Rejetting for a new exhaust

[FJTillDeath]

For those that are aware I purchased a cowley exhaust system, which is arriving tomorrow and after reading some other threads I would like to know if I will need to rejet anything? Anybody have experience with them on their FJS? I have heard a couple on other bikes and sound very good(will post a video when its all installed) and they have quite a reputable name>they can last anywhere between 5 and 10 years according to how well the bike is stored and what its put through..

Anything I need to take heed of? The dealer is fitting it for me so I wont actually be doing the work myself but I would like to make sure they do a proper job. They said they will supply the exhaust gaskets and sort out the nut and stud problem I may have.

When I get the exhaust (since it will be new and all) should I work it in or can I go blazing down side streets with WFO throttle?

Many thanks
Jesse

[Knuckles]

Okay, the Cowley pipe on my FJ was a major pain. It is impossible to reach the oil drain plug with that thing on, hence my shift to a T-spoon exhaust.
Everytime I needed an oil change, the whole exhaust system had to be removed. Not good as the exhaust studs are disturbed and eventually they fail one by one.

[andyb]

You can add another drain plug to the oil pan, or drain it by removing the left (nearest #1) oil cooler line, if needed.

If that's a typical open 4-1, rejetting will give you a pretty respectable hp jump, in the neighborhood of 10% rwhp if you also put individual UNI pods on it.  There will be some bottom end loss in power (not that big a deal unless you really like riding under 3k rpm much).

[FJTillDeath]

Hi Knuckles, thanks for the Heads up, always good to see a South African here.

And Andy, thanks for the advice on the oil pan and the rejetting. I was actualli interested in purchasing the UNI pods from Randy(the dual foam) just wasnt sure between the K&N and the UNI dual pods) Now that I know they actually do give some extra horses its nice to know.

As for bottom end power and riding much under 3k rpm.. I do that a lot in 5th gear. While on the subject, what is the ideal RPM range for town/ traffic driving? I have heard running a bike too much in the low rpms isnt good for the motor and also running it in the excessively high rpms isnt good either. Due to that i have kept shifting up in the lower gears(1 to 3 at 5500rpm while gear 4 shift up at 3000rpm.

I prefer not to ride in the high rpms in town as its easier to manouver the bike in the lower rpms.

[Arnie]

The engine vibrations are much stronger below 3000 rpm, so I rarely ride below that.  High revs make more power and noise and use more fuel.  Most of the time I find the comfortable rev range to be in is 3-6ish.  If trying to become the next Rossi/Stoner/or even Edwards, that range would be 5-9 thou., but the FJ mill is very flexible with lots of torque everywhere so use the rule of ..... Don't lug the engine, and don't over-rev it.  The exact rpm range is up to you.

Arnie

[FJTillDeath]

The engine vibrations are much stronger below 3000 rpm, so I rarely ride below that.  High revs make more power and noise and use more fuel.  Most of the time I find the comfortable rev range to be in is 3-6ish.  If trying to become the next Rossi/Stoner/or even Edwards, that range would be 5-9 thou., but the FJ mill is very flexible with lots of torque everywhere so use the rule of ..... Don't lug the engine, and don't over-rev it.  The exact rpm range is up to you.

Arnie

Unfortuntaely I often lug the engine and was hence asking. It may be me but it seems sometimes when I ride the bike between 4 and 6k rpm in the 4th and 5th gears its like the engine starts to shrink and contract(well thats my impression from the sound and the reaction the bike gives off) it hasnt really worried me as sometimes I get really smooth and crisp throttle response from the engine as if it wants to be limited.

And no this condition does not happen when the bike is cold(i keep it under 4k revs until it reaches running temp

4 to 6k sounds good though and comfy too