If I’m honest, there wasn’t that much wrong with the old exhaust on my Burgman 650 daily transport and airport express. But we’re always on the lookout for more performance here at BSN – so the heavy old stock pipe had to go. A quick call to the good folks at GPR Exhausts, and we had a full stainless system in the post. Bosh.
The new pipe is a smart, no-fuss system from GPR. Dubbed the 4Road, it’s a straightforward design, without any fancy carbon trims or exotic conical sections. A pair of nice shiny stainless header pipes feed into a 2-1 collector link pipe, then into a polished round silencer, with a choice of removable baffles. It’s much sleeker and far lighter (4kg) than the stock setup – so I needed little encouragement to get spannering.
Removing the old pipe started off quite simply: the manifold allen bolts into the cylinder head weren’t too tight or seized, and the silencer is mounted with a couple of M8 bolts. You don’t even really need to take off any plastics: getting at two of the header bolts is a little fiddly if you leave the fairing lower on, but I persevered and got there in the end, with a small ¼” ratchet and a universal joint with an extension bar.
The pipe was off in ten minutes – but then came the real ballache. There’s a lambda sensor in the link pipe, and mine was properly, bastardly seized in place. I needed it to fit into the hole in the GPR pipe or the Burgman wouldn’t be going anywhere, so I got the big guns out: blowtorch, impact gun, breaker bar, hammers, chisels, the whole bit. Nothing. I left it overnight, soaked in penetrating oil, still nope.
In the end, I finished up Dremeling the shit out of it, gradually disc-cutting a series of slots to try and gently ease it out, before losing the heid, and just grinding the threaded boss in half. The sensor was finally out, so I threaded it into the GPR system, and fitted her up.
The headers were a breeze, and the silencer clamp slips on a treat too. I got it all together, flicked on the ignition, to see an ‘FI’ warning light on the dash – yep, I’d fucked the sensor getting it off. Gah! No big drama though: the bike still starts and runs fine. I ordered a Lambda sensor eliminator kit off the eBay, which came in a day or so, and that sorted the FI light. It’s just a small resistor plug that slips into the wiring loom, and a neat stainless blanking plug and gasket to go in the hole in the link pipe. Sorted.
Back to the GPR pipe – and, of course, I have to try out the different baffles. No baffle at all is violently, murderously loud, a real nasty bark. And, of course, with a CVT transmission, you’re sat on peak torque revs all the time, so you appear genuinely deranged riding through town with it. The least restrictive baffle is still pretty loud, though far less obnoxious, and the full dB killer is still nice and fruity. I’ve got an MOT coming up in a week or so, so I plump for the road-legal baffle – it’s literally a ten second job to swap them round anyway.
So – the GPR 4Road system is a fab choice if you need to replace a rotten stock pipe for the MOT. It’s not at all dear, at just £255 – which is worth it for the 4kg weight loss alone, and it sounds much beefier. I’ve not been down the dyno shop on her as yet, so can’t speak of power gains on my bike – but GPR reckon a couple of bhp extra at the top end.
I’m also looking to fit a Power Commander if I can: the new pipe gives the odd pop and bang on the over-run, especially when cold, so I wonder if the stock fuelling is a little rich on my bike now. We’ll find out…