New 6.5HP Bicycle Trailer

Hi Motorbicycling folks!!!

This is my 2nd bicycle trailer build now. The first trailer was great, but I wanted to improve for speed and safety, and lower cost! So far so good.

I'm using the old 6.5HP engine from my first trailer, and went to a new #40 chain drive and a PocketBike wheel.

Here's my first picture, and when I get more time and the rest of my pics, I'll upload them as well.
I have a rollcage/rack on it now, I just didn't get pics yet.

The hitch is special design made from EMT. I originally made a pivot hitch to connect to the rear wheel, but due to handling, I found the seatpost to still be the best place for the hitch.

There's still more to come, and if you folks have any suggestions about concealing the engine, more cargo space, or dressing it up a bit, let me know.

The "Blue" pole part of the hitch is 1.5 inch regular fence post, and solid steel 1/2 thick bolts as supports, and the frame is 1.5inch heavy-duty fence post, with a steel plate for the engine, so this trailer is very heavy because of the frame and heavy engine. The EMT part is where it's connected on the bike seat, it's bolted to the main bar, so it's replaceable if it gets damaged, but so far, it's still in great shape. It's awesome on roads, or grass, but don't get it in the sand, lol!

The one wheel trailer coasts really far, so I'm not on the throttle as much to stay rolling at low speeds! Gas mileage is a little better than before, and it rides smooth with my clutch lubed slightly with white grease spray. It has a lot of torque, so I can't hit the gas too much until I get up to speed, or it will bounce the tire and chirp it.

It's very stable. I can go around turns twice as fast as a 2-wheel trailer, but I still like the balance of a 2-wheel trailer. However, in comparison, the one-wheel trailer feels more like you are just riding a bike by itself, but just heavier.

I made a cable sheath coupler for the bike/trailer connection with a bolt and 4 nuts welded on it. Each cable end fits in the pair of nuts, and a mini cable clamp connects the two cables. It makes it so I can disconnect the trailer, and makes adjustment simple. I'm using a bicycle brake lever as a throttle, and it works well.

The main throttle cable is a slightly thicker cable than bike cable, but it fit the cable sheath I bought for it just perfectly. I also used plastic tube to couple two sheathes further up. The throttle works much better than the other trailer. I also have all the old stock engine governor and throttle assembly stuff removed, so my throttle play is minimal, because the throttle lever goes right to the carburetor.

Here's some more pics. They were taken at a high resolution, so I had to cut them down to fit for uploading. My newer pics with the rack were too dark, so I'll have to take more pics.

I hope to get more close up soon.

macarollo said:

Awesome build! Looks really strong. Are your engine and wheel perfectly centered?

On my pusher my engine is slightly off center to the right and my wheel is slightly off center to the left. This is because the frame I used was a little too small, just barely fit on there.

Your trailer is way beefier than mine. Keep improving that design Z!

Click to expand...

My wheel is centered. My engine is somewhat close to the center, being the block is off some to the left, so it would align with my sprocket, and fit properly on the frame and have a centered look. My sprocket isn't up against my wheel, so it made things easier, but I did have to clear some space so the chain won't rub the frame, but everything is good. I've had no issues with the chain drive, other than re-tightening it every so often. The engine plate slides back and forth to allow the chain to be tensioned by moving the engine, and tightening it down in the right place.

Thank you! I'm glad you like the new frame! I made it strong with lots of welds, and because of that and the thick steel fence-posts used, it's very heavy. It's not the prettiest welding job, but I used my DIY Car-Battery & Jumper Cable welder for all of it, because I still have yet to get a welder, and I went through about 20 6010&7014 rods, and almost two boxes (32 each) of 6013 welding rods as well. Not bad for not being able to control my amperage very much. A bit of wire-brushing and blue gloss paint on everything, and the metal doesn't look 20 years old anymore, lol.

I have tested it for strength, even before it was on the bicycle. I can stand on the trailer while it's on the bike, and it supports my weight. I triangulated two spots for the hitch post, to keep it stiff. This frame doesn't even flex, so I know it will be safe and nothing breaking. I got lucky when I got those solid steel bolts, they are strong, and easy to work with compared to tubing.

The beauty of these trailers, is that they are similar to each other, but every single one is different.

Macarollo, we gotta ride together sometime!

Dan said:

Been saying I wanted to build a pusher since the first time I saw your previous build. Purty work Znane

Click to expand...

Maybe you'll have one you like soon!

In the process of improving the first 2-wheel trailer, I helped my bro make his trailer, then I finished my new trailer, so you can see some similarities, but so far, my bro's trailer is the most unique and complex one so far. It has more cargo space than engine space! Also a little tiny 2.5HP 79cc 4-Stroke OHV engine with governor removed, and opened intake. The little lightweight engine makes the trailer ride excellent for curves and turns.

It has a 15" Flat-Free solid foam tire. It rides excellent because of that tire. He also is using the large 48T Sprocket as a disk brake with bicycle brakes and four brake pads, and it works very well.

38MPH on flat ground. Fast for such a small motor and big trailer.