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NF Bike Setup: By Steve Newey of Formby Models

Reproduced with permission

Hello, my name is Steve Newey, I’ve been involved in a lot of different aspects of radio control since 1980. My first model was a Graupner Elec Rider motorcycle, from which some friends and myself got tremendous enjoyment, racing them around the local car parks.

The first organised racing began when Kyosho brought out some 1/8^th scale electric bikes which looked very realistic, based on the Honda, Suzuki, and Yamaha Grand Prix machines. Normally we would have 25 to 30 entries per meeting from drivers, or should I say riders, from all over the country, racing at a number of tarmac circuits including the original Halifax and Stafford circuits, which are no longer used. We also were involved in a number of promotional events at circuits like Oulton Park and Donington Park at the British Motorcycle GP’s and World Superbike meetings where we entertained thousands of motorcycle fans with our antics. However, during the mid to late nineties numbers dwindled for one reason or another, and eventually faded away altogether.

Whilst competing at a 1/5^th large scale car meeting at Tibshelf, I spotted a large model electric motorcycle on the track, unfortunately, it would only stay upright for about three or four meters before falling over, so I decided to offer my assistance. The owner let me bring the bike home to sort out and with the help of Barry Walker, we soon had the bike up and running and testing took place on the local car parks. We returned the bike to it’s owner at the next large scale meeting at the Halifax circuit, where we gave the bike a run before racing began, completing about twenty laps without falling over once, I was hooked and impressed, and had to have one.

Just at that time Thunder Tiger and Nuova Faor brought similar models out, again, 1/5^th scale using 540 motors and sub c 7-2 volt batteries, as used in 1/10^th-scale buggies and touring cars. Both bikes have their own plus points.

The TT bike comes ready built, and looks nice, only requiring radio installation, batteries and motor fitting to get you up and running quickly. The NF bike has to be built and painted, but has proved to be the better option as far as racing is concerned.

As I prefer to build from kit, I decided to purchase the NF bike, and was immediately horrified by the instruction manual, or lack of it, just a few sheets of paper containing some drawings and pigeon English text. I built the bike mainly from studying the pictures on the box, the drawings, and limited text, but was not too impressed when I ran it. With a stock motor fitted, it ran ok in a straight line but cornering was very sluggish at low speed and a non event at high speed, it just went straight on, and when a faster motor was fitted (12 turns) it became impossible to drive, tying itself in knots and throwing itself on the floor when flat out, not good. So, despite building the bike exactly as per the instructions, the model performed very poorly, not like the Associated and Losi models that I was used to building, and being near perfect ‘out of the box’. As I learned more about constructing the chassis, I found that it was very easy to build it with the main frame sides out of alignment, which in turn, can put the back wheel out of alignment in, both horizontal and vertical planes.

Once I found a way of building the chassis accurately I found that this cured the high-speed instability, the bike would now run flat out without any sign of it weaving or getting into ‘tank slappers’. This is how I now go about building an NF chassis from scratch. Some simple tools are needed, and also a 12” steel rule, a good quality set square, and two open ended 8mm spanners, as well as your normal tool kit, I also strongly recommend that the standard frame spacers (X21) are discarded, and the upgraded alloy spacers (X21A) are used, this increases the strength of the frame, and resistance to it twisting, and becoming misaligned after a crash. First step is to build the top frame with the steering arm, including the crash-back spring, fuel tank mount, and the alloy frame spacers, (Pic 1).

To save time the steering servo can also be fitted, I prefer to screw it to the INSIDE of the LEFT top frame. Make sure that the steering arm can be pushed back against the spring and return freely, but without any side play, do not fully tighten up the frame spacers at this stage, finger tight is fine. Fit the main frame sides to the top frame spacers with the supplied Allen screws, do not fully tighten, and then fit the three alloy frame spacers that are used to hold the battery tray in place (without the battery tray). Place the chassis the correct way up, on a flat surface, push the chassis sides down firmly and slowly tighten the battery tray spacers all the way up (Pic 2).

Check the frame sides in two planes, vertical and across, with the set-square (Pics 3 & 4).

