Oil change fixed the transmission..?

Discussion in 'Tech Area' started by Jlloyd, May 5, 2018.

  1. Jlloyd

    Jlloyd New Member

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    A few weeks ago I bought my very first CT70, a very faded Candy Ruby Red, build date 10/69 with over 10k on the odometer. The previous owner had gotten it for free and put a few bucks into it; new tires, cables, CHP carburetor and replaced the points with CDI. Runs like a champ and didn't cost me a ton to buy it. The only problem was that the transmission took considerable effort to get into gear. Up shifting was clunky using my foot, but downshifting was impossible. In order to shift from 3rd to 2nd to 1st, it was necessary to reach down and yank the gearshift by hand. Definitely NOT the way I remember these being when I was a kid.

    Fast forward a couple weeks. I called the PO and asked what oil he used. His answer was, "whatever I had around the barn". I did some research here and other sites and learned that, first and foremost, to use motorcycle oil that was formulated for a wet clutch. I went with synthetic Lucas 20w-50 high-zinc. The old oil didn't look horrible, just a little thin with a sort of grayish tint. After it was drained and replaced, I started it, warmed it up and checked for leaks. Immediately I noticed it went into first a little easier. Second and third were much the same. The surprise came when I put my toe under the shifter and thought "I know this isn't going to work". It popped into second!! Granted, it isn't the buttery smooth shifts that I remember when riding my friend's Trail 70, but it worked. The more I ride it, the easier it is to shift up/down. Clutch adjustment hasn't really affected it much. I've read the articles and watched the video of the guy with the Z50, but I'd really like to have a hands-on lesson on where the "resistance" is felt when taking up the play in the clutch.

    Anyway, I just thought I'd share my little moment of success. I love this site. I have learned and hope to continue to learn from it and its members, who seem to have been enamoured by these little machines so many years ago, as I was/am.
     
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  3. racerx

    racerx Administrator
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    With 10K+ showing on the odometer, there's little doubt it's actual mileage. So, either the motor has been rebuilt, at least once, already...or, it was well-maintained.

    Best guess is that the shift forks & pins are worn, that could account for the balky shift quality. A bent shift shaft could be part of the "equation" as well, but I'd not bet on it, unless the bike shows obvious signs of having been dumped on its LH side. Yes, oil can have some big impacts, as you've seen...and other ways you've not, such as clutch slippage and accelerate tranny wear (shift forks, mainly). Use an oil labeled "wet-clutch compatible" and "JASO" spec, that'll keep the motor & trans happy. If the Lucas product you've chosen meets those criteria, which it may (I'm unfamiliar with this oil) you're probably fine. Only way to inspect the tranny is by splitting the cases, not on the top of your wish list, I reckon. I would, however, recommend learning about the oil spinner...and cleaning it; that's major factor (along with timely oil changes) in keeping one of these motor healthy well into five-digit mileage.

    As for clutch preload adjustment, best way to learn the "feel" is while installing the RH (outer) clutch cover. As you twist the adjuster, the cover will be lifted away from the crankcase, providing visual reference you can then match with the "feel" as the preload adjuster is twisted beyond zero lash. Personally, I prefer the preload set to ~1/8 turn out from zero lash, a little tighter than factory spec. The important parameter is having at least some lash, otherwise, it's equivalent to "riding the clutch" in a car...resulting in unwanted slippage and wear.
     
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  4. cjpayne

    cjpayne Well-Known Member

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    "Whatever I had around the barn."lol
    Just asking, but does the bike have the original motor?
     
  5. Coastal Redneck

    Coastal Redneck Well-Known Member

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    Which means used oil drained from a tractor... many years ago, LOL. :eek:
     
  6. Jlloyd

    Jlloyd New Member

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    So far as I can tell, yes it's the original. Frame number is CT70-1217xx and engine is CT70E-1215xx.

    The more I examine it the more I think I'm going to have to start ordering parts. I know the transmission needs work, but I also noticed the seals around the kickstarter and gearshift shafts might need replacing. It runs and idles like a sewing machine, but the PO did some wonky things. When he installed the CDI, he just zip-tied the module to the frame near the chainguard. Brake lights work, but no head/tail lights...probably because he discarded the handlebar switches when he changed out the cables. For now, I'm enjoying the ride, but I KNOW some issues are about to rear their ugly head.
     
  7. OLD CT

    OLD CT Well-Known Member

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    Lucas 50w.jpg I just bought a 5 gallon bucket of Lucas 50w racing high zinc last week, for the Harley's. $99 delivered to my door. Good stuff.
     
