• Hi everyone,

    As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.

    When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.

    Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.

    Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.

    Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.

    Thanks for your patience and support!

G.P.R. Motorcycle exhausts - I'm working for you

For warmth I can say that the original exhaust warmed much more. On these after an average journey can rest your hand without burn me. I do not think that the single exhaust heat up as much as I've heard. but there is to say that I have removed the catalysts.


Per il calore posso dire che gli scarichi originali scaldavano molto di più . Su questi dopo un tragitto medio posso appoggiare la mano senza ustionarmi. Non credo che lo scarico singolo scaldi così tanto come ho sentito dire. c'è però da dire che io ho tolto i catalizzatori.
 
Chuffa said:
I just fitted my GPR single system :banana: Sounds a bit nasty - in a good way!!

I'm really happy. I just have to work out a tool tube or wait to see what GPR come up with.
Click to expand...
wow you have been quick to make the purchase. you saw that wonderful?
can not upload any pictures? which model did you choose?
I do not however understand what you say about the tube and waiting for something from the gpr. speak of the glove compartment?
 
Chuffa said:
I just fitted my GPR single system :banana: Sounds a bit nasty - in a good way!!

I'm really happy. I just have to work out a tool tube or wait to see what GPR come up with.
Click to expand...
We want pics! Not to mention a full report once you get some miles on that puppy!
 
fastkx125 said:
The bike runs really lean right out of the box, Id really like to see a AFR plot with this exhaust on.
Click to expand...


I will not be adding the exhaust until I have the power commander and auto tune to compensate for any lean conditions. Has any one thought if there is enough back pressure. Last thing I would want to do is it flowed too much then burnt the valves. Does any one have experience in this subject??
 
Riding Again said:
I know it won't be accurate but can you load a sound video?
Click to expand...

I think I've reduced the mic level on my cam because it is louder than this. It sounds like the GPR YouTube clip. I've also still got the db reducer fitted...



megatiker75 said:
I do not however understand what you say about the tube and waiting for something from the gpr. speak of the glove compartment?
Click to expand...

Yes, something to replace the second silencer.

TerraLeftSingleCan_zpsaed78d48.jpg


TerraRightSingleCan_zps731aff3a.jpg


I've done about 300km and have noticed no difference in the way the bike reacts. It just sounds better :banana:
 
Starting to sound like a real thumper. Probably has the deeper sound like a real 4 stroke dirt bike with out the db in. Nice set up on your bike and thanks for the audio clip!
 
Chuffa, sounds great! When you say no noticeable difference, so nothing freed up down low end? Is it running any cooler, i'm guessing you went with a non cat in header? Also like to know how the sound compares to stock at hwy/freeway speeds, chheers!
 
Thumpa, I've got the WukaKing the so low end is fine on my bike anyway. That said, the bike felt awesome today. I think that is probably more to do with my added enjoyment with the new sound and working it up the rev range.

I haven't noticed the heat before or after the change so can't really offer comment on that. I can't recall the deal with the cat converter but I wouldn't have gone out of my way to get one with it.

The noise is beefier ;) (much beefier) but not really much louder (but it sounds like it is because of the deeper note). It's by no means too loud. The wind noise in the helmet is way worse than the pipe when I'm going at highway speeds. Like the stock, you do notice it more when you really open the throttle but not when you are cruising. Same same, just different.

It will be a day or two before I pull the db reducer out to see how it sounds then.
 
Although it is more complex than this description, basically....
A max horsepower pipe will be shorter than a max torque pipe. On the Husky with the 2 std pipes it MAY be that the longer length is the harmonic for peak torque rpm ( the right side) and the short one is the harmonic for max HP. This of course means that the boost waves at their respective peaks would be much less ( half...maybe). So a single short pipe would give max boost at higher rpm and 2 pipe would give a max rpm boost at the max power rpm (higher rpm but less boost ) AND a boost at max torque point ( lower rpm)...maybe. I still have my doubts about the effectiveness of a one into 2 pipe if the header is at optimum internal diameter.
GPR's are note for their deeper sound. I haven't checked out the waveform but suspect they use the tricky method of damping the wavefront ( higher frequencies) but leave the rest of the flow alone with the lower frequencies . This means it is MUCH less sound pressure level overall but still sounds good, It is the big high frequencies that attract the unfavourable notice of the constabulary, inter ailia.
A very good example that gas flow and sound are NOT the same thing.
 
I know without doubt that when I pull the baffle on my single can, my torque increases on the low end quite noticeably. No real change in HP.

According to other dyno sheets, I lost HP and Torq with my single pipe.

Well, that may or may not be true, as I did not use the same dyno or altitude, so if I want anything definitive, I need another run with the stock setup. I tend to think I did loose some torque, that would be by nature of going to a single can, and a semi restrictive pipe for quiet.
 
Chuffa said:
Thumpa, I've got the WukaKing the so low end is fine on my bike anyway. That said, the bike felt awesome today. I think that is probably more to do with my added enjoyment with the new sound and working it up the rev range.

I haven't noticed the heat before or after the change so can't really offer comment on that. I can't recall the deal with the cat converter but I wouldn't have gone out of my way to get one with it.

