Hi from Vermont!

Discussion in 'Introduce Yourself' started by Zachary, Sep 28, 2014.

  1. Zachary

    Zachary New Member

    Hello forum,

    I just got my motorized cranbrook in working order a few days ago - bought it from a guy on Craigslist for a steal but it needed work. I believe it has a 66cc Grubee but am not sure. One of the front studs was broken off inside the engine. I removed it with a drill-out tool and mounted it more better with a new mount from SBP.

    It runs great now but isn't finished. Mostly I'm concerned with the rear wheel. It has too much wobble in it and I can actually see bearings just inside the rear sprocket... I suspect the original builder removed the dust cap?

    Top speed is 35mph but I've been riding at 27ish super comfortably. Vibrations become interesting faster than that.

    Pictures to come...
     
    Last edited: Sep 28, 2014

  2. Zachary

    Zachary New Member

    I noticed this after a ride today. Grease coming out of the bearings?
     

    Attached Files:

  3. Zachary

    Zachary New Member

    The whole bike, of course!
     

    Attached Files:

  4. Zachary

    Zachary New Member

    More things about this bike:

    The bottom (and guts?) of the muffler fell off in a mystery location on the first or second ride. Part of a beer can is working well enough until the new stock muffler comes in.

    I removed the chain tensioner. The included one never stayed put. I picked up a spring loaded tensioner. Didn't like it either. Taking out one link gave a tight enough #41 chain. I have a 410 bmx chain coming that will hopefully improve wheel and frame clearance.

    The pedal chain came off twice on my last ride. First while assisting up hill, then on a mild downhill. The second time I had to stop with my foot + engaged engine. I have since pulled the rear wheel back tighter and so far so good.

    So fun.
     
  5. Fabian

    Fabian Well-Known Member

    If you are enjoying the bike now, just wait till you get gears.
     
  6. Zachary

    Zachary New Member

    And go faster than 35??? Maybe after I get the rear wheel feeling better. I'm thinking of just getting a new rear wheel without a coaster break once the side pull breaks come in... and installing a 41 tooth sprocket on it. I haven't installed a sprocket myself yet. The 44 tooth on there now was installed by craigslist guy.

    Last night I installed a new (not broken) stock muffler and Jaguar's CDI. The bike definitely has better low end power and feels smoother up until 20ish mph, but gets a little funny around 30 and kind of hesitates. It's like it pulls then gives up, pulls then gives up. It did feel like it had extra power just past 30 but I couldn't always get there. Probably I should play with the jumpers. I've also had a little trouble starting since installing the new CDI. Not sure about that yet.
     
  7. Fabian

    Fabian Well-Known Member

    You need to look at other aspects of engine operation, because the CDI won't give those symptoms.
     
  8. Zachary

    Zachary New Member

    Thanks seriously for the feedback, Fabian. I went on a 15 mile ride before installing the CDI... and didn't have those symptoms. I did (re)install a chain tensioner the same time I did the CDI. The replacement stock muffler was earlier in the day and it did fine with just that change. I had put about 35 miles on the bike before yesterday.

    The "hesitation" I described reminds me a little of my old Monte Carlo, which would do something similar and shortly after die completely. The shop said it was likely being starved for fuel because of rust clogging the filter (we never found out if that was true, however). My bike only does this at higher RPMs, unlike the old car, and doesn't die afterwards. Could this be a carb problem being revealed by the new CDI? I'm thinking out loud. Maybe I'm not getting a consistent spark and something is up with my wiring job. Maybe the vibration at faster speeds is shaking something perfectly wrong with the new electricals. I wonder how the starting problem and high RPM oddness are related.

    Can't wait for lunch so I can troubleshoot more.
     
    Last edited: Sep 30, 2014
  9. Zachary

    Zachary New Member

    I got it starting super consistently - at least in the parking lot. The CDI came with two different connectors, spade and ring, for the ignition coil (I got them together from JNMotors) but the coil had two male spades on it. I had found an old female spade end from another project and swapped the ring terminal for that while installing the CDI. Testing today makes me think my old spade end was just all corroded and dirty. Wiggling it around where it connects to the coil *seemed* to make things a lot better. I could start the bike just releasing the clutch for half a second at <5mph. I haven't taken the bike up to 30 yet, but it hit 24ish in the parking lot without any bad behavior.

