Monday, July 19, 2010

Pipe reduction

With all the recent performance upgrades fitted, I decided I'd give the bike a test run to see how it goes now. I must admit that I've been rather disappointed. I thought this would have made a much more noticeable difference. With all these parts fitted, I could even have expected a large improvement on how the engine pulls.

The first problem I immediately spoted was the fact that the bike was way too loud with its new Laser exhaust system. And despite the fact the tiny db killers were said to reduce the noise by 3db (cutting the noise by half), fitting them in the cans didn't not really improve the situation. Worse, with this system on, the bike became hard to work in the city streets. I could feel a sensible loss of torque in the low revs. At that point I was really disappointed, even more when thinking about the hours I've sweat trying to mount every single performance parts.

I was decided to cut off the noise first, because I had already experienced a similar problem with a very loud exhaust system on another bike. It totally spoils the general impression you can get from a motorcycle. Not only a very loud exhaust does not always mean optimal performance improvement, but it does also prevent you from trashing the bike and get the most out of it (I remember I once even removed a Micron system from a track bike because I could not concentrate).

In my opinion, the whole problem with this noisy cans, came from the db killers. They were too short compared to others I had seen before on other systems. In my mind, they had to be lengthened. I had spotted a new shop where I wanted to go to see what they were up to, because the guys were told to be pretty good mechanics with one who had worked for a Formula 1 team (Prost Grand Prix) before. I was just curious what they were able to do and since I had these tiny pipes to modify, I thought it would be a great opportunity to pay them a visit.

We immediately aggreed on how to proceed. We all knew we could not find the right solution by making just one attempt. So I came with bike to the shop and they started to work with the db killers and a 18cm piece of pipe coming from a higly modified Akrapovic system, which means the db killers woud receive 9cm of extra pipe each. One of the new db killers is shown below :

The result ? A much more usable bike with torque back at low revs and far less noise (but still a grunty one). I rode a little more than 30 km on my way back home and trust me when I say there's a huge difference now ! I'm heading to the dyno shop to put figures on what I feel. And yes, it took us only one attempt to build these. The guys at Metal Machines really rock ! They know what they're doing and won't bullshit you for hours.

The Metal Machines workshop

Home made trike. There's also a home made ATV (powered by a R6 engine) being built in the back of the shop

1 comment:

hot rod said...

Hi! as% decreased the noise?