Cruiser Trike with 4-stroke dirt bike motor

Greetings from OB,

I took the trike for a test ride today. It needs a freewhell gear in the jackshaft, or fixed chain idlers. The engine/tranny will freewheel in neutral but not while in gear, so with spring loaded idlers, it will not work. The test was educational. I have never shifted a motorcycle before so I didn't know what to expect. Now I see how the shift works. I will be adding a shift lever just behind the tank.

I accidently started it in gear, once, and ran over my foot. No harm done, but now I can see that a shift indicator would be useful. It looks like the engine has a pick-up for it. Also it needs a couple of brakes. It has a coaster brake in the trike hub, and I plan to add a disk brake in the front and a couple of rim calipers in the back, then it will be ready for the bed and roof.

Thanks for not flaming me. I like the frame too. When it was sitting in my yard for 3 years, I hated it because it had rediculosly high ape hanger bars, then I discovered that if I held up my hand to block the handle bars, then it was actually beautiful. I need to give credit to my son, because if it was an ugly bike, he would have left it in the dumpster.

You're right, Fine-tuning the gears is the "fun" part. I could have calculated the gear ratios before I started, but I was going to assemble it from the contents of my junk boxes anyway, so why bother with calcs? It seemed best to just throw it together and adjust it later. As a result, the motor drive train seems about right, but the pedal drive train is too high. The ratio is about right for pedalling fast down hill, but I don't want to do that, even with 4 brakes. LOL.

In the mean time, I have been thinking about installing a freewheel or hard mounting the idlers. Based on the test ride yesterday, I need to do one or the other. It would be nice to be able to pop start it and use the engine to assist braking, but then it occured to me that I can't do either with a centrifical clutch, so I will leave the idlers spring loaded and get a freewheel sprocket.

The axel length is 30 inches, and the width between the wheel center lines is 26 inches. Good question, I wondered the same myself before I bought the trike kit.

I worked on the suicide shifter today. I will post more pics as she progresses.

Thank you, BarelyAwake for your message. I owe you a note of acknowledgement for your excellent thread about "Alternate 50cc 4-stroke engine list" and other useful posts that were inspirational for my trike build.

Before I started my trike build, I was looking for all possible 4 cycle engines to use, and there they were on your thread, with details on how to implement them. This forum is truly a valuable resource of technical details for planning and building.

My first build was with the 49cc Huaseng engine, shift kit, and 3 speed shifting hub. I am satisfied with this setup, but wanted to try something different. My level of confidence is higher with the integral tranny of the horizontal engine, vs the 3 speed bike hub, so I will be able to wander a little further from home.

I share your quest for a 50cc V-Twin. I wish I had a foundry and machine shop and the know how to make one.

Thanks again to you and the other members for their valuable posts.

Salutations,

I finished the suicide shifter (see pics below). I'm going to call this a "Safety Suicide Shifter" for now. If anyone asks what's so safe about it? I can proudly state that we never seem to have any accidents with it. It worked good on the test drive, then I looked up suicide shifter on Wikipedia, and there it was. It looks like I copied it, but I didn't, I swear. The article is interesting about various motorcycle shifting arrangements. I can see why some of them fell out of favor (no pun intended).

It is suicide to ride a motorized contraption with one coaster brake, especially on a trike where braking jerks hard to one side. I knew that would happen, but it also jerks hard the other way when the clutch grabs. I got a good idea on another thread of how to make a differential using two freewheels.

I just finished adding a freewheel to the jackshaft, so now I will restore that to the way it was, and move the freewheel to the back axel. This will disable the coaster brake, which is a good thing.

I ordered two disk brakes for the back and a cantilever brake for the front.

Next week will be brakes and differential week.

Happy Palm Sunday,
Pete

Greetings,

Got some work done on the brakes. Added a V-Brake on the front, and still working on the rear disk brakes. I knew I would need to have platform supports at the ends of the axel, so I was able to make brackets to mount the calipers, and support the platform.

The trike kit comes with one wheel locked to the axel with a drive flange, and the other freewheels so that it doesn't bind on turns. I'm locking both wheels with a new drive flange, cutting the axel in the middle, and installing a differential. So I made a drive flange with 3 prongs to lock the other wheel.

The new drive flange is made out of a home made fender washer: 2 1/2" OD x 7/8" ID x 1/8" T. Then I made a shaft collar out of schedule 40 pipe. Welded the washer to the pipe and brazed in the 3 prongs. The pipe is a sloppy fit on the 15mm axel, so I made a sleeve out of a corrugated dog food can, then brazed the whole shebang together on the axel.

