NOTE: This came out to be a lot longer than expected so just be prepared to read lol.
So I'm gonna use this to show where I'm at with my hobby for now and also point out what I've learned from personal experience. What I say may not apply to everyone so don't take my words as something general. But basically, when I first built this bike I got the help of a friend who knew about it more than me. The build was solid at first but there were many things I should've changed about it looking back at it. Leaving things stock came out to become a nightmare and many things were breaking/not working at their fullest.
- First thing I think I should mention which ultimately cost me the most and caused the most headache is the rear sprocket. The rag joints I've used have always failed and destroyed my rims. I got lucky and never broke them while going fast. To try to improve the setup I bought the hub adapter but sure enough that also did not work as it would slip all the time even with a screw I drilled in to try to keep it fixed. Didn't break any rims but it did bend some spokes. What I use now is a disc brake rim to install the rear sprocket and it has been a beauty since. If you do not run this setup already I highly recommend it. Even if you don't have a disc brake rim there is a good chance you can make it fit. The frame I have is Nishiki Montour 700c hybrid and I was able to make it fit with plenty of space. I will point out tho that you most likely need to offset it so it stays in line with the drive sprocket. I offset as much as I could and could not get it perfectly aligned. It is only by millimeters honestly and it's enough so that I don't need to worry about the chain popping or derailing since it won't wobble as it might do with a rag joint. The only downside of this approach is I was not able to fit a disc brake on the rim so I had to stick to using regular rim brakes. The piece I used to offset is the following link. (FYI I put some spacers from some rim brake pads to offset the sprocket more.)
https://www.cdhpower.com/cdhpower-d...for-gas-motorized-bicycle-48cc-66cc-80cc.html
- Second thing, the gas and oil ratio makes a big difference. I honestly still don't even know 100% what ratio I am using right now but I will say I have noticed a notable difference in performance when I put less oil compared to when I put more. I gained almost a whole 10 mph when I ran less oil than normal but I will say be careful because you can overheat the engine and damage the cylinder. I think I ran enough oil so that wouldn't happen but then again I'm not too sure.
- Third thing, CDIs are extremely unreliable. I always heard people say this but I've never had trouble with my stock CDI until recently it decided to die on me out of nowhere. Since then I've bought 3 different CDI's with two of them not working and one of them I have not tried. To be fair though, I may have also broken the CDI before I tried out. I didn't know some CDIs take the spark plug without the little screw thing it has on the tip. I never had to take that off for the stock CDI I had so I assumed they were all like that as well but I stood incorrect. So I tried to mess with them and tried some things that may have broken the CDI leading to no spark. I bought one more and am planning to try to see if starts tomorrow.
- Fourth thing, change the connections on the stock wires. These connections just suck in general, I used new connections that look like this.
I cannot confirm if this works since I have not tried it but these connectors plug right in and only took a few minutes to install.
- Fifth thing, the last problem I ran into before I completely rebuilt my bike is air leaks. The stock intake manifold I had ran just fine and actually fit pretty well with my carburetor. However right before my bike broke I noticed it was running incredibly lean and would not idle. I would rev the engine and it would take forever for it to rev back down. I still do not know what the source was of this issue but I know that the manifold and carburetor connection is usually where the problem occurs for most people so I decided to buy that short aluminum manifold that comes with an o-ring already built-in. If this doesn't fix it I wouldn't honestly be sure what the problem would be but I know that another to fix an engine running lean is to move the carburetor needle clip down to increase the fuel that goes in the motor. (Correct me if I am wrong). The following is the link for the intake.
www.cdhpower.com
Mods I have done and things I have noticed/learned from modifying my bike.
- Pull starts are a pain but can be done right if you take the appropriate approach. I tried to install a pull start with the intention of also installing a centrifugal clutch so that I wouldn't have to pedal again. The first thing is that your pull start will most likely get in the way of your pedals so if you're going to buy it, buy the wide pedals as well. Also when I installed the pull start and tightened the cover the rope would not retract unless I loosened the screws which is not desirable considering the magneto needs to be sealed. Someone did say that running two gaskets could possibly work but at this point, I just decided to sell it because I did not want to deal with it anymore. So if you do plan on buying a pull start, just know it won't be a quick and easy install especially if you want to make it reliable. A quick note too, I would not recommend starting your bike with a power drill and turning the crank from the magneto. I tried this and stripped something (either the nut or the actual crank bolt) so if I have to change the magneto for whatever reason, it is gonna be a nightmare.
