Motorized Bike Project.

[Megadan]

I finally started to assemble my bike now that pretty much most of my parts have come in. I am still waiting on my dang handlebars but after 11 days of waiting they should be delivered tomorrow. That means I can get my controls and everything else sorted out next week.

In the meantime I went ahead and installed the motor so I could check sprocket alignment and get an idea of my hub adapter position. Fits in the frame rather well with decent clearance all around. Carb has enough room to install without having to unbolt anything, and I also think I can make my VM18 carb work with an angled foam filter on this reed block, which would be awesome.



I am currently waiting on some jets to use with this stock carburetor. I do believe they are a Keihin 99101-124 jets. I measured the one that came in the carburetor and the only real difference is it is .3mm longer. Otherwise they should install and function all the same. While the original jet is unmarked I did size it out to a 75, so I went ahead and ordered 78, 80, 82, and and 85. Many phantom owners complain of them being jetted on the lean side, and with the port matching and other work I have done I likely made it a little worse, so I wanted a decent range to work with.

In the meantime, I have another obstacle to overcome. My front tire and the exhaust are trying to be buddies. It's actually not too bad, so I should be able to fix this issue with a little torch and bend action.



My other obstacle is a little more frustrating, but I have to work within the parameters that I am given. It's the fitment of the disc brakes and sprocket/chain setup. Unfortunately, the 40 tooth, which I would love to run, is just a tad too big to clear the caliper. My attempts to space out the rotor created other issues and didn't buy enough room anyway.



My options here are 2. Both of them simple.

First option is to use a 36 tooth sprocket. This is the normal sprocket setup used on bikes with 26" rear wheels when using a 203mm rotor, so I know it will clear. The downside to this option is that it will gear me even taller, similar to a 32 tooth on a 26" bike. I don't mind if I have to pedal assist the bike a little, but it may prove too much gear. Lots of speed demons on the 26" bikes like using the 32 tooth with the Phantom. With an expansion chamber pipe and stock carb I have watched a guy do 52mph with no other work. Thats a little faster than I desire to go on a bicycle, but inversely, if the motor has the power it should cruise rather well at 30mph lol.

Second Option, if I decide the gearing is just too tall for what I want, is to get rid of the rear disc brake and go with a regular old rim brake out back. I will still have the bigger/better front brakes which is a plus. This would also allow me to pick almost any rear sprocket setup I want.

[Megadan]

Got my 36 tooth sprocket in and got it mounted up with the disc after servicing the rear wheel bearings. Kind of glad I checked them too because they were bone dry.

Honestly, it reminded me of the bearings the Hawk came with where they just had a little smear of that clear goop that they pass off as grease. Definitely going to check the front wheel and crank set now.

The other issue I stumbled into while working on the back wheel was I noticed one side of the axle is actually already bent a little bit. I'm just going to roll with it for now and look into some possible upgrade options in the meantime.

So, I am just going to install the rear wheel and check/tighten the spokes for now. If I can get those things done tonight I will get the bars and controls sorted out, then work on the exhaust. Supposed to be a rainy day tomorrow, so it will be perfect for some garage time.

My only other decision to make at this point is what size fuel tank to use. The half gallon tanks are nice because they are small. I bought a 4 liter tank, because why not? It's a bit big, but not obnoxiously so. I do like how it mounts better, with bolt-through tabs instead of the welded on studs like the small tank that are notorious for breaking off.

Hopefully I find this sprocket combo works out well because I really like how simple and clean it all went together. The caliper clears the chain perfectly and everything lines up just right. I took another note from my experience as a Chinarider and replaced pretty much most of the cheddar grade hardware that came with the hub adapter and on the hub itself for the brake rotor. They were already rounded out a little by whomever assembled the bike, so it was a good excuse.

[wheelbender6]

Lookin good! I would try to mount the engine so that the float bowl on the carb is level. Unfortunately, that will make the conflict between the exhaust and front tire even worse.

