Suzuki TC90, the coolest $30 I've spent in awhile.

Discussion in '2 smokers' started by Bandit240, Nov 4, 2009.

  1. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    72E485D1-9F77-4656-A230-DDCCFFA329F5.jpeg Got my Chinese carb installed. Perfect fit. May need to rejet. What I figured out is, Suzuki A100, AS100 and etc. motorcycles are still being made in Asia and use almost the exact carburetor except for jetting and the small port on the choke side needs a cap. These carbs are made in China and Taiwan and are sold through eBay for one. But they are not listed as fitting the old TC/TS’s. Anyway, here’s a picture!
    #81
    aptbldr likes this.
  2. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    Love that video!
    #82
    slideways likes this.
  3. SpeedFourJoe

    SpeedFourJoe Been here awhile

    Joined:
    Jun 16, 2010
    Oddometer:
    143
    Location:
    Indiana
    Yes, it is. It was like that when I bought it, and I haven't had it off yet. With the low miles on the bike it makes me wonder if it came from the factory like that. As far as the combustion chamber is concerned it doesn't make any difference. What's funny is that the bike in the video posted is the same way. Maybe it is good luck on one of these bikes. :1drink
    #83
    LandsVW likes this.
  4. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    Mines been started and is running. Still waiting on a clutch cable.
    #84
  5. Ever Onward

    Ever Onward Older,Wiser, Smarter

    Joined:
    May 1, 2011
    Oddometer:
    8,609
    Location:
    Weed Town USA
    With the head backwards , the head cant flow air correctly.

    It will run hot.
    #85
  6. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    Rode it around the block! Still not running exactly right, but has 4 gears, high/low, brakes, clutch feels good and starts right up. Messing with jetting now, to make the chinese carb wake up and take notice.
    #86
    aptbldr likes this.
  7. beeker12

    beeker12 Been here awhile

    Joined:
    Aug 2, 2014
    Oddometer:
    244
    Location:
    West Eugene
    i-mP8TNsk-L.jpg my TC90 is hiding next to my Hodaka Road Toad at this years Vintage campout. The 90 is Hands down my favorite trail bike.
    #87
    Mambo Dave, LandsVW and slideways like this.
  8. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    So, I bought, off eBay, a TC125 tank badge. It’s longer and wider than my 1972 TC90 tank badge. I only need one. I’ll trade someone straight across, and mail this one to them, with maybe a few $$ for postage?
    #88
  9. prima19rider

    prima19rider Adventurer

    Joined:
    Jul 15, 2018
    Oddometer:
    37
    Location:
    Virginia
    I had a red one just like it. Suzuki K15, 80cc’s fantastic bike. Purchased it new in 1965.
    #89
    LandsVW likes this.
  10. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    F69FB4D5-6498-4257-8798-5F93F6A1D24A.jpeg Chinese carb with 114 main jet is running really nicely. Evidently the original Mikuni takes a different style main jet with the numbers 170 on it. This will not fit the Chinese carb. Threads are different. A modern carb jet will work tho, and the 170=approx 120 on the modern carbs. I had a 118 and was slightly rich I think. So, went to the 114. I have idle jet per stock, 17.5, and screw adjusted to 1 1/4 turns out. I did have to mess with the float on the Chinese carb, as it was lean, I think. But got the bowl to hold gas about 1/2 way full. Just some bending and manipulating of the float and the needle tab.

    Slightly leaner might even be ok, maybe a 110 or a 112, but my next size down i own is a 107 so won’t be trying that as I think it will be too lean.

    Bike is running top notch! Winding out very nicely and idling and starting nicely too! Very happy! Will throw some plates and mirrors on it and test it on a long ride later today maybe.

    Woo hoo! Go Rotary Suzi!

    Still need to drain and change shock oil and seals. Maybe a new rear tire would be good. And, then, if it tests out well, get a title application in the works.

    Thanks for all the encouragement and help! Will keep updates flowing.
    #90
    Mambo Dave and slideways like this.
  11. aptbldr

    aptbldr easy rider

    Joined:
    Apr 20, 2009
    Oddometer:
    1,577
    Location:
    Upstate South Carolina, USA
    Be careful in short pants!
    A TC90 heat-shield branded my leg a long time ago.
    Ahh, first muffler burn ... :-) well done before you know you're cookin'.
    #91
    LandsVW likes this.
  12. slideways

    slideways España

    Joined:
    Mar 1, 2003
    Oddometer:
    14,394
    Location:
    Spain
    So true , I put a hooker header exhaust on my tc 90 and branded the heart on the heat shielding to my leg.
    #92
    dpforth and LandsVW like this.
  13. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    Still messing with the TC. Might try a smaller main jet today. Is bogging at full throttle.
    #93
  14. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    Have the 1972 TC90 running very well. Remember, I bought a brand new Chinese knock off mikuni which is still used on the A100’s in Asia. So, I put a mikuni 17.5 slow jet in it. And then, since it doesn’t take the old style mikuni jets, finally figured out that a 105 main jet and the mixture screw turned to about 3/4 and the needle clip still in the middle makes it run almost perfect. I haven’t long distance tested it for rich or lean, but has full range of rpms and takes off from a good idle with no issues. So, if a used carburetor can’t be found, a 29$ knock off brand new one is definitely useable.
    #94
  15. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    Still messing about with the TC90! Nothing else to report.
    #95
  16. LandsVW

    LandsVW Been here awhile

    Joined:
    Oct 20, 2012
    Oddometer:
    758
    Location:
    Tri City, Oregon
    Traded the TC90 for a 1970 Honda CL100 Scrambler project. Really like the process of fixing these old bikes. Am now joining the CL100 thread and leaving this one! Ride on inmates.
    #96
  17. Keith Moran

    Keith Moran n00b

    Joined:
    Jun 24, 2020
    Oddometer:
    3
    Location:
    Ohio
    sooo, this vacuum line, how do I attach it back onto the injection system? Do I need to remove the right side cover to get in there to reattach it, or is there an easier way. I can get no help from anyone on this.
    #97
  18. Carmackle

    Carmackle Been here awhile Supporter

    Joined:
    Jan 1, 2017
    Oddometer:
    405
    Well, there isn't any vacuum line involved with the injection system. The oil tank has a supply line feeding the oil pump, the pump has 2 output lines to the intake tract & the left side main bearing, and that's it.
    The carburetor has a vent hose coming off the left side of the carb body that runs into a passage in the crankcase,if I remember correctly. And there is a overflow hose from the bootom of the float bowl to a passage behind and slightly to the right of the carb into the crankcase. I THINK,lol.
    #98
  19. Keith Moran

    Keith Moran n00b

    Joined:
    Jun 24, 2020
    Oddometer:
    3
    Location:
    Ohio
    THAT hose, right? Definitely goes up in crankcase, I can see the hole. The hose looks like it was on a fitting, the end is kinda swelled up. Does it connect to anything, or does it run up there into nothingness? If I do have to connect it, do I have to remove the whole right cover to get in there?

    Attached Files:

    #99
  20. Carmackle

    Carmackle Been here awhile Supporter

    Joined:
    Jan 1, 2017
    Oddometer:
    405
    I THINK since it is noting more than a vent hose it just hangs out inside the clean air environment inside the carb cavity.
    I'm trying to find my engine diagrams-hang on a sec.