I finally decided to dump the cat!
I'm not interested in having an alternative flee-flow silencer because I really don't want the noise but having read extensively on here, I decided that keeping the existing system and getting rid of the cat was probably the best choice without dangerously running into lean mixture problems.
Whatever I do to the bike I tend to keep the original bits to enable me to return the bike to standard if I want to, so first job was to source some replacement downpipes. I've kept looking but everything has been either over-priced or tatty but then last week I found a set for sale in Northern Ireland for £60.
Downpipes received and other than one very small stone dent on the underside, pretty well perfect condition. So how do I remove the cat? After a bit of a search around the net it appeared that it's simply a case of getting into the cat bit of the pipework, drill/chisel/hammer/hack whatever's needed to get the cat out and weld it all back up. Initially I wasn’t sure how tough the stainless steel pipes would be, but surprisingly it was easy to cut through with a couple of new 12” hacksaw blades. I made the cut where the rear clamp is fastened so the new weld would be hidden when finished.
The cat is contained in a short section of additional pipe inside the main exhaust pipe, so there are 2 options, either remove just the cat material or remove the cat ‘pipe’ complete. I decided to take out just the cats internals so I drilled a series of holes round the outside of the cat, then some easy work with a wood chisel all that remained was the extra piece of short pipe.
I then took the empty assembly down to JP Exhausts in Macclesfield who are a specialist stainless exhaust manufacturer. They looked at the 2 halves and then asked “Is it plated? It certainly looks like it is.” I hadn’t even considered that the new downpipes I’d bought might be the chrome version rather than plain stainless as my old ones! It seemed that welding might now be an issue but they’d see what they could do. Literally 10 minutes later one of the lads arrives back with my pipes, I’m thinking bad news, he’s looking happy with himself and wow, some impressive welding! Side by side with my old pipes the new chromed assembly is a far nicer piece of kit, how much cleaning it’ll need to keep it rust free I’ll just need to wait and find out.
The result ….
I rode 2-up down to the NEC for the bike show yesterday, icy A-roads going and a deluge on the motorway coming back, but a little over 200 miles to get a feel for any change catless. Other in the past have ranged from no different to massively better - my personal experience is that the engine has lost its’ small-throttle-opening hesitancy that was a real pain previously, making it much sweeter maneuvering at low speeds. Also the mid-range pickup has improved, very noticeable with a pillion. Top end power? Unlikely to have changed and I don’t really care! I find the power of the GS ample it’s just the smoothness through the rev range that needed a little tweeking and this has really helped.
I’d already fitted an Accelerator Module and that helped a little, but this has been a much bigger step in the right direction. Might still be tempted to get a Hilltop remap but now it’d be more for peace of mind over the mixture than the actual rideability. Also I've always recorded my fuel used and mileage so over the next few months will know whether economy has improved.
Sorry about the poor quality iPhone pics.
Stu.
I'm not interested in having an alternative flee-flow silencer because I really don't want the noise but having read extensively on here, I decided that keeping the existing system and getting rid of the cat was probably the best choice without dangerously running into lean mixture problems.
Whatever I do to the bike I tend to keep the original bits to enable me to return the bike to standard if I want to, so first job was to source some replacement downpipes. I've kept looking but everything has been either over-priced or tatty but then last week I found a set for sale in Northern Ireland for £60.
Downpipes received and other than one very small stone dent on the underside, pretty well perfect condition. So how do I remove the cat? After a bit of a search around the net it appeared that it's simply a case of getting into the cat bit of the pipework, drill/chisel/hammer/hack whatever's needed to get the cat out and weld it all back up. Initially I wasn’t sure how tough the stainless steel pipes would be, but surprisingly it was easy to cut through with a couple of new 12” hacksaw blades. I made the cut where the rear clamp is fastened so the new weld would be hidden when finished.
The cat is contained in a short section of additional pipe inside the main exhaust pipe, so there are 2 options, either remove just the cat material or remove the cat ‘pipe’ complete. I decided to take out just the cats internals so I drilled a series of holes round the outside of the cat, then some easy work with a wood chisel all that remained was the extra piece of short pipe.
I then took the empty assembly down to JP Exhausts in Macclesfield who are a specialist stainless exhaust manufacturer. They looked at the 2 halves and then asked “Is it plated? It certainly looks like it is.” I hadn’t even considered that the new downpipes I’d bought might be the chrome version rather than plain stainless as my old ones! It seemed that welding might now be an issue but they’d see what they could do. Literally 10 minutes later one of the lads arrives back with my pipes, I’m thinking bad news, he’s looking happy with himself and wow, some impressive welding! Side by side with my old pipes the new chromed assembly is a far nicer piece of kit, how much cleaning it’ll need to keep it rust free I’ll just need to wait and find out.
The result ….
I rode 2-up down to the NEC for the bike show yesterday, icy A-roads going and a deluge on the motorway coming back, but a little over 200 miles to get a feel for any change catless. Other in the past have ranged from no different to massively better - my personal experience is that the engine has lost its’ small-throttle-opening hesitancy that was a real pain previously, making it much sweeter maneuvering at low speeds. Also the mid-range pickup has improved, very noticeable with a pillion. Top end power? Unlikely to have changed and I don’t really care! I find the power of the GS ample it’s just the smoothness through the rev range that needed a little tweeking and this has really helped.
I’d already fitted an Accelerator Module and that helped a little, but this has been a much bigger step in the right direction. Might still be tempted to get a Hilltop remap but now it’d be more for peace of mind over the mixture than the actual rideability. Also I've always recorded my fuel used and mileage so over the next few months will know whether economy has improved.
Sorry about the poor quality iPhone pics.
Stu.
