Known Problems & Troubleshooting

Basic maintenance, a bit of care when driving, and maintaining your service schedule should provide you with a reliable Rocket. But occasionally something can go wrong.

If you are having a problem, check the list of symptoms below, and it might save you a frustrating time in the garage. Although the list is quite long, we must stress that most of these problems have happened in just the one case. As we have said throughout, the Rocket is a remarkably reliable car in its class.

Known Problems

Tail Light Failure
The taillight/brake light bulb fails occasionally, and there is no indication of failure. Check them regularly, e.g. against the back of the garage. The normal clue is that both brake and tail light have failed on one side. On inspection, you will probably find that one filament has burnt out. Do not panic, as it is unlikely to be a wiring problem
Battery Collapse
Bike batteries use a gel medium, and are notorious for collapsing. this can happen much more suddenly than a normal car battery. It may seem in perfect condition one day, but be dead by the next morning. Symptoms may include strange instrument reactions when you turn on the ignition, followed by no reaction to the starter button. To check this, disconnect the old battery and rig in another (a car battery will do) with jumper cables. If the car starts perfectly, the battery has collapsed.
It is advisable to keep the battery well charged. A weak battery may give similar symptoms and a weak battery is more likely to collapse. See the section on storing the car under Maintenance.
Spongy Brakes
This is often a symptom of under-use. The pedal should be firm with just a slight movement. If it has gone soft, and you haven’t used the car for a while, some air has got into the system. Bleed them thoroughly until the pedal firms up.


Troubleshooting

Symptom: Engine Stutters at 4,000rpm
You experience a slight stutter under heavy acceleration, before the engine clears itself and races ahead. Your intuition suggests that this is an electrical issue, but there is one alternative. It is possible that the EXUP valve in the exhaust is sticking.
Reach under the car and check actuation with your finger. The valve is on the left of the gearbox, and you will see two cables (push-pull) entering from above. Apply Copaslip grease to the cables and cam. Repeat manual actuation to spread the grease. then take the car for a run.

Symptom: Engine stumbles and stalls once warm
When totally cold, the engine runs perfectly. But once there is heat in the engine, tickover becomes erratic and the engine may stall. Pulling away becomes difficult or impossible, but once up to about 4,000rpm, the engine clears.
This is almost certainly an electrical problem. First check all HT cables and spark plug condition. The next suspect is the coils, which sit on the bulkhead above the engine. there has been a report of these degrading when hot (hence why they work well when cold). It is not practical to test the coils in this condition, so replace both units with new parts.

Symptom: Brake Lights Fail, but bulbs appear sound
The brake sensor has failed. This unit measures line pressure, and is mounted in the brake pipe above the gearbox.
Before removing the unit, jack up the rear of the car – this will reduce the amount of brake bleeding you will need to do later. Unbolt and replace the unit. Thoroughly bleed the rear brakes.

Symptom: Scraping Noise From Rear Wheels
This is most noticeable if you push the car around, a faint sound of two pieces of metal grazing against each other. Assuming this is not the brake pads grazing the disc, it will be wheel hub bolts grazing the hub carrier. On one production batch, there was a slight machining fault that allows contact. It is nothing to worry about.

 

If both brake lights fail, particularly after a long lay up, the most likely cause is the sensor sticking. Before you start stripping the brake lines, follow this procedure:

 

1) Have you turned the ignition on, and is the battery connected and working?

 

2) Check the bulbs - it is always possible that both have failed

 

3) Locate the brake sensor, It is on the left hand side, just in front of the upper fuel tank, where the rear brake line splits left and right. With a medium weight tool (a wheel spanner works well), give it a sharp tap. Then climb in and press the brake pedal hard a couple of times (you can just see the lights from the driver’s seat). With a bit of luck, the sensor will release.

 

4) It may be an electrical problem. With a multimeter, check there is voltage at both the lights, and on the sensor.

 

If none of these work, unfortunately you are probably going to have to replace the sensor. Jack up the rear of the car, then unbolt the sensor. Remember to place a drip tray under the area, and have a lot of towelling to hand to wipe up the brake fluid. Once the new sensor is installed, bleed the brakes thoroughly, particularly the rears. Finally, thoroughly wash down all components that have been soiled by the brake fluid, then take the car for a short drive to check the brakes.

 

 

 

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