Today, for some odd reason, my OEM exhaust fell off the 'cycle while riding. Luckily, i was close to my apartment complex and a friendly postman helped me by loading and bringing it to my apartment. Without the muffler, i kind of fell in love with the aggressive sound and was thinking about doing a short exhaust.....until i bombarded myself with research on "back pressure" and fuel/air mix issues causing the fuel to run rich, thus potentially ruining valves, manifolds, pistons.....etc. I have seen a lot of back and forth on this issue, so is the aggressive sound worth the potential risk to the engine and components involved? Will i need to somehow remap and reconfigure my fuel/air mix? Just need some insight from actual F4i owners. Thanks for your time.

 

I've been running a short exhaust for a year now. I originally put it on because: 1) it weighs about 11-12 lbs less than the stock, 2) it looks a lot better, and 3) it does sound a-real nice! If I had known about the potential fueling issues, as well as the slight loss of HP, I probably wouldn't have done it. That being said, I haven't experienced any issues after 10,000 miles and it still has more power than I can exploit, so I've just kept it on...

 

My F4i is nearing 30,000 miles with good compression on all cylinders. I just don't want to mess around with something that is only going to be a somewhat "cosmetic" improvement with no practical increase to longevity. I was thinking more along the lines of getting a Yoshimura slip on exhaust. I found one used on EBAY. It looks like it is in very good shape. I may jump on it instead.....or just stick with the OEM, but at this stage of the cycles life, i don't know if the shorty exhaust would make much sense.

 

That Yoshi will be fine! It's when you do the real short ones, like mine, that you are looking at the hp loss and running a little rich. I'd say if you are looking for complete piece of mind re: longevity, just stay stock... or get the Yoshi and get it tuned...

The only issue I've noticed with my Coffman is that I will get a whiff of unburnt fuel while at a stop. MPG hasn't changed, my plugs looked good when changed, and it does sound really nice so I keep it on.

 

How many miles do you currently have? The F4i model is getting harder and harder to find "unstunted" versions, at least. The used Yoshi i am looking at is $200 with a "best offer" option. May jump on it and get a power commander.

 

there she is......very rare color and i have never seen the seat conversion on this particular scheme. Just wanted to show her off a little.

 

Nothing wrong with that! Looks good and I like that seat!

I have 18,800 on mine. Original owner kept it completely stock and put just over 8,000 miles on it in the 12 years he owned it. I bought it last May and have put 10,500 since then...




Here's mine with the short pipe but before I installed frame sliders.

 

-Ok to start its running lean that will ruin everything not rich just so you know where we're coming from.
-Backpressure is not the issue its cylinder scavenging and flow reversion. A proper exhaust will have no backpressure at all, but designed so it also doesn't have reversion. The problem is "cold" [outside temp] air coming backwards and hitting the very hot exhaust ports, the fast cooling can cause cracks to form.
-I've had a yoshi slip on for over 50,000 miles with no tuner what so ever. The slip on does not change anything power or flow wise enough to matter. Your totally fine. Running just a header with no slip on is totally different. Which brings the question, how did your oem fall off? Its clamped on and bolted to the rear peg.