    Turn it on again, no charge. Try jumping the field coil manually from the battery, still no charge. Also, when I tried this a couple times, the reg/rec unit got fairly warm. That has to mean it was getting some power into it right? Im at a loss here...:doh:

    I unplug the stator from the harness and try to measure output in DC directly from 2 of the white wires, but I'm not sure which setting to use on my meter for this.

    Not sure where to go from here...
  5. BBS360

    BBS360 XS400 Guru Top Contributor

    Before the rectifier you should us the AC setting on your meter, after the rectifier use the DC setting.

    That's as far as my expertise goes, but I would not think it's a good idea to run the bike with any of those components disconnected.
  6. Vroom4

    Vroom4 XS400 Addict

    Thanks for the note, I had meant to write AC. I'm going to give it another go in a few minutes...
  7. Vroom4

    Vroom4 XS400 Addict

    Still no luck:banghead:

    Can't get it above 11.9v with the bike running. Battery returns to 12.6 after turning it off, so i don't think it's the battery.

    I also added an extra ground connection to the black wires at the unit. Maybe I shouldn't be connecting the black wires together??

    Also, I want to clarify that I wired the reg/rec into the location of the oem units. The new unit isn't supposed to go directly to the stator and field coil right?

    I feel like I'm going in circles at this point...:wtf:
  8. Jessechop

    Jessechop XS400 Member

    I would check continuity from plug to plug on you reg/rec to the stator. Possible broken wire in there some where
  9. unitedhow

    unitedhow XS400 Addict

    When I replaced my VR it wasn't charging though everything was in spec and someone suggested that I hadn't grounded it well enough. So I tried grounding it better and after that it's been working like a dream. I don't know if it'll help but it's free to try and helped me. hope it's something that easy for you too.
  10. volcomskater77

    volcomskater77 XS400 Chopophile Top Contributor

    ^ word
    ive been thinking one of those braided cables from the mounting hole to another ground point on the frame might help my issues as well. might be worth a shot
  11. Vroom4

    Vroom4 XS400 Addict

    Okay, so I've gone through the harness and fixed what I think may have been a bad ground. I tested the black(ground) wires at both the reg and rec plugs and both seem to read perfect against the battery. I also tested my new reg/rec and it seems like it's flowing both ways on the test, which would be a fail. Maybe I ruined it when jumping the field coil directly to the battery??? Idk though...

    I think I may wire both the oem reg and rec back in just to see what happens. Then eliminate one or the other one at a time.

    Hopefully this helps me trace it down. This is just taking forever because I get to it once a week and feel like im always starting over :doh:
  12. Vroom4

    Vroom4 XS400 Addict

    So I wired the oem reg and rec back in. Crazy enough it charges, but only at 12.3v @3k rpm. Not where it needs to be, but a step in the right direction. I took it for a spin around the block and it died again, so not enough to keep it going at idle.

    Next I'm going to wire the oem headlight cutoff switch back in. See what that does.

    Does anyone know where I can buy those little spade and connectors that go into the oem block connectors??? I'd really prefer to solder those and be able to swap them out than having to cut and re-solder wires for every time Im testing something new!!!
  13. BBS360

    BBS360 XS400 Guru Top Contributor

  14. Vroom4

    Vroom4 XS400 Addict

  15. BBS360

    BBS360 XS400 Guru Top Contributor

    Off the top of my head I think that seller on Amazon, uxcell, is one of the ones I bought from on EBay.

    I believe most of the stock connectors are probably 2.8mm for the wiring harness. Headlight H4 spades will be bigger. My little 360 doesn't have all the connections of the later bikes. Definitely double-check yours.

    I wish Radio Shack were still up here in Canada.
  16. levdir

    levdir Rounded bolt brigade

    There's no Source in BC? They've got reasonably-priced crimpers here.
  17. Sesty

    Sesty H.E. Pennypacker

  18. Vroom4

    Vroom4 XS400 Addict

    That's a pretty good price. Where do these guys ship from? I'm also wondering what other sizes are on the bike...

    I'll be measuring all the connections I can get to tonight. I'll post up what I find:thumbsup:
  19. Vroom4

    Vroom4 XS400 Addict

    Parts n More has a shipping estimate of $15 on an $8 order...ouch

    I need a different option since I'm down here in FL
  20. BBS360

    BBS360 XS400 Guru Top Contributor

    We have the Source here. Their selection is pretty bad compared to what it used to be when they were Radio Shack. Maybe selection varies by location. I rarely find what I need when it comes to components or tools. I've pretty much given up on them.

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