New 78 Trail 90

Discussion in 'CT90, CT110, ST70, ST90 Discussion' started by Clayton, May 12, 2020.

  1. Clayton

    Clayton Member

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    I was able to get this 78 trail 90 today and am super excited. It doesn’t run but has a clean Texas title. I’m hoping it won’t take much to get it going. I’ve piddled with it a little this evening and found it has no spark so I’m gonna trouble shoot that issue this weekend. If anyone has any tips on one of these guys please holler. Also if anyone has any good places for parts let me know please. Thanks everyone for such an amazing site to get info on all my lil Honda’s! B0D6502C-B695-423D-97BB-6BB93968E0D8.jpeg A810B41E-924E-48F7-A3A7-F2B424C6B1DF.jpeg E2820E2C-C77D-4C71-87E7-E297C58A4F93.jpeg
     
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  3. b52bombardier1

    b52bombardier1 Well-Known Member

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    Hello,

    It absolutely needs a good six volt battery and this battery is also the voltage regulator for the bike. Without a good battery that can accept recharge current, the lamps and bulbs scream in agony as they flame out. And headlights are expensive. Look for parts here:

    http://dratv.com/

    Looks like a good bike and that fuel jug is kinda rare. Your bike will likely need a tune up which will include a valve adjustment, timing adjustment and points gap adjustment. My prediction is the fuel tank will be heavily varnished and so will the carburetor. Maybe will need a condenser replacement.

    Let's talk about the spark advancer under the points plate. It may be rusty and sticky with a need for some lubrication. Please use a sharpie marker before you take the major components of the advancer apart because you have a 50-50 chance of putting it back together wrong. Mark it for alignment. If you do it wrong, it'll look perfectly normal but the cam lobe will place the spark exactly 180 degrees out of phase for the combustion cycle. Please don't ask me how I found this out - it was not a happy time that afternoon when I was a noob neighborhood 90 CC Honda engine mechanic.

    Rick
     
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  4. Tripod

    Tripod Active Member

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    Looks like a solid foundation. You shouldnt have too much trouble getting it going again.
     
  5. Clayton

    Clayton Member

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    Thanks for the reply’s!! @ B52bombardier1 thanks for the info I’m gonna order a new battery today. I think your right about the gas it smells super crazy when you open the gas tank lol! I’m gonna check out the spark advancer this weekend and mark it correctly so I don’t reinstall it wrong. Great tip! I am totally new to the CT90 and have already found MANY differences between it and my CT70 and my Trail 50. Thanks for the info guys.
     
  6. b52bombardier1

    b52bombardier1 Well-Known Member

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    Let's hope nobody monkeyed with your spark advancer before you got the bike. It would not be the first time this waylaid an old Honda bike for no good reason.

    With that varnished up gas tank, you will want to run an inline gas filter on both the main and reserve fuel lines. New fuel will act as a solvent and will loosen that stuff up and send it to your carburetor. And you will be perpetually rebuilding your carb without a filter. Use caution with any clear plastic fuel filter here because they don't tolerate heat from the exhaust pipe.

    Rick
     
  7. Clayton

    Clayton Member

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    All very good info (y) I’ll keep all of this in mind and will definitely keep y’all posted about everything. I’m just super excited about the whole thing lol.
     
  8. Clayton

    Clayton Member

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    So I got her to crank!! But she will only run with the choke on? I took the carb apart and clean it real good but it still only runs with the choke. No matter where the throttle position is as soon as I start to move the choke it bogs down and dies. I’ve attached a couple of pics of my carb. I was wondering if the brass piece that I am pointing at with my screw driver is removable? If so hat is this part? My Clymer manual doesn’t show this piece in the exploded view. Any and all info is greatly appreciated. F352F7AF-3EE0-4331-8C3A-CE149C5F18CF.jpeg 01A34C79-1A75-43D5-9B44-27A137BF7C36.jpeg
     
  9. Tripod

    Tripod Active Member

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    I'd bet its pressed in. Im not a fan of the late 70's round bowl. Just like the ct70 carbs, i'd get an early 70's rectangle bowl carb.
     
  10. Clayton

    Clayton Member

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    Good to know!! Is that one of my jets?
     
  11. Clayton

    Clayton Member

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    CT9()_Carb_1.JPG CT90_Carb_2.JPG So I disassembled my carb last light and soaked it in Berryman CHEM-DIP for a couple of hours. This morning I reassembled it and it seems to run a little better but it still wants the choke to idle. I was able to ride it around the neighborhood and once I was in 2nd gear (about 25 mph) I was able to ease the choke off. It ran descent but was a little "boggy". I rode around for probably 10 minutes with the choke off but as soon as I would come to a stop it would die. I was looking this morning for a replacement carb but am nervous about the ones I found due to my small knowledge of carbs lol. I would love a NOS but I don't think that's gonna happen lol. Does anyone have any suggestions for a new carb or maybe what I could do to mine? I want to be able to use my factory air filter assembly. Any and all info is greatly appreciated!!!! Iv included a few pics of my carb part number if that helps. Also its a 1978 CT90.
     

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