[Megadan]

Originally Posted by wheelbender6

Lookin good! I would try to mount the engine so that the float bowl on the carb is level. Unfortunately, that will make the conflict between the exhaust and front tire even worse.

Won't mount that way in any case. This is with the mounts aligned, and not unusual for these things to be angled anyway. This is a single jet carburetor without a pilot jet or idle circuit.

[Darkrider]

I gotta say looking in this thread is a dangerous game lol. It has me considering the idea of building such a bike and as it is i am already considering picking up two Supercycle SC1800s from Canadian tire. One to keep stock with some mild mods and the other specifically for building into a motorized bike. And now that i see sprockets out there that use the disk brake hubs to make them work its got me thinking about it further. I already have a disk brake rear wheel on one of my bikes here that does not have disk brakes. So that would be a perfect donor for that...though on the flipside that bike in itself lends itself well to a motor conversion.

[Megadan]

Originally Posted by Darkrider

I gotta say looking in this thread is a dangerous game lol. It has me considering the idea of building such a bike and as it is i am already considering picking up two Supercycle SC1800s from Canadian tire. One to keep stock with some mild mods and the other specifically for building into a motorized bike. And now that i see sprockets out there that use the disk brake hubs to make them work its got me thinking about it further. I already have a disk brake rear wheel on one of my bikes here that does not have disk brakes. So that would be a perfect donor for that...though on the flipside that bike in itself lends itself well to a motor conversion.

The hardest part is finding the right style of adapter for your bike in terms of alignment, but yeah they do make it easier. I am using a clamp on sprocket adapter secured to the rear hub. I keyed both surfaces and applied Loctite 638.

[Darkrider]

Originally Posted by Megadan

The hardest part is finding the right style of adapter for your bike in terms of alignment, but yeah they do make it easier. I am using a clamp on sprocket adapter secured to the rear hub. I keyed both surfaces and applied Loctite 638.

Took me a moment to understand what you meant there but i see now that there is an adapter that bolts to the hub itself then the sprocket bolts to that to make it a fixed mount instead of the rubber isolated set up of the clamp on hub. Kinda wonder if the electric motor kits out there use the same chain as the gas motor...would make for a clean install on one of those as well.

[Megadan]

Originally Posted by Darkrider

Took me a moment to understand what you meant there but i see now that there is an adapter that bolts to the hub itself then the sprocket bolts to that to make it a fixed mount instead of the rubber isolated set up of the clamp on hub. Kinda wonder if the electric motor kits out there use the same chain as the gas motor...would make for a clean install on one of those as well.

Well, in my case the adapter clamps to the hub inside of the spokes and 3 bosses stick out through the spokes for the sprocket to bolt to. This is the one I had to buy because my Hub is a goofy diameter, so instead of one of the cheaper ones, I had to shell out about double. Thankfully this is a good high quality unit.
https://www.bikeberry.com/products/b...37807830761638


The other style I was talking about for the disc brake hubs is this. It bolts on where the disc would go and the sprocket bolts to it. Depending on the bike or wheel hub you may or may no be able to run a disc with it. This particular company offers three different rotor offset options depending on wheel and tire setup.
https://mbrebel.com/product/medium-3...tal-thickness/

[Darkrider]

Originally Posted by Megadan

Well, in my case the adapter clamps to the hub inside of the spokes and 3 bosses stick out through the spokes for the sprocket to bolt to. This is the one I had to buy because my Hub is a goofy diameter, so instead of one of the cheaper ones, I had to shell out about double. Thankfully this is a good high quality unit.
https://www.bikeberry.com/products/b...37807830761638


The other style I was talking about for the disc brake hubs is this. It bolts on where the disc would go and the sprocket bolts to it. Depending on the bike or wheel hub you may or may no be able to run a disc with it. This particular company offers three different rotor offset options depending on wheel and tire setup.
https://mbrebel.com/product/medium-3...tal-thickness/

Im perfectly fine with the idea of using the disk flange as the drive flange and just live with the rim brakes on the rear with a disk brake front end if i were going gas powered like you. From what i have seen the electric kits use the same rubber flange set up so at least that part might be standard between the two. If so i would probably look at just solid mounting the sprocket and leave the brakes alone. As it is i happen to have disk brake type wheels on my Supercycle XTI when its supposed to have non disk wheels like the SC1800 im looking at doing the Ebike with. As it is im thinking i might convert my Triumph dual suspension bike first as the electric power would def help off road with it.

