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New to XS member, project bike excited to wrench

Discussion in 'The Garage' started by buztabuzt, Feb 10, 2019.

  1. Thanks Chris, that is understood . Just posting as reference and observational. It Surprised a newbie like me even tho you had previously warned this when I came across the exploded 79 carb diagram. I'm just teaching an old dog new tricks ;)

    My Float needles:
    IMG_20190310_180457.jpg IMG_20190310_180508.jpg IMG_20190310_181150.jpg
    Last edited: Mar 10, 2019
  2. Having trouble removing bloody float needle valve. It had a screw and crescent ring holding outside flange, but with that removed it still doesn't want to come out... Circular so nothing good to grab onto. Tried light pliers but no success and worried I'll tear it up...


    IMG_20190310_185349.jpg IMG_20190310_185332.jpg
    Last edited: Mar 10, 2019
  3. xschris

    xschris a lifestyle not a trend Top Contributor

    The o-ring is stuck as it tends to be. Use a little oil around it and then grab the lip with a set of small wire cutters then twist. With as old as the valve looks I would just replace the entire thing.
    buztabuzt likes this.
  4. What o ring???
    :laugh: so covered in crap I couldn't see it haha

    Thanks for suggestions! Oil overnight with locking pliers did the trick

    Attached Files:

    Last edited: Mar 16, 2019
  5. I'm buying replacements, but would these undisturbed gaskets be prospects for reuse? IMG_20190316_103325.jpg IMG_20190316_103314.jpg
  6. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Theres a set of XS360 carbs in the classifieds. Theyre better for the 400s. I use my 360 carbs on the 400.

    I know it takes away from the fun of rebuilding, but I think it the end it will cost less.
    Last edited: Mar 16, 2019
  7. xschris

    xschris a lifestyle not a trend Top Contributor

    Get new gaskets. Make sure the hole in the lip that goes to the bottom of the bowl is clear. Those get clogged very easy.
  8. Little discouraging I found these 2 washers after having removed what I thought were all main components and began spraying carb cleaner and air. Both fell out separately when carb body was on my cloth and I can't say I had any idea where they fell from... any thoughts, don't see them in the diagram. Pilot included for size reference only:
    XS400G ya4234_10.gif
  9. Any knee jerk reactions on this carb kit?
    It's only the gasket, float needle, and seat I'm after. Not worried about jets. Since it includes shipping it's significantly cheaper...
  10. xschris

    xschris a lifestyle not a trend Top Contributor

    The kit is missing the pilot jet plugs. Non-mikuni jets are not made as well and sizes can be off so keep that in mind.
    buztabuzt likes this.
  11. Thanks Chris!! My 1980 400G didn't have a rubber or brass plug sitting on the pilot jet... I'm guessing that isn't unrelated to the fact it wouldn't run properly. From what I gather from the parts diagrams, it should have the plug sitting over the pilot jet.

    Anybody have dimensions of the rubber plug? EDIT: Just realized I can measure ID with my gauge, will update accordingly. Reasoning: rubber plugs are expensive with shipping from certain sources!

    Update for thread integrity if anyone looking for pilot jet plug opening per my measurement: 5.45mm inner diameter. 9.57mm outer diameter
    Last edited: Mar 18, 2019
  12. Ordered! In my experience manufacturers generally don't place parts in places because they run better without them... even with environmental regs. Mine had them removed :rolleyes:

    Any thoughts as to what these washers came off? I don't see them in the parts diagram for my model year. I know the mixture screws in earlier models had an extra washer... but not that I could tell in the 1980 SOHCs...
    View attachment 33253
    Last edited: Mar 18, 2019
  13. xschris

    xschris a lifestyle not a trend Top Contributor

    You need those plugs or the bike will run poorly. 80-82 sohc xs400 had caps over the pilot mix screws and where preset from the factory. You need to remove the caps to access them. There are threads on this. The 80-84 xs650 also had this. Looking at that model bike might yield more results. The pic is what they look like and how they are assembled. With a stock bike 2-3 turns out from lightly seated is a good starting point. I am not sure where those washers go but if your bike was missing the pilot jet plugs who knows what the p.o. was doing with it.
    buztabuzt likes this.
  14. Doug Smith

    Doug Smith XS400 Member

    Save them little itty bitty screen filters!....lol....I ordered new needles / seats but screens are separate.
  15. xschris

    xschris a lifestyle not a trend Top Contributor

    I ditch those valve filters. Use an in-line one between the petcock and carbs and those are un-needed. It's easier to replace an in-line than remove carbs to get to those nets.
    Doug Smith likes this.
  16. Doug Smith

    Doug Smith XS400 Member

    I installed an in line filter too....tank interior had quit a bit of surface rust so bike needs as many filter barriers as I can get before the carbs.
    Tank cleaned up pretty good but still has collected a bit of "finite" material in the fuel filter.
    Using one of those "epoxy" fuel tank liner kits is my last resort.
    I've seen some of those fail miserably and are a big mess when that happens.
  17. Finally got A few hours to dedicate to it with a mate. I cleaned thru passageways a second time and reassembled carbs, now with pilot rubber plugs. Installed new fuel filter and replaced all fuel lines, installed new carb boots. Petcock I bought didn't fit so refastened original for time being to test.

    Installed my new float valves seemed to be a good fit and then float needle sits somewhat loose in the opening. Brass floats set to 26mm from gasket seat (no gasket when measuring).

    Set to prime to fill bowls and tried to start it up without luck. Gas started flowing at modest rate out of the left air filter (lower on side stand) and even a bit began to leak from where my new boots met the engine.

    I now plan to: rubber mallet moderate knock to see if it free floats, otherwise disassemble and inspect valve seat (again) and verify no holes in floats by submerging in hot water. 1 Diaphragm has some spots that look poor/dried out that are concerning but shouldn't be causing free gas flow into filter/engine. I'll inspect anyway with filters off.
    I'll also use goo-gone on boot seat where there was a leak to better prepare gasket seat and then use high temp RTV gasket sealant as well (on both sides of gasket I presume).
    Last edited: Apr 1, 2019

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