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82 XS400J/Maxim - Oil Problem - Top end not getting oil

Discussion in 'The Garage' started by Ben Thompson, Jun 5, 2022.

  1. Ben Thompson

    Ben Thompson XS400 New Member

    Hi everyone
    I'm new to the forum. I recenetly bought my first ever motorcycle. Eager as a pig in shit to get going.

    1982 XS400 Maxim that has been modified with 33,000kms.Previous Owner Upgraded/Mofidied:

    I have uploaded a picture of the original and one of the bike currently.

    Front controls
    Clutch and brake levers
    Front brakes
    Rear taillight
    Front and rear signals
    Foot pegs
    Used black engine enamel paint on the engine
    New tires

    When I bought it, it fired up well and revved. Previous owner said the bike ran well. I didn't test drive it and we only let it idle for about 5 Mins when buying it. Yes, I know. Rookie mistake. Live and you learn.

    Anyways, I brought her home from Chiliwack to Kelowna (4 Hour Drive). Started and ran, but noticed she was leaking only when being driven. Some sort of Fuel + Oil mixture. In addition to the leak, she wouldn't hold idle.

    My mechanical experience is limited. I called up my local Motorcycle Repair Shop (Redline in Kelowna, BC). I informed them what was going on and figured (from basic research) that the Carbs needed cleaning.

    Anyways, fast forward 2 MONTHS of my bike sitting at the shop. Here's what the shop says:
    Bike needs:
    1. Ignition Coils Need Replacement - Ok, done.
    2. Valve Adjustment - Ok, done.
    3. 'Sorry, top end of engine is not getting any oil. You should walk away from the bike or sell her for parts - it's not worth fixing'

    This past Thursday, I picked her up from the shop after settling a $720 bill.

    Invoice states the following:
    -L/H cylinder compression 115psi
    -R/H cylinder compression 110psi
    - Spark plugs look rich
    - both spark plug boots look good
    - major oil leak out of shifter plunger
    - fuel pet cock leads, needs seal kit
    - no oiling to top end
    - sight glass full
    - no oil pressure
    - oil was mostly fuel when drained
    - valves are in spec

    I need help from any XS400J (Maxim) guru's out there.

    Do I source a shop to do an engine rebuild or source another engine to replace it with?

    I am prepared to put time + a bit of $$ into this project. I bought this bike for a decent price as these issues were not evident upon purchasing (or lack of my own due diligence) Anyways you get the point.... Looking for advice/direction or troubleshooting .

    Attached Files:

  2. JPaganel

    JPaganel XS400 Addict

    Worth is subjective. If you want to spend money on it, ain't no one can stop you.

    So is the concept of "upgrade". You may think this stuff makes the bike better. That's fine. Be aware that not everyone will agree. Especially important if you are selling.

    Such is the way of old bikes. Few shops would even take the work.

    Part of me is curious as to how they determined this.

    I also think they aren't necessarily wrong. You are looking at fairly major engine disassembly to figure it out, and labor is the expensive component here.

    I am not immediately sure if that's any good. Try a search here.

    These would point to carbs leaking fuel into the engine. You are in for at least new needle valves and probably some messing with floats afterwards. Carb rebuild rather than just a clean. Oh, and bad petcock is also part of this.

    Shifter plunger seal is a $10 part. Takes 20 minutes to replace, if you do it right.
    Petcock kit is like $30. Maybe a half hour. The whole thing is two screws to attach it and two to hold it together.
    Neither is a major problem.

    This is a problem. These are probably related. You are likely looking at pulling the oil pump to figure out what it is. If I remember right, this is inside the crankcase, accessible from the bottom. You may be able to pull the bottom off without total engine disassembly, but this is still pretty major surgery.

    Good luck with that. Shops don't want to work on 40 year old bikes. Ones that do charge through the nose.
    Good opportunity to develop some skills, tho.

    It's a possibility. These aren't super-common, though, so it might take some looking.
    tstidham likes this.
  3. Ben Thompson

    Ben Thompson XS400 New Member

    Certainly worth it. These bikes are too beautiful. As for the other stuff - I found an engine in Richmond for $800. Thing is, it is stand alone. How can I test a stand alone engine?
  4. Buddha

    Buddha XS400 Addict Top Contributor

    Hey Ben
    You can crank the engine with a 12V battery and booster cables, +ve to starter cable, -ve to ground - use the ground as your "switch". Remove the plugs and take a compression test. I would also hook up a manual oil pressure gauge in place of the OEM sending unit to visually see the oil pressure whilst cranking the engine.
    The first thing I would do before buying an engine is hook up the oil pressure gauge to your original engine, crank it or start it to prove there is no oil pressure just to reconfirm the shops diagnosis.
  5. Buddha

    Buddha XS400 Addict Top Contributor

    Too bad you're on the other side of the rock pile, lol
  6. Ben Thompson

    Ben Thompson XS400 New Member

    Thank You, Buddha! Questions : Where would I hook up an oil pressure gauge? Apologies for rookie questions.
  7. JPaganel

    JPaganel XS400 Addict

    Hm. I didn't realize they actually had pressure switches. Many other Yamahas of the time had oil level instead of oil pressure indicators.

    Parts fiche says the pressure switch is on the bottom of the engine.
  8. Buddha

    Buddha XS400 Addict Top Contributor

    That's correct, the oil pressure switch is what puts out the OIL light that's displayed in the pilot box. The switch is located on the LS of engine just below the neutral switch. You would need to get an oil pressure test gauge with a metric fitting/adapter, remove the oil pressure switch and screw the gauge into the switch port. This will allow you to see actual oil pressure in psi or kpa.
    EDIT It takes a special oil pressure socket to remove the switch.
  9. Buddha

    Buddha XS400 Addict Top Contributor

  10. tstidham

    tstidham XS400 Enthusiast

    Having had my top end apart, I can share that the oil galley for the head is the right side rear head bolt hole. Then a smaller drill hole diagonal from the rear cam journal down to that hole. Maybe your passage is all sludged up and blocking the oil. You'd have to pull the head and cylinders to check and clean it out. Maybe just pulling that head nut and washer you could look down there?

    Attached Files:

    Last edited: Jun 15, 2022
    JPaganel likes this.

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