Hopefully the pics will explain it better.
Happy building.

Been working on the differential, and have gone through some revisions. Using the contents of more than one junk box, I'm trying to cobble something together with chicken $hit & water, using a cutting torch & hammer.

As mentioned before, I got a great idea for a differential on another thread, then I changd it a little to fit my trike kit. I am in no way advocating this design, just showing how I plan to do it, just becaue, during planning, it is interesting to see how the other guy did it.

The first pic is the sketch, Revision A. It shows how I would like to do it. On the original design, I was planning to use a RH and a LH freewheel adapter. On a phone call with David Staton, he mentioned that there is a RH reverse adapter. This changed everything, because it was possible to use two RH adapters and RH freewheels. The RH freewheels are easier to find, in case I need to use heavy duty freewheels later.

I will try to break the cheap ones first. Sick Bike Parts has heavy duty, serviceable RH freewheel flanges.

The second pic shows what I had to work with. Upper Left is the axel sprocket that came with the trike kit. Upper right is a pair of half sleeves that I made from EMT. Lower Left is a LH freewheel, and Lower Right is a sprocket that I got from Sick Bike Parts. WoHoo!! I am just a few pieces of junk away from cruising down the road.

Since I have a LH freewheel, and I want to avoid using those, this is a perfect opportunity to see if I can destroy it with a torch and hammer.

The third pic shows the spacer ring (not yet drilled for bolts), and RH threaded adapter, and a LH unthreaded adapter that I made. I cut the hub out of the original sprocket and brazed the EMT sleeves on it to make an unthreaded adapter that is a pounding fit in the LH freewheel. This tangled web of intrigue is getting complicated.

The fourth pic shows the homemade adapter bazed into the LH freewheel. I spot brazed it in 2 places to see if I can break it. There are LH, RH, Reverse RH adapters, and this homemade thing may be the first LH, Reverse, unthreaded adapter.

So all I need now is a RH freewheel, which I ordered today. I will let you know how it works.

The fifth pic shows the space I have avaliable in the trike for the differential.

Just as I'm finalizing my conglomeration, Mr Station sent me an email that he just finished a stock differentialand and it is available now. It looks heavy duty with two freewheels and two more berings, but I'm not sure if it will fit my trike. I think a differenial from a lawn tractor would be another good solution, but you would probably need to plan it into the build at an early stage.

Cheers.

The trike is working well with the differential. Instead of jerking to the side without a differential, now it jerks the front wheel up when accelerating too quickly, and the front wheel loses traction for steering. It's just a matter of getting used to it, and not twisting the trottle too hard.

I'm thinking of putting a rack with saddle bags over the front wheel, then I can put some tools, locks, and chains in the bags to hold the front wheel down.

The first pic below shows the half axels, brake disks, and RH freewheel adapters to hold the disks. The spokes on the disks should be in tension when the brakes are applied.

The second pic shows the adapters brazed to the axels.

Pics 3,4 & 5 show the differential.

Happy building & biking!

Thanks KC. Your bike looks very nice, with clean lines and well put together.

I like the engine and tranny a lot. It will idle in any gear, but it creeps forward if you don't hold the brake, similar to a car with an automatic trans. So if you start it in gear, it wil try to get away. Nothing really wrong with that if you expect it and have a free hand to grab the brake. No, the idle is not set too fast, it creeps even at slow idle.

So technically it feels like the clutch never completely disengages, as it is always trying to move, except when in neutral. For safety, I think it should disengage when you release the throttle. It may be that the clutch pads will get a glaze after they wear in a little, and not have such a propensity to always grab. I have noticed on some stick shift cars, that a new clutch plate will drag (not completely release) until it has worn a little. Otherwise a simple clutch adjustment should fix it.

When stopping at a stop sign, it is not necessary to put it in neutral. I downshift to first or second, apply the brakes and stop, then when it is my turn to go, I release the brakes and twist the throttle. It will get going in first or second on flat ground. That is because I have it geared low. In first, it is a real hill climber. In third, it goes as fast as I would want to go on a light bicycle frame. In fourth, well that would be for the thrill seekers. I'm planning to get a steering dampner before I try 4th at WOT.

I like the of mind of having a tranny that was designed for a motor. I'm still a little gun-shy around internally geared bicycle hubs since I blew out 3 on my chopper. In every case it was my fault. The fourth hub is holding up well, but I don't completely trust it to go far from home.

With a shifting hub, it is in the wrong place in the drive train where it has the most torque at the drive wheel. The gears should be right after the clutch where they will spin faster, but with less torque, and that is why I trust the dirt bike tranny more than the bicycle shifting hub.

