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Gunson Colortune Issues

Discussion in 'XJ Technical Chat' started by Mjolnir, Apr 18, 2020.

  1. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    With the oil that diluted, that doesn’t sound good. Can you Look into the drain hole? Does it turn over With the starter? Don’t spin it long, just enough to make sure it turns!
     
  2. Mjolnir

    Mjolnir Member

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    Ya, anything in particular that I’m looking for? I’ll see with the starter tomorrow. Should I see if the crank spins with a wrench first or try the starter first?

    in the process of pulling the plugs I learned that I was right about the carb synch so that means I’m at least learning something. C1, 2 had higher vacuum and those plugs were wet which is why I couldn’t get the colortune correct. 3 looked good and 4 was a little black but not bad which all lines up perfectly with what the carbtune was telling me.
     
  3. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Just put in neutral and hit the starter to verify that it turns over.
     
  4. Mjolnir

    Mjolnir Member

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    In neutral without spark plugs it does turnover and the pistons move freely!

    so I definitely didn’t get nearly the amount of oil out of it that’s currently in it. I have the drain plus on the left side and the front oil filter both removed and the bike is on the center stand. I can see oil when I look through the filler hole but it’s not coming out the bottom holes like it should be. After an initial rush, the rest of it is coming in short bursts about 1 minute apart and it’s only 2-3 oz at most but it’s still pretty gassy. Not as bad as before but still a lot thinner than 10W-40. Any ideas why the oil is stuck in it?
     
    Last edited: Apr 21, 2020
  5. Mjolnir

    Mjolnir Member

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    64C9C40E-E465-4756-B091-E0AE76D4B40D.jpeg B40A97D2-85C1-4ED1-852D-61F1FB545B25.jpeg 64C9C40E-E465-4756-B091-E0AE76D4B40D.jpeg I wish I could go back and delete a whole lot of posts...I’m an idiot :D tons of oil now flows out the bottom can someone tell me the purpose of the Allen plug on the side of the crankcase...because man that looked like an oil plug when I took it off and oil cane out of it...low and behold I checked the manual and forgot that you had to lay on the ground with your head between the pipes to find the real oil plug lol

    now I clean the petcock, clean the tank this weekend, put it back together and go ride while keeping the rubber side down!
     
    Huntchuks likes this.
  6. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Nope, that’s not the drain plug. You found the right one finally... right below the filter
     
  7. Mjolnir

    Mjolnir Member

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    what is it called then?

    What do you use to seal up the bottom of the tank with the phosphoric acid solution?
     
    Last edited: Apr 21, 2020
  8. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    I use either heavy piece of plastic and an old gasket, bolt hem on like the PETCOCK and sending unit would mount, or a piece of metal backed rubber bolted on
     
  9. Mjolnir

    Mjolnir Member

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    6B3D89EC-327A-4F45-93F0-8CFFA50D4298.jpeg 28CC57F3-D9FD-4361-99B1-A1B8C5DBE145.jpeg So bike is back together minus the tank (waiting on some petcock parts for chacal) and runs, but I’m getting a ton of smoke out the pipes especially when I rev it and more and more as the bike warms up.

    The carbtune was showing me that there’s a little erratic behavior between 12 and 34 as far as vacuum goes.

    I only checked Colortune on 1, but but even at 4 turns I couldn’t get away from blue. I tried to make it go yellow so I knew where everything was at and it wasn’t letting me. When I revved the engine I got yellow like normal.

    any suggestions to get it dialed in? I’m going to check for vacuum leaks tomorrow.

    pics show smoke after a few seconds of shutting the engine off
     
  10. Mjolnir

    Mjolnir Member

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  11. XJ550H

    XJ550H Well-Known Member Premium Member

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    it is an oil drain that no one attempts to remove because it shears off, your very lucky it did not. that drain is to remove the last of the oil in motor that will not drain from main oil plug it is a very small amount of oil . it is why when you look at oil spec you see 3 quanities, total oil , oil with filter and oil change only.

    and just a little tip . when oil is drained turn on your key to see if oil light comes on . this is a test to see if oil switch is working.

    I had a bad diode block and my XK550RJ started to turn over when I did this test.
     
  12. Mjolnir

    Mjolnir Member

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    Thanks @XJ550H

    Any suggestions on the smoke and no adjustment in the mixture screw? Before it was running rich (yellow/blue) all the time, now it won't run yellow and only runs blue.

    btw, it has been Carbtuned so I know that's good to go, but it is slightly erratic where some cylinders will drop in vacuum pressure (1/2) compared to 3/4, but other times they are all the same.
     
  13. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Did you put the vacuum caps back on?
     
  14. Mjolnir

    Mjolnir Member

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    Can I Carbtune it and Colortune it at the same time? Because the Carbtune tubes would be taking the place of the vacuum caps right?
     
