Putting a 1988 Suzuki Kan of Tuna back on the road

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

  1. mrchristian

    mrchristian Been here awhile

    Joined:
    Nov 23, 2008
    Oddometer:
    808
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    Wheel bearings felt OK, one side was a little less smooth. Decided to pop them out of the back wheel to check - these are ball bearings. 28 year old factory grease ain't really grease any more. Surprised only one side of the bearing has a seal but that's how they were.

    [​IMG]

    Could probably get away with cleaning and regreasing them but I ordered a $11 set of new sealed bearings anyway.

    Back wheel cush drive looks to be in good condition - new Kenda Cruiser tire spooned on.

    [​IMG]

    I think I finally have the carb fixed up. Popped it off for the five hundreth time, unscrewed the fuel screws (they are on the traditional "fuel" side, I think the Katriders FAQ is wrong), hit them all with carb cleaner on both sides of the passage, set them all to 2.5 turns and buttoned everything back up. It idles good now. No choke needed to start it when outside temp is warm. I think from this point on it just needs to be ridden with some clean gas.
    #81
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  2. mrchristian

    mrchristian Been here awhile

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    Got a $32 kit off eBay with all the fasteners I need. Good quality, stainless steel, allen key with good instructions. Applying lots of blue Loctite to everything and replacing all the old worn out, missing hardware. Some of the bolt heads are smaller than stock but that's OK. The cheap stock hardware is so rough bolts have rusted into speed nuts and I have had to soak in PB Blaster to get them out.

    [​IMG]

    There are a couple cracks in the plastics. I'm not going to bother repainting (I like the stock graphics and don't mind the dings and scratches) but am doing some research into beefing up the plastic or adding some cement behind the cracks. Not sure what the best approach is. I've got some plastic gas tank cement that you cut, knead to get the chemistry going and apply which I might use.

    Maybe I'll grab some of this stuff from Walmart

    [​IMG]
    #82
  3. zap2504

    zap2504 Dave E.

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    Much of bike plastics are ABS. You can "glue" ABS with plastic plumbing cement. You should also get some backing material to reinforce the crack area; fiberglass mat can be used as well as 1/8" ABS sheeting (if going the plumber cement route).
    #83
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  4. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
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    Trigger Warning: hackery ahead

    Back in my teenage days I did a few terrible fiberglass surfboard repairs. Time to bring those skills back. Bike stops, goes, has lights and now has license and registration. I really just need to get mirrors on it which necessitates fixing up the fairings.

    Taped up the front to keep anything oozing through from going anyplace it shouldn't.

    [​IMG]

    A closer look at the cracks. These were minor, the really bad one is creeping into the mirror area. I cleaned them out with some rubbing alcohol.

    [​IMG]

    I ended up using the automotive store ABS "Plastic Weld" - seems to be the same as the glue, just uses a catylist to get it going. But took your advice and added some fiberglass to the back for extra strength.

    [​IMG]

    Added a layer of goop, added fiberglass. Let that cure. Add more goop, add more fiberglass, let it cure.

    I'm going to let it all sit overnight.

    Next issue is the kickstand which I have been dreading. Going to need a buddy's welding skills for this one. I'll need to figure out how to build up some material as it was cut off in a problematic way. I also really need some close up pictures of how it mounts to the frame so I can get it just right.

    [​IMG]
    #84
  5. mrchristian

    mrchristian Been here awhile

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    Took it for a short spin today. 99% of the time the bike drops back down to idle (set at around 1500rpm for now) but 1% of the time it dies unless I blip the throttle. I've got a full tank of gas in it and it pulls pretty good although it's not super fast so there might be some issue there.

    Got it nice and warmed up and started getting some weird electrical problems. Bike dies if I try to use too many lights at once and I can hear the rev's bounce when I use the turn signals.

    I think my battery is pretty healthy, it's new and I've had it on a battery tender most of the time. It's putting out 14.83V when the bike is running. Off it's at 13.31. When I flip the lights on it's super bright. Cranks the bike no problem.

    [​IMG]

    None of the fuses are blowing either. Terminals to battery are nice and tight and clean. Headlight has a slight flicker which leads me to believe something is goofy.

    EDIT: just screwed around with it on the stand some more. At idle the only thing that really disturbs it is the turn signals which drop it from 1500rpm to 1000rpm where it stays even if you turn them off. Blipping the throttle brings it back to 1500rpm. Brake light makes it dip a tiny, almost imperceptible amount. Switching between regular and high beams doesn't do much.

    Some funkiness in the turn signal flasher perhaps? Or bad flasher switch? The switch was super gummed up so I shot a bunch of CRC Electronic Parts Cleaner into it to get it going again...
    #85
  6. Dino de Laurentiis

    Dino de Laurentiis Working on it

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    14,83 V when running sounds high. Usually it should be around 14,0 V. As for your other issues you have, I’d bet get good money on it being a ground fault or two and/or a faulty voltage regulator.