    #6 OLD CT, May 6, 2018
    Last edited: May 6, 2018
  8. Jlloyd

    Jlloyd New Member

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    The transmission is definitely working better, but clutch adjustment is completely trial and error. I've rebuilt a few traditional clutches on my motorcycles so I'm familiar with how they work, but this semi-auto isn't one of those. The only resistance I feel when adjusting it clockwise or counterclockwise is when it comes to FULL stop. I see a new RH gasket in my near future...and a clutch pack...and a Clymers...and a.....
     
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  9. Jlloyd

    Jlloyd New Member

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    I forgot to mention that when it's idling in gear, it feels like it's kinda surging forward. I haven't figured out if it gets better when adjusted clockwise or counterclockwise.

    I really just need to see how it works firsthand and stop posting goofy, vague concerns.

    Did I mention that this is all being done in the kitchen of a duplex in west Texas that also happens to be corporate housing?
     
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  10. Jlloyd

    Jlloyd New Member

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    I thought the same! The thing is, the oil seemed really thin on the dipstick. Like, olive oil thin.
     
  11. racerx

    racerx Administrator
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    "Vague, goofy, concerns" are oftentimes the only things we have to go by...until accumulating enough experience to identify what's right and what's not. So, by all means, ask away, it's the only classroom instruction available, circa 2018.

    The bike should not pull forward, at idle...if the idle speed is within spec. OTOH, if the idle rpm is too high...then, of course, the clutch will grab and ther's no way to adjust that out of the clutch; it'd be a carburetor issue. That said, it is possible (though unlikely) that the clutch assembly was incorrectly installed and that would be eminently fixable.
     
  12. Coastal Redneck

    Coastal Redneck Well-Known Member

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    HaHa, these bikes are subtle, they work on ya by devious methods and, next thing ya know, you're pouring money into 'em, LOL. :eek:

    But when you're flyin' down some road or trail, feeling like an asphalt hero or Metal Mulisha god, you won't care about the expense... :whistle:
     
  13. cjpayne

    cjpayne Well-Known Member

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    This will give you an idea on what's inside and how to set the clutch adjuster. Made it awhile back.
    https://lilhonda.com/index.php?thre...pinner-screen-cleaning-on-74-k3-3speed.19143/
     
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  14. CLEC66

    CLEC66 New Member

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  15. CLEC66

    CLEC66 New Member

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    Greetings all, long time member and obvious lurker. Decided to chime in on this one. jlloyd I sold that bike to the rancher about a year ago. When I purchased the bike someone had converted it to a 3-speed clutch instead of semi auto. I changed it back to original but as you know the trans would not shift right so I decided to turn the bike. Oh, my PO welded the cross bar in to keep his kids from bending the bars repeatedly.
     
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  16. Jlloyd

    Jlloyd New Member

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    HOLY SHNIKEYS!!! What a time to be alive!! What an amazing sequence of events and what are the chances of...IT ALL?!!?!?

    My hat has officially been blown into the water.
     
  17. Jlloyd

    Jlloyd New Member

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    The transmission is working much, MUCH better by the way. Today I noticed the gear shift lever's travel wasn't clearing the actual LH case. With all the work you mentioned, I can't imagine that somebody didn't notice it. Probably another coincidence!

    Any idea where the title is or have a possible name? Wow. This is amazing.
     
  18. CLEC66

    CLEC66 New Member

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    Person I purchased from had no title as most of these bikes never had titles. The gear shift issue is pretty normal as most were bent from falling over or hitting something while riding, just needs some massaging to get the right curve back to clear the case
     
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  19. Jlloyd

    Jlloyd New Member

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    I don't really have the tools here to straighten it out. What I DID do (for now anyway) is loosen the shifter and slide it a tiny bit outboard, just enough to clear the case. Worked a treat.
     
  20. Jlloyd

    Jlloyd New Member

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    If there's anything at all that you remember about it, I'd be grateful. You said you changed the manual back to the semi-auto..does that mean that the clutch is less than a couple years old?

    I just realized I haven't thanked you for chiming in. So, THANK YOU!
     
  21. CLEC66

    CLEC66 New Member

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    Your welcome!! Glad it made it to Lilhonda. I changed the manual clutch cover and components back to semi auto cover but did not replace the clutch. Originally thought the manual conversion was the issue. Simply did not want to split the cases to replace the worn parts so I let it go. The bike was resale bike for me to fund other ct70 projects I had going. Sorry I don't have any other history of bike. Beware as these are very addictive bikes.
     
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