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-   -   CAT Vs Expansion chamber Vs RX100 Silencer : For RX 135 5Speed (https://www.team-bhp.com/forum/motorbikes/96214-cat-vs-expansion-chamber-vs-rx100-silencer-rx-135-5speed.html)

HI BHPians,

I was fortunate enough to ride a well modded RX-100 with an expansion chamber and I was blown off my feet.

It was sheer riding pleasure, and the way the bike 'opened up' with the expansion chamber, was something unexplainable.

I want to get an expansion chamber for my RX-135 5Speed as well ( After the completion of the running in period, as its re-bored)

My second preference would be the RX-100 Silencer, which I assume will give me the near beat of the legendary 100.

No stock CAT silencer for me, the RX experience is missing in that.

Can the experts please suggest and clarify the following ?

Will the expansion chamber

1. Increase the power ?
2. Decrease the mileage ?
3. Affect the engine life / bore life in any way in the long run ?

Need to know some reputed places/ mechanics in Bangalore catering to the need of expansion chambers. ( With approx prices please)

PS: They are called calculated chambers in Bangalore

in my honest opinion, a retrofit expansion chamber is not really needed for the 5 speed. the engine is already peaky (i love it) with the standard cat con exaust. cant really say how a chambered 5 speed would behave while street riding. for the track, most certainly you need a chamber.
and with the stock setup, a half decent 5 speed should manage true 115 kmph on a 700-750 mts straight and with enough time to brake. i think thats fast enough for our roads. how often do we need to go faster than that?

coming to my recommendation, get ron chinoy's cdi for the bike and that will be the best deal for you and the bike. and its much easier for you since youre in bangalore.
the rx100 pipes may not be the best idea for the 5 speed.

if you do decide to go for the chambers, pm me. i ll be interested in picking up the cat con exaust from you. will use it for another bike which i am planning to get back in shape.

I do agree with you. The speedo certainly keeps climbing up. However in my opinion, the absence of sound fails to give you the feel of it. There is no music to the ears :) .

Great.clap: I read somewhere on this forum that a modded 5 Speed can give the RD some anxious moments. Is there any amount of truth in this ?
I personally have too much of love for the RD to imagine something like that.

Thats certainly on the cards. Have got good reviews about it. I believe it increases power along with the FE. Do you have any links of how exactly it works ?


If I go ahead with the chambers, that will be temporary in nature and will switch back to the stock ones later. So no plans as such. I can help you with some if I come across.

Would I require any mandatory mods if go for the expansion chamber ?

Is this your daily commuter?

And you are in Bangalore, the cops will stop you at every junction and label you a drag racer.

So whatever you do see that you don't attract too much attention by the noise. If its for track use then you are good.

Yes its my daily commuter. If I get the expansion chamber, I might not keep it as a daily commuter.

Yes, you are right. I will be a prey to all the cops. I don't mind that though. Anything for the love of the sound. The CAT Con really makes you feel as if you are riding a 4 Stroke. Moreover my pop is in the Civil services, so I can manage something :)

I am no expert , but here I what I know ,

The expansion chambers can be tuned to the band you want, Low end , top end , Mid range or wide band. Power increase will depend on the expertise on the tuner , how far you are going with the porting and how ride-able you need the bike to be. Highly tuned will have a narrow power band and difficult to ride on road ,best is the wide band tune.

Reduction on mileage again depends on the state of tune. Could actually increase for a mildly tuned chamber , since it pushes some charge back into the combustion chamber after the scavenging. But most chambered bike owners did say the mileage dropped.

Badly tuned ones can PIT the piston , But i don't have much info about the impact on the life of the engine.

Hope this helps.

sameer,

i know its a very personal choice, but i certainly enjoy the sound of the 5 speed. In fact i dont like the way the RX100 sounds :) I may attract some strong reactions for this. but its just my opinion.

the 5S can definitely give the RD a run for its money. I have both bikes in very stock shape. But the lure, charm and the pleasure of an RD is very different. with the rx, i can open the throttle mid corner and still be comfortable and not slide around. with the rd, i dont dare to fool around with the throttle. have learnt it the hard way. The 350 is a much bigger bike and hence its potential cant be harvested in the busy city traffic. its very quick on the gas but i am not sure how well it will stop if some nutter comes in my way. the rx is a proper city tool. you can swerve left right centre and ruin the happiness of unsuspecting pulsar and zma wannabes (with all due respect to four strokes)

with chambers, you ll almost certainly need to rejet the carbs. i personally dont fiddle around too with the carbs. yamaha engineers know their job better than me.

most importantly, the rx is a fun, everyday bike and you can thrash it around. the rd deserves more respect and mature riding. thats all i can say.

cheers

nitro

Expansion chamber .... more than the power , you will save about 5-6 kgs on your bike so that is a big bump in power to weight ratio!!

My 2 cents don't play with this pipe its very well tuned for low and mid range I have tried all the options with RX135 including old RXZ chrome pipe and nothing worked as the OE pipe did until n unless you are opting for a proper chamber designed for you ports.
Start with CDi, Uni filter and bigger jets still if you feels like need more go for big bore, I have got it done for one of my friend, cant open all the secrets gone into that build but it's over 30 BHP set-up at crank.
I never enjoyed RX in any form and sold one by one 3 of them after brief use, RD's are addiction and still no other bike gave me that kind of adrenal rush(SBK's are not in picture till now)

I will put my money on the wide band tuned one

Pretty obvious I guess

Thanks mate. I am looking for some info on professional guys who can cater to my need of wide band chamber in Bangalore



I am just a little surprised that the comment on RX-100's sound did not invite any responses yet lol:
But again yeah, To each his own. I am too much of a sound buff. When I was in my school, (Read 8th standard), I had got a bigger exhaust pipe for my dad's 1989 LML Vespa . I would enjoy the ride on it, and history repeated when I did something similar to my 2003 Bajaj Pulsar.