- Exhausts all depend on personal taste and performance. So I only ever actually ever ran the stock exhaust and the f2 thrust exhaust but I tried different things and got many different outcomes. First I will say, if you plan to use these bikes as just something to commute and to not bring too much attention, the stock exhaust is perfect and is in a convenient spot so I would keep it unless you want something that looks cooler. I ran the stock exhaust and didn't think much of it until I took off the end cap. For those who don't know what I am talking about, you can unscrew a nut at the end of the exhaust and take off that whole cap at the end. When I did this I also noticed a big difference in performance and torque. I gained about around 4 to 5 mph in speed when I did this which is great but I will say it is very loud. Personally, I liked it and I think it actually sounds pretty good even though it is pretty loud, it has a nice low sound when idling which I thought was pretty sick so just beware of that. When it comes to the F2 thrust pipe it is also pretty good when it comes to performance and I do not think it is as loud as the stock exhaust without the cap but I could be wrong. I definitely also gained more speed compared to the stock exhaust without the cap but the only downside is its position. It's pretty high up and can burn you if you pedal too closely. I haven't burned myself on it because I positioned my legs in a certain way so that my leg wasn't near it which wasn't it problem because it was comfortable but I definitely could have burned myself on some occasions. Also, something that was super annoying that I am not sure if anyone with this pipe has experienced is that the screw on the side where the pipe bends are impossible for me to tighten. I couldn't get it with a regular screwdriver or a normal Allen wrench. Now I am sure there is probably a tool that allows to tighten the screw properly but the fact I couldn't do it with regular household tools was annoying.
- New fuel lines and fuel filters have stopped most leaks on my bike. The stock fuel line and fuel filter were super leaky for me and were super annoying so I decided to get a thick rubber line from the plumbing aisle at Lowes as well as a lawn mower fuel filter. I do not think this has affected performance in any way but it eliminated all leaks for me.
- Not really a mod but I swapped my 700c front fork for a 27.5 front disc brake fork. I did this so that I would sit a little lower to the ground and also run better brakes and thicker tires. Since I haven't ridden it with the engine one I can't say if this has been effective but I will say when I pedal around I feel more grounded and more secure on turns. The only downside to running smaller rims is that I had to buy an adapter for my rear rim so that my pads can reach the rim wall which wasn't expensive but just an extra cost.
- Also not really mod but I would highly recommend getting a dual cable brake lever. Having a brake handle and a clutch on the same bar was very annoying for me personally so I would recommend to buy any of them.
Some problems I am still experiencing and some new ones I am running into
- So I haven't been able to get my bike started on three different CDIs and I am sure this is the problem because I tested the wires coming straight from the magneto and got 12 volts.
- Not sure if this also contributing to my no-start but I noticed fuel leaks from my spark plug and I can actually hear air escaping from it when the engine is turning. This is when I am actually turning the engine myself slowly and not while it has run. If anyone has experienced this or has a solution please let me know!
- The new exhaust I use is really close to my chain and sometimes my chain will hit it when I try to pedal around so I bought the spring tensioner to keep it from touching my pipe but the tensioner roller barely clears my tire which concerns me a little bit and may pose problems later.
Lastly, before you see what my bike looks like just know these few things first. It does not start but I have basically rebuilt it and adjusted many other things than what I mentioned above. If you plan to build a motorized bike and have no experience with them I would pay attention to this. (Any mistakes I made should be corrected in the replies so read those too). If you want something reliable you will need to spend more money on just the kit and a bike so be aware of that. I'm glad to answer any questions from anyone if you have any also I am located in Maryland and have some of these parts mentioned for sale so if you're in the area and are interested let me know!
