Trials and errors of operating a motorized bicycle

Discussion in 'Travelling, Commuting & Safety' started by Timbone, May 2, 2014.

  1. Timbone

    Timbone Active Member

    It's been two weeks since I completed my first build. I enjoy this thing immensely, but I have already spent countless hours on this thing. I've burned about 2 gallons of gas mix, so I have had some good rides. But I have had several fails, too.

    My idea is to ride this thing to work a couple of times per week, and do lots of coffeehouse runs and general errands around the area. I have tried 2 runs into work and I have had 2 fails.

    After an initial successful period, I ran into some roadblocks.

    I became focused on improving the chain tensioner. I cut out a nice block of 16 gauge metal, drilled out some holes, got a strong spring and a idler pulley from a 9- speed derailleur and went to work.

    First plan was utter failure. The chain just rolled off the cog, no matter how I set it up. I even tried using pressure from the spring upwards from near the saddle. Even using the idler pulley it just would not work. My best approach was to use the spring to help hold the top of the tensioner up to maintain support and pressure away from the spokes.

    Well, the next morning - while doings first commute run - I had gone about a mile when the chain came off the sprocket and settled into the spokes. In the dark there was little I could do other than observe i had broken one spoke. I dragged it home, skidding the tire badly, then drove to work.

    After my workday, I quickly repaired the broken spoke and replaced the wheel, and was cruising nicely. Even though the tire now had a couple of bad spots, I didn't change it. All I had to do was survive 12 miles to work.

    The next morning, the bike was running perfectly and I was zooming into work on a brisk morning. Very little traffic and the city was mine. At about 4 miles, I hit an expansion joint on a bridge and very quickly I felt the stark hardness of the asphalt through the machine. Flat!

    I yanked the bike out if the drive lane and pondered my options. I decided to soft pedal home. I had made such good time to the bridge that I had plenty of time left to get to work.

    Back to the garage after work. I removed the wheel, changed the tire and tube. And replaced the wheel. I am getting very good at this! The first 10 miles of my shakedown cruise went very well. The chain was loose, but was feeding in very naturally and smoothly. My sprocket - at that time, was very close to perfectly true.

    But again, on the way home, something changed. The chain started jumping, wanting to jam into the spokes. Somehow, the sprocket was now very out of true. After using a combo of pedaling and cruising under power at a very smooth 15mph, I was able to make it home.

    In just a few minutes, I worked the sprocket joint and got it very true. Evidently, the chain has stretched significantly (it's a 415). I figured it would be best to remove another link of chain. Even though there seems to be an excessive amount of slack, I can't remove a full link. No way I could draw it together.

    I adjusted the chain tensioner yet again and, to my newbie eye, things look perfect. I'll do another shakedown cruise tomorrow afternoon or evening. My plan is to make a successful commute on Monday.


  2. Timbone

    Timbone Active Member

    24 hours later and I am ready nowfor along cruise to the hip end of the city.

    I decided to stop fighting the rearwheel. First fix was to draw up tension on the sprocket bolts and get it perfectly true. Done! But for whatever reason, the wheel wants to pull right,bringing the tire dangerously close to the seat stay. Can't ride like that. I got out my spoke wrench and retrued the rear wheel and increased the dish closer to the left/drive sprocket side. This appears to be success! Sprocket and wheel are true, chain has good tension, and the chain is feeding very nicely.

    Let's see what happens.

  3. cpuaid

    cpuaid Member

    reminds me of when i first tried to commute 11 miles each way to work using the HT 5 years ago in the Texas heat. i lost count of how many times i've had to either peddle the rest of the way to work or back home after the darn thing broke down. make sure you carry a basic set of tools, spare fasteners, and tube. hope you have better luck than i did commuting by HT.
  4. bluegoatwoods

    bluegoatwoods Well-Known Member

    I'm also certain that every bike has it's own trouble spots. Or at least there's a variety of trouble spots and a particular bike might suffer with some or with others, etc.

    The only thing I can say is that it sometimes, especially with happy time engines, takes a while to get to know those parts that need more attention than others. And it can take a while to learn what to do about those troubles that your particular bike has. I went through a couple of happy times that were troublesome enough that I had grown disenchanted. Gave it up for a while. Then I decided to try again. Third time was a charm. A little trouble at first, then smooth sailing.

    There comes a day when you understand. After that, these are wonderful little vehicles.

    Best of luck.
  5. Timbone

    Timbone Active Member

    I've had two very successful commutes in 4 attempts. 50% reliability! I do carry lots of tools in my backpack: a cycling multitool, a spokewrench, 2 crescent wrenches and a multi screwdriver.

    My engine is running like a top, and seems to be getting better. LOTS of gear chatter, though. The motor does best when it is cranking fairly high RPMs, like climbing a hill or rolling against a headwind or strong crosswind. Cruising speed is 24-27mph. I rarely get close to WOT.

    My 24 mile round trip commute requires less than a quart of fuel!

  6. Timbone

    Timbone Active Member

    Update: I seem to have crossed an important milestone in my motorized bicycle experience. While this thing REQUIRES almost daily maintenance, I am finding a certain degree of reliability. I've burned 3 full gallons of fuel - which translates into hundreds of miles! - and my last very active week has been mostly positive.

