Tech Tuesday Fuel Moto blog

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Tech Tuesday 1/26/2016


Today we will talk about the importance or choosing a proper exhaust for your combination. While stock bikes are relatively friendly to most exhaust setup's, having the correct exhaust combo becomes far more crucial when you start making engine modifications such as cams and big bore kits.
Exhaust choice can make as much difference in a combination as the cam and it can make or break your setup. One needs to look at the big picture when putting a selection of parts together, each component needs to complement the next. The dyno chart in this post is from one of our dealers that tuned one of our FM 107 kits with TW-777 cams, they changed mufflers and it shows the specific difference between what just a set of mufflers can do.
Run #17 was with a extremely large stepped/open baffle, and Run #20 is with conventional straight thru baffles. Both setups got full dyno tunes. There is a difference of 20+Tq in the lower RPM's just from a muffler swap. Dyno chart courtesy Sheffer Performance
This is one example and individual results are relative to the combination. Thank you for tuning in and choose your exhaust wisely!

[fuelmoto]

Tech Tuesday 2/2/2016. This week we are going to discuss the importance of having the correct O2 sensor orientation in your exhaust system. While improper installation is easiest to mix up on 2010-later FLH bikes, this also applies to many other models. When installing a new exhaust it is absolutely critical to get the O2 sensors in the correct position. Yes they will only plug into the harness one way as the connectors are different front/rear however it is VERY easy to install them in the actual pipe position incorrectly. On bikes with 12mm O2 sensors an easy way to note which sensor goes where is to remember "Black is Back", meaning the rear cylinder O2 sensor has a black connector, while the front sensor has a gray connector. If the sensors are switched essentially the ECM will apply closed loop correction to the opposite cylinder and this causes the system to chase its tail, it will lean one cylinder and richen the other from one extreme to the other. The most common effect to the rider is the bike will not run smoothly and it will somewhat studder when at a steady cruise. It will also skip and buck at light throttle. This will completely affect the state of tune. Please check your O2 sensors, and if necessary switch them to the proper position, your bike will thank you.