Removing The Catalytic Converter Element

As this bike originally came from California it has some very stringent emission control add-ons. The biggest and most restrictive of these is a catalytic converter element in the resonator box portion of the stock exhaust.

Now I know many people will argue that it should be left alone and that if you remove it you are evil and that Greenpeace will come to get you (and drown you in a vat of lentil soup whilst beating you with their woven hemp sandals) BUT bear this in mind; there is no CAT fitted on bikes that are sold in Canada, Australia or here in New Zealand... and possibly other markets that I'm not aware of.

My past experience with second-hand Japanese import cars has been that removing the CAT not only increased performance BUT also significantly increased fuel economy. My Toyota Celica got an extra 50km per tank after removal of it's CAT. Now this says to me that if I am using less fuel I am causing less pollution.

Hey, it's up to you, if you are happier leaving it in then leave it in.

After removal of the CAT on my bike I have observed the following:

At this point I have not done enough mileage to verify if fuel economy has improved but watch this space...UPDATE 07/10/2005: After running through a few tanks full I have recorded an increase in range of 25 miles (40km) per tank up from 230miles to 255.

To sum up, the bike feels like a different machine. The engine is more responsive and runs easier. It no longer feels as if it is being held back.

At this point I have not touched the CCP code plug, I have only removed the CAT element. I plan to make up a three-way connector and experiment with the different CCP configurations and will post up my findings.

OK, for those who wish to carry out this modification read on...

First remove the exhaust system from the header pipe. I found that after removing the rear hanger mount and loosening the forward pipe clamp a few blows with a rubber mallet got the exhaust moving and I could then grab the rear and wiggle it off.

Remove the O2 sensor.

Get the exhaust on a work bench and draw a line where you will make the cuts, I used an indelible marker. You can see from the photo below where to make the cuts.

I used my angle grinder with a 1mm cut-off wheel to make the cuts and my smaller die-grinder to get into the corner at the bottom left where the big grinder wouldn't fit.

As well as safety glasses and earmuffs I also wore a dust mask as I did not want to be breathing in all that concentrated exhaust residue.

Once the cuts had been made I used a small pinch bar to pry the "flap" open.

As I don't have access to any stainless steel welding equipment I took the exhaust down to my local muffler guy and had him gas-torch out the CAT element (where I have drawn a line in the next photo) and then got him to MIG-weld up the flap. Bear in mind that although this doesn't look pretty you don't see it once it is back on the bike.

Once that was done I reassembled the exhaust, reset the Motronic unit (by removing the number 5 fuse for 30 seconds) and that was it.

Above: Post-surgery, the offending tumourous growth

If you wish to remove the CAT from your exhaust you can of course buy one of several after-market exhaust systems for the RT. Two possible negatives to this (and it depends on your point of view as to whether they are negative) is:

The reason I did the CAT removal above was indeed because of the cost of these other systems plus, if I wanted loud I'd have bought a Harley