You are right. With all due respect to the 4 strokes, the confident Pulsar and ZMA riders don't like it one bit when you surprise them with the acceleration. Recently, the excuse that I got from a friend of mine for it was, "Its only initial pick up about the RX" :uncontrol


Agreed mate, the RD is altogether a different machine. I was fortunate enough to ride it for a few days in the absence of its owner. By the way, whats the max you have done on both your bikes? and the 0-60 & 0-100 factor ?



Sounds great. Will appreciate if some one can post pics of the various expansion chambers. In dire need of professionals or mechanics who would do the job for me in Bangalore



Certainly do agree that the pipe is good for low and mid range. However, as stated earlier I am a sound fanatic . I am obsessed with it, and the absence of it leaves me incomplete.

When you say, nothing works as good as the OE pipe, in which context do you mean it ?

Me on the look out for good tuners in Bangalore



PS: If only my 5 Speed could sound like an RD, I would never even dream of changing/ altering it stupid:. The sound of the twin!



Note from Support: Please use Multi-Quote / Quote+ when responding to multiple posts. Thanks!

By OE pipe i mean to say retain the cat con pipe and dont think of even trying original RX100, RX135 chrome pipe or even old RXZ chrome pipe on your bike all are waste for this bike until n unless you get chambers done with proper bore, stroke and port calculations.If you are really keen on getting it tuned, ported and chambered be ready to blow the equivalent cost of our bike once again.
Sashi Chamber Works at siddiya road 2nd cross does good chambers ask him that you need a calculated one done by Mr. Bhatt (ex TVS race team guy).

Thanks for that Ajaybiz. When you say that RX-100 and Chrome RX-135 are all waste, in which context do you mean it. Do you mean in terms of mileage, power or harm to the engine/Bore ?

I was thinking of getting the RX-100 silencer as a second alternative because :

1. Pretty inexpensive modification
2. Will get the feel of the original Yamaha RX beat ( Atleast near to it)
3. Even if the power doesn't increase , It will atleast give me music to the ears
4. it would not harm the engine or the bore, because logically speaking it is also an original Yamaha silencer ( I understand that the tuning is different, but still believe from the feedback that it does not cause much harm)

I have the following questions :

1. If I get it chambered , Is it compulsory to get it ported?
2. Are any other modifications compulsory, if i get it chambered? I thought it was just an easy modification. Something like Plug-and-play ?
3. Approximate costs for getting it done?
4. Will it harm the engine/ bore ?

But even then, please do not.
There are lot of ppl on the road who do not prefer the "mosquito fogging machine" sound of an un-silenced two stroke engine.

Will the expansion chamber
Increase the power ?
It changes the power band of your engine. Expansion chamber works on the principle of using standing waves to suck/slow the exhaust gases from engine. Since two stroke engine doesn't have valves, the exhaust pipe can control a lot.

That means currently if you bike has peak torque at 5000-6000 RPM, you can change it to 2000-3000 or 7000-8000.
However keep in mind, that the street bike engine is not particularly designed for high revs, and you may end up inducing a lot of wear and tear.

Since you will remove he cat con, you will also reduce the back pressure acting on the exhaust - thereby increasing the power.

Decrease the mileage ?
No. It depends on your driving style. If you tune the chamber for low revs, you may save on fuel because you won't need to rev hard to produce torque.
But then kiss the racer bike feeling away.

Affect the engine life / bore life in any way in the long run ?
Already told you about the revs. Another thing is that when the chamber acts like suction device, there would be unburnt exhaust entering your exhaust port and chamber. The Material of construction has to withstand that.

RX100, RX135 or old RXZ chrome pipes wont harm your engine but your low and mid range pull will go for a toss, it's not compulsory to get ported you bore for chambers but calculations for tuned length pipe is compulsory, leave that part on your chamber builder if you wanted to jump in chambered bikes class otherwise ride it as it is :) , still they are capable enough to show dust to many modern bikes.

A very well summed up post by Alpha1, thanks for that.

I really thought its the other way around. :Frustrati I remember riding another friend's 5 Speed with the 100 Silencer, and I felt lower and mid range was better. Probably the sound made me feel that way.

Guys you know what, I guess my OIL pump has stopped working. After re-bore the mechanic had filled the OIL pump fully. I have riden the bike for 1,200 Kms now, and the OIL pump is still 80 % Full ( As I can see from the level- indicator in the left side shield). :eek:

I really wondered how it can be still 80% full, because I must have atleast filled 40 Litres of fuel ( To travel 1,200 Kms)

I immediately filled fuel with 50 ML 2T oil per litre. I know thats in excess, But i feared an engine seize. Actually the bike had just been restored from an engine seize

When I was riding back, I could see lot of excess smoke out of the CAT CON. I really wish it doesnt leave too much of Carbon on the silencer and block the expensive and rare to find silencer.

1. How do I determine if the silencer is blocked?
2. Can the CAT CON be cleaned of blockage ? And the recommended places to get it done in Bangalore
3. What is the full capacity of the 2T OIL tank? Once completely filled, how many KMS should it ideally last for ?
4. How to judge whether the OIL PUMP is working correctly or not?

Instead of fearing that the OIL pump is working or not, I guess its better to switch the OIL pump off and go for petrol mix