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Post by tp555 on Oct 5, 2007 11:32:25 GMT -5
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Post by 90GTVert on Oct 5, 2007 14:27:42 GMT -5
mid $ as long as you are a machinist. That's a bit of time at a healthy labor rate for those of us without a machine shop at our disposal. Kinda cool though.
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Post by earlwb on Oct 6, 2007 7:07:50 GMT -5
Very nice.
I would have probably done dual muffer clamp mounts, just in case.
But it turned out real nice.
Oh yeah, what do the insides look like?
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Post by tp555 on Oct 6, 2007 11:09:43 GMT -5
Clamp works and is at the heavy spot.Muffler only weighs 3'12" so no big deal.I made 2 options
for this,1 glass pack style,Long 1" od tube with lots of holes,about .850"id.Didn't have any glass
pack material.Was a bit loud empty.2 made baffles with 3/4" hole about 4 of them.This was also
a bit loud so I put some screen mesh inside between the baffles.This quieted it down but no different performance from stock.Sounded good though.So Will remove the screen mesh and run
just baffle system on my test track.Timed over a stretch of road.See what happens.
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Post by fulltimerart on Oct 6, 2007 16:05:31 GMT -5
 Nice machine work-looks real good. Its always nice to be able to show off your trade. Art
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Post by tp555 on Oct 6, 2007 18:29:31 GMT -5
After running around today I got to change the main back to stock. Original 108, went to a 118 but i'm getting black exhaust color and the plugs show it.I did move the needle up a notch so that should help. I swapped out my stock exhaust and my mod exhaust and drove around. Conclusion
118 main is too much. Will go back to stock 108 and leave the needle jet at 1 notch lower. I did get 3mph more going up this long hill. My mod exhaust is flow thru didn't matter.Top speed didn't change with either exhaust or with the rich jets,60mph. Go figure.
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Post by earlwb on Oct 6, 2007 20:19:20 GMT -5
Are you running a better air intake system?
Usually a better exhaust doesn't do much of anything performance-wise until you free up the air intake more.
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Post by tp555 on Oct 6, 2007 20:35:40 GMT -5
I tried no air filter. It helped a bit but still was too rich.I removed the small foam strips on the bottom of the air box.I run without them anyhow.So the change was main 108-118 and moved 1 notch on the needle jet.That was too much. My mod exhaust has 3/4" open passage. Conclusion
118 is too much. I will leave the needle jet at its 1 notch change and go with that. Find out tomorrow. I'll measure out the diaphram and piston when I open it up so i know if the specs match up.
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Post by tp555 on Oct 7, 2007 10:52:02 GMT -5
Runs way better with stock 108 main jet.So now the only difference is one notch on needle jet.
Probably better to change needle jet groove first then changing main jet.Also easier to do,don't have to remove the carb.
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Post by tp555 on Oct 9, 2007 18:42:38 GMT -5
More R&D and some conclusions. I made 2 systems for this muffler,1 baffle system,4 baffles spaced apart a few inches.Made 2 flavors of this. First was one large hole 3/4" off center random placement .Second was lots of small holes in the baffle about.136" .It was a no. 28 drill. The multi small hole baffles reduced the noise the most,but added more back pressure then stock.It ran richer then stock when I had the large jet in ,118.Sound was low pitch a bit of the dirt bike sound, but not loud at all. The second flavor of the baffles with the 3/4" hole had flow thru with offset to quiet the sound.This was less back pressure then stock.burned leaner then stock. Worked just fine with 108 stock main.It would be a toss up for performance.The flow thru had better sound.Still the dirt bike sound but not overly loud. My stock muffler wasn't totally stock either.I removed the pig tail extension.Ground it down with a 4" side ginder.. I had to remove the rear cover to do this,pic. wm14.inbox.com/thumbs/1a_3c44f_7575f9c_tn.jpg.thumbThe only problem with this is that you now have an echo chamber and you get a small putt sound from the echo chamber.The only way to make this disappear is to add a small tube over the pigtail that exists out to the open air and the putt sound magically disappears.You can also drive without the rear cover and the putt is gone.This can be a problem if you don't like it. I made a small cap to fit in the end tube with a 3/4" hole.The putt is diminished and I can live with it. Baffle pics: wm14.inbox.com/thumbs/22_3c447_1f422fd_tn.jpg.thumbStock: wm14.inbox.com/thumbs/23_3c446_d6f21fbd_tn.jpg.thumbNow this brings us to the last option, the glass pack. I used 1"od tubing about .850"id.A small piece is at the top of the baffle pic. A single long piece with lots of small holes drilled thru.Very boring drilling the holes. I purchased pipe wrap fiberglass and packed it in completely. Fired it up and sounded good. A higher pitched sound full like a small harley,but not overly loud. Most bad ass sound,top for sound.The test ride wasn't good.it hesitated so i have to check the plug and see if the air hose came loose. If both items are normal then this has the least back pressure and requires a bigger jet.The 118 would probably run fine. i could not accelerate smoothly and wot just about stalled.This is using the stock 108 jet.So for tomorrow I will swap the stock muffler back in and go for a ride to check systems like fuel pump and make sure everything is working normally.Next test glasspack and bigger jet. |
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Post by earlwb on Oct 9, 2007 20:59:17 GMT -5
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Post by tp555 on Oct 10, 2007 7:00:30 GMT -5
That's it.I made a cap that screws in on the back.So I could remove the guts and test out different
systems.The back cap is 2 5/8" dia.It blends in.The small cap is for extra small baffle designs.See the black line near the end,thats the joint for the large end cap. The small cap holds the long
1" tube in place. So I can remove and install baffle system or glasspack tube using the same outer case.When testing is finally done,I open up the stock muffler for r&d. I ordered a mrp air filter for another option to add to the rejetting test.Will test out new air filter,stock jet and stock muffler.Then jump to 116 jet,air filter,stock muffler.Then try out my glasspack with 116 jet and the 2 air filter options.best performance will be the glasspack and jet.Felt strong starting out.
