cat bypass and JT's air filter

[Larry t]

Has any one installed both the cat bypass and air filter kit? if so any negative effects? seems to me that the PCM should be able to compensate for the better air flow, would like to know from someone with experience before I spring for the big bucks already have the bypass
Thanks Larry

[lwrydr]

I have them both but they are not installed yet. Am going to install the cat-bypass today. From what I have seen there should not be any problems. Stay tuned.

[Chupaca]

I have the kindel exhaust and JT's air filter with a K&N filter. The increased performance is noticeable but so is the sound of the air flow to the throttle body. I love the sound but some don't. JT has added a muffler of sorts so if sound is an issue with you get that as well. Both will help a lot with the heat in the engine compartment....

[SNOOPY]

I have JTs filter and the Akrapovic exhaust, would like to know if adding the bypass "also" will adversely effect it.

[900Dave]

I have them both but they are not installed yet. Am going to install the cat-bypass today. From what I have seen there should not be any problems. Stay tuned.

Please keep us updated. I installed JT's system about 6000 miles ago and plan on istalling the CAT bypass this winter as well as an aftermarket muffler. I am really interested in the positive and/or negative effects, if there are any.

[SNOOPY]

Please keep us updated. I installed JT's system about 6000 miles ago and plan on istalling the CAT bypass this winter as well as an aftermarket muffler. I am really interested in the positive and/or negative effects, if there are any.

You can be my guinea pig.

.

[jthornton]

IMHO the muffler is the key to how much air flow the engine has. Even with a K&N with huge holes and a cat bypass if the muffler maintains near stock back pressure the flow will be the same.

I learned a valuable lesson about back pressure in '68 when I took the muffler off my Honda 50 Super Sport and replaced it with an after market exhaust pipe (my mom's vacuum cleaner pipe). After a few days of riding around in the mountains of Alaska all of a sudden the motor quit running. So I pushed the bike home (nothing like a few miles hike with a bike for a yute). Upon further investigation I found the piston with a hole in the middle (from running too lean). Getting some kind advice from the Honda dealer about adjusting mixture and a new piston and I was on my way again.

JT

[SNOOPY]

IMHO the muffler is the key to how much air flow the engine has. Even with a K&N with huge holes and a cat bypass if the muffler maintains near stock back pressure the flow will be the same.

I learned a valuable lesson about back pressure in '68 when I took the muffler off my Honda 50 Super Sport and replaced it with an after market exhaust pipe (my mom's vacuum cleaner pipe). After a few days of riding around in the mountains of Alaska all of a sudden the motor quit running. So I pushed the bike home (nothing like a few miles hike with a bike for a yute). Upon further investigation I found the piston with a hole in the middle (from running too lean). Getting some kind advice from the Honda dealer about adjusting mixture and a new piston and I was on my way again.

JT

Wow! You did all that when you were 5 years old?

[jthornton]

Wow! You did all that when you were 5 years old?

Tack on another 10 to your guesstimate

JT

[bscrive]

I am interested in this as well. I put JT's air breather on my wifes STL and I am going to put the cat bypass this winter as well. I don't think we will be going to an aftermarket exhaust though. Don't want to get in to the juicebox thing again.

[jcthorne]

I am interested in this as well. I put JT's air breather on my wifes STL and I am going to put the cat bypass this winter as well. I don't think we will be going to an aftermarket exhaust though. Don't want to get in to the juicebox thing again.

If you keep the stock muffler, you will be fine with this combo. Spyder Nanny will be happy.

[clueless]

but that stock muffler weighs a TON .. plus sounds too quiet IMO

[bluestratos]

I did it all with sad results.

• The Akrapovic muffler made a slight improvement, mostly in the midrange, nice sound but not loud
• The airfilter did nothing but the noise was horrendous
• The y pipe did nothing but the lack of the cat created even more noise, at this point I started getting a loud backfire
• I added fuel controller, this improved the back fire but overall not noticeable improvement
• I added a gauge to monitor Air to Fuel Ratio so I could dial in the fuel controller, no help
• I took the headers and wire pipe off and wrapped them, no help in sound or power, a little less heat

If you are convinced a loud bike is faster than they all work, lol. For me it was a waste of over $3,000. I took it all off again and just left the Akrapovic muffler.

[900Dave]

I did it all with sad results.

