Planet Minis

BigUncleT · 09-18-2009, 10:19 AM

Hey guys,

I've been messing around with a design that uses an existing muffler end cap, and provides adjustability for noise levels. I will do sound level testing over the weekend, and post the results. I made a prototype with parts laying around the garage, and it works pretty well. I was able to adjust it to the point that the engine was louder than the exhaust! Check it out, and let me know your thoughts:

BigUncleT · 09-18-2009, 10:32 AM

Here's some pics of the prototype:

50rider340 · 09-18-2009, 10:49 AM

very impressive. What program were you using for the drawings? Im guessing the spring loaded part is so you can either crank it in or out depending on how loud you want the bike to be?

BigUncleT · 09-18-2009, 10:54 AM

I use Autodesk Inventor.

Yep, you got the concept right. I can also run it without the bolt and springs, with just the inside flange bushings in place. It kind of allows 2 stages, if you will.

Wandell · 09-18-2009, 10:55 AM

Interesting. How much is power affected. Please, keep us posted.

BigUncleT · 09-18-2009, 11:00 AM

After I do the sound level tests, I'm planning on just doing some top speed runs with my GPS mounted to the bars.

I can tell you that the sucker still has plenty of torque, cause the front end still comes up abruptly. I have no idea how to measure for torque or HP though, so this is just for fun. You know, those late nights or early mornings for the damn neighbors, when I'm not done playing!

Xare50 · 09-18-2009, 11:05 AM

very nice work post a video so we can hear it great idear

bollie69 · 09-18-2009, 12:16 PM

I've been trying to figure out how this works but still havent... The end nut on the bolt is fixed to the bolt or the copper housing?

BigUncleT · 09-18-2009, 12:24 PM

The nut is press fit into the bronze flange bushing. The prototype I built is a regular nut, cause I didn't have a flanged nut laying around. When I did the 3D model, I thought it would be a good idea for the nut to be flanged, so it won't pull out.

The concept is that I can either run it stock, or:
Stage 1 - I can drop in the bushing / nut assembly and loose some Db.
Stage 2 - Screw in the bolt / spring assembly for Stealth Mode.

bollie69 · 09-18-2009, 01:05 PM

Right I understand. So the bigger the gap between the washer and the endcap get the more sound. Couldn't you attach the brushing on the inside so the thing doesn't fall in the exhoust when you screw the bolt completely out.

Niceone btw, i'm building myself one too in the next couple of weeks.
How dit you lock the bolt in the brushing?

BigUncleT · 09-18-2009, 01:07 PM

Ok, I modeled in the can, packing and baffle for clarity.
In Stage 1, the exhaust exits hole in the nut, and the 4 holes in the bushings.
In Stage 2, the exhaust exits only the bushing holes, and is further adjusted with the bolt / spring assembly.

Hope this helps, and I will be doing tests with a sound meter very soon.

BigUncleT · 09-18-2009, 01:16 PM

Quote:

Originally Posted by bollie69

Right I understand. So the bigger the gap between the washer and the endcap get the more sound. Couldn't you attach the brushing on the inside so the thing doesn't fall in the exhoust when you screw the bolt completely out.

Niceone btw, i'm building myself one too in the next couple of weeks.
How dit you lock the bolt in the brushing?

It doesn't fall in - The flange catches the baffle. I think the last pic I posted will clear it up.

bollie69 · 09-18-2009, 01:16 PM

Don't understand the first sentence. Though I completely understand how the system works. How did you mount the bronze piece to the alloy exhoust can end? Or is it still loose in the prototype

BigUncleT · 09-18-2009, 01:25 PM

It's not permanently mounted. When I slide the stock cap off, I insert the bushing assembly, and there is a flange on the bushing that catches the end of the baffle screen. This keeps it from dropping in any further. I made a 1/16" gasket that fits between the bushing assembly and the cap, to keep it from rattling around.

BigUncleT · 09-18-2009, 02:39 PM

I'm not sure if anyone will even bother to follow this thread, but I have a few questions for the pros out there. I want to mount a tiny tach to this thing for my tests, as well as fab up a back pressure gauge (I'm not spending $120+ dollars for a legit back pressure gauge!).

