Looks real good. My memory is vague but as I recall, all of that style of engine is the same size. The one that was in the original kids 3 wheeler was smaller. I believe they only came with the high and low range trans. I used a 90cc version in the original 3 wheeler. Bored to 105, cam and a carb off a cb350. It did run nice. Happy riding. 
Looks real good. My memory is vague but as I recall, all of that style of engine is the same size. The one that was in the original kids 3 wheeler was smaller. I believe they only came with the high and low range trans. I used a 90cc version in the original 3 wheeler. Bored to 105, cam and a carb off a cb350. It did run nice. Happy riding. [/QUOTE
Thanks, Von Zipper. I think what you are saying about engine dimensions makes. After all, why would a manufacturer tool up especially for small changes in stroke or bore.
[/QUOTEThanks, Von Zipper. I think what you are saying about engine dimensions makes. After all, why would a manufacturer tool up especially for small changes in stroke or bore.
Brake pedal should have a substantial return spring and a return stop, if it doesn't already (I can't tell from pics). To make your next shifter bike build much easier, check out "universal rearsets", used to relocate the foot pegs and controls rearward (and usually upward) on motorcycles. The more versatile rearsets are indexable (the position of the linkage lever, relative to the position of the shifter/brake pedal, is adjustable). A simple linkage is used on the shifter, allowing relocation of the left peg. Combine that with choices of vertical and horizontal master cylinders and the indexable rearsets, and you should be able to locate the pegs wherever you want them. Even though they are designed to move pegs/controls rearward, they could also be used to move them forward.
https://www.google.com/search?q=uni...osTVAhVMuo8KHcy4CkoQ_AUICygC&biw=1680&bih=898
Congratulations on a very successful build! :thumbsup: Manual transmission and electric start on your first build; can't wait to see what you do next! :wink:
https://www.google.com/search?q=uni...osTVAhVMuo8KHcy4CkoQ_AUICygC&biw=1680&bih=898
Congratulations on a very successful build! :thumbsup: Manual transmission and electric start on your first build; can't wait to see what you do next! :wink:
They look fine; just saying the brake will drag without a return spring on the pedal. A return spring will necessitate a return stop that locates the pedal slightly higher than where it rests without a spring (1/4" - 1/2" should suffice); you could adjust the linkage to retain the current pedal position. This would allow the brake to release fully. To be even more of a PITA than I have already been, I'll mention that it looks like the kick-start lever is not on all the way; should be a groove in the shaft to locate the pinch bolt. You have great redundancy; electric start, kick start, and since it's a manual, you could also bump start it!
Charles, I don't know where you are getting your information about a spring return to retract brake pads. The only thing pulling the pads back away from the disc when you let off the pedal is a gasket called a "square cut "O" ring". The ring is in a groove around the piston. It distends slightly when the brakes are compressed and when the hydraulic pressure is removed it returns to its resting shape, a shape much like a large faucet washer. That return to shape pulls the brake's piston slightly back from the disc, relieveing the drag. However, the travel is slight. It can leave a slight drag.
I know the kick start lever doesn't seat all the way home on its shaft, but the splines are engaging. That's the way it came from the factory.
I know the kick start lever doesn't seat all the way home on its shaft, but the splines are engaging. That's the way it came from the factory.
Getting my information from decades of owning motorcycles and learning all I could about them.
Return spring doesn't retract the piston & pads, it prevents the weight of the pedal from applying pressure on the master cylinder. The pedal has considerable leverage over the lever, so the pressure applied to the master cylinder would be several times the weight of the pedal. What the return spring does is to prevent the pedal from applying the brake; without it, it's like riding the brake all the time. With the power you have, I doubt you would notice the drag, but your brake components will wear more quickly and generate heat. Millions of motorcycles have a return spring and stop on the brake pedal (cars and trucks do, too). Just trying to be helpful. If you are happy with it as is, that's great.
https://www.google.com/search?q=mot...0MbVAhUDx2MKHY99D5oQ_AUICygC&biw=1680&bih=898
Kick start lever is probably the result of sloppy factory work. To get the lever all the way on, you will need to remove the pinch bolt, slide the lever in until the pinch bolt hole is aligned with the groove in the shaft, then reinstall the pinch bolt. The bolt sits in the shaft's groove so that the lever won't fall off if the bolt becomes loose.
