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Compression help after PMA swap

Discussion in 'The Garage' started by Braux424, Oct 18, 2017.

  1. Braux424

    Braux424 XS650 Member

    Hello everyone! I'm new to this site and, in fact, pretty new to riding as well. So, I have a problem I hope you can help with.

    I have a 1981 XS650SH that rode beautifully apart from it's typically lazy charging system. I bit the bullet and installed a new PMA from xs charge. Since I put the new coil and flywheel on, the compression on the engine is really erratic. If I try to kick-start it the lever gets thrust back into my foot. Not fun. It seems to hesitate with the electric ignition as well. Stranger still, the crankshaft continued to try to turn over even after I turned the kill switch and pulled the key! Any advice would be greatly appreciated!

    Thanks!
     
  2. hooser

    hooser XS650 Addict

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    It not compression you timing is off.
     
  3. xjwmx

    xjwmx XS650 Guru Top Contributor

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    Ever drive a car from the 70s?
     
  4. hooser

    hooser XS650 Addict

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    I grew up in the 70's , I would almost think you have the timing 180 out. left and right turned around.
    Lets start at the beginning, it ran good ,then you put a pma now it runs like shit, what to you think is wrong? go through it again,
     
  5. CoconutPete

    CoconutPete 1979 XS650 Special

    Are you measuring compression with a gauge? Compression in the cylinder shouldn't change with installation of a PMA.

    Miesha's timing is pretty spot on, but she still likes to kick me back every once in a while.
     
  6. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Your first mistake was removing the stock alternator/charging system, which is high quality, and replacing it with low quality Chinese PMA parts. Now, with the stock TCI (ignition) gone, what ignition are you using? Whichever ignition you installed, you likely have the timing set wrong, which is giving you kick back.

    You really are a newby, when you say ," typically lazy charging system". The stock charging system is only "lazy" when the owners don't do any maintenance, which means the owners are lazy.
     
  7. Braux424

    Braux424 XS650 Member

    Thanks to you all! I was talking about this with a buddy of mine who is very knowledgeable about bikes.

    We came to the same conclusion that the timing is opposite now.

    Now, retiredgentleman,
    I only have owned this bike since July, and it was well kept before me. It only has 4800 miles. The charging system IS the Achilles heel of this bike. I had done everything to the stock charging system to make it work and no dice. I even had this region's foremost expert on this bike to come look and he suggested the swap. It wasn't cheap. I used a pamco ignition and I'm getting spark. I am fully aware that I'm a newbie, and that's why I'm on here asking for help. I don't appreciate being called lazy.

    Thanks to everyone else who helped me out!!
     
  8. xjwmx

    xjwmx XS650 Guru Top Contributor

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    Blame yourself, not the bike.

    The World's foremost experts on this bike are on this board daily and they would disagree with your expert. Except for the one or two promoting kits to newbs by telling them how awful stock parts in general are :)
     
  9. Braux424

    Braux424 XS650 Member

    So, I hope I haven't ticked everyone off on this forum by now, and for those of who that I did make mad, I'm sorry.

    I have an update on the situation. I got the timing sorted out most likely. The engine turned over with the electric start and ran beautifully for about 10 seconds. I discovered a fuel delivery system issue, fixed that, and now the electric starter doesn't do anything.

    Any ideas? Could it be a missed wiring hookup from the pma swap or maybe a bad switch? The starter button only worked about 2/3 of the time before all this mess anyways.

    Thanks!!
     
  10. azman857

    azman857 '80 XS 650SG Rider Top Contributor

    Worked 2/3 of the time how? Press button nothing? Spun but not engaged? We need the facts not tidbits to help your XS....I'd start taking the RT switch group apart and clean contacts. Check solder joints. Battery well charged? I've taken the starter solenoid apart and cheaned those contacts when mine acted up.
     
  11. hooser

    hooser XS650 Addict

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    And Retired this is what they get into.
    Common problem with the 650, search starter not engaging in the forum and you will find your answer.. I am sure there are post with pic.s be easier then me trying to explain. gary
     
  12. hooser

    hooser XS650 Addict

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    Common problem with the 650, search starter not engaging in the forum and you will find your answer.. I am sure there are post with pic.s be easier then me trying to explain. gary
     
  13. Braux424

    Braux424 XS650 Member

    Thanks, guys
    When I said that the switch worked only part of the time, I mean I would press it and absolutely nothing would happen. No sound, no buzzing, nothin. The battery is fully charged, until I try to use the starter button, which virtually drains the charge. Again, it ran for a brief time since fixing the timing issue, but then died. I can't even kick it over after the PMA and ignition swap. Is it possible that it blew a fuse or relay? There was an entire wiring harness that became "obsolete" when installing the new systems, but I'm beginning to think that the lack of wiring is a big problem. I'm getting a tad bit frustrated at this point, and really appreciate all the help!
    The idea of getting in and cleaning the solenoid is good. I'll do the search that Gary has suggested. Hopefully this is just a small issue.