The noise isn't bad.A normal harley makes more noise.So will probably have all the parts by weekend for R&d.
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Post by tp555 on Oct 12, 2007 7:10:42 GMT -5
My spark plug stripped its threads,so testing is on hold until I fix that issue,probably this weekend.The plug did show lean conditions as expected. I did get my mrp air filter in which is a small foam covered thing.Really small about 4 oz in weight.Something to add to the mix later on.
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Post by tp555 on Oct 12, 2007 16:17:03 GMT -5
I did the disassemble on the scoot .Wasn't bad at all. Working on a plug for the spark plug thread. Found a problem with the cylinder.Took a look at the walls of the cylinder.Hardly worn in at all so i spec'd it out.its 2.260 which is bigger then 57mm and smaller then 57.5mm.There is a large gap visible between piston and cylinder over .015" and you see the rings.This is not good.Pic wm14.inbox.com/thumbs/24_3c445_b9c2bc79_tn.jpg.thumbI was getting oil on the plug doing top speed tests .It doesn't do this if I keep the revs under 6000rpm.So, tomorrow I'll break loose the cylinder to measure the piston diameter at the skirt. Then I find out if its really .015" too big for the piston or not.Going to a 58mm piston isn't a problem for me ,but damn its supposed to have .0015" not .015" clearance.Lost in translation, right? I did find out that my air cleaner hose came off under the air box.So it leaned out way too much for my glasspack muffler.Now I know. |
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Post by tp555 on Oct 13, 2007 17:11:27 GMT -5
My cylinder has a 57.4mm bore.Motogino has them,so I don't have to bore out the cylinder.Back to the spark plug repair.I made a bushing out of 416 stainless and tapped the head. Pic wm14.inbox.com/thumbs/25_3c444_7172d939_tn.jpg.thumbThis is the after pic. wm14.inbox.com/thumbs/26_3c443_fe233fd_tn.jpg.thumbI used blue loctite on the plug.Its the only one I had and antiseize on the spark plug.Will see what happens. I did a little extra massaging on the head.A 4" c clamp and a U shaped bushing worked for valve spring compressor. I got the scoot buttoned up and had some daylight.Guess what I was doing.Did about 35 miles today.It feels the best performer of all the exhausts. I am still using the stock 108 jet and middle groove on the needle.What I plan to get is a 112 or 113 main jet.That would work. I will change the needle jet to groove #4 after I test out this setup. That will be tomorrow.regards. |
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Post by tp555 on Oct 14, 2007 15:02:33 GMT -5
Results from testing.This exhaust kicks ass.Running my 0-40mph test 2 sec. faster. Running the uphill test 2 sec. faster.You can feel the difference easily. So further testing will continue but i'll end this thread. Tuning the jets will help, but as to design flow thru no obstruction wins.The variations
were baffle with single large hole and multi small hole designs.The small hole design had more back pressure and less noise.Compared to stock the large hole was even to stock.The multi small hole was slower then stock.The flow thru glass pack has significant performance gains.Sound can be altered by changing the packing material. I packed mine a bit too tight,but its still quieter then a new harley no contest there.regards.
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Post by tp555 on Oct 18, 2007 15:17:30 GMT -5
Have been running around enjoying this exhaust,but I heard a rattle.The source was inside the exhaust. Opened up the can and I found the center core which is aliminum got a bit warped from the heat.Really strange. I guess it got a bit hot. I made a steel replacement and its back in business. wm14.inbox.com/thumbs/28_3c441_1d81e771_tn.jpg.thumb |
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Post by earlwb on Oct 18, 2007 15:30:36 GMT -5
Cool. I wonder if the hot exhaust gases got hot enough, temperature-wise, to cause the aluminum to soften a little or not. How long did it take you to drill all those holes?  But then with all the holes in the aluminum maybe it just bent on its own, as it isn't as stiff as steel. it might be that one needs to maybe leave some extra aluminum along the length in a few places to make it stiffer. sort of a hole pattern with some spacing in a few places. |
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Post by swampsniper on Oct 18, 2007 17:30:12 GMT -5
I'm surprised that piston isn't slapping like crazy.
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Post by tp555 on Oct 18, 2007 17:46:31 GMT -5
The piston is ok.Its got a 57.4mm dia.A piston with .015" clearance won't run and make a bit of noise.
The exhaust pipe probably got close to 1500* F or something like that to shrink.The pipe was under tension,but it shrank and got smaller making a rattle.The glass material got blown back
and about 5" of the front was free space. Well i made the new piece steel.See how long it lasts.
Drilling the holes took about 3 hrs, very boring.
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Nice machine work-looks real good. Its always nice to be able to show off your trade. Art