[Megadan]

Originally Posted by Darkrider

Im perfectly fine with the idea of using the disk flange as the drive flange and just live with the rim brakes on the rear with a disk brake front end if i were going gas powered like you. From what i have seen the electric kits use the same rubber flange set up so at least that part might be standard between the two. If so i would probably look at just solid mounting the sprocket and leave the brakes alone. As it is i happen to have disk brake type wheels on my Supercycle XTI when its supposed to have non disk wheels like the SC1800 im looking at doing the Ebike with. As it is im thinking i might convert my Triumph dual suspension bike first as the electric power would def help off road with it.

It's actually pretty common to use the disc flange for the drive and run a rim brake out back on a motorized bike. Often done with a dual pull single brake lever to prevent having too much braking power in the rear when combined with a front disc brake.

I have considered an e-bike, but I may hold off for now since they are expensive as heck, both to build or to buy. I am starting a new job soon that makes using the bikes as transport to save money a bit more difficult due to the distance and the routes available to me, so for now they are just a hobby anyway. 12 miles of city riding is a bit more than I want to deal with for a commute on a bicycle of any kind.

[Megadan]

Finally got the last of my parts in to hopefully finish my bike this weekend. In the meantime I have started working on a backup engine. I purchased it for 50 bucks less than this one on ebay, but it's basically the same engine. The "110cc" engine that is actually 85cc.
https://www.amazon.com/DONSP1986-CDH...ps%2C95&sr=8-3


Funny enough it's the same bore and stroke as my Phantom motor, but if there could be a polar opposite, this would be it.

For starters, the port timing numbers are pathetic. As delivered the squish gap is 2.77mm. Some of that is thanks to the .95mm thick head gasket it comes with. If the squish gap wasn't hilarious enough, that head gasket has a bore hole of 58mm, so it leaves a large open area for combustion to get into. All of this on a head with a pretty large combustion chamber too. I am dead serious when I say this engine probably wouldn't even make 90psi on a compression check with the ports wide open.

The intake, exhaust, and transfer port timing and durations are also pretty miniscule thanks to the way the iron cylinder liner is installed/machined. Blocking a lot of the ports, not that it is a great design to begin with. Thankfully, a lot of that can be corrected. These are the timing numbers I got with one base gasket.

Intake - Opens 62 BTDC/118 ATDC and 124 Duration. Exhaust - Opens 68 BBDC/112 ATDC and 136 Duration. Transfers - Right Side 53 BBDC/127 ATDC, 106 duration. Left Side 51 BBDC/ 129 ATDC, 102 duration.
Blowdown - Right side 15 degrees. Left Side 17 degrees.

One thing I have decided to do is run 2 base gaskets. This will help add a little more to the desperately needed transfer port and exhaust duration numbers. It harms the intake timing a little, but I have a lot more room to work with on the intake port in terms of timing than I do with the transfers, so it is a fair trade.

This is how the ports look with 2 base gaskets.
Intake TDC and BDC:

Exhaust BDC:


As you can see, the iron sleeve protrudes down from the roof of both ports quite a lot. On the intake side it's actually perfect as it is. I plan on using some epoxy to ramp up to that lip to try and eliminate turbulence and cut back the bottom of the skirt flush with the lip. On the exhaust side it needs to be ground away fully, and that will really open up the port.

The issue is, it increases that already enormous squish gap to 3.12mm. As you can see here with the head gasket and a 3mm allen key in place just how far down the piston sits in the bore now.