So I'm gonna use this to show where I'm at with my hobby for now and also point out what I've learned from personal experience. What I say may not apply to everyone so don't take my words as something general. But basically, when I first built this bike I got the help of a friend who knew about it more than me. The build was solid at first but there were many things I should've changed about it looking back at it. Leaving things stock came out to become a nightmare and many things were breaking/not working at their fullest.
- First thing I think I should mention which ultimately cost me the most and caused the most headache is the rear sprocket. The rag joints I've used have always failed and destroyed my rims. I got lucky and never broke them while going fast. To try to improve the setup I bought the hub adapter but sure enough that also did not work as it would slip all the time even with a screw I drilled in to try to keep it fixed. Didn't break any rims but it did bend some spokes. What I use now is a disc brake rim to install the rear sprocket and it has been a beauty since. If you do not run this setup already I highly recommend it. Even if you don't have a disc brake rim there is a good chance you can make it fit. The frame I have is Nishiki Montour 700c hybrid and I was able to make it fit with plenty of space. I will point out tho that you most likely need to offset it so it stays in line with the drive sprocket. I offset as much as I could and could not get it perfectly aligned. It is only by millimeters honestly and it's enough so that I don't need to worry about the chain popping or derailing since it won't wobble as it might do with a rag joint. The only downside of this approach is I was not able to fit a disc brake on the rim so I had to stick to using regular rim brakes. The piece I used to offset is the following link. (FYI I put some spacers from some rim brake pads to offset the sprocket more.)
https://www.cdhpower.com/cdhpower-d...for-gas-motorized-bicycle-48cc-66cc-80cc.html
- Second thing, the gas and oil ratio makes a big difference. I honestly still don't even know 100% what ratio I am using right now but I will say I have noticed a notable difference in performance when I put less oil compared to when I put more. I gained almost a whole 10 mph when I ran less oil than normal but I will say be careful because you can overheat the engine and damage the cylinder. I think I ran enough oil so that wouldn't happen but then again I'm not too sure.
- Third thing, CDIs are extremely unreliable. I always heard people say this but I've never had trouble with my stock CDI until recently it decided to die on me out of nowhere. Since then I've bought 3 different CDI's with two of them not working and one of them I have not tried. To be fair though, I may have also broken the CDI before I tried out. I didn't know some CDIs take the spark plug without the little screw thing it has on the tip. I never had to take that off for the stock CDI I had so I assumed they were all like that as well but I stood incorrect. So I tried to mess with them and tried some things that may have broken the CDI leading to no spark. I bought one more and am planning to try to see if starts tomorrow.
- Fourth thing, change the connections on the stock wires. These connections just suck in general, I used new connections that look like this.
I cannot confirm if this works since I have not tried it but these connectors plug right in and only took a few minutes to install.
- Fifth thing, the last problem I ran into before I completely rebuilt my bike is air leaks. The stock intake manifold I had ran just fine and actually fit pretty well with my carburetor. However right before my bike broke I noticed it was running incredibly lean and would not idle. I would rev the engine and it would take forever for it to rev back down. I still do not know what the source was of this issue but I know that the manifold and carburetor connection is usually where the problem occurs for most people so I decided to buy that short aluminum manifold that comes with an o-ring already built-in. If this doesn't fix it I wouldn't honestly be sure what the problem would be but I know that another to fix an engine running lean is to move the carburetor needle clip down to increase the fuel that goes in the motor. (Correct me if I am wrong). The following is the link for the intake.
CDH CNC Air Intake Manifold 40mm
<ul class="a-unordered-list a-vertical a-spacing-mini"> <li><span class="a-list-item" style="font-size: medium; font-family: arial, helvetica, sans-serif; color: #000000;">CDHPOWER 32mm and 40mm 2 in 1 air manifold intake matching the intake port 32mm an
Mods I have done and things I have noticed/learned from modifying my bike.
