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Putting a 1988 Suzuki Kan of Tuna back on the road

Discussion in 'Some Assembly Required' started by mrchristian, Feb 17, 2018.

  1. VX Rider

    VX Rider Long timer

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    Dec 11, 2015
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    This phrase confuses me, doesn't want to crank, or doesn't want to start without a lot of cranking?

    One could be your battery, the other fueling....?

    Maybe check the condition of the hoses from tank to fuel pump, etc... for cracks or other leaks
    mrchristian likes this.
  2. mrchristian

    mrchristian Been here awhile

    Joined:
    Nov 23, 2008
    Oddometer:
    844
    Location:
    LA, CA
    Start up the next day before work (sitting 10 hours in a cold shed)...one touch of the starter and it fires up nice and strong barely any choke.

    Let it sit over the weekend...spin the starter 20+ times for a few minutes before it barely fires/sputters to life. It almost seems electrical, like it won't even burble for a while.

    No gas leaks, no vaccuum leaks (tested with starter fluid), bike runs solid after it starts although it's a definitely cold blooded.

    I just put in a new Yuasa (new acid, fully charged before using) but it did the same thing Monday morning when I went to start it. It's been fine all this week after that.

    Oil level is super consistent. Changed it a few times now with no gas in it.

    I pulled the spark plugs before changing the battery as the bike wouldn't fire. They were wet with fuel and on the darkish side. Maybe I'm too rich but the bike needs some choke to start when cold and feels right on the money while riding and the gas mileage is fine/consistent.
  3. baloneyskin daddy

    baloneyskin daddy bikaholic Super Supporter

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    southcentral PA.
    Sounds like maybe the chokes aren't working 100%.Check for too much play in the cable and also keep the throttle closed when cold starting. The extra vacuum is needed to draw fuel thru the choke system.The next time it happens just try blocking off the air inlet on the airbox and see if it helps a little.
    mrchristian likes this.
  4. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
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    Good point. It's actually a choke plunger on the carb not a cable (maximum power per dollar here haha, couldn't even get a handlebar choke lever) but I'll go through the linkage and give it a once over to make sure it's all working properly. When I got the bike it was completely seized up until I hit it with WD40 but maybe something is still tweaked.
  5. Fubars

    Fubars What would Scoobydo?

    Joined:
    Aug 20, 2003
    Oddometer:
    2,230
    Location:
    Ventuna, CommieFornia
    Is your petcock vacuum operated? Replacing it with a new one may help.
    mrchristian likes this.
  6. mrchristian

    mrchristian Been here awhile

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    Yeah, I bought a brand new one. Seems to be functioning fine when the bike is operating. I'll imspect the vaccuum line to be safe. Might be a crack or something.
  7. wolfcreek rider

    wolfcreek rider Adventurer

    Joined:
    Sep 4, 2012
    Oddometer:
    25
    Location:
    Earthquake Central NorCal
    I'm not familiar with this bike or these carbs but I have a question about the choke system. Is it an enriching system or a butterfly system? If it's the enriching system, do all 4 carbs get activated? These sound like odd questions but I have an '86 XR600r that's a twin carb. One carb has an enriching circuit and one float bowl has passage ways drilled for it. The other is not drilled. The float bowls are interchangeable and someone switched them. Near impossible to start when cold.
  8. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    844
    Location:
    LA, CA
    Believe it's an enriching system. There is a linkage to all four carbs. Only the idle adjustment screw moves the butterfly.
  9. mentolio

    mentolio King of the island of unwanted toys...

    Joined:
    Jul 14, 2016
    Oddometer:
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    mrchristian: since you have a vacuum petcock, may I assume it has a "prime" position (most do)? If so, try starting the bike on "prime" instead of "on" when it has been sitting for awhile. This may help...could be your fuel in the bowls is evaporating over time (low fuel level), and the vacuum petcock is having trouble catching-up and filling the bowls at initial startup.
    baldman1, TonyKZ1 and mrchristian like this.
  10. baloneyskin daddy

    baloneyskin daddy bikaholic Super Supporter

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    The enricheners draw their fuel from a orifice at the very bottom of the float bowl so fuel level would almost have to be zero for them not to work. However,these orifices are almost always overlooked when cleaning the carbs because they aren't in the carb body with all the other jets and passageways. A lot of times a small wire or jet drill is needed to open these passages and they are usually one of the 1st areas to get gummed up because they lie at the bottom.
    TonyKZ1 and mrchristian like this.
  11. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    844
    Location:
    LA, CA
    Thanks for the replies everyone. Up to 10,000 miles.