  15. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    I wouldnt—- we did do a bike with 4 colortunes on it one time... theoretically it would work but it it didn’t really. It sure looked cool though——-
     
  16. Mjolnir

    Mjolnir Member

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    Hahaha that’s awesome, good to know though, I’ll see about messing with it tomorrow
     
  17. Mjolnir

    Mjolnir Member

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    So been messing with the bike:
    Right now it’s warmed up (hot) and if I add the slightest amount of choke it dies instantly. Carbtune readings are posted but still move around some. I am running an auxiliary fuel tank as I tune it.

    Colortune still isn’t really working. C1 I have all blue all the time (went out to 5+ turns) and still blue. C2 same deal. C3 I can’t remember lol C4 was yellow/blue but when I went all the way in to bottomed put it was Bunsen blue so 0 turns.

    Any ideas? I’d check the valve clearances but I’m worried I’ll damage and have to replace the head gasket. I’ll check them if that’s the only option but I’d prefer if it was something else.

    Images are plug 2 and 4. I’ll take it for a ride and plug the plugs and see what they look like.
     

    Attached Files:

  18. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    If adjusting the pilot mixture screw has no effect, the your pilot mixture circuit is clogged (typically, internally) or there is some other issue with it (wrong sized jets, o-ring missing, etc.). I assume the spark plugs are black/sooty (rather than oily).

    Cylinder 4 is getting fuel from somewhere besides the pilot circuit, either the choke plunger isn't fully seating, the bore or plunger tip is worn, or the fuel levels in the bowls is way too high.
     
  19. Mjolnir

    Mjolnir Member

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    Here are the plugs and corresponding turns out.

    Initially, it ran the best it ever has, super smooth, great sound, everything. After a few mins, I noticed that it was bogging taking off from a standstill and then when I would really get on it, it would bog and run rough then take off. The long the ride went, the higher the idle would be when at a stop. Starting off it was 1200 and by the end it was around 1700 but wanted to stay higher than that at times.
     

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  20. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    RICH, LEAN, or possibly even ritually UNCLEAN or OBSCENE: THE CARB REBUILDING FAQ:

    Let us begin by warning you, though: an engine that is out of synch may perform AS IF it has a lean, or a rich, or a hanging idle, or a no-idle, or a run-away idle, or any variety of different conditions------if your engine (carbs) have not been synched, then that at is the #1 issue that you should attend to first, before you even READ any of the guidelines below and go and try to adjust and fiddle with things and change settings THAT AREN'T THE CAUSE OF THE REAL PROBLEM!!

    And here are a couple of very good visuals of how a Hitachi or Mikuni CV ("constant velocity") carb actually works. For those of us who are not intimately familiar with these carbs, these videos provide a great basic understanding of what is actually "going on" with your carbs:









    Question #1: Why Isn't It Running Right?:

    Below is a semi-useful "general rules-of-thumb" list to help you recognize and diagnose fuel-mixture problems.

    All of these descriptions assume that the carburetors are cleaned and operating properly, are stock (no jet kit), the valves are adjusted properly, and the engine has been synched.

    If any of the above procedures, tasks, actions, or activities have NOT been checked or performed, then do them first, or otherwise all your other efforts will barely even give you "casino odds" at striking it rich and determining what the real cause(s) of your symptoms are......

    Here are the 3 rules you should always follow whenever trying to troubleshoot [i[anytime[/i]:





    Typical Symptoms and Causes of a Lean Fuel-Mixture Condition:

    - Poor acceleration; the engine feels flat.

    - The engine won't respond when the throttle is snapped open, but it picks up speed as the throttle is closed. (A too-large main jet also mimics this symptom.)

    - Idle speed falls after you blip the throttle, then creeps back up.

    - The engine runs hot, knocks, pings and overheats.

    - A lean pilot circuit condition can be responsible for a creeping or hanging high idle, where the rpms stay high then slowly drop down to the set point.

    - The engine surges or hunts when cruising at part-throttle.

    - Popping or spitting through the carb occurs when the throttle is opened. Or popping and spitting occurs through the pipe on deceleration with a closed throttle.

    - The engine runs better in warm weather, worse in cool.

    - Performance gets worse when the air filter is removed.

    - Fuel levels that are too low will cause a lean condition.

    - Pilot fuel circuit that are partially or completely clogged.

    - Fuel jets that are too small for your application.

    - Pilot mixture screws being set too far "in".

    - In cases where an overly lean fuel condition is suspected, the application of a small amount of "choke" may decrease or eliminate the symptoms.

    - Here's the main reason you don't want to run lean over an extended period of time:

    http://www.xjbikes.com/forums/threads/head-gasket-1982-maxim-650.85273/#post-504365

    A holed piston. Notice how it's right where the plug fires (the hottest point anyway, and made ultra-hotter by a lean fuel condition).



