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For sure quieter, but at the expense of flow no doubt. Likely less of an issue for your riding style if you're staying at lower rpm's.
 

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Discussion Starter #242 (Edited)
For sure quieter, but at the expense of flow no doubt. Likely less of an issue for your riding style if you're staying at lower rpm's.
I use gas mileage logs as my indicator of performance efficiency as they record differences too sutble to be felt. TOCE mufflers are way oversized. The dual cores are the same diameter as the ones they use for 600cc sportbikes. That's why TOCE exhausts are so freaking L O U D. :eek: The combined cross section area of the necks of the funnels on the dual inner inserts are larger than the head pipe exit, so there's no flow restriction.

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And they exactly match the area of the two exits.

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I'm enjoying the option to have my exhaust nice and quiet whenever I want. :)

This is the sound of first gen dual inner and outer inserts.


The 3rd gen inserts are WAY quieter as I'm continuing to refine the design. :) When the weather clears up I'll post a sound video of the latest version of inserts.
 

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Discussion Starter #243
This is the 3rd generation quiet inserts. :)


Regular riding, no full throttle. The GoPro attenuates the sound so you can't tell on the video, but in real life the exhaust is WAY more quiet than before. So now I'll be doing gas mileage tests to see how the latest configuration works compared to the others.
 

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Discussion Starter #244 (Edited)
Oooh... the Kepspeed aluminum rear swing arm arrived today. :)

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The arm including all of the mounting hardware weighs only 5 pounds 3 ounces.
WAY lighter than the stock steel swingarm.
When everything is apart I'll weigh the stock one to log the weight reduction. I'll bet it will be a BIG difference. :)

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Really nicely machined chain adjusters.
WAY better than stock ones.

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Precision needle bearings.
WAY better than the stock rubber bushings.

The price was right, too... $110. Shipping from Belgium added another $27. Not too bad for $137. :)
 

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Discussion Starter #245 (Edited)
I shortened the DingerBuilt intake just to see what happens. It's still longer than any other intake sold as I make far better use of low rpm torque than high rpm horsepower. the pipe consists of a 180 degree "U" section out of the throttle body, then a 90 degree "J" section extending laterally across the engine to the other side. The engine now pulls strong from 3,000 rpm without lugging. While it ran good before with the longer intake, compared to how it runs now I know the tuning was too low and out of the stock cam's torque curve. The filter tucks nicely inside the fairing. I added a stainless steel shroud to keep wind from blowing directly on the side of the filter. This way dirt and grit doesn't hit the filter surface directly and the engine pulls in calmer less turbulent air.



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The Winter gas mileage average has been established at 125 mpg, while the Summer gas mileage averaged 145 mpg. This is a difference of 14%. Air cooled engines are more sensitive to ambient air temps than liquid cooled. In California we also have different Summer and Winter blend gasolines, but I'm not sure how much difference they make. I don't yet know the effect of the intake change but I'll find out after a few fill ups.
 

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Discussion Starter #246
Installed a Kepspeed aluminum rear swing arm yesterday...

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...and rode it today. I live in the middle of a canyon with one winding road to town so I'm going around curves more than I'm going in a straight line. The rear of the bike feels solid and dialed in and it doesn't feel like it's "waggling" in the curves like the stock swing arm. In my opinion it's an incredible deal at only $137 shipped from motorkit.com.

It has three advantages:

Precision swing arm needle bearings instead of bushings
Four pounds lighter than the stock rear swing arm
Includes accurate easy to adjust billet chain adjusters
 

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Discussion Starter #247
The combination of Kepspeed aluminum rear swing arm, IXIL exhaust and an aluminum rear sprocket alone knocked off a total of 11 pounds from the stock weight.

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With all of the other mods the bike now weighs 208 pounds.
 

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Discussion Starter #248 (Edited)
The original rear tire was close to the wear bars at 7,500 miles so I replaced it with a Kenda 140/70-12 street tire. The weight difference between the worn 130 and the new 140 was 8.75 pounds and 9 pounds.) so it's likely a new 130 and140 would both be quite close in wieght. Diameter difference was 58.5 inckes for the worn 130 and 62 inches for the new Kenda 140. Allowing for the wear difference, the 140 will gear the bike up by about 5%, which is totally fine as my engine has plenty of low rpm torque to pull the higher gearing. :) I'll check how the speedo reads with my gps equipped camera.

