Modifying a standard exhaust..

[properperson]

 

Does anyone know a place in Pattaya that can modify a standard exhaust to make it a tad louder / sportier, without attracting too much attention from the Police. ??

 

I'm not looking for a "cut and shunt" job - more a skilled engineer with knowledge of what to remove to get the desired effect..

 

Its for a CB650F (old model) if that makes any difference ..

 

 

[eisfeld]

This place did the mod you want for a few CB650F that I saw in the wild, but I believe they are in BKK: https://th-th.facebook.com/fixsperformance/

You can find some videos on youtube of the result. Just search for Fix's performance or Fix's bypass.

Probably can find something similar in Pattaya but I can't tell you any specific place.

[properperson]

Just now, eisfeld said:

This place did the mod you want for a few CB650F that I saw in the wild, but I believe they are in BKK: https://th-th.facebook.com/fixsperformance/

You can find some videos on youtube of the result. Just search for Fix's performance or Fix's bypass.

Probably can find something similar in Pattaya but I can't tell you any specific place.

 

yes i am aware there are places in Hua Hin and BKK - just wanted a place in Pattaya....

 

 

[NormanW]

Good luck with that. All the advice points to leaving it as standard.  Not really a lot of fun but minimizes any issues so to speak. 

[properperson]

2 hours ago, NormanW said:

Good luck with that. All the advice points to leaving it as standard.  Not really a lot of fun but minimizes any issues so to speak. 

 

stick an aftermarket can on and you are at the mercy of the Police, eager to issue the golden 1,000 baht ticket.....

 

a good mod on a standard one will look standard and if you don't go bonkers on the sound - The Police are unlikely to nick you....

 

[stubuzz]

Look for an approved aftermarket box.

[canthai55]

I removed mine, cut the box open, removed all the tubing inside but kept the cat, rewelded. Sounds deeper, no issues so far.

[NormanW]

I think the law is 95Db 3 metres away. However, you'll have to carry the Thai transcript with you to show the BIB. And you'll have to have an approved manufacturer's badge on the silencer as stubuzz mentioned.

 

Again, good luck. 

[eisfeld]

If money is not an issue then I'd look into Akrapovic which might come with a TIS stamp. Honda used to also offer Mugen/Yoshimura exhausts for the 500 range which I hope also came with TIS stamp.

[AllanB]

If money is an issue, drill a few holes in the end plate may be the answer 

 

 

A friend of mine did his CBR250 with smaller holes and he was happy, shouldn't effect the back pressure either, as the "orifice plate" created has no pressure drop.

[Rhys]

Slip ons are not that bad, even the Thai Apravorich is ok.

 

[AllanB]

If any of you find a man who really knows about baffles, I would be interested to know.

[canthai55]

8 hours ago, AllanB said:

If any of you find a man who really knows about baffles, I would be interested to know.

What info are you looking for ? They are pretty simple.

[Techno Viking]

TYGA are just up in the road in Sattahip, they will be able to sort you.

[canthai55]

https://www.google.ca/search?q=motorcycle+baffle+design&client=firefox-b&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjzreKdzfjUAhUO82MKHbJFCkQQsAQIJw&biw=1261&bih=619&dpr=1.2

[AllanB]

9 hours ago, canthai55 said:

What info are you looking for ? They are pretty simple.

I have a single silencer on my NV400 V twin and I understand the bike needs some decent back pressure. What would the design look like? I understand that there are a number different stages needed?

 

I am not modifying anything, actually starting from scratch.

[AllanB]

8 hours ago, canthai55 said:

https://www.google.ca/search?q=motorcycle+baffle+design&client=firefox-b&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjzreKdzfjUAhUO82MKHbJFCkQQsAQIJw&biw=1261&bih=619&dpr=1.2

Most of these baffles are designed to fit into the pipes and are in any case straight through with insufficient back pressure. I have a single silencer box, around 10cm diameter and trying to get the bike back to stock.

