roughrider
Member
Madness, because trying to get screaming performance out of a motorized bicycle seems kinda silly, doesn't it? I mean, if you really want to go fast, get yourself a sport bike and twist that throttle. :helmet:
Method, because there is more to performance than top speed. Me? I have a game I'm playing. I'm trying to extract smooth running reliability out of an engine that is notorious for its unreliability. That's the challenge.
Procedure, because I've evolved a step-by-step approach.
First, I started with a basically stock build. Then, I got it tuned so that the powerband was pretty smooth and the spark plug was a nice tan for my operating speeds. Right now, I'm still breaking the engine in, so that meant getting the air/fuel mix right at less than 3/4 throttle on the stock, NT carb.
That accomplished, I then replaced the stock CDI with a Jaguar CDI and a quality spark plug. I have only occasionally opened her up, but I can tell you that I noticed an immediate diminishment of vibration at higher rpms and quite a boost in acceleration from about 3/4 throttle. In fact, even with the 48 tooth rear sprocket, my bike already goes faster than feels safe. I have not even topped her out.
One problem I have is that the Schwinn style springer forks, even with the brazed in bushings I installed, just don't handle high speeds very well. They are just not strong enough. I can feel it, and I can see them kinda tweaking around a bit at high speeds. I think I need to go with mountain bike forks to get a solid, safe feeling at speeds in excess of 25mph. (Again, I'm still breaking the engine in. I've only ran her at WOT for ten to fifteen seconds at a time. Also, I use an iPhone app to check my speed.)
Next, I'm gonna mod a spare muffler by installing some undetermined (as yet) number of inches of pipe between the exhaust port and the muffler. I have some flex hose for this purpose, but I'll have to weld some bits of adapter pipes to make it fit nice and snug. Since I'm already happy with the top end, it's the bottom end I'm working on. The bike could still use some more scoot at the bottom of her curve, and given my desire for a reliable little putter rather than a race demon, this seems appropriate.
I have a Dellorto clone carb I have not installed. Sadly, I've heard mixed reviews. Well, I bought it, so I'll try it. We'll see, but that's for later.
Last, I was surprised to discover that these HT engines actually are not that loud. I was all worried about the exhaust note, but from the rider's position, it is other engine noises that seem to be the louder tones. Quieting that all down is another project.
One thing at a time. In the mean time, I'm having fun.
Cheers,
Rick
Method, because there is more to performance than top speed. Me? I have a game I'm playing. I'm trying to extract smooth running reliability out of an engine that is notorious for its unreliability. That's the challenge.
Procedure, because I've evolved a step-by-step approach.
First, I started with a basically stock build. Then, I got it tuned so that the powerband was pretty smooth and the spark plug was a nice tan for my operating speeds. Right now, I'm still breaking the engine in, so that meant getting the air/fuel mix right at less than 3/4 throttle on the stock, NT carb.
That accomplished, I then replaced the stock CDI with a Jaguar CDI and a quality spark plug. I have only occasionally opened her up, but I can tell you that I noticed an immediate diminishment of vibration at higher rpms and quite a boost in acceleration from about 3/4 throttle. In fact, even with the 48 tooth rear sprocket, my bike already goes faster than feels safe. I have not even topped her out.
One problem I have is that the Schwinn style springer forks, even with the brazed in bushings I installed, just don't handle high speeds very well. They are just not strong enough. I can feel it, and I can see them kinda tweaking around a bit at high speeds. I think I need to go with mountain bike forks to get a solid, safe feeling at speeds in excess of 25mph. (Again, I'm still breaking the engine in. I've only ran her at WOT for ten to fifteen seconds at a time. Also, I use an iPhone app to check my speed.)
Next, I'm gonna mod a spare muffler by installing some undetermined (as yet) number of inches of pipe between the exhaust port and the muffler. I have some flex hose for this purpose, but I'll have to weld some bits of adapter pipes to make it fit nice and snug. Since I'm already happy with the top end, it's the bottom end I'm working on. The bike could still use some more scoot at the bottom of her curve, and given my desire for a reliable little putter rather than a race demon, this seems appropriate.
I have a Dellorto clone carb I have not installed. Sadly, I've heard mixed reviews. Well, I bought it, so I'll try it. We'll see, but that's for later.
Last, I was surprised to discover that these HT engines actually are not that loud. I was all worried about the exhaust note, but from the rider's position, it is other engine noises that seem to be the louder tones. Quieting that all down is another project.
One thing at a time. In the mean time, I'm having fun.
Cheers,
Rick
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