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4rt Exhaust

Featured Replies

I`ve just been told that my 07 repsol still has its exhaust restrictors fitted. Just wondered if its worth my while taking them out and what the benefits will be. The bike seems to go well enough as it is so I`m thinking if its not broke dont try and fix it.

Also how many restrictors are there and where, the obvious one is bolted into the back of the silencer and there seems to be a loose pipe behind the exhaust seal at the front of the silencer.

Cheers

Andy

post-516-1284113134.gif

Just left the rear one in the other 2 are out :thumbup:

How much of a difference does it make in performance, and how much louder is it with the front two removed?

How much of a difference does it make in performance, and how much louder is it with the front two removed?

Performance is much improved with the front two out, the reason I put the back one in is that performance wise it was pretty much the same whether it was attatched or not, but it just took the ''Bark'' slightly out of the exhaust note.

Of course the noise factor is only relevant to how much you open the throttle :) I would say a 2-stroke ringing its neck to clear its throat in the hands of some young lad at the start of each section and rock step is a lot louder than my 4RT :thumbup:

Thanks. That seems to be the consensus.

Has anybody ever dyno'd the bike or tested with a decibel meter to get some hard numbers on the changes?

Thanks!

Made a big difference when i took mine out.

Love the pretty diagram Gizza, you must have some time on ya hands, lol.

East yorkshire 2 day roll on

what level do you ride at?

"sea level" :thumbup: good un.

If you ask him what gear he uses most he'll probably say an old Babour jacket and pit boots.

Are you suggesting just removing the front because as I newish rider I don't need the power, or is there another reason?

Oh, and I ride primarily in first and second gear. :thumbup:

  • 1 year later...

Evening all,

Sorry to bump this old post however I wondered if anyone could shed any light on the following.

I have just got a 06 4rt and have been out on it a few times, I have searched the site for all the exhaust related posts, most are for the removal of the restrictors.

On inspecting my bike the exhaust has two threaded points at the end but that is all, so I assume the previous owner has removed the rear restrictor and the other two, I havent opened it up to check.

I have searched high and low for a replacement but I cannont find one on the net, I'm also looking into a Jitsie DB Killer which would replace the rear restrictor anyhow but will it quieten the bike down more than the standard restrictor. I havent been able to find one as they are sold out, I even tried a shop in Austria and they did not know when more would be in stock.

Does anyone know where i can get a replacement rear restrictor or a DB killer? Not that I mind the noise, but you always feel a bit self consious on a noiser bike!

Any help would be great.

Thanks

For a replacement std part would suggest MSport (Munch) Sandifords or Pidcocks. Original Honda/Montesa parts are surprisingly sensibly priced.

Thanks Jimmy, will look into it.

Cheers

  • 1 year later...

post-516-1284113134.gif

Thankyou for this diagram. My manual is in Spanish and I had sort of deduced the "casquillos" 18 and 19 are the restrictors.

Another question on the subject of exhausts; the front pipe on my 2005 appears to be a smaller diameter and has a thick weld after the first bend. When I compare it with images of a later pipe the later pipe has no weld and appears to be a larger outer diameter.

  • Is the weld another restriction?
  • Is the 2005 front pipe a smaller OD than the later ones?

My 2005 here:

2005-4RT-front_pipe-18320-NN4-000_zps57232659.jpg

And here is a later type:

18330-NN4-G10_zps82e6af28.jpg

Thankyou

Edited by esteve

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