Update on my Stalled Project, Exhaust Almost Done...

[Fry]

First off I must say I've been a slacker on this project, I think it's been almost a year since I did anything loosing interest, mainly due to the price of Swingarm bearings.

This week I decided to try and get the exhaust figured out, knowing that I didn't want to run the big obnoxious Hindle Can up the side of the bike. I did a lot of reconfiguration of the subframe and seating area, hiding a lot of the wiring and additional components in the process so I played around with the idea of running some type of exhaust system up under the seat area and centered out the back, yet felt that was above my ability and budget.

One day while at my brothers I got to looking at his sons YZ125 Silencer, I really liked the angled end cap and it's textured look. The more I looked at it the more I thought, damn 2 of those, laid flat and side by side right under the engine would like insane (IMHO), so I ordered 2 KX 65 "Take Off" Silencer from EBAY and went about the process.

My major concern with this phase of the build up is NOT performance, it's a GS500E, a 300 Shot of Nitrous would do little for the performance of this bike, however my goal is to make something, a completed project, that was cheap to make, was my own creation and something that was pleasing to me, I like things hidden. I know there are many who will say my exhaust plans are rubbish, it won't flow close to the stk. system, it will be too loud, too quiet, restrictive and or will ruin my valves and while I may agree with some of those things I'm still going for it and if changes need to be made later so be it, right now I'm heading down a path to creating something that I like the looks of and fits with the bikes theme.

Here is a pic of the initial mock up, once finalized, the can will sit further back, more than likely flush with the main frame down tube.



This is a pick of the Hindle Header and the KX Silencer, un modified.



After about 10 seconds under a Chop Saw





Here, the inlet end cap has been opened up to accept a 1 1/2" to 2" Exhaust Coupler. The Header Tubes are roughly 1 1/2", so using the Coupler going from 1 1/2 on the header side, to 2" going into the can, flow shouldn't be hampered that much.



Here is the Exhaust Coupler, I squished it in a vise slightly to oval it's shape to help it match up better with the Inlet End Cap.





Yes, my Welding sucks, nothing a Die Grinder cannot fix, LOL...





In this pic you can see that the Internal Baffle Cone (?) is still attached to the Outlet End Cap, and I think I am going to leave it in tact. I was thinking about removing it from the End Cap, and opening up the End Cap Outlet Hole to increase the flow. Doing this would create a complete blow through exhaust, the entire Silencer assembly would be open internally with no baffles, packing, nothing, basically 1 big sound chamber. Yet, I think I need some type of back pressure and some flow/sound deadening ability so the baffle tube will stay, and the Outlet Hole Diameter will stay the same size also which I think is about 1"~1 1/4" I may pack the can with steel wool but will try it first without it. I know the Outlet Hole Diameter and the way the tube is affixed internally to the end cap, will really limit the Output flow, but I'm hoping it will be OK.



Almost completed, here the Header Tube is slid onto the Silencer. I may leave it a "Slip Fit" welding on 2 Posts on either side of the pipe and 2 on either side of the Silencer Coupler and use an exhaust spring set up, like on Dirtbikes.




Here it is test fitted to the Bike...





I plan on getting some Black Fiber Header Wrap and wrapping the entire header tube ending right at the Silencer. Additionally I will make a bracket, in the shape of a Butterfly, weld 4 studs to it, and affix that to the bottom of the frame in the center. These 4 studs will tie the 2 sides together and will allow the stock silencer rubber mounts to be used, just sliding up onto the 4 studs, then putting 4 nuts on or Pull Pins for quick release.



Here is a pic of the bike in stock form, no suspension changes have been made so judging by this pic, I think I will have adequate ground clearance, I hope, LOL...



Here are some old pics that I like and to show the little progress I have made from the stk look of the bike...















So, what do you guys think of the Exhaust? I still have to make the other side and would appreciate some feedback so if I do decide or need to make changes, I'll only have to do it to one side, making the 2nd with the changes incorporated.

Also, need some thoughts on how to hang the Passenger Foot Pegs. I bought a set of Generic Street Pegs that fold up, and would like to mount them so there either hidden when not in use, or quickly removable, yet safe.