For my next build I will probably use the same engine. When you consider the cost of a shift kit and geared hub, these all-in-one dirt bike power plants with integral tranny are a real bargin.

Hope this helps. If you have any other questions, I will be happy to help.

The dimensions are 16 L x 10 H x 11 W. The width is 6" to the right of the centerline, and 5" to the left.

<< my forte is building shifters >> I love shifting, it reminds me of the cars I have had; nothing fancy, just stick shifters.

<< that anything over 20 MPH was just too crazy fast >> Yes, I tell interested by-standers that my trike is an exciting little death trap. With the new diff, it handles well, but you need to be careful on corners, and don't twist the throttle too quick or it will throw you off the back. Don't tell my wife I said so.

<<in 1st or 2nd they would promptly pop a wheelie and spin like a top around the left static back wheel.>> Yes, that's what mine did before the diff. I recon that it could look like an elegant ballet if done right, otherwise it may look like a calamity that is fascinating for everyone to watch.

Interesting about the Nuvinci 50% failure rate; I'm glad I didn't get one. Also interesting that the Nexus is so successful. I scoured this forum about shift hubs, and the Nexus seems to be the most popular. I used a Sram iMotion 3 speed on my chopper, because it was available locally, and I didn't have room for the Nexus click-box.

When my Sram gives up, I plan to mod the rear end to accomodaye the Nexus, because the click-box is a much better arrangement with indexing at the hub, instead of indexing at the shifter as with the iMotion.

<< will guess your failures were caused by the same thing I have seen eat a couple of 7-speed derailleur shifters, downshifting too low when you think you'll have to stop but don't and hit WOT causing a high power hi torque hit on the back wheel.>>

Actually I think I have the freewheels set up so that it is immune to that treatment. I destroyed my hubs in the following 3 ways:

1. When I bought the first hub, I asked the guy at the bike shop if he had one without a coaster brake. He said to just take the coaster brake out, so in blind faith, that's what I did and looked no further. It turns out that the brake shoes that I removed were important spacers for a pair of pawls, so when those slid loose, they jambed and the hub blew.

2. The second hub also had a coaster brake, so this time I made a spacer out of copper pipe to hold the pawls in place. All was well until the shift cable housing slipped. I did not have a proper cable stop, so when the housing slipped, it changed the cable adjustment and I applied power between the gears, and it blew. That is when I learned why indexing at the hub is better than indexing at the shifter.

3. The third hub was a Frankenstein job that I made from the first 2 hubs. I slathered and packed it in grease so that it would last forever. Well the grease caused one of the pawls to stick, forcing the other pawl to take the whole load. Now I know that when that happens, it will break, jamb, and blow out.

For the fourth hub, I found one without a brake. I put it in without messing with it, and it is still working well. As long as I make sure that the cable is correctly adjusted, I think it will hold up.

Your pic of the cranks is interesting. On the trike, I have the spindle and cartridge shown on the top, with the cranks shown on the bottom. The spindle is from SBP and it is longer on one side than the other. Since the engine is wider on one side, I put the wide part of the spindle on that side. As a result the threads are backwards, but it works OK with some Locktite.

The specs say the sprocket takes a 420 chain.
Will it take a 415 or maybe a 41?

Good question. The first thing I did when I got the engine, was to see how the chain fits. I'm using 41 chain and it fits good. I tried heavy duty cruiser chain, and it is too narrow (not sure what size it is).

Happy to share as others here have helped me so much. I appreciate your interest. I am such a gear head nerd that I can ramble about mechanical toys forever.

I will post pics as she progresses, and maybe a video.

KC, glad to hear that you are getting one of these engines, I hope you will have a build thread or at least some pics. It looks like you have already built bikes with almost every type of engine, so it will be easy for you. Are you planning to put it on the 29" Macargi ? Whatever you use, I will be very interested to see it progress.

The trike looks awsome. My next door neighbor wants to go electric, so I will show him your bike pics. All your other builds also look great; I can see that we will not need to spoon feed you through your next build.

Glad you posted the pic of the crank sets. I plan to get the GasBike spindle since it is wider than the SBP spindle.

Happy building/biking.

KC- Kool bike, it looks like the one I got with that classic hunch back curve. You didn't waste any time getting the engine and bike. Will you need to mod the frame any? Do you plan to start soon? I look forward to seeing it progress.

Both the freewheels in my new differential gave up today. They still spin nice, but now they spin both ways. LOL. Anyway, I ordered 2 new heavy duty, serviceable freewheels from SBP.

Also I picked some 1/2" EMT and elbows to make a front rack.

Happy building!