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MisterP's revival/build thread: 1977 XS650

Discussion in 'The Garage' started by MISTERPROFESSIONALITY, Aug 28, 2019.

  1. The only reason i was looking for a kit was because I have no real way of knowing specifically which parts I need and don't need, even after reading the carb guide, i don't know if i'd be able to identify exactly which parts i'd need, nor would i know when looking at a used part whether it's good to keep using or needs to be tossed. it just seemed safer to replace everything that is typically replaced and start from scratch. If i had a specific and clear list of exactly which parts I need to buy and put in, i'd gladly do that rather than buying a kit.
  2. lakeview

    lakeview XS650 Guru Top Contributor XS650.com Supporter

    As far as wiring goes, just order a new harness from Mike's, about $70.00 and you are good to go.
  3. 70? is that all? I was under the impression wire harnesses were in the hundreds. Others have expressed distrust in mike's products, can anybody comment on the reliability of the mikesxs wire harness?
  4. 5twins

    5twins XS650 Guru Top Contributor

    For the most part, reports on the MikesXS harnesses is good. There have been occasional small issues reported, like wires arranged wrong in a plug or something like that. Best you compare all the harness plugs to the component plugs to make sure the wires are in the correct spots and color matched.

    My buddy put one of these on his '80 Special II and has encountered one small issue. The headlight now comes on with the key. It's not supposed to do that. It shouldn't come on until after the motor is started and the safety relay gets tripped. For some reason, his is feeding power from the key directly to the headlight.

    The carb rebuild kits are aftermarket so the quality of the parts can be an issue. The float needle and seat assemblies are hit and miss. Sometimes they work but sometimes they leak right out of the box. My dealer stopped using them because he had too many bikes come back leaking, which he had to fix on his own dime. Best you get original Yamaha float needle and seat assemblies if they need replacing.

    The jets, as mentioned, most likely are the wrong sizes. You may not need to replace them if they're still in good shape. If the screwdriver slots in them are all buggered up by some P.O. then yes, I would replace them.The main and pilot jets used in these are just common Mikuni jets, readily available from many places.

    The gaskets in the kits are about the only thing that might be useful, if you even need them. Original float bowl gaskets are very good and can usually be re-used indefinitely as long as they're not damaged. I usually don't even mess with the choke housing gaskets. There's no need to remove the housing from the carb body so I don't disturb it. The choke plunger can be pulled out of the top of the housing for cleaning.

    Floats don't come in the rebuild kits and again, if you need replacements, genuine Mikuni ones are best. 650Central has about the best deal on them.

    So, bottom line is you'll want to disassemble your carbs first so you can determine exactly which parts need replacing, if any. I've overhauled quite a few sets without having to replace anything, just giving them a thorough cleaning.
  5. i'm seeing what you mean. I always have to make sure i have *everything* necessary to 100% complete a task before i start it, but the way you describe it, it's impossible to know what i need until i've already started it. I guess that's just how it works.
  6. lakeview

    lakeview XS650 Guru Top Contributor XS650.com Supporter

    It gets a lot less intimidating as you build up a bit of experience.
  7. Greyandridin

    Greyandridin Got nothing to do and all day to do it XS650.com Supporter

    Speedo and Tac are driven by magnet ?? I guess I learn something everyday
    Mailman likes this.
  8. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    If interested odds are I have a decent or better (used) stock harness for a 77
    Last edited: Sep 9, 2019
    Mailman and YamadudeXS650C like this.
  9. YamadudeXS650C

    YamadudeXS650C Central New York XS650 Top Contributor XS650.com Supporter

    I hope your build goes well. You are in good hands at this forum.

    A few suggestions:

    > On sealing the petcock contact surface, I make such plates out of 1/8 inch aluminum bar stock (available at your local hardware store), which is SO much easier to work with than steel. And years ago, I bought a tractor trailer mudflap; it has served a multitude of uses, since.

    petcock 002.JPG

    > As for buying tools, It has been my experience that every tool purchase eventually pays off with dividends. Ultimately, you might even realize that you have become a motorcycle mechanic. Wouldn't that be cool?

    > Lastly, I would take Gary up on his offer in a heartbeat.
    Mailman, Jim and gggGary like this.
  10. aluminum! that's a good suggestion. I was up last night cutting steel plates and hating my life. i think i'll grab some AL instead. Think i can buy a mudflap from Auto Zone?
  11. YamadudeXS650C

    YamadudeXS650C Central New York XS650 Top Contributor XS650.com Supporter

    I imagine so. Or Walmart; look in various other departments for similar inexpensive rubber products. Probably could find a children's bicycle inner tube for real cheap, or try kitchen products.
    I get thick second-hand truck tire inner tubes for free at the corner garage. They toss them out.
    Bicycle repair shops throw out used bike inner tubes. Just ask nicely.
    59Tebo likes this.
  12. solved the issue of sealing the tank by just purchasing an inner tube for a wheelbarrow. it was the cheapest bit of rubber i could find anywhere.

