As some here already know , i bought a 94 CBR 900 RR Fireblade Urban Tiger less than two months ago and since the full exhaust system has been replaced , i hear the engine quite differently ; so much that i really thought there was a problem with the engine j

î Bought an Akrapovic full exhaust Racing system that was installed a few weeks ago on my 94 CBR 900 RR but since the sound i hear from my engine disturbs me as it is really different from'what it was and the exhaust sound ,different from what i was expecting !
What i mean is that the engine sound does not sound normal anymore to my ears !
I was really curious to hear The Akrapovic full exhaust Racing system sound as i thought it would be nice but the result was far from my expectations, so maybe someone might have an idea why .

Before that i had what seemed to be an original stock header ( or the first half of it ,it seemed to have been black color and a stainless steel mid pipe with the 3 bolts on setup at the extremity, might have been soldered i to it by the half of it, At least the first half looks more like it was black and the second half , stainless steel ) with a MIG dual output carbon muffler that was shortened by a 1/3rd.
The previous owner had told me it was a full exhaust MIG system but i am not sure the header was made by MIg !.
The sound was alright at idle and in the low rpms but was a bit thin above that .
I could hear the muffler ( exhaust system ) correctly and the engine sound seemed normal to me .

But when the Akrapovic full exhaust system was intalled instead , the sound of the engine became quite louder and weird , covering the sound of the Akrapovic exhaust , i have the feeling all the engine sound comes from the front of the bike and the muffler/ exhaust sound is barely heard !
I was really surprised about that , especially the evening when i went to pickup the bike from my Kawasaki workshop ( where they service my Kawasaki ZRX1200s but also my other bikes , as the chief of workshop got the same CBR900 RR in 1994 as one of his first bikes and also had some GSX-R 1000 from the same era as my 750 K8 ).
So, thinking there was a problem on the bike , it took it back to my chief of worrkshop the next day but he did not notice any problem on the engine / bike by itsel !
The problem is that it is a workshop in the middle of Paris where there is much traffic jam and they can't really try the motorbike past the second gear and really push the engine in the rpm's , whereas it's above 3000-4000 rpm that i think the sound of the engine is weird !

I really don't understand what's going on , wheras i was really hoping to get a a great exhaust sound with that Akrapovic full exhaust system !
I don't understand why i hear the engine so loud and with a different sound from what it had before !
I can understand the exhaust sound is different but not why the engine sound is different and so loud !

The exhaust replacement was not the only thing done on it a that time, it had the spark plugs replaced as well ( all parts bought from a Honda dealer ) , the air filter ( with an original stock one ) , oil drained and oil filter replaced , cooling liquid and brake liquids replaced , Avia hoses installed front and back with direct installation on the front .
The fork oil drained and everything opened and cleaned inside ( including cartridge ) the fork , with the gaskets replaced .
Carburator's ramp removed and cleaned ( not with ultra sound bath as he die not think it was needed ) , all the gaskets inside replaced and the carbs synched .
i noticed one silent bloc under the tank was missing , so i bought some new ones i have to install ( not sure if it fell when the tank was removed or if it was already missing).
So ,if anybody has any idea what ´s going on and why the engine sounds like that and like if ut is coming mostly from the front (at least that is the perception i have when riding the mototbike ) and why i î barely hear the Akrapovic exhaust/ muffer ?

Usualy when you replace the exhaust system on a bike , it's the exhaust sound that changes , not the engine's one , whereas here i really feel S like if i had a big fan or some kind of apparel making a loud weird noise in front of the engine ( and covering the exhaust sound so much it is loud ) !

 

I think you're in a situation where you're going to need someone local to listen to it. Sounds are subjective. A ticking sound coming from some specific location might be easy to diagnose, but the overall audible sounds not so much. I'd suggest seeing if you can locate someone knowledgeable locally. Take it to a shop and just have them listen.

 

Thanks for your answer !
i took it back to my chief of workshop at Kawasaki as he had this bike and knows it well and did all the service on all my bikes but he dien't find anything not working correctly in the engine !
For him, it is the sound i het with that Akrapovic full exhaust Racing system , that makes the engine sound different but he doesn't see what it could be !
The problem as i said is that he can only try the bike in static in the workshop , at idle or up to the second gear in the streets around the workshop as it is in the middle of Paris , where there is much traffic jam on the avenues and boulevards and also many little streets ( the workshop is in a very small one way street and there are many like that around the workshop ) , so he can't push it in the above the 3rd gear max , at 3000-4000 rpm , when he can even reach the third gear cause i suppose most of the time he can only ride in second gear and about 3000-4000 rpm but not much more due to the location of the workshop in Paris !

 

Well, you're not going to get any sympathy from me because you live in Paris... LOL

 

What do you mean ?

