I was thinking about buying a Yamaha and in looking at the list of upgrades on it I noticed they had remapped the factory ECU and thought to my self I wish someone would would remap the GS. I went ahead and contacted all of the tuners here in the USA to see if they did and was told No. They had no interest. So I started searching outside the USA. Bingo! I found a nice long thread on it over at UKGSer. They have been taking their GS both 800 and 1200 to Geoff at Hilltop Motorcycles in the UK. I almost fell off my chair when I saw the dyno charts. 100+ bhp at the rear wheel. No way I thought to myself. My 09 GSA has 80bhp at the rear wheel. So you would be talking about 20hp just by ECU tuning. I went ahead and sent Geoff at Hilltop a email to see if just the ECU could be sent to him and have it remapped. In short YES
. OK how much was the next question? 300 UK including return shipping. Alright let me see that's $477.08 I then thought back on all the HP goodies Ive bought in the past and noticed that in every instance I had spent $100.00 per hp. That would mean 20 hp should cost me $2000.00. And if I did the bigger valves with new cams and new sprockets yea $2000.00 . So $477.08 is pretty cheap if it works. So the emails flew back and forth between Geoff and I with questions like should I leave the cat on the bike and fuel types. Make the cat go away he says. OK I don't want a new header so I can cut the cat in half and remove the core or I can attempt to get it out of the hole. Worst case I cut the cat in half and pull the core so I sent the ECU to Hilltop and went to work on the cat. Here is what I came up with.
Removing the guts from the cat just wasnt that hard. I looked around online and was headed down the cut the header in half and once I got the header off the bike and saw I had a fair shot at getting the core apart I figured why not try. The worst that I would have to do is cut the header in half which is what I was planing on doing anyway. I was going to make a video of doing it but it was so easy it was boring to watch so I deleted it. As far as tips for anyone who wants to do it here is my hind sight on it.
1. Put on a pair of gloves. I had several small cuts on my hands when I got done.
2. Get a piece of carpet to work on. As you are working on the cat end of the header the curved end will get scratched up if you dont.
3. Get a hose clamp and put it on the opening of the cat where you will be working. It will keep you from distorting the portion of the header that the muffler slips on.
4. The core its self is about 70mm thick and is a metal honey comb. As you are tearing it apart in the housing make sure the piece you tear of will fit out of the opening. Once its loose in the header its hard to make it smaller.
As for the tools I used.
1. 48oz Hammer
2. Long needle nose pliers. Mine were 12 inches long
3. A sturdy vise mounted to a work bench.
4. A 19 inch pry-bar that can be struck with a hammer.
5. A 16 inch heel bar made in China. You will need to be able to bend it.
How I did it. I started by putting the hose clamp around the opening for protection and trying to drill a hole in the core with a long drill bit and quickly realized that wasn't going to work. I next took the cheap heel bar and sharpened the pointed end like a chisel. I could then use the hammer and without driving it thru the side of the pipe hammer it thru the core in several spots. After you have driven it thru the core you will need to clamp the remaining part of the heel bar in the vise and twist the header by hand as you pull the header off the heel bar. Once you have a few holes in the core you can then switch to the pry-bar and do the same thing. Now that you have some room to work you can pick a spot and start knocking the pry-bar thru then clamping the end of the pry-bar in the vise and breaking pieces of cat off by twisting the header by hand being careful not to bend up the lip of the the opening as you work. The hose clamp will only help so much. After about an hour and a half I had most of the cat removed. I then put a few more bends in the other end of my cheap heel bar and used the hook end to scape the remaining cat from the housing. 2 hours spent. No cutting or welding.
Now a word about shipping to the UK. Make sure the shipper puts for repair on the shipping label or the queen of England will get involved and want a VAT tax as they will think you sold it to the motorcycle shop. It took about two weeks there and back. Their is a procedure you will go thru when you plug the ECU back into the bike which Geoff explains to you. OK did it work? Hell yes it worked!
This thing runs great. The first thing I noticed was it didnt need as much throttle or clutch on take off. The bike can be ridden now in 6th gear under 3k without jerking and I can open the throttle with out down shifting and have it pull away. The surge the bike had at 55-60mph is gone. It pulls even all the way to red line and it gets their quick. I know what about the 20bhp? Well yea it has a lot more hp. I was playing around with it trying to get it to stumble or hiccup in second gear and chopped the throttle in second gear and then pinned it and almost took it over backwards. i have a app on my Iphone that will allow me to do a 1/4 mile time with hp but it needs to dry out and warm up some before I do this. I have been trying to figure out the fuel mileage but with the freezing temps is making it difficult. Ridding around town I was getting 38 and now its 42 so I know the mileage is better just not how much. Would I do it again? In a heart beat. Geoff at hilltop motorcycles in the UK has done hundreds of GSs both 800s and 1200s and the mapping is spot on. Here is a few dyno charts that where sent to me from another fellow in the UK