Yoshi install help

[Greg_imp]

Hi Chris

You don't need to buy an expensive socket. I bought an inexpensive 17mm box end wrench and cut a 1/8" slot in it with a hacksaw. I selected a wrench that had a thin profile; the diameter of the end is about 1.03".



You don't have to use the O2 sensor. The Yoshi doesn't have a catalytic converter, which is the reason consumer EFI systems have an exhaust sensor. The ECU uses the signal from the O2 sensor to lean out the air fuel mixture to keep it in the 15:1 range. Richer ratios do not allow the cat to function properly and can shorten its life, even though the ratio for optimum engine performance is in the 12:1 to 13:1 range.

If the O2 sensor is bypassed with this inexpensive plug the air fuel ratio will drop from the 15:1 range to the 13:1 range. I know this because I did back-to-back dyno runs with and without the O2 sensor connected and can show charts of the different air fuel ratios. I did re-install the O2 sensor in my Yoshi exhaust but with it bypassed I can get 50 mpg, so the slightly richer fuel mixture is not costing me at the pump. You might also want to check out the threads on the PAIR valve mod. The PAIR valve introduces fresh air immediately after the exhaust port to enable additional combustion of any remaining unburned fuel. This combustion takes place in the exhaust headers and the fresh air also enhances the catalytic process in the cat, which begins functioning at 600°F.

These mods will allow your engine to run cooler, with less vibration and quicker response. There's no point to modifying the air intake. Any change you make to "open it up" will be immediately and easily compensated for by the ECU which is capable of maintaining consistent performance over a huge range of atmospheric pressures.

http://www.ebay.co.uk/itm/Oxygen-o2-sens...1215348991


Did you get a steel bracket to replace the center stand stop? It comes with a bunch of little parts, including 2 big rubber grommets, that should be shown in the installation instructions.