    Typical Symptoms of a Rich Fuel-Mixture Condition:

    - Engine acceleration is flat and uneven and loses that "crisp" feel.

    - The engine "eight-strokes" as it loads up and skips combustion cycles.

    - The engine's idle is rough or lumpy, and the engine won't return to idle without "blipping" the throttle.

    - An overly rich pilot mixture is usually the culprit when the idle drops low then slowly recovers.

    - The throttle needs to be open continuously to maintain acceleration.

    - Black, sooty plugs, a sooty exhaust pipe and black smoke from the tailpipe that stinks of unburned fuel.

    - Poor fuel economy.

    - The engine works better when cold. Performance falls off as it warms up or the ambient temperature rises.

    - Engine performance improves when the air cleaner is removed.

    - Fuel levels that are too high will cause a rich condition.

    - A choke system that is slightly hung open or has leaky plunger valves. Leaky valves can be determined via a measurement of vacuum using your synch sticks (or vac gauge) --- while watching the gauge, apply a small amount of downward force on the top of the plunger valve. If it vac draw changes, the plunger isn't sealing very well. Over time a small ridge may build up on the tapered brass plunger valve surface (Hitachi carbs) that may be possible to polish out, or a deformity forms on the rubber seals (Mikuni carbs) that may be possible to reform back into shape.

    - Fuel jets that are too large for your application.

    - Pilot and main FUEL jets being reversed.

    - Pilot and main AIR jets being reversed.

    - Pilot mixture screws being set too far "out".

    - Main jet needle set at too "high” a position (on some Mikuni models), or that has "risen up” within its head cap (on Hitachi models).

    - A simple test for an overly-rich condition is to remove the air filter element, and see if performance improves. A very dirty air filter will cause an overly rich condition, AND, even if the filter was in good condition, the great increase in airflow accomplished by removing the air filter will tend to dilute an overly rich fuel mixture, and thus allow you to focus on determining the cause of that situation.



    Some common causes of a high idle:

    - Engine has not been synched, as each cylinder "fights" the others for dominance, it can lead to a run-away idle situation.

    - A lean air-fuel mixture condition, which can be caused by a variety of problems......vacuum leaks, plugged or too-small fuel jets, etc. Old or "stale" gas may also cause a lean fuel-air mixture to occur temporarily (until the fuel is used up!).

    - A vacuum leak somewhere in the intake system.....intake boots, internal o-ring seals, etc.

    - Mixture screws not properly set or adjusted.

    - Vacuum piston sticking or stuck in a partially raised position.

    - Idle speed screw set too high, or set to create a "proper" idle speed when the engine was cold (and thus results in a "high idle" once the engine reaches operating temps). The idle speed when the engine is cold should be modulated via the use of the choke (enrichment) control system.

    - Butterfly valves opened too far; synch screws out of adjustment.

    - Throttle cable wear, adjustment, or throttle lever brackets installed incorrectly or interfering with other nearby objects (cylinder head fins, etc.).

    - Choke (enrichment) circuit is stuck "open"....this can occur even if the choke lever is rotated to the fully closed position, if for some reasons the choke plungers are not fully closing (cable wear, cable adjustment, bent finger brackets, or installation problems). In addition, even if the choke plungers are "closing" fully, if the choke plunger valve face or its seat are worn or scarred, this will allow fuel to leak part the plunger and richen the mixture even if the plungers are closed.



    Why your engine seems to be schizoid:

    A hanging idle---one that stays high and slowly comes down when decelerating---is a sign of lean mixture. The opposite case, where the idle drops dangerously low then rises, is a sign of rich mixture.

    A bike that runs better when hot is probably lean, and a bike that runs better when cold is probably rich.

    But sometimes a bike that can be adjusted "just right" when cool, but actually starts exhibiting signs of running lean (hanging idle) as it warms up. And if the idle speed is then re-adjusted while the engine is warm, but eventually falls and the bike dies (especially when sitting at a stop light). Or if the pilot screws are adjusted, then it's too rich when cold---all in direct contradiction of the above observations.

    Experience shows that this is a sign of worn throttle shaft seals.....the aluminum carb bodies expand with the heat, but the steel throttle shafts---resting comfortably in a nice cool airflow---don't heat up and therefore don't expand. Once the shaft seals get old and hard, they no longer are able to flex and fill the gap.....so the carb starts drawing air around the shafts, leaning it out.



