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82 xs400 Maxim

Discussion in 'The Garage' started by MoonClipper, Apr 22, 2020.

  1. MoonClipper

    MoonClipper XS400 Enthusiast

    Picked this beauty up the other day, I have some plans for her. Currently she runs and drives, tires are in great shape with tons of tread left, and the carbs were rebuilt when I bought the bike.
    Immediate things that need to be done: throttle cable, replace RH mirror, fix the brake pedal from scraping the side cover, and tighten up the clutch lever, it's fairly loose.
    Some pics for y'all!
    00P0P_jpBK15DBSUB_600x450.jpg 01616_4DIzn2FgoEQ_600x450.jpg 00U0U_j879tZmT2Ow_600x450.jpg IMG_20200422_104856.jpg IMG_20200422_104926.jpg

    As you can see the mirror at some point broke off in the mounting holes.. here's hoping I can drill it out, may have to retap it if I do though.

    I also have to replace the throttle cable, the adjustment knob is broken and held together with tape. It also isn't adjusted correctly... Turning the handlebars either way results in the bike revving, and there is no dead zone for the grip, so the slightest shift of the throttle results in the bike revving. On that note, anyone have a idea of what the proper routing should be?A have a new cable ordered.

    The foot pedal for the brake scrapes the side cover, it seems it may of been bent at some point, there's almost no clearance between the pedal and the side cover.

    And finally the clutch lever is loose. It seems the bolt that holds the lever itself to the assembly is loose, should be a simple fix. It could also just be worn out, may have to be prepared to replace it. At least the club cable can be adjusted.

    Attached Files:

  2. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Hey there you are! Welcome.

    The mirror mount can be repaired I suppose. That coloring inside the sight glass worries me. Mikes XS sells new reproduction master cylinders and you can get good used ones. Could just be the glass though and the inside is completely clean, or the brake fluid is very very old. I would definitely inspect the brakes. If the brake line is original, you absolutely need to replace it. Some of the newer lines have a date of manufacture on them. Lines over 5 years old should be replaced as they deteriorate from the inside out and you wont know until you jam the brake and the line pops.

    I DONT CARE what the previous owner said, its something you need to know for yourself.

    As for the throttle. You do not adjust it at the handlebars. The adjustment at the handlebars is there to take up the slack in the cable housing. This should be loose all the way until you set the idle at the the idle adjustment screw. The adjustment at the handgrip eliminates the slack so when you twist the throttle you get an instant reaction, instead of having a loose throttle grip that you need to turn a 1/4 way before you a reaction.

    The clutch lever is usually sloppy. The lever gets worn over time. A new lever might tighten it up but its nothing to worry about, unless its really bad and therefore weak. When my clutch lever was loose, I purposely over-tightened that bolt to bring everything closer together. Then I loosened it and it was fine.
  3. MoonClipper

    MoonClipper XS400 Enthusiast

    Thanks for the welcome!

    My plan for the mirror mount was just PB blaster, and if I can't repair it then it's no big deal. Can always go with aftermarket mirror mounts.

    The sight glass also has me worried. I haven't taken off the master cylinder cap yet because I don't want to contaminate the fluid with water, it's been raining for the past couple days. Definitely going to check it out. Replacing the fluid is on my to do list for safety anyway, although I predict about a month before any serious driving. Currently the gravel road I drive on is a speed limit of 15, and if the brakes did fail there's plenty of cushiony places for me to lay the bike down. Nice soft grass :p

    The throttle cable is definitely the wrong one, the sleeve is plenty long but I would have to modify the sleeve to have enough slack cable. A new one is on the way.

    I tried tightening the bolt on the clutch lever and no dice. It's quite a lot of play in the vertical direction, for now it's not a issue but I don't think it has much life in it. Maybe a washer on the bolt will help tighten it? Probably just going to leave it for now and just keep a eye on it.

    I plan to tinker with the bike when I'm off work and I'm going to take a video showing the issues I've noticed, since I suck at explaining with words. I figure you guys can tell me if you see anything out of the ordinary that way. :)

    Look forward to being a active member of these forums!
  4. Nat X

    Nat X XS400 Enthusiast

    It looks as if your rear brake pedal bent from a drop or lay down. My 83 Maxim has the same issue.