• The Akrapovic muffler made a slight improvement, mostly in the midrange, nice sound but not loud
• The airfilter did nothing but the noise was horrendous
• The y pipe did nothing but the lack of the cat created even more noise, at this point I started getting a loud backfire
• I added fuel controller, this improved the back fire but overall not noticeable improvement
• I added a gauge to monitor Air to Fuel Ratio so I could dial in the fuel controller, no help
• I took the headers and wire pipe off and wrapped them, no help in sound or power, a little less heat

If you are convinced a loud bike is faster than they all work, lol. For me it was a waste of over $3,000. I took it all off again and just left the Akrapovic muffler.

I have to disagree a little. Most of these items I did not try as of right now. BUT JT's air filter and the removal of the factory airbox was the only reason we could ride our ST comfortably over this summer. before I removed the stock air filter and resonator my gas boiled riding in temps at 80 degrees and the gas fumes from the charcoal canister was horrible. NO boiling gas after the air filter install and the gas smell was only apparent after we had parked and the Spyder sat for a while and the heat soak into the gas tank had begun.

Now I also have the new air flow panels and it is even cooler and I have not noticed the gas smell after being parked for a while.

If I can elimate the heat generator (CAT) it should be even better.

[jcthorne]

but that stock muffler weighs a TON .. plus sounds too quiet IMO

with the JT air intake and cat bypass, its not near as quiet. Has quite a rumble. Its actually louder than I would like now. Would not want a louder muffler as well. I did not think the stock muffler was all that heavy when I took it off. Much lighter than the cat section.

[clueless]

They both weigh a ton. Glad to shed both of the weight

[jcthorne]

I did it all with sad results.

• The Akrapovic muffler made a slight improvement, mostly in the midrange, nice sound but not loud
• The airfilter did nothing but the noise was horrendous
• The y pipe did nothing but the lack of the cat created even more noise, at this point I started getting a loud backfire
• I added fuel controller, this improved the back fire but overall not noticeable improvement
• I added a gauge to monitor Air to Fuel Ratio so I could dial in the fuel controller, no help
• I took the headers and wire pipe off and wrapped them, no help in sound or power, a little less heat

If you are convinced a loud bike is faster than they all work, lol. For me it was a waste of over $3,000. I took it all off again and just left the Akrapovic muffler.

I think you kept the only piece that should have gone away. If you had kept the stock muffler, you would not have needed the fuel controller or bothered with the air fuel ratio gauge (which is worthless for tuning part throttle operation as it moves far too quickly.)

Getting rid of the air box and cat make for a MUCH cooler ride and far less gas fumes from boiling gas.

[clueless]

You can get a quieter exhaust or go with the quieter exhaust tips for the two brothers. I tested it both with and without the stock tip. Major difference between with and without. And you can but 2 more level of quieter tips

[bluestratos]

I had already fixed my heat issue 100% so I was not looking to cool the "hot foot" I was looking for a bit more power as I had found the 11' to be far too tame for my liking. I did a lot of comparative testing and the results were non conclusive. The muffler definitely made a small improvement and I thought taking the air box off would compliment that but it did not. The only change was noise, and noise on a touring bike ruins a long trip for me.

[jthornton]

I had already fixed my heat issue 100% so I was not looking to cool the "hot foot" I was looking for a bit more power as I had found the 11' to be far too tame for my liking. I did a lot of comparative testing and the results were non conclusive. The muffler definitely made a small improvement and I thought taking the air box off would compliment that but it did not. The only change was noise, and noise on a touring bike ruins a long trip for me.

The Throttle Muffler (as Doc Riverside calls it) restores the stock intake sound level...

JT

[jcthorne]

The Throttle Muffler (as Doc Riverside calls it) restores the stock intake sound level...

JT

Any noticeable reduction in performance when adding the intake muffler?

[jthornton]

Any noticeable reduction in performance when adding the intake muffler?

None, it has larger pore size and higher flow rate than the filter. The main thing it does is to confuse the sound waves so they get lost and can't find their way out.

JT

[jcthorne]

None, it has larger pore size and higher flow rate than the filter. The main thing it does is to confuse the sound waves so they get lost and can't find their way out.

JT

Cool! When I order the filter assy for Louise bike, I'll order 2 of the mufflers. Thanks JT.

[jthornton]

Cool! When I order the filter assy for Louise bike, I'll order 2 of the mufflers. Thanks JT.

I should have Air Filter Kits back in stock next week. The aluminum parts are at the anodizer and everything else is on hand.

JT

[gordo2050]

Just wondering how the JT air kit helps with the heat?

Is it smaller than stock, thus allowing more air around the motor? Also, I see that there is a cold air kit coming soon, ??

Just looking for anything to cool down the wife's 2011 RTL.