    I’ve had bikes die when coming back to idle due to a poorly adjusted low speed circuit. Either the mixture screw or pilot jets being to small or gunked up (or clogged pilot air jet?).
    #86
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  7. mrchristian

    mrchristian Been here awhile

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    Dino - you might have pretty much called it dead on.

    So, status update...I cleaned up a bunch of the plugs spraying them out with CRC parts cleaner and filled them with dielectric grease. Went for another test ride.

    I should note that this is my first sport bike besides a Ninja 250 I had ages ago. I've been putting around the neighborhood and not really getting on the throttle that much but the bike feels not slow but not particularly fast and only really gets going when you get into the upper revs. It's an air cooled sport bike and all the "reviews" say it doesn't have that much power but still something felt a little off in the back of my head.

    In reality, it was REALLY, REALLY, REALLY off.

    Was riding around a empty industrial area and suddenly the bike bogged down and then surged back to life with (for me) INSANE POWER. Some sort of carb passage must have free'd itself. This morning I topped off the tank and stuck some Seafoam type cleaner in (second batch after some two weeks ago) which must have cleared something out. The motor spins up super quick and became crazy smooth.

    Anyway it rev's like a freaking GP bike now and pulls HARD.

    #87
  8. neppi

    neppi Been here awhile

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    Good job!

    And you were thinking of parting it out! Ü

    Go through all the electrics with generous amounts of el parts cleaner (maybe a bit sanding if badly oxidised) and dielectric grease. Clean all the earthing points and add some more. That's something I always do with all my vehicles, no matter what. Thick-ish leads straight from the battery - to the engine, to the frame, to the body. If I'm working on some electrical stuff e.g tail light or so, I'll add an extra lead from the light - to the frame and so on. Keep them clean and lubed!

    Another thing I do, is to get a "light amp" for the rig. You can get them cheap or expensive (or make your own!), but the basic idea is to use the bikes / cars orig wiring just to run a relay and get the juice to the lights straight from the battery. Not easy for me to explain, but maybe the internet can help...

    First hit: http://www.painlessperformance.com/webcat/30815

    My Honda Transalp for example didn't have any kind of relays for the lights, but all the juice for them goes through those tiny contacts in the light switches. No good! Ü

    Ground you regulator / rectifier too! I put my battery-frame lead under the reg/rec mounting bolt, battery-engine lead under the starter motor mounting bolt and the third one goes to the fairing support rack, so I can do all the handlebar / dash earthings up there.

    A lot of words, Sorry for that!

    Cool build! Happy for you to get it going like that! Keep up the good work!

    Cheers!
    #88
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  9. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    808
    Location:
    LA, CA
    Took the bike on a long ride - went 90 miles without any issues.

    Some observations - for some reason the turn signals really mess with the idle. It noticeably bounces up and down when the signs are on. Nothing else does - high beam, brake lights, etc. Maybe it's a ton of resistance in them, not sure. I guess I'll keep cleaning and tinkering.

    Got to make use of all the stickers I got for free.
    [​IMG]

    The gearing is very, very low. It's fun for very tight canyon roads but that's about it. It's screaming about 6,000rpm's in 6th gear at 65mph. There's a 48T sprocket on the back, not sure what is on the front and I'm not super eager to remove the fairing (again) to find out so I guess I'll just enjoy it as is for right now.

    My friend says the kickstand is a ton of work since it was cut in a very problematic way - basically I need to machine a new mounting bracket from scratch. Neither of us felt like digging into that so I just ordered this as a temporary (potentially permanent depending on how it works) solution. Did some measurements and it should bolt right onto the swingarm.

    [​IMG]

    Anyway, it's not remotely comfortable, it's loud, it drones, it's twitchy on the throttle. It's fun though! For short bursts at least.
    #89
  10. neppi

    neppi Been here awhile

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    Well, you'd need to replace the chain & sprockets in some point anyway, so might aswell go stock then...

    Good job mrchristian!
    #90
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  11. mrchristian

    mrchristian Been here awhile

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    I'm going to see if I can get away with just gearing up the front sprocket a tooth or two and considering it good. Probably not this weekend, may just ride instead.

    I got a kickstand. It clamps onto the swingarm OK, just wiggles a little bit. Will need to figure out a shim and probably need to cut about 2" out of it.

    [​IMG]

    I had to position it far enough back so it doesn't sit in the chain line. I might just weld it on permanently, will have to mess with it.

    It looked pretty cheap on eBay and I wasn't holding much hope but it's sturdy and well made.
    #91
  12. bwringer

    bwringer Gimpy, Yet Alacritous

    Joined:
    Jan 22, 2008
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    Location:
    Indianapolis
    Sounds like you may have low voltage at the ignition coils. Slap a voltmeter on there and see what you've got.