If there is any discrepancy, back the screws off a little, adjust the frame sides then re-tighten the screws and check again, do this until the main frame sides are correct in every plane. Next tighten the upper frame spacers to the top chassis, using the 8mm spanners then lastly, tighten the Allen screws that attach the main frame sides to the spacers. Re-check the frame as before with the set square, and make sure that there is no ‘rock’ between the main frame sides when placed on your flat surface. Getting the frame set up correctly in every plane can take time but it is well worth the effort to get this part of the assembly as accurate as possible.

Next step is to assemble the rear sprocket, wheel hub and axle onto the swinging arm, as per the instructions, and tighten up with the nylock nut. Then fit the bearings in the swing arm and push the transmission shaft though, making sure it is the correct way around. Fit the thickest of the three alloy spacers (PT NUM 17/4 as shown in the manual) and the chain sprocket, again, making sure it is the correct way around. Make sure the two sprockets line up exactly, by using the steel rule as a straight edge against the sprockets (Pic 5).

If there is any discrepancy, then it needs to be corrected, either by filing the alloy spacer down or using shims (Team Associated number AS 6373) to get the correct position so the chain runs true. Once happy with this, fit the spur gear assembly and the other two alloy spacers as per the instruction sheet, do not tighten the sprocket or spur gear assembly onto the transmission shaft yet. Jiggle the transmission shaft and swinging arm into the main frame then fit the bearing supports (X03) in the LOWEST holes, followed by the bearings and circlips, there will be some end float (side to side play) this is normal, we will address this problem later on. Nip up the grub screws that hold the sprocket and spur gear and also fit the rear wheel without tyre. It just so happens that the width of the rear wheel and the gap between the circlip grooves in the lower frame spacers (that hold the battery tray) are the same, so it makes it very easy to check the rear wheel alignment. Simply hold your straight edge (12” metal rule) against the rear wheel, and it should line up with the grooves in the lower frame spacers (Pic 6).

If the wheel is pointing across the frame, then it’s probable that the frame has been assembled out of true, if the wheel is not centred, then it is likely that the two outer spacers on the transmission shaft have been fitted on the wrong sides. Do whatever is necessary to get the rear wheel correctly aligned, this is of vital importance. Also check that the wheel is vertically correct in the frame by placing the frame back on your flat surface, then check the frame and wheel are both vertical with the set square. Once all these aspects are correct, yes I know it can take a long time, but it’s worth the effort, then carry on building the model. The rear sub frame can be assembled and fitted next, nothing special to mention here. The next thing to consider is fitting the rear shock absorber, there can be a few issues to address here. Screw up the shock spring adjuster to put maximum tension on the spring. Fit the shock as per instructions and measure the distance between the screw in the rear sub-frame that holds the plastic seat mount, and the centre of the rear axle, it should measure between 100mm minimum and 110mm maximum (Pic 7),

we shall call this measurement the amount of ‘droop’. This distance can only be set by altering the overall length of the shock. To alter the length of the shock it has to be taken apart, the piston rod removed and spacers (not soft tubing) added between the piston and internal spring to achieve the correct length. Once correct, the shock has to be refilled with good quality 5000wt silicon oil, making sure that there are no air bubbles in the oil. At this point it’s worth replacing the standard diaphragm with a better quality item from Lauterbacher or Hobao.

We can now move on to assembling the front end of the model. The Front forks can be assembled as per the instructions, some damping can be achieved by dropping ONE OR TWO SMALL DROPS of 5000wt silicon oil in the fork legs before assembly, it’s also worth polishing the fork stanchions by placing them in an electric drill and using a polishing compound with a cloth while they are rotating in the drill. After assembling both fork legs, check that they work smoothly and have the same feel before fitting the top and bottom yokes. Make sure not to miss out the spring washers when fitting the yokes to the steering arm. Take the front wheel axle and screw an M4 x 6mm grub screw into one of the threads, as far in as it will go.

Fit the axle to the forks with the side containing the grub screw on the right hand side (as if you were sat on the bike). Take the two M4 axle Allen screws, put a washer on each, and fit a 1/8^th “O” ring on the screw that will be fitted to the right hand side of the axle containing the grub screw. Tighten the left hand screw fully then start to tighten the screw with the “O” ring, this screw should ‘bottom out’ against the grub screw just as the “O” ring touches the fork leg when fully tightened (Pic 8).

