Does anyone know what size exhaust for an SSR?

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ThisGuy

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not fimliar with the ssr but what you should do is grab a tape messure it and see what diameter the exhuast outlet is on the motor , so you should probably take the old exhaust off and messure it, and i saw the link and if the outlet 28mm purchase that bugger and install her and should be ready to go ohh yer u might need so copper o-rings to seal the pipe to the head
cheers
 
my67xr said:
one of these might be better?
does the bike have a CRF bend/style exhaust?
http://www.ebay.com/itm/Big-Bore-Ra...Parts_Accessories&hash=item337c1cd574&vxp=mtr
http://www.ebay.com/itm/GOLD-BIG-BO...Parts_Accessories&hash=item1e78105932&vxp=mtr
Click to expand...

xLOCOx said:
not fimliar with the ssr but what you should do is grab a tape messure it and see what diameter the exhuast outlet is on the motor , so you should probably take the old exhaust off and messure it, and i saw the link and if the outlet 28mm purchase that bugger and install her and should be ready to go ohh yer u might need so copper o-rings to seal the pipe to the head
cheers
Click to expand...
No not really a bend, Ill take a pic. Hold on
 
photo21_zps52cad374.jpg
[/URL][/IMG]
 
most anything with 28mm end will fit, and yes, as mentioned, get a copper o-ring unless you like backfiring and popping when you back off the throttle...

the yx has the different angle header, right? (im asking everyone else) so they wont fit. or theyll fit but end up not lining up with the frame, the bike, the everything. dont know, i havent dealt with a yx yet... :(

but the big bores shown WILL fit.


now, what do you get by changing the exhaust?

backpressure. anyone that says you need backpressure is an idiot. the less restriction you have in the exhaust, the faster it can get out, the more air/fuel you can get in, the more getupngo you get... backpressure is a restriction, and is a term that people like to throw around without understanding it cus it makes them feel smart :D.

yes, you can ruin an engine by having no backpressure... but its because you have failed to compensate for the different running conditions, not the lack of backpressure!


a narrow pipe will assist performance on the low end but tend to be restrictive at the top end. its to do with inertia of the exhaust gasses. length of pipe also plays a part. the skinny pipe requires the exhaust to flow faster, it has more momentum when its going faster, it tends to help "suck" the cylinder clean, and "suck" in more air/fuel.

a big fat pipe helps "deepen" the exhaust note, and can help on the top end by, once again, letting the gas flow faster which helps suck out that cylinder... but at the bottom end it can be a slight drawback as you dont get a very effective "suck" because its so big.

valve overlap plays the biggest role when it comes to exhaust fiddling. theres other things like pipe length, that creates pressure waves both positive and negative... a certain length pipe suits a certain rpm and certain valve timing, but wont suit the same valve timing at a different rpm.

its complicated. consider saxamaphones. theres four different sizes, the little one is highpitched, the big one is low pitched... and all them holes are in specific places!

cus yes, a motor running is a LOT like a musical instrument. when something isnt right they sound like $hit, ja?
(so does gay sebastian, but as long as i got my media player, im fine)

freeing up the exhaust usually means rejetting and tuning the carb for the new improved airflow... once again, compensating for changed running conditions!
 
Last edited:
zwebx said:
that was a great read, yeah i was also wondering why people would ever want to restrict anything
Click to expand...

look into "velocity porting" and your head will hurt... DEcreasing port sizes to INcrease power? contrary to everything we ever thought we knew?
higher velocity means more inertia means the gas gets to where its needed faster...(and increases volumetric efficiency cus you can get more in!) very logical. more logical than opening ports up to the limits and fighting carby bog cus the lowered speed of the air through the venturi results in a big fat lean spot...

its not the restriction that causes the problems, but knowing WHERE to restrict and where not to...
 
photo22_zpsce395c16.jpg
[/URL][/IMG]
headsmess said:
most anything with 28mm end will fit, and yes, as mentioned, get a copper o-ring unless you like backfiring and popping when you back off the throttle...

