raw motorbike easy auto chain tentioner and expansion chamber exhaust

Discussion in 'Performance Mods' started by joey d, Jan 21, 2010.

  1. joey d

    joey d Member

    I have just done 2 new mods to my motorbike but I haven,t been able to test them yet. just wanted to see what you guys thought. Now I have to fix a major gas tank leak or finish aluminum tank. I am waiting for my aluminum brazing rods to show up. I got e expansion chamber on ebay for 30 including shipping and jb welded the copper pipe fittings together. put the pipe pretty much the only place it would fit. then then I attached it to the frame with 2 hose clamps. the heat guards was something I found in the shop. It had little spikes on it that I snapped off with some pliers.
    The chain tensioner was just the stock one with a piece of flat stock bolted to it. I drilled a couple holes drilled in it got a spring at the hardware store and attached it to the frame with some bailing wire. let me know what you think. thanks Joey D

    Attached Files:

  2. tacoshell4

    tacoshell4 Member

    does it run good?
  3. MikeJ

    MikeJ Member

    Joey -

    I like that chain tensioner idea. I will use that same basic setup for a pending build I will take on soon.

    The JB Weld joints... Keep an eye on them. I have no knowledge that anyone every used JB Weld in an exhaust system that close to the engine. JB Weld is a two-part plastic resin, not true metal. My concern is that the joints will fail because they melted. I suggest you fasten the back end of your single-length exhaust pipe with some kind of safety wiring such that if the copper sections fall to the ground, the remaining unit does not fall backward, whip around, and jam the output pipe into your spokes. Your day will begin very badly after that one-millisecond turn for the worst.

    Keep us posted how well that JB Weld works for you.

    Last edited: Jan 31, 2010
  4. retromike3

    retromike3 Member

    expansion pipe

    Do you get any problems with the pipe that close to your leg?

    Mine goes under my B.B.

    Mike Frye the bike guy
  5. MikeJ

    MikeJ Member

    Joey -

    Another suggestion.... Take a test joint of copper segments and the JB Weld and put them together. Then take a propane torch (or maybe borrow one) and heat the joint. See how much heat it takes to make the joint fail. Exhaust under severe stress like hill climbing has been documented on this forum to heat steel exhaust pipe to cherry red; still, the true welded joint did not fail.

    I once made an exhaust pipe out of copper and 350 degree solder for a .40 cid model airplane engine. After 30 seconds of running, the whole good-looking assembly just melted into separate parts. I suspect JB Weld will do the same.

  6. joey d

    joey d Member

    jb weld failed

    I was thinking about trying high temp silicone for sealing fire places or I'll just weld up a good steel exhaust. I just liked the idea of all these premade angled pipe fittings some times the easy way isn't that easy.
  7. joey d

    joey d Member

    I put a little heat shield on the pipe to keep it from burning my leg and haven't even felt any warmth after a 40 mile ride. pretty much put the pipe the only place I could make this one fit. I tried holding it up to the bike in every way possible and this was the only place it fit. I did seem to loose some low end torque from stock. I learned this while riding with a friend who has the same engine. lost a lot of hill climbing power but on flat to slight down hills I am cruising past him at about 38mph give or take. My friend has a speedo and his bike tops out at 32 mph stock. It was his estimate that I was hitting 38mph.

    The auto chain tensioner made the ride so much smoother. also I suggest everyone do this Cause its cheap and easy and also takes out any chain slap. I am no longer getting chain rub on my tire and don't have to adjust my chain any more
  8. Mountainman