    Will test more on the way home and probably clean out that terminal best I can.
     
  10. Fabian

    Fabian Well-Known Member

    It sounds more like a fueling issue.

    Get the carburettor jetted correctly before chasing electrical troubles, if the engine is running without any spark miss.
     
  11. Zachary

    Zachary New Member

    So, on the way home I noticed a distinctive electrical buzzing sound. Suspecting it was the connection to the spark plug, I looked at home and noticed there was a brass connector with clip in the spark plug boot, just like was attached to the stock spark plug, so I was stacking a brass connector on a brass connector ontop of the spark plug.

    Sadly, my gas tank apparently developed a crack today, too. Back in a week or so...
     
  12. Imthegrt1

    Imthegrt1 Member

    So on rear wheel have you check make sure it's not warp?
    Also have u reback the bearings?
    Look at the rear and have the back tire off the ground to let it spin at idle
    Make sure wheel straight.
    Just a few things for your vibration problem.
     
  13. Zachary

    Zachary New Member

    I suppose now is a good time to work on the rear wheel while I wait for the new tank.

    Sheldon Brown's website describes my wheel perfectly:

    http://sheldonbrown.com/coaster-brakes.html

    Time to get a cone wrench! I think the cranbrook wants a 15mm.

    I will add that on the ride home yesterday I managed a new top speed, even with the (what I suspect was) bad electrical connections - 35.5mph! Before, even going downhill, the engine would stop me from going any faster. I could have kept accelerating yesterday. There is MUCH less vibration above 30 with the new CDI... because of better spark timings, I assume. It's very tempting to make a "temporary" fuel tank to keep experimenting...
     
  14. Fabian

    Fabian Well-Known Member

    A cone wrench is an absolutely essential item to have in your tool kit.


    kept accelerating into the arms of injury?
     
  15. Zachary

    Zachary New Member

    For full disclosure, I forgot my helmet at work for that ride. Bad bad bad naughty. Didn't even occur to me that I hadn't worn it until I couldn't find it this morning.
     
  16. Zachary

    Zachary New Member

    This worked great getting me to work today. The tube coming out the muffler is high temperature silicone. I am not sure what it's doing to the engine power-wise but is super quiet. I am seeing a lot less hesitation in the upper 20mph range with the spark plug properly connected now. It's still there but maybe 20% of what it was before the change. I'm interested in what is different at around 3/4 throttle (where it hits the "hesitation" speed range). I imagine that's right around the transition between the needle in the carb controlling how much fuel and the main jet taking over completely. It seemed like being very gradual about increasing throttle at those speeds alleviated the problem... too much fuel? It's running slightly rich at that throttle position? Once I hit 30+, the bike takes off smooth up to 35. I may try moving the clip on the carb needle up a space to see if that makes a difference.

    bike1.jpg bike2.jpg
     
  17. Fabian

    Fabian Well-Known Member

    From about half throttle position, the needle has minimal effect on the fuel delivery coming from the main jet. At 3/4 throttle, the needle virtually no effect on fuel delivery, regardless of where you place the e-clip on the needle.

    I am sure the reduced exhaust noise afforded by the silicone hose is music to your ears, and to everyone else.
     
  18. Zachary

    Zachary New Member

    Half a beersworth of gas is only enough to get me the 5ish miles uphill to work, with none left to ride around the parking lot at lunch :(
     
  19. Zachary

    Zachary New Member

    Hmmmm his crud seems to be coming out from a round the spark plug... image.jpg
     
  20. Zachary

    Zachary New Member

    It did a wheelie today. I was starting it on a mild downhill and gave it some gas and bam front wheel off the ground on engine power. Since last posting I've flipped the dishing on the rear sprocket, installed front breaks, broken a muffler, made a fankenstein muffler from parts, broke a clutch cable while riding(!), made a better temporary fuel tank, found loose head bolts, and fixed the coster brake/rear wheel wobble problem.


    New top speed 36.8mph. There is now hardly any hesitation around he 28mph range like I was seeing before these changes
    image.jpg
     
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