BP Hobby Spirit BP-12 1/12 Electric

I love rc bikes. Lots of wonderful products on the market but no hobby grade mini ones. I have the tools and the skills so how about I build one myself. That's what Peter must have been thinking for some time now. Long story short, he built it ! He actually did it. Starting with a blank screen he managed to design and build his own mini rc bike. If that is not "wow" then what is !!!

Such a project is not easy to carry out. After lots of testing and redesigning the model has reached its final revision few months back and a small production has been running since. Bastelpeter's BP-12 1/12 scale rc motorcycle (Bastelpeter is Peter's nickname) is here with us to have a closer look and see how talent and determination can lead to a truly unique high quality product.

Chassis

The main chassis consists of two thin parallel black composite plates. Plastic parts hold the plates together resulting into a durable frame construction. This type of chassis layout has been, and still is, used by larger scale racing rc motorcycle models as it is very rigid but also lightweight, both crucial in a competitive environment.

Transmission

At such small scale it would be too much to ask for a real steel chain. Not to mention how fragile such a component would be. A toothed belt even if it sounds as a better idea it would again be prone to failure due to the its minimal size for such a stressful application. However, the actual system implemented resembles more that of a toothed belt but... without the teeth. Power from the motor is transferred to the rear wheel via a set of mini pulleys and an o-ring style rubber belt. Cheap to replace, extremely lightweight and under hard acceleration it can also do the work of a slipper clutch ! Additionally, a pinion - spur gear set makes possible for the final gear ratio to effortlessly be modified, matching your performance needs.

Suspension

When I opened the box and realized how much small the parts of the rear shock are I would bet that this was going to be just a spring actuated shock. Unfortunately for me this was a bet that I was about to loose. The BP-12 comes with a tiny oil filled shock. How tiny ? Well, let me just say that a couple of drops of silicone are enough to fill it up ! The stiffness of the damper spring can not be adjusted, however, four mounting holes drilled directly onto the chassis plates are ok for some minor fine tuning. Of course if this is not enough and you feel adventurous you can drill some additional shock mounting points yourself. This is a very very delicate job though so I don't recommend trying this if you really don't know what you are doing. A broken or severely weakened frame is not going to make your day.

On the front, an aluminum fork system takes care of the bumps. The the spring preloaded fork has a tendency to grind a little but a single drop of oil at each of the moving inner fork tubes faded away any irregular motion. Spring rate is again adjustable, by reversing the lower wheel axle mounts, providing two settings, soft and hard. So is the rake angle, something I did not expect for a model at this size. Just another confirmation of how well designed this rc motorcycle is.

Steering

I was pleasantly surprised to see that this little bike uses ball bearings in the headstock. As a result side to side steering movement is extremely smooth. The steering mechanism is quite simple and consists of a linkage - one end connects to the upper triple clamp via a ball link while the other end attaches on the servo horn. No servo is provided on the kit so you will have to get one for this job. A dual spring setup on the linkage eases out the steering response and eliminates any unwanted behaviour. Simple and effective.

Stability

The BP-12 was designed as a competition model. As a result, no gyro is provided. If you are not into racing and just want this bike for your local mini track don't let this scare you away. The bike is still easy to balance and drive around given that you maintain speed a bit above low. Another crucial factor here is the placement of your electronics. Keep everything as low and as close to the bike's center as possible and you should have no problems at all. The battery position, which is on the lowest part of the chassis, also helps in having a greatly balanced motorcycle. Crash bars are also provided, actually more like crash rollers than simple bars, since there is a small plastic wheel attached on the end of the bar reducing the friction drag when touching the ground.

Motor - ESC

Bastelpeter's BP-12 comes with a brushed FK130 motor. A bit outdated you might think at a time everything around goes around but let me tell you that this little thing can deliver some serious power. Of course the overall weight of the rc bike help a lot as well. No ESC is provided with the kit so you can use any "brain" you like, the smaller in overall dimensions, the better.

Wheels - Tires

This is the part where things got a bit trickier as the foam tires needed a bit of extra work before fitting them on the wheels. The kit comes with two foam pieces that I had to carefully shape up. I wasn't much sure in the beginning if I could manage this as I had never done something similar before but it was a great opportunity to learn something new. There are quite a few ways to get the desired tire shape depending on the available tools you have. Actually, it was a little time consuming process but the end result was very rewarding so nothing to scare you away. The tires are fitted on plastic three spoke wheels, the wider one being the rear one as well.

Body - Rider

Even though the bike is small, body detail has been preserved which is a great achievement. The rider is integrated onto the body keeping the body parts number and weight to a minimum. The two polycarbonate transparent body halves need to be cut, trimmed and painted to your desired color scheme. There is no protective film on the outer side of the body so masking tape is going to be your friend in this one. The stickers must also be cut to proper shape before being applied.

Radio - Servo

The BP-12 comes without radio or servo. You can use any two channel (or more) radio of your preference but due to the small size and the limited room in the chassis for electronics installation it is advised to use a micro receiver. The steering servo should again be in the micro family with a length up to 22mm. Since the force needed to steer the front wheel is relatively low a high speed servo should be able to cope with this task just fine instead of a high torque one resulting in a slower steering response feel.

More Info - Questions

You want to know more about Bastelpeter's BP-12 ? Then have a look at the on road rc motorcycles discussion board. If you still can't find what you are looking for then you can simply create a new topic and we will try our best to help you out.