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I think it looks neato. :)
 

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Discussion Starter #249
Well, since I put a 140 on the rear, I went ahead and put a 130 on the front. :)



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Will be interesting to see if any discernible difference in fuel economy but sounds like tire weights were comparable so perhaps not.
 

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Discussion Starter #251
The Kendas are lighter than the stock tires so the weight difference is slight. I'm really curious to see how the fuel economy works out as now I'm geared up by about 5 to 6%. It's similar to putting a 16T on the front. Took it for a test ride and I can definitely feel the higher gearing. I'm going faster and the enginer is turning slower. The engine makes really good low rpm torque so this isn't an issue for me. I really need to make a gps embedded video with my gopro so I can see how the speedo reads with the big tires. :)
 

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Discussion Starter #252
My trip from the gas station ran 9.1 to 9.2 miles with the 130. It's now 8.8 miles with the 140, for a difference of 5%. So that's the odometer correction for gas mileage calculations. :)
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Discussion Starter #253 (Edited)
I have lots of fun experimenting with exhausts. This is the latest... a modified OG. :)
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It weighs just 3 pounds, which lowers the curb weight to 207 pounds.

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...and if anyone is wondering what a cat looks like inside, here it is. :)

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I chopped off the end of the OG exhaust to rotate it 90 degrees, and then welded it back on.

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Ever thought of running an oversized head pipe to a stock catalytic converter?


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Discussion Starter #255
Ever thought of running an oversized head pipe to a stock catalytic converter?
I'm always thinking up things... :)

This was just another experiment. Man this exhaust is crazy loud! It's so loud it set off car alarms in the Home Depot parking lot. It's not practical to run it the way it is. I'll come up with something else. to quiet it down. My modified SF cat turned out a LOT better.

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It's super quiet with a deeper sound than when the stock muffler was attached.
 

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I plan to get either a dingerbilt or mnnthbx intake for torque, and I’m going to try the modded stock sf exhaust you have pictured. I’m really curious about running an oversized header to the stock cat. I would prefer a quieter exhaust over a loud one.

It’s going to be a daily commuter for me, and I get home after midnight, so I want to keep the neighbors happy.


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Discussion Starter #257 (Edited)
For a stock 125 with a stock cam there isn't much over 7,000 rpm anyways, so the small headpipe is just fine. Because it keeps the gasses hot and under high velocity, the engine is quite responsive in the 4,000 to 6,000 rpm range.

I'm also a daily transportation rider and my engine is always running between 3,000 and 6, 000 rpms, so the stock cat with a stock headpipe works great for my uses.

I also run TOCE and IXIL exhausts when I'm in the mood, and of all the exhausts I've tried, the TOCE is the best all round.performer because of it's extra long uniform diameter headpipe that doesn't get too large by the time it reaches the muffler like most all of the other exhausts do. This combination of length and diameter offers excellent low rpm torque.

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Discussion Starter #258
I plan to get either a dingerbilt or mnnthbx intake for torque...
I have a Dingerbuilt intake and really like the high quality and design. I got his Long Intake when he used to sell them, and made it even longer. I also got a $16 stainless steel filter cover off ebay, and cut ut down to size. It keeps road grit from getting blown directly onto the filter element and really helps to keep it cleaner longer. It tucks neatly into the left plastic cowl. I highly recommend a filter shroud no matter which intake you get.


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Discussion Starter #259
I had another go at the modified OG exhaust. Here's everything I did.


First I removed the muffler. Then I cut off the pipe exiting the catalytic converter. then I cut off end cap of the cat itself. rotated it 90 degrees, and welded it back on. Then I enlarged the hole in the end cap, installed a home made quiet baffle, and then welded on a larger 3/4 inch inside diameter turn down exhaust pipe.

It turned out to be a really neato setup.


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The whole exhaust weighs just a little over THREE pounds which rivals the weight of the lightest exhausts, and yet the bike sounds reasonably quiet.

Here's a sound video...


The cat is a straight through honeycomb. At first I ran this exhaust with the small diameter stock pipe as the exit and it was WAY too loud and harshly high pitched. A much larger exit pipe lowered the pitch considerably. And the combination of turning the exit down to the ground and adding the internal quiet baffle made the sound much more reasonable..

Even as light as it is, all of the weight of this exhaust is at the bottom of the bike which is good for handling. Nothing hangs out of sticks out anywhere either. The exit clears the rear tire with room to spare and angles downward and outward so as to not point at the tire.

I'm interested in flow design so I'm constantly trying out new ideas. So far I have 4 modified exhausts I run on my Grom, and will likely have more in the future as I continue to experiment.
 
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