[Deros514]

Exhaust looks good. I think a muffler designed for a 125cc 2 stroke should be able to handle the gas flow of half of a 500cc 4 stroke. I'd advise against regular steel wool, that stuff wont last long at all. At the least go for some fiberglass insulation or stainless steel wool.

[Fry]

Silencers are actually off of '09 KX 65 2 Strokes, but have been opened up considerably at the inlet. I still have the formed Fiberglass Wrap and Stainless Steel wool that came out of these Silencers, we shall see what I need to use...

[Fry]

Well, I got the 2nd Silencer the other day and was able to finish making the 2nd Pipe/Silencer Combo.

The Cans are still a Slip Fit to the Header Tubes as there maybe some fitment issues with the Shock Dog Bones which won't really be an issue as I can just push the Silencers further onto the Header Pipe moving them away from the Shock Linkage. So right now, everything is a loose fit, so if you see somethings slightly off line or crooked, nothing is permanent at this point.

Additionally, I need to lengthen the straight downward portion of the Header Pipes that come out of the motor, about a 1/8th Inch, this will drop the Silencers about an 1/8th" away from the Oil Pan, right now there barley touching it, something I will not accept.

Once I mock up the Shock Linkage, and Drop the Silencers away from the Pan, Ill be able to fab up the secondary mounts of the Silencers.

Here are some pics...

[romulux]

Those exhausts look awesome!

[Fry]

Thank you, I appreciate the comment...I know I don't have the best of skills, or anything that resembles a budget, but I'm happy with the results so far.

I'm pretty close to being able to assemble it entirely, one more time, to make sure all the bugs and kinks are worked out, before I tear it all down again, paint the frame and swing arm, and assemble it, carefully, one last time.

[Homer]

Tried it.  It sucked. 
No offense. 

Had fun building it, though.  Same internal baffles, almost at the same position.  Had mine a little more to the rear, and angled. 
Could never get it jetted right.  Always too rich at the low end (and killed power) and too lean at the top (killed power). 
As in - about 10~15 horsepower. 
Looked really cool sitting still, though. 

[Fry]

Thanks for the Info, that sucks to know.

I guess I'll have to see how the motor feels once I get it running, I've already jetted for the Hindle Set Up when I 1st put that on many years ago, and know I will need to mess with it more, once this is finished.

Homer, Why didn't you lean out the bottom throttle settings and fatten up the Mid-Upper end, or was it that far off in both directions? I would think upping the Main Jet and Messing around with the Needle/Going down on the Pilot Jet would help? I haven't had the carbs apart for many many years, but am hoping for the best when test running it and tuning it.

[Twism86]

I think that looks really cool and original! Post a video when you fire it up, i want to know what that sounds like.

[Fry]

I'll post a "Start Up" video once the Mock Up of the entire bike is finished...Then I can rip it all apart, again, and start the final assembly.

Thanks for the positive comments.

Honer, do you have any pics of your exhaust set up that was similar to mine? Any more specifics about your jetting woes? I'd like to get a jump on it, and possibly Jet my carbs for this exhaust prior to installing them, or at least jet them to get them close. Thanks for anything you can pass on.

[pookiebear]

being a 2 stroke guy from way back. Do not use the original 2 stroke packing. It will burn up. 2 stroke exhaust gases are much lower in temp and the glass is different. Get some 4 stroke packing from any store and use that.
here is some it is super cheap. http://www.rockymountainatvmc.com/productDetail.do?&navType=type&brandId=365&navTitle=Exhaust&webTypeId=51&webCatId=18&prodFamilyId=16170

loving the mod. This would be a cool mod to do with wideband fuel injection setup.

[T1z3R]

whether it works or not i dont know but it looks fantasticin my opinion.

nice work 

[Fry]

I'm actually thinking of running it without packing, just using the perforated inner core/tube and the can itself as the silencing material/device....We shall see how that goes...

And thanks for the advice on the 2 stroke packing, I have a ton of that, as I pack my '01 300EXC KTM silencer atleast once a year. If the empty can doesn't do the trick, Ill source some 4 stroke material, thanks for the link.

Thanks for all the positive comments....If it works out, I'd be willing to make some for others that are interested?

[O.C.D.]