The noise is beefier ;) (much beefier) but not really much louder (but it sounds like it is because of the deeper note). It's by no means too loud. The wind noise in the helmet is way worse than the pipe when I'm going at highway speeds. Like the stock, you do notice it more when you really open the throttle but not when you are cruising. Same same, just different.

It will be a day or two before I pull the db reducer out to see how it sounds then.
Click to expand...
Great feedback, helped answer a few questions. I really get that it's a deeper beefier sound more so than loud. Which is a concern in Ca, loud pipes draw cops and so on, besides many hours at 70/80 mph gets old the louder it gets. I'm booking in for a Moss first, see how that fairs, before springing for the Wuka. But pretty much sold on the GPR.
 
Greg Jetnikoff said:
Although it is more complex than this description, basically....
A max horsepower pipe will be shorter than a max torque pipe. On the Husky with the 2 std pipes it MAY be that the longer length is the harmonic for peak torque rpm ( the right side) and the short one is the harmonic for max HP. This of course means that the boost waves at their respective peaks would be much less ( half...maybe). So a single short pipe would give max boost at higher rpm and 2 pipe would give a max rpm boost at the max power rpm (higher rpm but less boost ) AND a boost at max torque point ( lower rpm)...maybe. I still have my doubts about the effectiveness of a one into 2 pipe if the header is at optimum internal diameter.
GPR's are note for their deeper sound. I haven't checked out the waveform but suspect they use the tricky method of damping the wavefront ( higher frequencies) but leave the rest of the flow alone with the lower frequencies . This means it is MUCH less sound pressure level overall but still sounds good, It is the big high frequencies that attract the unfavourable notice of the constabulary, inter ailia.
A very good example that gas flow and sound are NOT the same thing.
Click to expand...
Thanks for posting this, and would it be possible to translate it into laymans terms? I kinda' get the gyst of it, but the part of my brain that processes this type of information is like a 3 yr old. i.e, needs to be really brass tacks simple. Else i find myself going round in circles:excuseme:
Now call me stupid but, way back when i used to have multi cylinder bikes. a twin or a 4 cylinder reconfigured after market pipe, would be a 2 into 1 or 4 into 1, or 2 - 2 or 4 - 2 also possible. So how come everyones referring to the Huskies as a 2 into 1 as opposed to a 1 - 2? Just trying to understand the lingo' seems to be half of the battle for my brain. I'm most likely going to spring for the single 'Full' system. Maybe you could provide us with some feedback of the characteristic differences between a 'Full' system with cat in head, and 'Full' system without? Much obliged!
 
The Husky is a 1 into 2. Single cyl/single port onto 2 exhaust tailpipes after the header. There are singles that have 2 exhaust ports ( inc. some Huskys). Usually they go 2 into one for ease of pipe tuning. So long as the ports have the same cam tuning this is relatively easy to calculate.
The refering to 2 into one is contextual to TR650's I guess, even though it is opposite to usual. Sort of " huskytr650 speak"

It is quite possible that you lost HP AND torque with a single pipe . For max HP (or torque) you need the CORRECT length , not just longer or shorter.
I have not degreed the TR yet ( and prob won't now) so I can't give you the calc. lengths BUT for the DRZ I have been working on. Peak HP length is 34inches ( from the valve face) and peak torque pipe length is 42inches for the 400SM cams with pipe at optimum ID. As an example if you made a pipe 36 inches long it would have less than peak HP AND torque.
The 1 into 2 is problematic as the harmonics is not determined by just length but the volume resonance. You start to get into serious computer power to calc. reasonable accuracy and are prob better off just playing on a dyno with pipe length and see what happens.
You are not stupid it is ridiculously complex as soon as you get away from single port single pipe.
And be thankful it ain't a two stroke. There the exhaust ( expansion chamber) is actually a part of the motor not just a pipe.
 
Greg Jetnikoff said:
The Husky is a 1 into 2. Single cyl/single port onto 2 exhaust tailpipes after the header. There are singles that have 2 exhaust ports ( inc. some Huskys). Usually they go 2 into one for ease of pipe tuning. So long as the ports have the same cam tuning this is relatively easy to calculate.
The refering to 2 into one is contextual to TR650's I guess, even though it is opposite to usual. Sort of " huskytr650 speak"

It is quite possible that you lost HP AND torque with a single pipe . For max HP (or torque) you need the CORRECT length , not just longer or shorter.
I have not degreed the TR yet ( and prob won't now) so I can't give you the calc. lengths BUT for the DRZ I have been working on. Peak HP length is 34inches ( from the valve face) and peak torque pipe length is 42inches for the 400SM cams with pipe at optimum ID. As an example if you made a pipe 36 inches long it would have less than peak HP AND torque.
The 1 into 2 is problematic as the harmonics is not determined by just length but the volume resonance. You start to get into serious computer power to calc. reasonable accuracy and are prob better off just playing on a dyno with pipe length and see what happens.
You are not stupid it is ridiculously complex as soon as you get away from single port single pipe.
And be thankful it ain't a two stroke. There the exhaust ( expansion chamber) is actually a part of the motor not just a pipe.
Click to expand...
Thanks for for going all out on this, little confusing and plenty of musing!
 
I am curious when some one will dyno their bike that has the uni filter exhaust and power commander. It will be interesting to see what it does actually change if any.
 
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