The plan is to take 2mm off the top of the jug, and then about half a mm from the surface of the cylinder head. That should set the squish gap to about zero with no head gasket, and about .8mm with it.

I already got a little bored and decided to polish the hell out of the combustion chamber. The top of the piston is getting the same treatment.
Before.

After.


The rest of the lost power is going to come from port matching the cylinder and crankcase transfers. As you can see from the gasket and cylinder, there is quite a bit of misalignment on the intake side of the transfers on both sides, as well as a bit of mismatch from the iron sleeve cutaway. All easily fixed.


Yes, I am building a motor for the same bike that my Phantom is on. Partly as a backup, mostly as a side project. Kind of an interesting exercise in opposites. I want this engine to be a tractor like a CG engine. Less RPM, more grunt down low. Paired with a longer header tube "clone" expansion chamber like this one https://www.amazon.com/dp/B07RR6Z7D8...roduct_details It should be exactly that.

[Darkrider]

Originally Posted by Megadan

It's actually pretty common to use the disc flange for the drive and run a rim brake out back on a motorized bike. Often done with a dual pull single brake lever to prevent having too much braking power in the rear when combined with a front disc brake.

I have considered an e-bike, but I may hold off for now since they are expensive as heck, both to build or to buy. I am starting a new job soon that makes using the bikes as transport to save money a bit more difficult due to the distance and the routes available to me, so for now they are just a hobby anyway. 12 miles of city riding is a bit more than I want to deal with for a commute on a bicycle of any kind.

Enlighten me on this dual pull single brake lever? Funny enough when i was looking into the two ideas i was actually saving money going Ebike. This was based off of the idea of buying a new bike from Ctire here as the base. Granted a cheap one with rim brakes to upgrade around the motor later kind of thing. But at this point there is also a plan i found on a site to build a cargo type bike that i may consider for the ebike idea. Modify the plans a touch to have a staggered tire set up similar to a dirt bike and have the smaller rear being a hub drive as i keep finding 24" hub drive wheels for reasonable prices. The goal there would eventually be to have a 2wd Ebike kind of set up like a Dual sport motorcycle. I would be taking advantage of the stretched wheelbase of the cargo bike to have somewhere to place the batteries in a lower center of gravity location.

[Megadan]

Originally Posted by Darkrider

Enlighten me on this dual pull single brake lever? Funny enough when i was looking into the two ideas i was actually saving money going Ebike. This was based off of the idea of buying a new bike from Ctire here as the base. Granted a cheap one with rim brakes to upgrade around the motor later kind of thing. But at this point there is also a plan i found on a site to build a cargo type bike that i may consider for the ebike idea. Modify the plans a touch to have a staggered tire set up similar to a dirt bike and have the smaller rear being a hub drive as i keep finding 24" hub drive wheels for reasonable prices. The goal there would eventually be to have a 2wd Ebike kind of set up like a Dual sport motorcycle. I would be taking advantage of the stretched wheelbase of the cargo bike to have somewhere to place the batteries in a lower center of gravity location.

Dual pull lever is just what it sounds like. One lever that pulls both the front and back brakes at the same time. Usually this is done because the left hand has to also operate the clutch for the engine. It's not ideal, and I am not a fan of it because you lose control of adjusting the brake bias on the fly, but for a purely road going machine it works ok.

One example of the type of lever. https://www.amazon.com/Sunlite-Alloy...a-335204177758

That dual drive cargo bike idea sounds interesting. I always thought those cargo bikes could have some serious range and a powerful motor on them due to how they are laid out.

[lakinxoe]

In the process of building my homemade motorized bicycle, I opted for a kick start engine. This particular type of engine is highly recommended because it doesn't rely on a battery for ignition. Instead, the engine can be started by utilizing a kick lever, providing a reliable and convenient starting mechanism.

[TominMO]

Originally Posted by Megadan

I considered electric as well, but I just love a good planet killing combustion engine.