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Discussion Starter · #1 ·
Hi all, well after I fixed the FPR issue I have stummbled across something else that may or may not be normal for the bike.

I seem to recall that once upon a time an F4i was the stunter bike of choice because of its low end throttle response and quick spool up. However my bike seems to lack that response with the throttle that I am looking for.

One thought was that the air filter is old and in need of replacement , how plausible is that?

Another thought is the spark plugs are fouled and in need of replacement.

Now since I live in the great white north the bike has turned into a pumpkin and I will be checking all of these regular maintenance items out.

So tell me, what would you suspect to be the issue??
 

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Excommunicated
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Have you put an aftermarket exhaust on it ?

I found with my Yosh it was boggy down low. way too rich

Power commander returned all the snap ( and then some ) to my low end.
 

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Discussion Starter · #6 ·
It is a mix between a bog and a hesitation, and it was commented on by another rider that tried riding my bike, after 2000 rpm the bike is a champ, too rich sounds right. Power Commander it is.
 

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Bikes are seldom too rich at any point unless a jet kit or Power Commander was added and mistuned. Stock bikes run a hair on the lean side in order to pass emmision standards but are tuned to operate in an acceptable manner. However if yoiu add on an aftermarket exhaust then it'll run noticably leaner and suffer in engine response. That's where a jet kit or Power commander can help out.

So it sort of depends on what's been done to your bike. Can you list the modifications that are on it?
 

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Gear whore
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my Hindle slip on causes a bit of roughness down low on my F4i as well.
 

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license to chill
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my Hindle slip on causes a bit of roughness down low on my F4i as well.
Ditto
I'm about to take possession of another with a Hindle and on my test rides definitely noticed this. I thought that, by going from carbs to fuel injected, the low end response would be noticeably smoother but at traffic jam speeds it's the total opposite. Also looking to do something about this sooner or later.
 

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Discussion Starter · #10 ·
The pipe is the root of all evil :D

The only mods on the bike at the moment are the D&D slip on. However, the lean condition was probably exaggerated by the fact that I had a leaking fuel pressure regulator.

I put the stock pipe back on for testing purposes and all misses and hesitation went away. A Power Commander III USB is on order and should be here soon.
 

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Swivel on it
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You don't really appriciate how bad it's running until you fit a PC. I was amazed when i fitted mine (Jardine RT-1 for a few months before i fitted the PC).
 

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Discussion Starter · #12 ·
Thats really wHAT i am hoping for, hoever, I would like to know if there are more maps floating around out there for my bike, the reason I am looking is because the DynoJet site does not have any maps for my bike with a D&D slip on pipe, but I know that there has to be one out thre somewhere.
 

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I have the same pipe and bike as you and I never noticed any roughness at low RPM.
You're probably just used to it. Even a slipon won't increase the issue enough to notice unless you know what you're looking for. But add on a PC and you'll be amazed at the difference.

I went through this with my Z this summer. Put Muzzy slipons onto the bike and noticed that while it seemed to be OK that there were a few things that suggested that it was lean. The sort of things you wouldn't notice unless you know what you're looking for. Added the PC and map and the bike totally woke up both with mid range punch and with far better respones to throttle inputs. And that was with a generic Muzzy&Z map. With some fine tuning the little teeeny things I'm still noticing would be gone and the front end would be even lighter... :D

T90, look around for some F4 specific websites and see if they have any PC maps available for sharing. The dynojet site isn't the only place they have maps for your bike. For example I got my Z map, along with about 20 others through a link to a private site on a Z discussion forum.
 

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Discussion Starter · #15 ·
Thats great, thanks so much for the information. I will revive this post when I add the PC III USB and tune it. I have no doubt that it will perk things up and eliminate the missing and flat spots.
 
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