the yx has the different angle header, right? (im asking everyone else) so they wont fit. or theyll fit but end up not lining up with the frame, the bike, the everything. dont know, i havent dealt with a yx yet... :(

but the big bores shown WILL fit.


now, what do you get by changing the exhaust?

backpressure. anyone that says you need backpressure is an idiot. the less restriction you have in the exhaust, the faster it can get out, the more air/fuel you can get in, the more getupngo you get... backpressure is a restriction, and is a term that people like to throw around without understanding it cus it makes them feel smart :D.

yes, you can ruin an engine by having no backpressure... but its because you have failed to compensate for the different running conditions, not the lack of backpressure!


a narrow pipe will assist performance on the low end but tend to be restrictive at the top end. its to do with inertia of the exhaust gasses. length of pipe also plays a part. the skinny pipe requires the exhaust to flow faster, it has more momentum when its going faster, it tends to help "suck" the cylinder clean, and "suck" in more air/fuel.

a big fat pipe helps "deepen" the exhaust note, and can help on the top end by, once again, letting the gas flow faster which helps suck out that cylinder... but at the bottom end it can be a slight drawback as you dont get a very effective "suck" because its so big.

valve overlap plays the biggest role when it comes to exhaust fiddling. theres other things like pipe length, that creates pressure waves both positive and negative... a certain length pipe suits a certain rpm and certain valve timing, but wont suit the same valve timing at a different rpm.

its complicated. consider saxamaphones. theres four different sizes, the little one is highpitched, the big one is low pitched... and all them holes are in specific places!

cus yes, a motor running is a LOT like a musical instrument. when something isnt right they sound like $hit, ja?
(so does gay sebastian, but as long as i got my media player, im fine)

freeing up the exhaust usually means rejetting and tuning the carb for the new improved airflow... once again, compensating for changed running conditions!
Click to expand...

Oh my goodness! Thats complex. So what im going to do is keep the stock on and see how it runs. Heres a pic of the end pipe and muffler...
 
headsmess said:
look into "velocity porting" and your head will hurt... DEcreasing port sizes to INcrease power? contrary to everything we ever thought we knew?
higher velocity means more inertia means the gas gets to where its needed faster...(and increases volumetric efficiency cus you can get more in!) very logical. more logical than opening ports up to the limits and fighting carby bog cus the lowered speed of the air through the venturi results in a big fat lean spot...

its not the restriction that causes the problems, but knowing WHERE to restrict and where not to...
Click to expand...

that makes perfect sense, i never thought of the air speed but if i went to efi i would be alright to not care much about the air speed over the manifolds then?
 
Ok so my carb came in today, its an ebay 19mm carb but it says Japan on it(if that means something) but anyways Im planning on installing it with my stock exhaust with the quiet raspy sound(ew). When I install my new exhaust(I believe the pipe has the same dimensions (28mm)) Would I have to change the jetting? or fuel screw/idle screw? Im pretty sure the only thing thats changing is the muffler when I buy the new exhaust system.
 
get on fleabay, look for "fractional" or "micro" drills. usually in a box in 0.5mm increments from 0.3 to 1.3, cost about 20-30 bux :) and a micro/pin chuck will help.

while most carbs are close to right when first installed, theres nothing quite like having a properly dialled in carb! and its definitely a worthwhile thing to practise. plug chops, how to "read" a plug, and knowing for ever and always, on any motor, whats happening when it "bogs" etc...

why the drills? some people like to wait two weeks and pay lots of dollars for a few jets. i just solder them closed and drill them out.

in other words, no, you DONT HAVE TO rejet the carb, but it is a nice thing to practise :)

some nice reading material :D

http://www.iwt.com.au/mikunicarb.htm


(and yes, with efi, you can go as big as you want on the intake side. no need for manifold vacuum, 100% correct :) the velocity idea still holds with REMOVING the exhaust gasses but!)
 
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