Return spring doesn't retract the piston & pads, it prevents the weight of the pedal from applying pressure on the master cylinder. The pedal has considerable leverage over the lever, so the pressure applied to the master cylinder would be several times the weight of the pedal. What the return spring does is to prevent the pedal from applying the brake; without it, it's like riding the brake all the time. With the power you have, I doubt you would notice the drag, but your brake components will wear more quickly and generate heat. Millions of motorcycles have a return spring and stop on the brake pedal (cars and trucks do, too). Just trying to be helpful. If you are happy with it as is, that's great.
https://www.google.com/search?q=mot...0MbVAhUDx2MKHY99D5oQ_AUICygC&biw=1680&bih=898
Kick start lever is probably the result of sloppy factory work. To get the lever all the way on, you will need to remove the pinch bolt, slide the lever in until the pinch bolt hole is aligned with the groove in the shaft, then reinstall the pinch bolt. The bolt sits in the shaft's groove so that the lever won't fall off if the bolt becomes loose.
Well, my slave cylinder has a built in spring action that holds the pedal all the way up, with about 1/2" of play before the pedal actuates the piston, so that's covered. The problem with the start lever is that it doesn't totally clear the case, not to do with anything but the length of the shaft or the design of the lever.
The bike turned out very nice!. But I see a flaw, it looks too good to ride! I thought of using the same motor on my "Jimmy Gote". I think by the time you price out a jack shaft, TC and assorted stuff, the little motor you used really isn't much more money, if any. My concern was the 125cc would not have enough power for what I was building. I wish they offered a high/low range like the old Honda 90's had. But I really liked the idea of a reverse gear as some of them had. Any of your local car shows allow bikes to enter? Yours really is a head turner, needs to be shared with more gear heads!
Thanks a lot for you positive comments! Since my bike has no suspension it is of course very rough riding over bumpy ground, so that is not any fun, for me anyway. So, I am just riding on the asphalt private driveway that serves the homes in my little neighborhood of large lots. Yes, it is not a bike meant for rough use and getting real dirty. Of course yours is, and it looks like you are doing a great job of addressing your use requirements. I especially dig the front suspension.
For your purposes, I wonder if you could just put such a large sprocket on the wheel that the first gear of a four speed would be like a granny low, and with fourth gear still high enough to allow for all the top speed you would need. This 125cc engine not only makes 8.7hp at 7,500rpm, but of course also has a rev range way greater than the typical Predator type engine. I am going plenty fast without coming close to using the top end of the rev range. Second gear comes on with a bang and an easy wheel stand. I think your point about the comparative costs of engine/transmission combinations is a very good one. Having said that, the centrifugal clutch type does allow for crawling in tough terrain sort of like a car with an automatic transmission. With a manual transmission I would want a first gear so low that the clutch could be left engaged at a very low crawling speed. Speaking of Honda Trail 90's, my Dad had one and I learned to ride on it. Of course thats a 90cc bike that would go just about anywhere in the low range, but it did have a centrifugal clutch, too.
I think a lot of people at car shows would enjoy seeing a minibike. What guy among them didn't have or want a minibike at some point in their life? I think not many. I wanted to approach the local Lotus club to see if they would want to have the bike with their group at the annual British Field Meet this year, but I finished it just a little too late for that. Maybe next year for that one and I am certainly going to try to do it. By the way, what with all of the tech industry money in our Pacific Northwest the big local car shows feature some incredible world class top-drawer cars. We see guys driving late model exotics on the roads around here on a regular basis.
For your purposes, I wonder if you could just put such a large sprocket on the wheel that the first gear of a four speed would be like a granny low, and with fourth gear still high enough to allow for all the top speed you would need. This 125cc engine not only makes 8.7hp at 7,500rpm, but of course also has a rev range way greater than the typical Predator type engine. I am going plenty fast without coming close to using the top end of the rev range. Second gear comes on with a bang and an easy wheel stand. I think your point about the comparative costs of engine/transmission combinations is a very good one. Having said that, the centrifugal clutch type does allow for crawling in tough terrain sort of like a car with an automatic transmission. With a manual transmission I would want a first gear so low that the clutch could be left engaged at a very low crawling speed. Speaking of Honda Trail 90's, my Dad had one and I learned to ride on it. Of course thats a 90cc bike that would go just about anywhere in the low range, but it did have a centrifugal clutch, too.
I think a lot of people at car shows would enjoy seeing a minibike. What guy among them didn't have or want a minibike at some point in their life? I think not many. I wanted to approach the local Lotus club to see if they would want to have the bike with their group at the annual British Field Meet this year, but I finished it just a little too late for that. Maybe next year for that one and I am certainly going to try to do it. By the way, what with all of the tech industry money in our Pacific Northwest the big local car shows feature some incredible world class top-drawer cars. We see guys driving late model exotics on the roads around here on a regular basis.
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