    So, I first day of "cold" weather (50F's) and my battery is exhibiting the same signs as before...think my laziness killed another one.

    So...my bike is at 14.8 at idle so basically overcharging but sorta close enough where I figured it would be OK, it's not like it's 16 or whatever. Well it's not and potentially what is causing the bounce from the turn signals according to some diagnosis from MotorcycleAnchor.com

    For those interested:
    http://www.motorcycleanchor.com/motorcycle/how_to/mc_electrical.html

    According to Katriders these bikes have a reputation for eating batteries if there's any corrosion in the harness...which I definitely have obviously. Apparently the rec/regulator sends a signal into via an orange wire and if that signal is lower than what is coming out of the battery it will overcharge the system. So the power gets routed through the harness, there are drop offs, by the time the signal hits the rectifier it has lost a few volts and the rectifier isn't dumping as much as it should into the ground (I think)

    So I'll check that when I can.

    Basically orange wire to alternator at idle should = battery at idle. (hopefully I'm reading this right)

    Solution is to clean all the contacts and hope for the best or do a "relay mod" which runs power directly from the battery to the orange wire. Can't find any picture or tutorial to help me through this, I guess this will be my deep dive into motorcycle electrical. I hate dealing with wiring, I feel like so clumsy messing with it. I've seen a few suggestions on this thread and basically ignored them (sorry, some of the terminology I straight up don't understand) but tonight I'll go back through and try and comprehend. I think right off the bat I'm going to run a new ground off the battery just to get that out of the way which was suggested.

    I'll try and clean check the float bowl feeder tube as well since one or more of those might be clogged.
  12. mrchristian

    mrchristian Been here awhile

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    Oddometer:
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    Tested a few things

    Battery voltage with bike off is 12.3

    Orange wire going into alternator/rectifier/regulator = 11.7

    So about 0.6 LESS volts are hitting the rectifier.

    It's supposed to read 14.5 max, it reads 14. 8-9ish even when revving. Basically 0.6+ too much, almost the exact drop.

    Think I'm on to something here. The plan is to bypass all the fudged wiring that is knocking the voltage down and put the exact battery signal directly into the rectifier.

    So my plan (somebody stop me before I start hacking if I'm wrong/being dumb) is below:

    Get this fused 4 block relay:

    [​IMG]

    1. Cut the orange wire and use that as the "signal wire". Stick a female spade connector and click it to the corresponding part of the relay.
    2. Female spade connector from the relay block ground connector to battery ground
    3. Make connection from battery positive terminal through the two poles that get activated when signal is detected at orange wire.
    4. Leave the red wire (presumably the regulated power coming off the alternator that goes back into the battery) alone and leave that connected in it's current form.

    Make sense?
  13. Vince

    Vince Long timer

    Joined:
    Oct 1, 2006
    Oddometer:
    1,000
    There is a relay mod done to Ducati Pantahs thats similar. Standard when you hit the go button all the electrical energy goes to spin the starter motor not allowing enough to produce a spark. A relay wired in allows both strong starter motor spin and strong plug spark to happen simultaneously. From memory before the mod the bike would tend to fire just after you let the button go, that's the TELL you have this issue.
  14. mrchristian

    mrchristian Been here awhile

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    I got the relay and found a nice place to mount, unfortunately the terrible auto parts store spade and ring connectors I had leftover from another project in a drawer were so cheap I could barely get them to work. I ordered some nicer looking ones from Amazon, should get them on Friday.

    [​IMG]
  15. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    844
    Location:
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    Added all the wiring in with some nicer connectors:

    [​IMG]

    And voila, charging in spec now - 13.3 - 14.3 depending how warmed up it is. All the electronics seem to be a little happier as I added a ground from the relay to the engine block.