You will find that this modification improves the front suspension, it will still work smoothly even if the forks get twisted slightly in the yokes after a crash. Always check the front fork alignment before every run by sighting them from one side.

After fitting the front forks to the steering arm, make sure that the steering moves very freely from side to side. The steering rod is made up with a ball joint, two collets, two springs, and a plastic pivot moulding. The pivot moulding is fitted to the steering servo horn, make sure that the pivot can rotate freely on the servo horn once screwed on, I also use an “O” ring between the pivot and the servo horn.

The instructions show the steering servo, mounted to the left sub-frame from the outside, I prefer to mount it from the inside, which gives the steering rod a straighter path. When fitting the steering rod and servo horn to the servo output, the angle between the steering rod and the servo horn MUST be ninety degrees when the servo is powered up and the steering trim centred. Next, adjust the two collets so they are putting the springs under very light tension and also so the steering is pointing straight ahead, move the steering side to side by hand and check that steering comes back to centre, or near enough to it. To check that the steering is working in the correct direction, push the transmitter stick to the LEFT, the forks should turn to the RIGHT, flick the servo reverse switch on the transmitter if the steering is moving in the wrong direction. IMPORTANT, make sure that the steering rod does not catch on any of the chassis or any other components when the servo is at full travel in both directions. Fit the steering damper without the “O” rings and check for free movement again, then fit the “O” rings if required. It’s also important that none of the bodywork, mainly the seat/fuel tank unit, causes any restriction to the steering mechanism, when it is fitted.

Before gluing the tyres to the wheels, drill a small hole in the wheel to allow for air movement. Clean the tyre with meths or similar to remove releasing agent. Glue the sponge tyre insert ends together using a contact adhesive, and fit the insert into the tyre. Fit the tyre to the wheel, then spin the wheel on it’s axle to make sure that the tyre is running true, then glue the tyre to the wheel with a good quality THIN cyno type glue. When fitting the battery tray, I only use the front and rear mounts, the middle one if left bolted tightly to the chassis, and the middle ‘hump’ in the tray is cut out (Pic 9).

Radio installation is reasonably straight forward, a bog standard servo can be used for the steering, it’s of no benefit to use a hi spec type, but it’s worth considering using a waterproof speed control as the bike is so open to the elements. When choosing a motor and speed control, you need something that will have a smooth power delivery, with not too much ‘bottom end’, also consider your own experience and ability, a novice will turn in better lap times using a geared up soft motor, i.e., 17 turn than an animal 12 turn motor.

When the bike is ready to run, the first thing to do is adjust the steering so that the bike runs straight. To do this, disconnect the steering damper, and drive the bike at about quarter throttle, note which way the bike starts to turn, if it turns to the right, move BOTH collets, on the steering rod, slightly towards the steering head, visa versa, if the bike keeps turning to the left. Get the bike running reasonably straight, then do any fine adjustments with the trim on the transmitter. Note putting more tension on the steering springs makes the steering more responsive but more difficult to drive, this is something that you can experiment with. So, hopefully by using the instruction manual combined with this article, you will be able to build your motorcycle to a good standard, which should perform well and be as easy as a model motorcycle can be, to drive.

Once up and running, you will need to find a suitable area to use it, a large area with a good surface of tarmac, (and no solid objects), is best to perfect your driving technique, which can take some time. You can make simple tracks using plastic bottles for practicing, which won’t damage the bike if you hit them. The bike is a lot more difficult, but more fun and rewarding to use than a car, and after some practice you will find that it’s possible to slide the bike sideways on the brakes into corners etc, AWESOME, just like the MOTO GP bikes. Then when you’re good enough, you may like to try your hand at a race meeting at a real model racing circuit. I’m planning a further article which will cover the development and modifications that we now do to the bikes in a racing environment. Last season at the Racer series meetings, the fastest bikes were lapping within three seconds of the fastest 1/5^th scale petrol powered trucks, which goes to prove how well these bikes can be made to go. ENJOY. For more info, you can contact me at, SALES@FORMBYMODELS.COM.