    Why does my engine sometimes backfire when I first turn on the key (without attempting to start the engine)?:

    - When you kill the engine, the intakes will still have some remaining (un-burned) air-fuel mixture remaining in them. Upon powering up the bike (turning the key on), the ignition system will apply 12 volts to the coils, thus charging them. Of course, that constant current is not good for the coils, so a few seconds later (if the engine is not started) the TCI shuts down the coils by grounding them (to protect the coils from overheating) which cuts the current to the coils and thus triggers a spark to the plugs. If there is enough un-burned fuel in the intake manifolds or the combustion chambers, and if the valves are held open by the camshafts, a backfire thru the exhaust header and/or thru the intake manifolds/carbs/airbox can result.



    Why is my engine hard to start, and using the choke makes no difference?:

    Most probably, the starter jets --- which are tiny, and are down inside the carb bowl ---- are plugged up with fuel varnish or the like.



    Why does my engine run poorly (or is hard to start) after it is fully warmed up?:

    This could be due to leaking throttle shaft seals (where extra seal-to-carb body clearance occurs after the carbs warm up and expand), or, it could point to valve shim clearances that are dangerously tight (the clearances close up after the engine gets fully warmed up).



    Why are my plugs carbon-fouled (dry, sooty black deposits)?:

    - Carbon fouling is the result of incomplete combustion----for any reason. It is most often associated with an overly rich fuel mixture (whatever the cause), but can also be caused by an overly lean fuel mixture (or poor spark, etc.) In a lean-mixture condition, most of the un-burnt mixture gets pumped out the tailpipe, but some fuel droplets remain in the cylinder and add themselves to the next intake charge. That's not a very precise way of metering the mixture, so when it's finally rich enough for a spark to ignite, that particular charge may be too rich, resulting in incomplete combustion and plug fouling. So carbon-fouled plugs can be due to rich or lean conditions.......your Colortune spark plug will tell you for sure. If you have a light blue or white-ish flame, intermittent flame, and/or intermittent flashes of yellow within an otherwise white-ish flame, then your fuel mixture is too lean.

    And by the way.........if the spark that happens to ignite this overly-rich mixture is the "wasted spark" (which occurs in each cylinder at the top of the exhaust stroke, it will occur JUST AS THE INTAKE VALVE IS OPENING ---- so the backfire pressure wave may be directed back up the intake tract!



    Why are my plugs oil-fouled (wet, oily black deposits)?:

    - worn or broken piston rings, excessive wear or damage to cylinders, *leaking intake valve stem seals.

    * while bluish smoke from the exhaust can be caused by worn exhaust valve seals, that situation will not foul your spark plugs. Consider what happens: oil pools above the valve guides, and coats the valve stems every time they rise. These stem "seals" really aren't seals, they are more like wipers, and their function is mainly to wipe off the excess oil from the valve stem. Now, when these stem seals get old and hard, they leave an excess amount of oil on the valve stem, which then drops down into the path of the exhaust gas flow as the valve opens and the oil is evaporated off, leaving blue smoke from the exhaust. But note that none of that oil ever enters the combustion chamber, so it can't foul the plugs.

    Of course, any excessive oil coating an intake valve stem will end up going through the cylinder, but intake valve stem seals rarely fail on these engines. Unlike the exhaust valves, which are constantly baked by superheated exhaust gas, the intake valves are bathed in cool and moist (with gasoline) air.



    Why is the inside of my carbs covered with a brownish-green goo?:

    When fuel mixes with water and sits around for a while, this is the result. Nasty looking, nasty smelling, and you can bet that the tiny passages inside the carb body are plugged solid with this stuff! Definitely time for a full rebuild.......




    What are my fuel levels supposed to be?:

    Here's the Holy Grail on this subject:

    http://www.xj4ever.com/setting fuel levels.pdf

    And here’s a good visual guide to some problems that you might run into:

    http://www.xjbikes.com/forums/threads/setting-the-floats-mikuni-not-gettin-any-readings-fixed.40395

    and here’s a wonderful video from TurpentyneTV that shows the whole process in excruciating detail:





    Fuel Level Cheat Sheet:

    Here's the proper fuel-level settings by model when using the "clear-tube" method of measurement:


    Hitachi all HSC32 series models:

    NOTE: all of the following models used HSC32 carbs:
    XJ650 Maxim, Midnight Maxim, XJ650RJ Seca (non-turbo), XJ650 Euro all use HSC32 carbs (various versions)
    XJ750 all USA 1981-83 models use HSC32 version 5G200 (Seca) and 15R00 (Maxim and Midnight Maxim)
    XJ750 all Canadian 1981-83 models use HSC32 version 5H200 (Seca) and 15T00 (Maxim and Midnight Maxim)
    XJ750 UK/Europe 11M models, XJ750 Police models 24L and 37H use HSC32 version 5N100

    -Fuel level measured via the clear-tube gauge: 3mm +/- 1mm (.12 +/- .04 inches)

    -Float height: 17.5 +/- 0.5mm
     

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