    Mountainman Active Member

    a little bailing wire or duck tape to fill the gap

    joey d

    I agree with Mike
    as much as I love JB Weld -- been using it for over 40 years now
    don't think that you have a winner with that one -- a little too much heat there

    regarding your chain tensioner -- should be fine
    noTHING like a little bailing wire or duck tape to fill the gap

    have fun as you ride that THING
  9. joey d

    joey d Member

    I try to be about simplicity with my building I care a lot less about form then function. rat bike. You got the one of guy that gets the expensive bike and has a stock engine on it and then brags about how his bike is always gona be cooler then yours. (my friend). (Then me) with the $30 beater bike and all the free/under $25 minimalist upgrades I have time to do plus some I dont have time for. I love it
  10. professor

    professor Active Member

    Silver solder might work on your pipes. You would need to remove all the epoxy.
  11. Ghost0

    Ghost0 Guest

    We have used copper fittings on our expansion chambers for well over a year and they hold up just fine. Solder on the other hand will not. Typical 2 stroke exhaust temp is around 800 degrees F. Melting point of copper is around 1300 degrees F. We use silicone tubing to keep the joints of the copper fitting from leaking.

    On another note, I would recommend replacing that 90 degree fitting with two 45 degree fittings. 90 degrees is just too tight of a bend. I think you will see a performance increase. Also it appears your header length is a little short. 12 inches from the exhaust port to the start of the expansion chamber is a good start. I think adding the two 45's will get you closer.
  12. MikeJ

    MikeJ Member

    I agree, copper joint pieces do make for a nice exhaust appearance. Silver solder *might* work for low temperature operations. Its melting point is above 800 degrees F, but that depends upon the alloy combination of the solder.

    But another thing to remember: Copper becomes brittle with exposure to vibration. These engines vibrate a lot! If the silver solder holds, at least one copper piece will develop a crack as the exhaust system flexes. The crack will eventually break completely apart in time. You will no longer have an effective muffler system. (Other than compliance with federal laws, that could be why auto and truck exhaust systems are not make of copper.)

    I have read of some guys using flexible gas furnace line, flexible steel exhaust tube for motorcycles, as well as electrical conduit. Have not heard of anyone using galvanized threaded water pipe. That would work, but it would be a bit heavy. (I use galvanized water pipe on my 4 horsepower lawnmower to redirect the exhaust. The pipe and joints went into place over 10 years ago and it still works. After the zinc coating burns off, the pipe assumes a battleship grey color. And it rusts when it gets wet. Maybe high temp exhaust paint from a NAPA auto parts store will help there. )

    Keep tinkering! Let us know what you decide upon.

  13. joey d

    joey d Member

    where do I get this high temp silicone tubing that doesn't melt? what is it called? and can I run it like piping from the header to the chamber.
  14. I got the expansion chamber from SBP and used muffler repair tape from Auot Zone to wrap the copper fittings. If I remember right it was around $7 and easy to use. After install a quick ten minute ride and the tape sorta melts together and seals it up. Have at least 100 miles on it with no problems.
  15. Ghost0

    Ghost0 Guest

  16. joey d

    joey d Member

    thanks guys I have a lot of options to think about now. I think I am gonna try some stainless steel flexible exhaust tubing. It would give me less restriction then all these copper angles and allow me to play around with tuning length.
  17. Ghost0

    Ghost0 Guest

    Give it a shot but in my experience the corrugation in that tubing does nasty things to exhaust flow and the pressure waves.
  18. joey d

    joey d Member

    didn't think of that am`I able to go from the header to the expansion chamber with say 8 inches of the silicone hose. or do I just use it for the pipe connections. Also am I ok with heat wrapping around this hose to hide it. or would this keep in to much heat and melt the tubing.
  19. joey d

    joey d Member

    I meant to say is it safe to use this hose as an actual exhaust pipe or just to seal the connections of the exhaust pipe. also is it safe to heat wrap it. any one know the melting temp.
  20. Ghost0

    Ghost0 Guest

    The silicone is good but won't last long directly exposed to the exhaust gases which is why we only us it to seal the joints and not as the pipe itself.

    I would think wrapping it would increase the heat is sees and will probably deteriorate it prematurely.

    I would just use two 45's in place of the 90 and then either just wrap it and hope the wrap itself helps reduce the leaks or use the silicone at each joint.