- Pull starts are a pain but can be done right if you take the appropriate approach. I tried to install a pull start with the intention of also installing a centrifugal clutch so that I wouldn't have to pedal again. The first thing is that your pull start will most likely get in the way of your pedals so if you're going to buy it, buy the wide pedals as well. Also when I installed the pull start and tightened the cover the rope would not retract unless I loosened the screws which is not desirable considering the magneto needs to be sealed. Someone did say that running two gaskets could possibly work but at this point, I just decided to sell it because I did not want to deal with it anymore. So if you do plan on buying a pull start, just know it won't be a quick and easy install especially if you want to make it reliable. A quick note too, I would not recommend starting your bike with a power drill and turning the crank from the magneto. I tried this and stripped something (either the nut or the actual crank bolt) so if I have to change the magneto for whatever reason, it is gonna be a nightmare.
- Exhausts all depend on personal taste and performance. So I only ever actually ever ran the stock exhaust and the f2 thrust exhaust but I tried different things and got many different outcomes. First I will say, if you plan to use these bikes as just something to commute and to not bring too much attention, the stock exhaust is perfect and is in a convenient spot so I would keep it unless you want something that looks cooler. I ran the stock exhaust and didn't think much of it until I took off the end cap. For those who don't know what I am talking about, you can unscrew a nut at the end of the exhaust and take off that whole cap at the end. When I did this I also noticed a big difference in performance and torque. I gained about around 4 to 5 mph in speed when I did this which is great but I will say it is very loud. Personally, I liked it and I think it actually sounds pretty good even though it is pretty loud, it has a nice low sound when idling which I thought was pretty sick so just beware of that. When it comes to the F2 thrust pipe it is also pretty good when it comes to performance and I do not think it is as loud as the stock exhaust without the cap but I could be wrong. I definitely also gained more speed compared to the stock exhaust without the cap but the only downside is its position. It's pretty high up and can burn you if you pedal too closely. I haven't burned myself on it because I positioned my legs in a certain way so that my leg wasn't near it which wasn't it problem because it was comfortable but I definitely could have burned myself on some occasions. Also, something that was super annoying that I am not sure if anyone with this pipe has experienced is that the screw on the side where the pipe bends are impossible for me to tighten. I couldn't get it with a regular screwdriver or a normal Allen wrench. Now I am sure there is probably a tool that allows to tighten the screw properly but the fact I couldn't do it with regular household tools was annoying.
- New fuel lines and fuel filters have stopped most leaks on my bike. The stock fuel line and fuel filter were super leaky for me and were super annoying so I decided to get a thick rubber line from the plumbing aisle at Lowes as well as a lawn mower fuel filter. I do not think this has affected performance in any way but it eliminated all leaks for me.
- Not really a mod but I swapped my 700c front fork for a 27.5 front disc brake fork. I did this so that I would sit a little lower to the ground and also run better brakes and thicker tires. Since I haven't ridden it with the engine one I can't say if this has been effective but I will say when I pedal around I feel more grounded and more secure on turns. The only downside to running smaller rims is that I had to buy an adapter for my rear rim so that my pads can reach the rim wall which wasn't expensive but just an extra cost.
- Also not really mod but I would highly recommend getting a dual cable brake lever. Having a brake handle and a clutch on the same bar was very annoying for me personally so I would recommend to buy any of them.
Some problems I am still experiencing and some new ones I am running into
- So I haven't been able to get my bike started on three different CDIs and I am sure this is the problem because I tested the wires coming straight from the magneto and got 12 volts.
- Not sure if this also contributing to my no-start but I noticed fuel leaks from my spark plug and I can actually hear air escaping from it when the engine is turning. This is when I am actually turning the engine myself slowly and not while it has run. If anyone has experienced this or has a solution please let me know!
- The new exhaust I use is really close to my chain and sometimes my chain will hit it when I try to pedal around so I bought the spring tensioner to keep it from touching my pipe but the tensioner roller barely clears my tire which concerns me a little bit and may pose problems later.
Lastly, before you see what my bike looks like just know these few things first. It does not start but I have basically rebuilt it and adjusted many other things than what I mentioned above. If you plan to build a motorized bike and have no experience with them I would pay attention to this. (Any mistakes I made should be corrected in the replies so read those too). If you want something reliable you will need to spend more money on just the kit and a bike so be aware of that. I'm glad to answer any questions from anyone if you have any also I am located in Maryland and have some of these parts mentioned for sale so if you're in the area and are interested let me know!