    Welcome to the forum! There are tons of informative folks here and good luck on the rebuild!!
  5. MoonClipper

    MoonClipper XS400 Enthusiast

    Hello there guys!
    Got the throttle cable in, and put it on the bike. Discovered that I'm missing the retaining clip that goes on the kill switch bit to keep the throttle from pulling out of the controls, so I'll have to source a new one. Not too big of a deal, I could probably fabricate one temporarily. This is how the previous cable was hooked up, as you can see the idle adjustment couldn't reach the throttle.
    I adjusted the brake pedal so it no longer scrapes the side cover, and I find the position note comfortable anyway. IMG_20200423_011719.jpg

    The brake fluid looked surprisingly good, but the sight glass is shot, so I can't visually check the level without taking the cap off. IMG_20200429_103806.jpg

    And I discovered some... Questionable wiring. IMG_20200430_043139.jpg
    I'm assuming that's one of the safety switch plugs, it has a wire in the inside of it that jumps the two terminals together. Not a fan of that, and I predict it being a huge issue down the road if I don't fix it. Also I would like my safety switches to actually work if at all possible.

    And finally, the big issue... I've been having some issues with idle and start up. Sometimes (like when I bought the bike) it would start up perfectly. No hesitation, sound great, yada yada. Other times it just doesn't want to start regardless of what I do, although it does eventually start.

    Discovered the reason, it seems the right side spark plug wire is messed up. I'm guessing the previous owner crimped the wires himself and messed up on the boot somehow, the wire will only work in certain positions. If it's turned too far out the wire won't work, preventing spark at the engine. Explains the fouled plug, and why I had a bit of a hard time tracking it down. Planning to get it fixed once I'm off work. I'm hoping it's as simple as re-crimping the plug wire, but if I have to order a new set of wires then I will.

    Thanks for being such a good community guys, I'm enjoying my time on these forums!
  6. MoonClipper

    MoonClipper XS400 Enthusiast

  7. MoonClipper

    MoonClipper XS400 Enthusiast

    So my plugs got fouled up. Again. Checked the mixture screws and for some reason the mixture were something like six turns out? If I'm correct, the looser the screw the richer the mixture? Either way, I set the mixture to 2.5 turns out. Any ideas why the mixture would be set so far out? Hide some issue with the carbs maybe? Airflow issues? I dunno, not super great with carbs yet. Anyway, some pictures including some super close ups, my new phone has 10x zoom and I wanted to see how well it worked, seems to work well.


    With the spark plugs so fouled they were oddly smoking when I out them to the engine to test for spark, after cleaning I got a decent spark. Battery is on charger to eliminate the possibility of week battery as well, not sure how old it is. Previous owner claims it's new. After tightening the boot it appears that I'm reliably getting spark on the right cylinder.

    Attached Files:

  8. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Im not sure about that brake fluid.The color doesnt look good at all, could just be the photo or my computers eye-reduction night display. Its wise (essential) to always change all fluids when buying a used bike. Its your life. Batteries without DOM markings got shelved too until I ended up buying a battery tester. Suspension especially gets overlooked. All these things add up when they arent maintained.

    Install new plugs. The ones you showed I would be putting on the shelf. New plugs and a good 100 miles without changing any settings. idle screws 2.5-3 turns out. New plugs will let you see whats happening inside.
  9. MoonClipper

    MoonClipper XS400 Enthusiast

    The color doesn't look bad in person, it is indeed the photo. It's still going to get changed, since I have a brake bleeder it's pretty simple job to do. Just need to grab the fluid when I run to the store next.

    Battery is going to be replaced with a AGM battery or gel, I don't like the idea of a flooded acid battery on a motorcycle. My charger is saying the battery is good, but I'll swap it out in the future either way.

    Suspension I actually haven't checked yet... I know I'm missing the plastic cap for the right fork, so that's another small piece I need to order. Also gave to order a holder with the appropriate screw, speaking of which does anyone know what screw I should use for the holder? I know Yamaha has a part number for it, but I imagine I could probably find one at the hardware store as well instead of buying just a single screw to have it shipped to me.

    The plugs definitely are getting replaced, they're only a couple bucks and I'm sure will eliminate issues in the future, or even currently. The right cylinder is firing but not quite right, kind of like it's firing every other cycle. Adjuster carbs to 2.5 turns out. I think the previous guy just kinda set the screws to whatever and didn't bother setting them properly when he rebuilt the carbs.
  10. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    AGMs are fine, stay above 120CCA if you want E-start. My bike always had an occasional misfire on the right cylinder on a cold start until it warms up. Never bothered to figure it out and Ive had the bike torn down multiple times in the last few years. Old dry suspension will be very soft wont feel good at all. There are ways to tighten the bike up a bit.