1.) Any idea what rpm these things tend to run at idle, and what's the redline rpm's?

2.) Should I be able to use any low pressure gauge rated for water, steam or air?

Thanks! Can't wait for Beer:30 so I can get home and start tinkering!

kawasakicoby125 · 09-18-2009, 04:16 PM

sell these. i would buy one cause im too lqazy to make one.

Wandell · 09-19-2009, 11:37 AM

I agree. Or at least give us a parts list needed to build one. I take it this can all be found at most hardware stores.

bollie69 · 09-20-2009, 01:04 AM

Quote:

Originally Posted by Wandell

I agree. Or at least give us a parts list needed to build one. I take it this can all be found at most hardware stores.

Yeah a nice little howto would be great

Bman33 · 09-20-2009, 05:52 PM

Very cool. Id buy one too.

BigUncleT · 09-21-2009, 06:21 AM

Well, I ran into a couple of glitches this weekend.

The Tiny Tach model I have is a 2C. It was reading very high revs, and I believe it is because the 2C is designed for 1 spark per revolution. I think these pit bikes have 1 spark per 180 degrees, so I will need a model 4C.

The next thing was the sound meter. I was able to accurately measure sound at idle, but simply revving the motor was not a true indication of noise while riding in gear. No matter what stage I ran the exhaust, I was still able to get to 120 dB revving at max throttle. I need to figure out how to measure sound while riding and shifting through the gears to get better data.

I'm actually happy just to be riding again! This thing sat in my shed for a couple years neglected, but now that my nephews are riding all the time I'm back in business! I'm just trying to quiet this thing down a little, since my bike's the loudest in our group, and this old lady on my street can be a pain.

I'll update when I get better data.

09-18-2009, 10:19 AM	#1 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	My quest for a quieter exhaust on my Xtreme CR107 Hey guys, I've been messing around with a design that uses an existing muffler end cap, and provides adjustability for noise levels. I will do sound level testing over the weekend, and post the results. I made a prototype with parts laying around the garage, and it works pretty well. I was able to adjust it to the point that the engine was louder than the exhaust! Check it out, and let me know your thoughts:

09-18-2009, 10:32 AM	#2 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 Here's some pics of the prototype:

09-18-2009, 10:49 AM	#3 (permalink)
50rider340 3rd Gear Member Join Date: Mar 2004 Location: CT Posts: 3,083 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 very impressive. What program were you using for the drawings? Im guessing the spring loaded part is so you can either crank it in or out depending on how loud you want the bike to be?

09-18-2009, 10:54 AM	#4 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 I use Autodesk Inventor. Yep, you got the concept right. I can also run it without the bolt and springs, with just the inside flange bushings in place. It kind of allows 2 stages, if you will.

09-18-2009, 10:55 AM	#5 (permalink)
Wandell 3rd Gear Member Join Date: Jul 2007 Location: Cairo, Georgia Posts: 1,467	Re: My quest for a quieter exhaust on my Xtreme CR107 Interesting. How much is power affected. Please, keep us posted.

09-18-2009, 11:00 AM	#6 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 After I do the sound level tests, I'm planning on just doing some top speed runs with my GPS mounted to the bars. I can tell you that the sucker still has plenty of torque, cause the front end still comes up abruptly. I have no idea how to measure for torque or HP though, so this is just for fun. You know, those late nights or early mornings for the damn neighbors, when I'm not done playing!

09-18-2009, 11:05 AM	#7 (permalink)
Xare50 2nd Gear Member Join Date: Apr 2009 Location: stockton Posts: 403 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 very nice work post a video so we can hear it great idear

09-18-2009, 12:16 PM	#8 (permalink)
bollie69 PM Newbie Join Date: Sep 2009 Posts: 14	Re: My quest for a quieter exhaust on my Xtreme CR107 I've been trying to figure out how this works but still havent... The end nut on the bolt is fixed to the bolt or the copper housing?

09-18-2009, 12:24 PM	#9 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 The nut is press fit into the bronze flange bushing. The prototype I built is a regular nut, cause I didn't have a flanged nut laying around. When I did the 3D model, I thought it would be a good idea for the nut to be flanged, so it won't pull out. The concept is that I can either run it stock, or: Stage 1 - I can drop in the bushing / nut assembly and loose some Db. Stage 2 - Screw in the bolt / spring assembly for Stealth Mode.