    I was riding back home in the twilight the other evening when - out of the blue! - the motor was REALLY LOUD! What happened? Did I blow a head gasket? It took me a couple of seconds to figure that one of the connectors of my exhaust came off! The open exhaust really made me appreciate how good the stock muffler is. Out if thoughtfulness for my neighbors, I shut down the motor and pedaled home the final half mile.

    Rag joint bolts loosened up. Took some time to slowly draw up tension and assure a high level of trueness to the sprocket. On the shakedown run, I noticed the wheel being slightly out of true. Had to adjust that.

    While doing a check of the carb / intake connection, the motor moved slightly under pressure from my screwdriver. I quickly found that my two motor mounts had loosened significantly. Tightened all that up!

    A funny thing: it's pretty easy to figure out where to position then fuel petcock to feed gas to the carb, but it seemed natural to turn the valve 180 degrees for shut off. Keep in mind that I have no indications in English of what the settings are. Under tests, it didn't seem like any setting stopped fuel flow! However, there is a setting that looks like a dot that seems to be closed! Took too long to figure that out!

    Starting seems a bit too violent. Since my fuel setting may have been faulty, this could have been a flooding issue. My feeling is quite the opposite, though, as it seems like it takes a while for good fuel flow to get to the engine. The best approach seems to be to begin with full choke. Then the engine will go into a soft, pedal assisted purr while the choke is closed. Then the engine may take off, or it will die only to be started on the next attempt.

    Tomorrow, we do commute #3. :)
  7. Fabian

    Fabian Well-Known Member

    2 gallons is nothing. I spent 2 years sorting out my bike; hand fabricating all manner of components to give me the kind of reliability i desire.
    That was a long 2 years of pain and heartache with non-stop unreliability problems; spending many miles pedaling my way home, and in some instances, not being able to pedal my way home.
  8. bluegoatwoods

    bluegoatwoods Well-Known Member

    Sounds like your coming right along and doing fine. You'll learn a bit more. But soon you won't be all that concerned about reliability because you'll know just what to expect.

    On my first bike I had a bit of trouble with the exhaust loosening up. The first time it happened there was a motorcycle coming at me a quarter mile or so down the road. The exhaust guts popped out onto the road and I said to myself, "Man, that bike is loud!...Wait a minute, is it me?" Sure enough. I collected the guts of the exhaust --this was the old pre-converter exhaust. It assembled a bit differently than today's--, waited for it to cool and put it back together.

    The second time it happened, it spit right under my rear wheel and flattened the tire. That was a drag.
  9. Timbone

    Timbone Active Member

    Thanks to you guys for your support! This site is so full of information.

    I am a good mechanic but there is no way I could have gotten so far along the HT learning curve so quickly without this site.I am hoping that I can give decent feedback as to what works and what doesn't work.

    First, I never planned to ride this motorbike in the rain. Still, I have been caught out a couple of times already and the bikebike was locked outside in a couple of serious downpours. I have read so many posts about concerns and warnings with regard to the stock kit CDI,but rain has had no negative effect whatsoever on my bike's performance. I was very seriously considering buying a high dollar CDI unit but that may not be necessary.

    Also, though I hate it's appearance, the stock chain tensioner is working flawlessly. It must be adjusted fromtime to time,but that's easy and quick.I still have a killer idea for creating a "be all, end all" tensioner and I am gathering the parts for it, but the stock item is functioning well.

    I have looked at several motorized bicycle parts sites and it's obvious that you could spend big bucks on your motorbike.I am honing the philosophy that one should maximize reliability and functionality with simple, cheap, creative fixes. If I were to start throwing money at this then,wouldn't make sense to just buy a motorcycle? There are too many cheap hardware pieces and too many junkyards full of usable materials to buy away every challenge! besides, I have a carbon fiber racing bike I need to maintain. My set of racing wheels cost more than all of the money I have dropped into this motorbike project!

    Keep rollin'!


    Another thing to report: the cops are letting me ride!
  10. Fabian

    Fabian Well-Known Member

    Having owned many types of motorized transport; high powered sports bikes being amongst the list, i can say that my motorized bicycle is "THE" most enjoyable thing i've owned and ridden.
    It's got nothing to do with how much money is spent on the motorized bicycle concept, and everything to do with the fact that the handling dynamics are that of a bicycle; with more responsiveness than a 125 GP bike, which weigh typically in at around 70 kilos (depending on spec). Secondly, you can access difficult places that are hard for a typical dirt bike to get to, because it's hard to lift a 100 kilo bike over large tree logs when you cant find a way around an obstacle.

    A motorized bicycle is a heck of a lot more than just cheap transport. Crikey, my bike is worth about $5,000 with all the stuff i've done to it; and parts that i have bought, tried and sometimes discarded as being worthless items in operation; a boost bottle being one of them.
  11. flashstar

    flashstar Member

    One of the big sources of unreliability on these kits is the drive chain and rear sprocket. I would purchase a disc mount rear sprocket and quality 415 chain. Then, ditch the idler and angle your engine so that proper chain tension is maintained. I recommend using tube protectors as well. Check your engine head bolts for tightness with a torque wrench frequently over the first 250 miles. Finally, use blue lock-tite on the engine mounts and exhaust nuts. Total extra cost is probably less than $150.

    With these changes, you will see your reliability increase a ton. I went from having break-downs each trip to riding for 100 miles without an issue. Good luck!
  12. Phil21

    Phil21 New Member

    I live in fla and its legal to ride here fla stat.316.001(003)
  13. Timbone

    Timbone Active Member