Bike accessory advice: Getting the most from an aftermarket exhaust

By Chris Dabbs -

Exhausts

 08 May 2009 17:28

MCN expert Chris Dabbs is here to answer any questions you have on anything bike related.

If you have any questions, ask an expert here

Q. After two enjoyable years riding on my totally standard Yamaha Fazer 600, I have decided to take the plunge and will be shortly taking delivery of a brand new 2005 Yamaha R6.

I want to fit it with a Devil Trophy aftermarket exhaust can, but I’m not sure what else I need to do to get the best performance from the engine, or is it just the case that I can fit it and go!
Dave Buck, Manchester. 

A. The devil Trophy can is road-legal with a removable baffle, so as long as you don’t remove that you can just fit it and go. If you want to get more power then the engine needs to flow more fuel and air.

The first step would be to remove the baffle and see how it feels. Remember that you are now running the risk that the bike will be too lean at the top end during prolonged high-speed running and that will damage the engine.

So I would have an appointment booked at a dyno-house that had already spent time on R6s and knew what set-up worked best. That way you can match the inlet set-up through the airbox and fuel injection to the exhaust set-up.

But don’t forget fitting a non-standard exhaust will invalidate your warranty if you make a claim and it transpires that the exhaust was to blame in some way. As it is to get any reasonable increase in power you'll need to fiddle with the fuelling which also invalidates any warranty.

Insurance companies operate on a principle of “good faith” and you should inform them of any changes, the trick to get around the race-can syndrome is to use the phrase “aftermarket” when you’re talking to your insurers.

That way you have informed them of the changes, but they aren’t faced with having to effectively endorse the use of an illegal component, so there should be no problems.

If they DO ask more questions you’re at the mercy of each companies’ policies, and most won’t cover race cans, or put tight limits on power increases etc that they will accept.

Unless the pipe was the cause of an insurance claim it shouldn’t stop a pay out, but if you’re claiming for damage or loss on your policy and it’s a flash titanium system worth thousandsmore than standard you won’t get the money to replace it.

You could also get into trouble with the Law. It is actually an endorsable offence, where the maximum penalty is a "level three" fine of £1000. In practice fines average £100 to £200.