09-18-2009, 01:05 PM	#10 (permalink)
bollie69 PM Newbie Join Date: Sep 2009 Posts: 14	Re: My quest for a quieter exhaust on my Xtreme CR107 Right I understand. So the bigger the gap between the washer and the endcap get the more sound. Couldn't you attach the brushing on the inside so the thing doesn't fall in the exhoust when you screw the bolt completely out. Niceone btw, i'm building myself one too in the next couple of weeks. How dit you lock the bolt in the brushing?

09-18-2009, 01:07 PM	#11 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 Ok, I modeled in the can, packing and baffle for clarity. In Stage 1, the exhaust exits hole in the nut, and the 4 holes in the bushings. In Stage 2, the exhaust exits only the bushing holes, and is further adjusted with the bolt / spring assembly. Hope this helps, and I will be doing tests with a sound meter very soon. Last edited by BigUncleT; 09-18-2009 at 01:14 PM.

09-18-2009, 01:16 PM	#13 (permalink)
bollie69 PM Newbie Join Date: Sep 2009 Posts: 14	Re: My quest for a quieter exhaust on my Xtreme CR107 Don't understand the first sentence. Though I completely understand how the system works. How did you mount the bronze piece to the alloy exhoust can end? Or is it still loose in the prototype

09-18-2009, 01:25 PM	#14 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 It's not permanently mounted. When I slide the stock cap off, I insert the bushing assembly, and there is a flange on the bushing that catches the end of the baffle screen. This keeps it from dropping in any further. I made a 1/16" gasket that fits between the bushing assembly and the cap, to keep it from rattling around.

09-18-2009, 02:39 PM	#15 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 I'm not sure if anyone will even bother to follow this thread, but I have a few questions for the pros out there. I want to mount a tiny tach to this thing for my tests, as well as fab up a back pressure gauge (I'm not spending $120+ dollars for a legit back pressure gauge!). 1.) Any idea what rpm these things tend to run at idle, and what's the redline rpm's? 2.) Should I be able to use any low pressure gauge rated for water, steam or air? Thanks! Can't wait for Beer:30 so I can get home and start tinkering!

09-18-2009, 04:16 PM	#16 (permalink)
kawasakicoby125 3rd Gear Member Join Date: Jul 2008 Location: Lynnwood, WA Posts: 2,356 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 sell these. i would buy one cause im too lqazy to make one.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

09-19-2009, 11:37 AM	#17 (permalink)
Wandell 3rd Gear Member Join Date: Jul 2007 Location: Cairo, Georgia Posts: 1,467	Re: My quest for a quieter exhaust on my Xtreme CR107 I agree. Or at least give us a parts list needed to build one. I take it this can all be found at most hardware stores.

09-20-2009, 05:52 PM	#19 (permalink)
Bman33 PM Newbie Join Date: Sep 2009 Location: Fort Myers Fl Posts: 26	Re: My quest for a quieter exhaust on my Xtreme CR107 Very cool. Id buy one too.

09-21-2009, 06:21 AM	#20 (permalink)
BigUncleT PM Newbie Join Date: Sep 2009 Location: No legal place to ride, NJ Posts: 13 My Mood:	Re: My quest for a quieter exhaust on my Xtreme CR107 Well, I ran into a couple of glitches this weekend. The Tiny Tach model I have is a 2C. It was reading very high revs, and I believe it is because the 2C is designed for 1 spark per revolution. I think these pit bikes have 1 spark per 180 degrees, so I will need a model 4C. The next thing was the sound meter. I was able to accurately measure sound at idle, but simply revving the motor was not a true indication of noise while riding in gear. No matter what stage I ran the exhaust, I was still able to get to 120 dB revving at max throttle. I need to figure out how to measure sound while riding and shifting through the gears to get better data. I'm actually happy just to be riding again! This thing sat in my shed for a couple years neglected, but now that my nephews are riding all the time I'm back in business! I'm just trying to quiet this thing down a little, since my bike's the loudest in our group, and this old lady on my street can be a pain. I'll update when I get better data.