Homemade Muffler

[Helltro]

Hay guys im fairly new here as only recently got my bike licence and wondered if any of you have done any stock muffler modification or from scratch muffler builds. Iv started making a muffler for my bike from scratch and just want to know what i should know about exhaust pressure before i continue i think iv done a ok job at making the baffles so it wont blow apart but i dont know as its my first muffler build. The bike it will be going on is a Suzuki Gsxr250 im not planing on it being to loud mainly making it because i want a belly muffler and just seeing if i can do it. Any knowledge would be good.

i do have some bad quality piks of what iv got so far but have no idea how to upload them

Cheers

[FJRider]

Any knowledge would be good.

'nuff said ...

[Akzle]

its a 250. Good luck 'blowing the cunt apart'

just stab some holes in the stocker with a no.2 philips..

[FJRider]

its a 250. Good luck 'blowing the cunt apart'

just stab some holes in the stocker with a no.2 philips..

Quite a few come on here willing to pay $$$ for a 2% increase in their 250's max horsepower.


And he wants it for free ...


suzuki riderss ... eh .. !!!

[bogan]

One of the key things with a muffler is exhaust length, both to the collector (if one is in system) and to the exit. This determines how well the exhaust 'scavenges' which is what happens as a low pressure reflected pulse hits the exhaust valve just as it is closing. Backpressure is more what you are talking about, and affects how well the exhaust is cleared from the combustion chamber. Another thing to bear in mind is changing the exhaust often changes how a big should be jetted (or EFI mapped). So it is reasonably complicated, but certainly doable.

I've done a undertail muffler, and plan on doing an underbelly one too, but I know the underbelly is tricky as it can be hard to get enough length.

Flick up your pics and we can take a better look. There is a manage attachments button in the additional options when you are in the full page post editor.

PS, the mech section is poorly moderated so just pay the idiots no mind.

[husaberg]

Hay guys im fairly new here as only recently got my bike licence and wondered if any of you have done any stock muffler modification or from scratch muffler builds. Iv started making a muffler for my bike from scratch and just want to know what i should know about exhaust pressure before i continue i think iv done a ok job at making the baffles so it wont blow apart but i dont know as its my first muffler build. The bike it will be going on is a Suzuki Gsxr250 im not planing on it being to loud mainly making it because i want a belly muffler and just seeing if i can do it. Any knowledge would be good.

i do have some bad quality piks of what iv got so far but have no idea how to upload them

Cheers

All you need to know is without 1000's of hours R&D its unlikely you will make anything legal that is better than it has origionally
You can however make a simple absorbion muffler as cheap as chips, that may sound a little better (to some peoples taste.)
Don't expect it to go any better or be legal.
Do expect it to run worse and attract police attention.
You can buy irrigation tube that is thin wall from mico's. or you can buy carbon tube on the net.
the inside pipe is either a shit load of time or buy some perforated tube.
Pack with proper fibreglass fill (not pink bats) if stuff it full of stainless steel turnings.
The end caps are the hardest to make but I just used to do a flat disk and roll and weld on the periphery.

All of this will be harder than just buying one.

A decent old style muffler shop should have bends so you can snake it about under the bike (just seene the under bike M-GP pipe bit.)

[AllanB]

Can you ever get enough length?


Post some pix mate of your design. The physical muffler part is not that difficult - check out any high end aftermarket can and the core is essentially a perforated pipe (diameter tends to be about 45-50 mm on the larger bikes) with suitable packing (metal followed by synthetic wrap). As above it is the length of the mid pipe that may play with your performance.

Still it's a 250 - high rever so f-all on the lower end. IMO don;t fuck with the stock headers - have a bit of fun from the collector back.

[Helltro]

One of the key things with a muffler is exhaust length, both to the collector (if one is in system) and to the exit. This determines how well the exhaust 'scavenges' which is what happens as a low pressure reflected pulse hits the exhaust valve just as it is closing. Backpressure is more what you are talking about, and affects how well the exhaust is cleared from the combustion chamber. Another thing to bear in mind is changing the exhaust often changes how a big should be jetted (or EFI mapped). So it is reasonably complicated, but certainly doable.

this i ddnt think of and is why i asked. I was just going to leave the stock headers and cut the pipe directly after the collector and wack the muffler on there and the muffler is a shorty only about 180mm but iv made it so its not straight through its a bit like a "turbo chambered" style from what iv seen online. but i still havnt finished it completley yet and could still make alterations to make it work.

Don't expect it to go any better or be legal.
Do expect it to run worse and attract police attention.
You can buy irrigation tube that is thin wall from mico's. or you can buy carbon tube on the net.
the inside pipe is either a shit load of time or buy some perforated tube.
Pack with proper fibreglass fill (not pink bats) if stuff it full of stainless steel turnings.
The end caps are the hardest to make but I just used to do a flat disk and roll and weld on the periphery.

Its only a 250 im not expecting much anyway its my first bike and all i could afford at the time. iv already had tons of police attention with another vechile that i drove around with straight pipes that doesnt worry me to much and i dont have alot ov money to spend in the first place thats why im making it from scratch with what i already have lying around.



and the piks arnt great i only had my cellphone on hand at the time and they turned out worse than they usualy do from it (i dont know if piks are gona show up i tried the Manage attach)

[husaberg]

this i ddnt think of and is why i asked. I was just going to leave the stock headers and cut the pipe directly after the collector and wack the muffler on there and the muffler is a shorty only about 180mm but iv made it so its not straight through its a bit like a "turbo chambered" style from what iv seen online. but i still havnt finished it completley yet and could still make alterations to make it work.


Its only a 250 im not expecting much anyway its my first bike and all i could afford at the time. iv already had tons of police attention with another vechile that i drove around with straight pipes that doesnt worry me to much and i dont have alot ov money to spend in the first place thats why im making it from scratch with what i already have lying around.



and the piks arnt great i only had my cellphone on hand at the time and they turned out worse than they usualy do from it (i dont know if piks are gona show up i tried the Manage attach)

That's a reversion and absorption muffler.

[Grumph]

Anything with CV carbs and a pipe cut after the headers is going to be a prick to tune.
No alternative needles available for those carbs either.

Personally, I'd have left it stock. By the time you have wasted time trying to get it to run properly, you'll feel the same.
Don't throw the OE pipe away or muck it about, you may well want to weld it back on.

[Helltro]

Personally, I'd have left it stock. By the time you have wasted time trying to get it to run properly, you'll feel the same.
Don't throw the OE pipe away or muck it about, you may well want to weld it back on.

Iv actually got a whole other bike for parts i just took the whole exhaust off that and am cutting that one up i defanatly wouldnt do what im doing to the one on the bike my welds arnt tidy enuf to refit the stock muffler and make it look any good im trying to make this muffler a slip on for that reason

[Lightbulb]

If you can't afford to rebuild the engine if it all goes pearshape, then just use it like it is.
Any experimenting with engines and pipes can mean a catastrophic failure.
But just cut and try and have fun.
Neil