SO, this will not work and it sucks?!  Damn, that sucks in itself as I want to do it now.  Sweet @$$ idea, I really like it.  Let me know how it works.  If you get anything near stock (or modified) performance i am buying a set and selling the V&H.

Let us know asap!!!  get her running.

Juan

[Homer]

It works.  Just a b!tch to dial in. 
Looks outstanding.  Really robbed my upper RPM range, though.  Didn't really care, because I was so proud of it. 
Tore it all off climbing stairs once, and went back to the Yosh.  (You'll want to reinforce those welds.)

Tried everything from about 130 to 147.5, forgot the pilots.  0 to 3 washers.  0 turns to nearly all the way out.  Just never really found the right combination.  Had the ignition advanced by a few millimeters, backing it out didn't really help.  Lunchbox filter.  Valves were decent, compression was spot-on.  Iridium plugs. 
3-stage carbs might make it easier, but don't take my word for it.  Allen-heads on the float bowls will help, so you don't have to pull the tank each time. 

Not saying it won't run well.  Just saying that midpipe's more important than you may realize.  And rejetting gets to be a pain after the 14th time in a week. 

[Fry]

Homer, thank you so much for sharing your wisdom and experience with this particular modification.

First off, I don't plan on climbing any stairs, so I'm hoping/thinking my welds should be strong enough, are you thinking different by looking at my picks or just trying to be proactive with your advice? I know I'll lay down a good set of beads at the Header/Can slip fit area, but are you saying the Can Inlet Cap to Coupler welds look insuffiecient? I also plan on using some supper high temp copper exhaust adhesive to seal the Inlet/Exit End caps to the Aluminum Can, the factory uses a rather weak looking clear silicone, I know that won't hold up to the heat and pressures. I will pay special attention to prepping these areas and getting them to seal tightly. I'm also gonna rob the packing material from the Hindle Can and use it in these.

Now for the jetting issues:
Can you recall what was your Best setting before going back to the Yosh Set Up?
A/S Turns Out=
Needle Shim(s)=
Pilot?
Main?

I assume when you reffer to washers, your talking about washers used to Shim the Needles up, leanign out Needle/Slide Circuit? What size thickness are these washers?

0-All the way out, I assume your talking about the Air Screw? I've found more than 2 turns out, atleast on a 2 Smoke, is the maxium effective range, once beyond that you should up the Pilot if I recall correctly?

Is Buddah still a source for Jets and Jetting components? If not, do you have a good source?

Nice idea on Allens for the Float Bowls to ease jetting woes, but I'm thinking it still would be easier just popping the tank off and pulling the carbs, seems like it would be really crammped working in the space between the bottom of the carb, and the top of the engine cases.

And your right about how fun jetting becomes after the 14th time, I just got done messing with a horrendous jetting issue on my KTM, I think I did about 10 Plug Chops and got so lost it wasn't, my neighbors where non to happy with WFO runs up and down the street for anentire weekend.

I'm sure I'll have more questions, thanks for takingthe time and wlaking me through this.

[pookiebear]

I am thinking that not only are you going to need to rejet, you may even need a different type of needle with a smaller or larger taper. Hence my comment on the fuel injection making it easier with wideband. But that is just me armchair quarterbacking. 

[Fry]

FI and Wide Band tuning is not an option, due to expense, would love to, but cannot justify it for a PLAY bike that I have no real money into, or want to put into.

Explain more about your Arm Chair QB'ing....Give me your thoughts on what you think I'll need for jetting? and why...I am famialr with the various circiuts and what throttle settings they effect, but I like all the input and advice I can get.

[pookiebear]

biggest thing I was thinking would be mid range transition. If the flow gets too much turbulance because the pipes are so short, you could run into a problem in the midrange where you would need a thicker/thinner needle or a vastly different degree of taper. Pumper carbs would solve the problem but that would put you in the same price range as FI. BUT Jets are cheap  just mess with those until you get close. Might take a call to sudco for needle options.  You could always weld up those two cans into an underseat config too because the size would be perfect. That would get your pipe length back.

[burning1]

From what I understand, the expanded volume of the Y-Pipe in an exhaust system creates a negative pressure pulse that helps to suck exhaust out, and fresh air in during valve overlap. You could probably recover a lot of your lost top end power by installing a X pipe ahead of the mufflers.