    There are a lot of connectors and a switch between the battery and the coils. Cleaning all the connections can get rid of most of the voltage drop, but some of us over on the vintage Suzuki forums end up powering the coils with a relay to ensure the coils get the juice they need.
    #92
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  13. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    808
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    I should be checking the voltage at the flat blade connectors that connect to the black cylinders that generate spark correct? I'll obviously clean everything with CRC parts cleaner while I'm there.

    When I have time I'm going to remove the plastics and do the following:

    -More connector cleaning
    -Re-sync carbs now that they are functioning correctly
    -Lower idle speed now that it's sitting around 1800-1900 with the carbs working good (can't reach my knob with fairings on)
    -Figure out the front sprocket on this thing, potentially replace with something bigger
    -Poke around and see if I can get the gas gauge to work. Anyone know the best way to troubleshoot this? As far as I know the gauge is hooked up and the tank sensor is plugged into the right harness connector but no reading on the gauge.

    Took a ride through the canyons, still have that low-RPM burble which I'll have to address but handles pretty good. Also the handlebar hits the tank on the left side (there's some evidence it was dropped at some point) so I might need to source one of those.

    [​IMG]
    #93
  14. mrchristian

    mrchristian Been here awhile

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    Oddometer:
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    Location:
    LA, CA
    So I finally got around to checking the gearing. Previous owner switched out the 530 chain to 520 DID gold chain.

    Surprisingly this thing has a 14T front sprocket with 48T rear - I was expecting a 13T front sprocket. Stock is 14T / 46T according to gearing commander so I'm only really losing 3mph in speed around freeway speeds. It feels geared stupid low to me but I guess I'm not used to sport bikes except a EX250 but that thing you had to scream everywhere. I figured these things were sorta long legged sport touring lumps stock but I guess they are setup sort of sporty?

    Probably going to leave it until it wears out I guess at which point I'll revert to stock.

    Resync'd the carbs (they were off again now that I have all cylinders going) and bike runs way smoother, cleaned more electrical plugs out with spray cleaner which somehow brought the fuel gauge back to life(ish). The fuel gauge doesn't go back down to 'E' when you turn the bike off now...not sure what happened there but at least it's registering something. Sprayed some ether around to check for leaks and all good there.

    Still got a friggen bounce in the idle speed though when turn signals are on.

    The speedo bounces a bit so something needs grease somewhere. I got the little spin stick to reset the mileage on the trip clicker and don't have a screwdriver that will fit to tighten the teeny tiny screw.

    Lots of little things but it's coming together.

    Oh yeah, need to replace the rear turn signal which is melting with some flush mounts to get it away from the exhaust.
    #94
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  15. neppi

    neppi Been here awhile

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    Good stuff!
    #95
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  16. mentolio

    mentolio Been here awhile

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    Jul 14, 2016
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    I wonder if that "melting turn signal" has anything to do with your "funky idle while turn signals are on" problem?
    #96
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  17. REALGRAVEROBBER

    REALGRAVEROBBER LEAVING GRAVES EMPTY

    Joined:
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    GFY, Montana
    A friend had a gsx600f Katana. I thought it was an excellently made bike. I liked it, and do not like every bike I see.
    #97
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  18. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    808
    Location:
    LA, CA
    The Craptana is still being ridden, almost daily for 14ish mile rides and such.

    Fixed a slow leak in the front tire (needed a new Shraeder valve core), pulled the fairings, shot some electronic cleaner up the spark plug boots, cleaned out the harness plugs more with no improvements this time. I think a coil might be going bad at this point, I still have that low RPM "miss" which I don't think is the carbs anymore because it starts and accellerates flawless. Replaced the rear turn signals with some shorter ones but I don't think they are short enough and might still get melted. Hard to find flush ones that are incandescent as I don't want to change to an LED flasher (although this might solve some of my issues, who knows).

    Somewhere along the way the high beam indicator light stopped working, annoying but not a big deal. This last ride the neutral indicator light got stuck on...OK, that is much more annoying. Please tell me I can remove a plate of some sort, clean up a sensor/switch of some sort with brake cleaner and put back on. Please?

    Gremlins, gremlins, everywhere.

    Here's a nice pic:

    [​IMG]
    #98
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  19. fast1075

    fast1075 Not a Lemming Supporter

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    You have done well to get it this far!
    #99
  20. mrchristian

    mrchristian Been here awhile

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    Nov 23, 2008
    Oddometer:
    808
    Location:
    LA, CA
    WHY WON'T THIS LOW SPEED MISS/STUTTER GO AWAY???

    Oh, I forgot to gap one of the spark plugs. How about that.

    Yup.

    Everything fixed now.

    Except the neutral safety light.

    Darn.
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