Yoshimura RS-4D Has anyone used one?

[supros88]

I am trying to deiced which between a RS-4 or a RS-4D exhaust to for my 2011 CRF250.

According to the Yoshimura website the RS-4D should make more power in the bottom end and the RS-4 should make more up top, but I must wonder if it is a bit of marketing hype.

Has anyone tried a RS-4D yet? I can't find any reviews on the RS-4D to make a comparison.

I prefer the look of the RS-4 but if the RS-4D actually makes noticeably more bottom end power then I will by it.

any help will be greatly appreciated.

[Eddie8v]

It likely makes more low-end at the sacrifice of top end power and over-rev capability. I prefer all the power I can get out of the 250-4 bikes because they aint no 450 and the loss of top end rev's/power is too much for me to sacrifice. 450 bikes with low-end pipes aren't so bad on top as there's plentry of power for most riders throughout the entire rpm range.

[paulie373]

i have a full rs4 system and it really wakes that bike up from the bottom all the way to the to the top you will be happy trust me

[supros88]

I emailed Yoshimura and asked them and they sent me these two dyno graphs.

But I can't seen to see a difference in the power curves between their two Systems.

[j368]

i have a full rs4 system and it really wakes that bike up from the bottom all the way to the to the top you will be happy trust me

Did you have to remap the ignition? Or did you leave it stock?

Jeff

[paulie373]

i left the bike stock no remap i asked the guys at yosh and they said that it wasent nesasary unless i wanted to do it no

[j368]

i left the bike stock no remap i asked the guys at yosh and they said that it wasent nesasary unless i wanted to do it no

Thanks for the info.

[supros88]

I emailed Yoshi asking the same question and got a completely different answer. Go figure!

Below is the response that I got.

I definitely recommend remapping when installing a full system. Ignition is not required but if you are looking for optimum performance then I would definitely consider it. If you decide to remap the bike I would suggest the PIM2 we offer, if you decide to get the ignition too then you may also want to consider getting the DATA Box. Thanks!

Lauren Waters

Yoshimura Lead Sales

Returns and Warranties

1-800-634-9166 x.428

Can anyone else shed some light on remaping?

[paulie373]

That's a sales person trying to make a commission im a sponsored rider they don't try to sell me anything I don't need but it's your money do what makes you happy

[Ricebowl]

You wont be getting the full benefit without remapping the fuel tables at least. The RS-4 (or most pipes for that matter) really lean the bike out on the top end.

jeff

[supros88]

Thanks for the response I think I might just get a local tuner to remap my standard ECU for $50.