    Thanks!
     
  14. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Braux;
    You're very typical of someone new to these old bikes. You found a bike that is in running condition, but is having charging problems. You should have spent time studying the electrical system to find out why there was no charging. It may have been as simple as a few corroded connections or worn brushes in the alternator. With the bike having only 4800 miles, that means the stock alternator, stock rectifier/regulator and stock TCI (ignition) all have almost no wear on them. These parts last for 40,000 or 50,000 miles quite often, with the only maintenance needed being to replace brushes every 4000 or 5000 miles, which takes 10 minutes to do.

    Spending a lot of money on new parts, is a waste of money, without knowing what the root cause of the problems. Your so called
    "expert" knows very little about these bikes. A Pamco ignition is a very good ignition, but there was no need to spend that money if you had stayed with the stock alternator and the TCI.

    I recommend you do some resistance measurements of the stock alternator stator and rotor. If you find the stator and rotor are in working condition, then you should remove the PMA and put the stock alternator back on the engine. Clean the slip rings and install some new brushes. Re-install the stock rec/reg and the original wiring harness. You had a working TCI, so re-install that as well. Once you have things back to stock, the lads on this site will help you sort out why the charging system was not working. It should be easy to solve that.

    If all goes well you could sell the Pamco or keep it as a spare.
     
  15. Braux424

    Braux424 XS650 Member

    Retired, I really appreciate you reaching out to help me. I felt that I did everything to preserve the stock charging system, I studied the manuals, tested all connections, replaced the brushes, etc. I most likely jumped the gun on replacing parts, you're right, but it's what seemed logical. I probably should have gotten on this forum before doing anything.

    Thanks for the help!
     
  16. XSLeo

    XSLeo XS650 Guru Top Contributor

    On your starter, it's a simple system. From the battery you have the big cables to the relay. At the relay try jumping from the big studs that the cables hook to with a pair of screwdrivers. Touch one screwdriver to each stud, touch the shaft of each screwdriver together. This bypasses the starter relay. If your starter turns and engages the engine then you know all that's good.
    This leaves the relay and it's connections to test.
    With a multi-meter set on the 20 volt dc scale, key switch and kill switch in the run position, check the red white wire on the relay for power, it should be very close to battery voltage. If so you can try jumping the blue white wire to ground. With power to the red/white wire and grounding the blue/white wire should crank the starter.
    If no power on the R/W wire you will have to back track along this R/W wire to find where it lost power. Could be a fuse, maybe the safety relay, or a bad connection.
    If the start cranks by grounding the B/W wire, move up the right side switch housing. Remove it from the bars and check the condition of the wires and push button. The push button grounds the B/W wire to the switch housing, Then the ground path goes from housing to bars, over to the left side to the left side switch housing where a black wire carries the ground down into the harness ground in the headlight bucket.
    Now when you open the right side switch housing you can try jumping from the B/W wire to ground, This should crank engine, If it does the push button and ground path need work. If not you need to check along the B/W wire for breaks.
    There can be more to the starter system depending on just what was on your bike. The later models had switches and relays. Hooked to the side stand, clutch switch and neutral light that would prevent the starter from working or stop the engine under certain conditions.
    A lot of us bypass these "safety features" to help avoid the problems these systems cause as part fail.
    Leo
     
  17. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Yes, you should have asked questions on this forum before buying expensive new parts. Thousands of new comers to the XS650 have repaired their stock charging systems, with help from this site, and it cost very little. There are several excellent threads that go step by step on how to trouble shoot and get your electrical up to 100%. It takes time and effort to bring back an old bike that has been neglected for decades.

    Lurking on the internet, are many websites that trash talk the stock electrical charging system, and offer the "amazing" PMA as the world's best solution. They take advantage of all the new comers, as they make large profits selling inferior Chinese parts.
     
    hooser likes this.

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