[canthai55]

10 hours ago, AllanB said:

Most of these baffles are designed to fit into the pipes and are in any case straight through with insufficient back pressure. I have a single silencer box, around 10cm diameter and trying to get the bike back to stock.

Without the dimensions of the stock baffle/silencer you are forced to experiment. Without a reading of the stock backpressure - same.

[AllanB]

13 hours ago, canthai55 said:

Without the dimensions of the stock baffle/silencer you are forced to experiment. Without a reading of the stock backpressure - same.

So not that simple then?

 

I think the problem is the bike I chose to buy, my push-rod 200cc Lifan is so uncomplicated and seems to start and run whatever. The NV400 engine is a sensitive little bugga, built for optimum performance, it even has (PITA) fuel enrichment cold start, which did leak, instead of a simple choke, just everything about it is a more complicated than it could be. Then Thais got hold of it for 30 years.

 

I made a bit of mistake when I first bought it, it failed it's MOT on noise levels, so I took it to a guy who built me quite a restrictive one and it was very quite. While I was busy sorting out all the many problems, with both fuel and electrics, I had the baffle modified, instead of just getting a new baffle made.

 

I think I will go back to stage one and get a couple of different baffles made they weren't expensive and play around. I really don't want to through the re-jetting malarcky, getting me further away from stock. 

[Gnasher328]

Don't think 'back pressure' matters so much on a four stroke. It's actually the size, shape and length of the pipe which causes pressure waves to be generated which help to extract or push back the gas.

I had a Thai made 'Yoshimura' put on my CRF 250 and it was horrible, lost all the low end torque and sounded vile. I read somewhere that a narrower downpipe speeds up the gas causing an 'extractor' effect at low revs.

I then had the original 'gutted', this improved the bottom end torque vastly, I can now use a lower gear when going up hills, the top end is the same as with the 'Yoshi', and it sounds nice. Plod never look twice .

[canthai55]

11 hours ago, Gnasher328 said:

I then had the original 'gutted',

Did you keep the CAT ?

[AllanB]

19 hours ago, Gnasher328 said:

Don't think 'back pressure' matters so much on a four stroke. It's actually the size, shape and length of the pipe which causes pressure waves to be generated which help to extract or push back the gas.

I had a Thai made 'Yoshimura' put on my CRF 250 and it was horrible, lost all the low end torque and sounded vile. I read somewhere that a narrower downpipe speeds up the gas causing an 'extractor' effect at low revs.

I then had the original 'gutted', this improved the bottom end torque vastly, I can now use a lower gear when going up hills, the top end is the same as with the 'Yoshi', and it sounds nice. Plod never look twice .

It does on this engine, pops a splutters like scheisse, I want to get it back to stock, so no rejetting.

 

My mate had the later 400 Honda Steed, took all the baffles out and it ran fine, engine virtually identical but 14hp less, so presumably the Steed is detuned?

[thaiguzzi]

Bike  still not sold?

Problem solving;

1. Get No. 1 Fully comp insurance.

2. Set fire to it.

3. Collect the insurance.

4. No more exhaust/carb/whatever problems.

    Simples. No need to thank me. A box of Chang in the post would be nice.

[Gnasher328]

9 hours ago, canthai55 said:

Did you keep the CAT ?

Hi

No, that was in the huge silencer. I put some pics on 'Rideasia'.

[AllanB]

5 hours ago, thaiguzzi said:

Bike  still not sold?

Problem solving;

1. Get No. 1 Fully comp insurance.

2. Set fire to it.

3. Collect the insurance.

4. No more exhaust/carb/whatever problems.

    Simples. No need to thank me. A box of Chang in the post would be nice.

This bike has become like a?...well I don't know what. I still think I can fix it, one day.... in another time zone. Anyway when I get back, going to build a small workshop with A/C, a few new parts for the old bastard..then you'll see!!

 

"How hard can it be?"

 

Sorry mate you cannot post beer, I checked.

[canthai55]

On 7/11/2017 at 2:14 AM, Gnasher328 said:

Hi

No, that was in the huge silencer. I put some pics on 'Rideasia'.

Excellent. Thanks