    So, i've completed the process of filling the tank with acid, soaking it, rinsing it out completely with baking soda and distilled water, drying out the tank with a heat gun, and trying to coat the inside of the tank with POR15. results are iffy. I certainly got a whole lot of the rust out, and it was very clean inside at first. After that it was a race against time to prevent flash rusting. i used a whole pint of por15, sloshed it around inside real good, or as good as I'm able to (you can't see anything inside obviously). it's now in the drying/curing stages. I've read it's best to leave it for 4 days minimum without using or filling the tank with gas.

    trying to look inside the tank, it's not altogether perfect from what I can see. it seems like the tank sealer coating was not completely perfect, nor was the coverage of the acid. i filled that tank up right up to the rim, but it still looks a bit like the acid didn't completely scour the top of the gas tank. the surface on the inside up there is kinda rough, and it looks like there are streaks of semi-reddish material running down the now-dry por15 surface on the inside of the tank. I'm thinking this looks really iffy and maybe I've failed to do this correctly. I'm going to let it cure, then attempt to fill it with gas with two new fuel filters installed on the petcocks. If this does not work out properly, i'm not going to attempt it again. too much time and money was invested the first time around. for only a little bit more than the cost of attempting it again, i can buy a new gas tank with no rust on the inside.
    gggGary and YamadudeXS650C like this.
  13. YamadudeXS650C

    YamadudeXS650C Central New York XS650 Top Contributor XS650.com Supporter

    Yes, there are many clean tanks out there to be had.
  14. 5twins

    5twins XS650 Guru Top Contributor

    When soaking the tank with the acid, I turn it several times, letting it sit on it's sides and upside down for a while. I seal and protect the cap by cutting a piece of rubber to cover the filler hole then just closing the cap over the top of it.
    gggGary likes this.
  15. now, see, this is where the internet can hurt you....several sources said not to bottle up the reaction at all, to always leave it open in order to prevent a buildup of gasses, so i did just that.
  16. Welp, it seems i don't have the skill required to get this done. After completing all the necessary steps, letting the tank sealer cure properly, cleaning off the outside of the tank, ect, i can see from inspecting the inside of the tank that the POR15 sealer has completely failed to adhere to the inside of the tank. it's peeling off in crinkly plastic-like sheets, and the metal underneath has re-rusted, putting me back at square one (or worse). purchasing more tank sealer and more acid is going to cost me another 45 bucks give or take. considering what i've already spent on this debacle, i'm not too keen on spending money to try again when i don't even know what i did wrong, or if it will ever work.

    So, no we're onto exploring what kinds of replacement gas tanks we can buy. Does anybody have any experience with a particular aftermarket gas tank they can share? some online shopping has yielded results like this:




    Considering non-aftermarket options, it seems like basically 100% of the XS650 gas tanks on the market have rust inside the tank, defeating the purpose of replacing the tank, since i clearly lack the ability to clean out rust. (edit: i realize i should insert the phrase "for sale at a reasonably affordable price" into this part. sure, if i were rich i could blow $350 on a mint tank, but that's not an option.)

    As a final option, have any of you had experience with taking a tank to a shop to have it cleaned out? What would a service like that cost?
  17. To continue the Gas tank saga:

    Even though I didn't get any real input from you guys on this, I've managed to come to the conclusion that aftermarket tanks are a huge problem. it seems like each and every one has some quirk or weirdness that prevents me from getting a seat that will fit properly without paying somebody to completely custom make a seat that fits perfectly. So it seems that unless i want to basically go broke over this i have no choice but to find a way to use a stock tank.

    Which brings me back to my existing tank. The por15 failed miserably, so I had to try and remove it. I decided to fill the gas tank with ice cubes from my refrigerator. It worked surprisingly well as an abrasive, and wasn't hard to remove. i combined this with a wire grill brush that i bent into a shape that would fit inside the tank and proceeded to scrub and scour out all the por15. using the grill brush to break it up and shaking the tank full of ice to knock all the loose bits off, i had almost all of the por15 out of the tank in about a half hour. i used the garden hose to blast out the inside and dump it out. then added more ice and shook it more to break up whatever was left. after the second rinse, the water was coming out basically clean, and huge chunks of por15 were coming out loose. i dried the tank using a heat gun and a swish of alchohol (not at the same time, lol).

    However, when trying to re-attach the little plates i made to seal up the petcock holes, the threads on one of the holes (tank side) stripped out completely. I'm now stuck because i can't seal up the tank. Purchasing a Tap and Die set tonight....i hate to go spending more money but one of those sets was on the approved budget for another part of the project down the line, so I dont feel too bad. If i can make a new threaded hole for the petcock mount, i can get a new bolt and seal up the tank this evening. Next up, it's time to try again to melt out the rust with Acid. Taking a look inside the tank after I broke up the Por15, I was really surprised to find that most of the tank was looking really good on the inside. The first round of this really did remove most of the rust, so the second round might just do it. I don't plan on using a tank sealer in the next try at this, because, frankly, it's too expensive to try again. I'm going to use an old trick and just fill the tank with Premix gas and oil for a couple of days to let the petrol treat the bare metal. My hope is that if i just keep the tank filled with gas and use additives to neutralize the effects of ethanol, I won't need a tank sealer.

    That's all for now.
  18. lakeview

    lakeview XS650 Guru Top Contributor XS650.com Supporter

    White vinegar will soak off all that rust, fill to brim, leave it in a couple days, dump it out, rinse with water, swirl premix around in it to prevent flash rust- easy and cheap and safe.
    Jim likes this.
  19. is there something i'm missing about the vinegar idea? because i get a lot of mixed results from reading about that one. Some folks seem to say it barely does anything even after 3 or 4 days. some folks seem to say it works wonders. i'd like to know what the difference between when it works and when it doesn't work is. it seems to be related to the quantity and thickness of the rust. Nobody reports the Acid failing to pull the rust out of the tank, though, that's why I chose it. Also because I still have lots of it from the first time around (i didn't dispose of it).
  20. lakeview

    lakeview XS650 Guru Top Contributor XS650.com Supporter

    Have you been filling this tank up to the neck, or just counting on your swirling a solution around to treat the inside?
    Vinegar is cheap enough to fill tank completely.

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