    When starting out on carbs, establish the baseline tune and work from there one step at a time. Take notes, keep track of your adjustments or whatever you need to do and get a few sets of plugs. I start with all carb settings at factory except for the idle mix screw I start at 2.5 turns out. Start at the main jet and make a few mid-rpm to redline full throttle runs. Bike needs to be fully warmed up first. The bike will either gurgle and stumble or run out of steam.
  11. MoonClipper

    MoonClipper XS400 Enthusiast

    Update time! I've been busy at work so haven't had much time for the bike.. but that changed! Last week I got dropped to part time (by my request) so I have free time to do stuff.

    I bought and put on a new set of spark plugs and the bike is running great now! Although I kept stalling making my way up a hill.. turned out I was out of gas, oops. Switching to reserve helped that.

    So now I'm able to putt around as much as I want, since everything is working at the moment. I do plan to fix the kickstand switch, someone had bypassed it when it stopped working, but I would like to get it working again. I also need a RH mirror still, and to drill out the stud of the old one. And I'm going to out in some sea foam to try and help clean things up a bit, and install a fuel filter.
    Last edited: Jun 3, 2020
  12. opcracer212

    opcracer212 XS400 Member

    In case you didn't know, that right hand mirror has a reverse thread -- turn clockwise to remove....
    xschris likes this.
  13. MoonClipper

    MoonClipper XS400 Enthusiast

    I had no idea, thanks for letting me know! It'll have to be drilled out, so I since it's a reverse thread I should be able to just drill it with a regular bit and back it out that way. After I soak it in PB blaster for the next week.
  14. MoonClipper

    MoonClipper XS400 Enthusiast

    Minor update: I've ridden the bike for a couple hours since doing my most recent adjustments, and it seems my bike enjoys being a bit learner than most on here. Many report 2.5 turns out is optimal, however mine is between 2-2.5 turns on the idle mixture screw.

    Itf firesr right up with no issues, and the right cylinder now fires even when cold. Before I swapped in the new plugs it would only fire on the right cylinder wants warned up a bit, and it also began to have issues starting and running.

    What I've done is just new plugs, adjusted mixture screw down, closer to 2 turns (not sure exactly what it's set at, but I adjusted it from the benchmark of 2.5 turns), and adjusted the idle to around 1200 RPMs.

    What I've discovered is my choke cable is completely fubard. Adjusting the slide on my handle bars does nothing.. most of the time. Sometimes it works okay. It seems that the cable has stretched as a result of it getting snagged on something in the past, possibly my fault not really sure. Easy workaround is to adjust the choke by hand, so I have to stop a few times on my way to work and home to adjust the choke until she's warm. Not really a issue, but explains why I had issues getting the bike to start in the first place.
  15. MoonClipper

    MoonClipper XS400 Enthusiast

    I finally got a fuel filter and some new fuel line installed. The last line seems like it was a bit too small, and was splitting on one end. This new stuff is working great, and I like the look of my new fuel filter. Although I'm not sure I like the placement of it, I should looked how large the filter was when I bought it. It would be more suited to a car.
    IMG_20200613_074337.jpg IMG_20200613_074330.jpg
  16. MoonClipper

    MoonClipper XS400 Enthusiast

    Last night on my way home from work I had to stop at a stop sign. No big deal, it was 11 and I had my high beams on and my turn signal on with my foot on the brake. After a couple seconds I got ready to take off (had to wait for a car) and the bike dies.

    Did some diagnostics today, and my charging system is putting out about 13.4v at 5000rpm. According to the manual it should be 14v at 5000. Any ideas on where to start looking at the charging system, it seems something's not working right, and I would love to get it diagnosed fully and parts ordered on the next week or so.
  17. Phoenix

    Phoenix XS400 Member

    Hey mate, I just got the same bike, with 60,000 km on it. Not like your 16k miles, you scored. If you found any juicy info hotspots on the web to help you with your rebuild, let me know! I've got a lot of work ahead of me, will post vids soon of bike.
  18. Gael

    Gael XS400 New Member

    Hey there, I find the easiest way to take the carbs off is to pivot the engine forward on the lower mounting bolt. If you have a hydraulic jack to hold its weight, it's just a matter of removing the upper metal stays that bolt the engine head to the frame (14mm) and the upper mounting bolt (14mm). Then, you just slide the jack under and loosen the 17mm lower bolt nut and gently lower the jack. The engine will pivot forward. Oh yeah, first loosen the metal rings securing the carbs to the air filter side inlets because that'll hinder the pivot otherwise. Lots of room to work with; way less wrestling required.

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