You don't like Paris or French people ? lol

As a matter of fact , i do not live in Paris but maybe 10-to 15 mn from one of Paris' west doors !
Or a bit closer if we start from the point that i live on the other side of the " bois de Boulogne " ( Boulogne's woods ), which is a part of Paris next to Paris' west suburbs .
First , I have to cross a bridge over " La Seine " .
The big river going through Paris from its South East then straight to the center of the old Paris , then after crossing 3/4 th of Paris to get there , it turns left to go back to the South West of Paris down to the suburb , passing very close to the Eiffel Tower and dividing Paris in more or less two non equal areas ( 2/3 vs 1/3 ) .

So , as i live near " La Seine ", i have to cross that bridge over La Seine first , then cross Le bois de Boulogne about 7km ( which is more like some woods than a forrest , although it must have been one centuries ago ) and then i reach one of Paris's doors at the west , at the frontier between the 17th , the 8th and the 16th disctrict of Paris .

That said, my Kawasaki workshop is in the middle of Paris as i said , near " la Place de la République " , where there is much traffic jam all the time , so to try a motorbike correctly in those conditions , is impossible if you want to try it in all gears and going up in the rpm's , At least past the 3000-4000 RPMs.
But this'is where i bring all my motorbikes since i discovered this Kawasaki dealer's workshop about 4 years ago,after î discovered it through an advice of some ZRX1200 riders , as i was looking for a good Kawasaki workshop , after a bad experience in another Kawasaki dealer's worshop.
And as i am satisfied with their work , i bring them both my 2005 ZRX1200Rs but also my 94 CBR900RR Fireblade ( as'my chief of' workshop knows it very well due to the fact he had the same when he was in his'early 20's and unmounted it totaly to clean it , before remounting it ) and my 2008 GSX-R 750 K8 ( as he had at least one or two GSX-R 1000 from those eras or maybe one 750 and one 1000).

 

Pretty sure he was saying he envy’s where you live in a light-hearted jovial way.

 

That is what i had imagined as a possibility of meaning ( especialy with the smile at the end ) but not speaking fluently and through internet , it is not always easy to be sure 100% if understanding subtle sentences correctly ! Lol

I am quite frustrated with the sound i get since i installed that Akrapovic full exhaust Racing system as i really thought i would have a much better soud than that with it , so i want to find a solution and resolve the problem !

i saw that There is Black'Widow which makes some Full exhaust Racing systems and it seems also a header which might be compatible with all the mufflers that were catible with the 94 ( and ther years ) CBR900RR ..
Delkevic also makes some full exhaust Racing systems based ona header and several mufflers to choose from , that is compatile with the CBR900RR Fireblade of thise years but i don't know if the header is also fully compatible,with all the mufflers made to be compatible with the 94-95 CBR900 RR .
Arrow might also still make some Full exhaust Racing systems compatible with that bike but which can only use their own mufflers.
And finaly , i saw some headers that are a reproduction of the original stock CBR900RR header , in stainless steel ( at least one named Esatz but i never heard of that brand before so i am not sure if it's not too cheap quality !

But i need to find a solution to resolve that problem, to get back the engine sound i had before installing the Akrapovic Full,Exhaust Racing system and try to make that full exhaust system sounds right on that motorbike , or replace it with another one sounding better .
But i would prefer to make the Akrapovixc full exhaust Racing system i bought for that bike , sound great and the engine sound " normal " , cause i can't understand an Akrapovic full exhaust Racing system not sounding good ( and on top of that i paid about 1250 to 1300 to buy it and import it to France , so i would prefer to get what i want from it than to buy another exhaust system or header / or muffler !
For me there is something not normale but not being a mechanic , i don't know what to look for to resolve that problem !
I simply can't believe that Akrapovic could have released a full exhaust Racing system for that bike, that doesn't make it sound better than that !

 

@Highway to Hell Was just poking fun, meant no disrespect for sure. I was only speaking of the small narrow streets. I do like Paris, and traveled there in the mid 80's. Living in or near one of the worlds most famous cities is a problem that many wouldn't mind having .

 

Don't worry , i have supposed you meant something like that but even if i speak / write / read correctly English , i don't speak fluently enough to understand every expressions , so sometimes i can have small doubts about the meaning of something but i thought you were joking as there was no reason why it would have been something else and also there was the smiley at the end which guided me to think about it this way .

But that doesn't resolve my engine loud sound / low exhaust sound problem whixh really frustrates me ! Lol
I was really thinking i would get a great sound with that Akrapovic full exhaust Racing system on such bike, so i really do not understand what's going on !

 

I wonder if i should have posted that directly on the 900 RR subforum, instead on this one ( 900 & + modifications ) , maybe i would have got more answers ?

Should it be moved there or do you think it is better here ?

i would like to open another topic , about good full exhausts Racing systems available in 2021 for the 94-95 CBR 900 RR but i wonder if i should post it here ( in this sub forum ) as well or in the 900 Sub forum ; what so you think ?


Technicaly it speaks about modifications as it is replacing the stock or any exhaust on a CBR 900 RR but it also talk about the 900 !
Obviously i would prefer to post it where i can get the most answers !