    [​IMG]

    Cleaned out the fuel bowls again. A good amount of rust seems to have round its way there in a tiny little pocket in the corner. Remnants from the tank or stuck in the body of the carb I am sure. Bike starts super easy, first touch of the starter but the real test is when it'll sit for a while.

    Choke pipes didn't seem clogged in any way, ran a tiny sliver of copper wire through them to be sure.
    NoelJ likes this.
  16. mrchristian

    mrchristian Been here awhile

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    Oddometer:
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    Location:
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    Seems to run a bit smoother, maybe a bit more acceleration too. It's possible the exhaust got quieter too. Most importantly the turn signals don't bounce the idle anymore.

    Still super cold blooded. I've heard that's caused by lean condition but this sucker is jetted rich. Maybe its due to the SACS cooling system shooting oil up at the bottom of the piston and you have 4 liters of oil to warm up.

    Made a new seat cover - took a few tries but I finally got it looking beater bike acceptable.

    [​IMG]

    Used this red stretch fabric and it's a decent match.

    https://www.amazon.com/gp/product/B00EDVWQDQ/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

    Don't buy that relay, the first one I tried was bad. Might put a Delphi and an inline fuse in on the next go around.
    NoelJ likes this.
  17. mentolio

    mentolio King of the island of unwanted toys...

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    Jul 14, 2016
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    Congrats on the fix and that seat cover, looks good!
    mrchristian likes this.
  18. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    844
    Location:
    LA, CA
    Bike was still doing the same thing with a brand new battery - starts right up when it's been started previously even if it's dead cold after 10 hours, sits for a few days and will crank endlessly, then BARELY burble to life, all sorts of weirdness. Once it gets going it runs perfect. Was contemplating pitching the whole bike into the LA River.

    Changed the spark plugs even they didn't look fouled or anything. Maybe rich but not terrible.

    Screw it, throw a pack of NGK $35 Iridium plugs. No gapping. Theoretically harder to foul since the tips get hotter. More consistent spark since I need all the help I can get with this thing.

    First day of 50ish morning temps after sitting for a full weekend + a day (usually when bike absolutely refuses to barely even putter)...fired right up with just a bit of choke. Maybe I got the issue solved, maybe not. Seems like I'm onto something though.
    yokesman likes this.
  19. mrchristian

    mrchristian Been here awhile

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    Spark plugs didn't seem to fix the hard start issue. It manifested itself yesterday. Cold day, battery had 12.7 volts when I went to start it up, so good to go there.

    I checked for a parasitic drain - 0.0 with the setting at 200 mA DC.

    With choke off ---> will spin starter but won't start (probably too cold so normal)

    With choke on ---> will spin until it sounds like a 'ping' of some sort, like it's getting hung up or having trouble spinning

    I took off the side cover to check the starter clutch and gear assembly. Everything looks good there, no teeth missing, nothing getting hung up. I've heard if the bolt backs loose on the clutch and it's supposed to be torqued down at 100ft/lbs so I hit it with the impact a few times. Buttoned it back together with a new gasket.

    Here's a video showing that issue but it doesn't seem to be the case:

    "


    So that eliminates the starter clutch, the battery, and any free fixes I can think of.

    Maybe the starter is bad? Like with a rich & cold gas mixture it can't spin the engine hard enough? I figured starters either worked or they didn't. It spins no problem with choke off or whatever. All the teeth look good and all the bearings in the starter clutch asembly felt good.

    I can roll the dice with a used one from eBay or get a brand new one. This company looks semi-legit and the price is right.

    https://www.dbelectrical.com/products/starter-suzuki-gsx600f-gsx600-katana-motorcycle.html

    [​IMG]
  20. VX Rider

    VX Rider Long timer

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    Dec 11, 2015
    Oddometer:
    6,328
    Location:
    Phoenix
    Sorry to hear it isn't solved.


    They claim the VX is a cold motor...
    Mine seems to be fine...a little choke on coldest of days....