Since borrowing Mary’s ZZR400 this last week or so, I noticed a few niggles with it’s running that I’ve been trying to address. Firstly the front brakes were sticking a little and secondly the running has been a bit on the rough, loud and underpowered side, especially at high speed. To tackle these issues I called up on the skills of Tim (‘Scorch’ on LondonBikers.com), who offers a mobile motorcycle repair service.
Tim popped over to went to work on my bike, whilst I was parked up at work myself. Very handy indeed. He quickly set to work on the brakes, found one of the pistons was a bit gunked up and air in the system. In a couple of hours he had the lot stripped down, sorted, new fluid in, bled and working well.
The second issue, regarding the running of the bike Tim managed to identify as being a leaky air box. Being a ram-air system, it’s important that the air box is sealed and can build up the correct pressure to ensure the valve floats work correctly and the right mixture of fuel/air goes into the piston. For some reason where the underside of the air box bolts down onto the top of the throttle bodes there is a huge gap, the two just don’t line up well. Tim wasn’t entirely sure why, possibly warped box, maybe wrong bolts, possibly throttle bodies had been flexed down too much, possibly missing a gasket. Although Tim wasn’t able to fix this at the time, at least he has identified what is almost certainly the fault, and it is something I should be able to address myself.
Further investigation myself on the internet reveals that a badly sealed air box can indeed lead to the exact symptoms I have. Checking out parts diagrams, it does seem that a gasket is missing. I have also ordered another air box with original fitments off ebay cheap. Hopefully replacing these will remedy the problem.
Overall, I’m very pleased with Tim’s work, his rates were very reasonable and I can’t fault him. I definitely recommend you give him a bell if you need some work on your bike doing.
Tim, Mobile Motorcycle Repairs – 07986 750384