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Discussion Starter #1
Just curious. Since there are quite a few running this pipe now, I got to wondering. Do you feel the vibration level of the bike is about the same or slightly increased over the stock or whatever exhaust was on the bike before.
Ron
 

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I dont have those Ron but I have the slip ons. And yep a bit more especially in the high rpm range 2nd ro 3rd. Not bad but enough to notice.
 

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Felt it after install. Buzz in the pegs and grips at higher revs but tolerable. I'm guessing, but maybe that hard mount on the silencer or a cylinder balance issue. Anything show up on the PV cells?
 

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Discussion Starter #4 (Edited)
Felt it after install. Buzz in the pegs and grips at higher revs but tolerable. I'm guessing, but maybe that hard mount on the silencer or a cylinder balance issue. Anything show up on the PV cells?
See PM. As for tuning and ve, did notice some imbalance but that's resolved and yes it added vibes early on. It's now just determining if the Akro hard mounted can adds more vibes then a system that previously had isolation in the mounting. I do have an isolation mount on mine now but wondered why Akro never used it, other then cheaping out or is there something I'm missing, yet to be determined. With my mount and current tune, objectionable vibes, or let's say, no more the then stock with ST fatshots installed.
Ron
 

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With all due respect I think it's the way that short silencer works, basically reversing the flow to dampen the noise. That's why that pipe doesn't perform as well as it should - Take that friggin' Akro muffler off, install a straight thru 2.5 " muffler of your favorite length to get the sound you want and be done with it. Less vibration, less " reversion " less Euro B/S. Just Sayin' - the head & mid pipes are awesome, the muffler, not so much .
 

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Discussion Starter #6
With all due respect I think it's the way that short silencer works, basically reversing the flow to dampen the noise. That's why that pipe doesn't perform as well as it should - Take that friggin' Akro muffler off, install a straight thru 2.5 " muffler of your favorite length to get the sound you want and be done with it. Less vibration, less " reversion " less Euro B/S. Just Sayin' - the head & mid pipes are awesome, the muffler, not so much .
I think you'd be surprised how well it works. Torque increase is noticed. As for the rubber mount, I canned it. I was getting resonant vibes at certain rpms. The pipes are quite flexible which compounds the vibes. Going with a longer muffler as you suggest will really cause some issues. For now the stock mount is back on but I do have a better option in the works. Basically, being so light and short, it should be hard mounted to engine but the only real spot to do it is the swing arm shaft. This is the back hard point of the engine. This way the whole system moves as one unit with engine and being there's no real over hang, that second mount isn't needed. I'm now finding the vibes not all that bad compared to when it got into resonance with the isolator but having the engine moving and a hard point on the frame for the can, still is not the correct method. It should be unitized with engine. Likely a winter project as the swing arm shaft will need some reworking for the attachment.
Ron
 

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Ron, I for sure noticed this as well especially in low RPM in 5th gear. It almost feels like something is wrong sometimes. I am also fairly confident that this is what is causing my issue with my battery cable post screws constantly backing out and now allowing the bike to power on. I now have to keep a philips screw driver with me just in case I need to tighten them down.
 

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Honestly I think all you guys need for that Akra muffler is the Original V Rod Muffler mount it's a beefy bracket ( for the original big swept muffler ) with two rectangular ears that have rubber sleeves in them that allow the muffler to move back and forth with temperature stretch and cold shrink - I bought a brand new one off ebay for like $ 70 but you could buy a used one, rattle can paint it and replace the rubber sleeves if it needs it, just as good. Fitting the Bub7 pipe to my R was a real PIA with the mid pegs but without that bracket I would've been screwed. It took some fitting, fancy measurement templates and drilling to get the holes to line up with the frame and a bushing to set the angle but the sliding metal angle bolted right up to the bracket on the back of the muffler and it slides where ever it needs to and dampens vibration. It even has an extra round ear you can use or cut off, I just left it on for future options. I have no vibration issues whatsoever with that H-D OEM bracket and my muffler weighs probably 4X what your Akra Ti muffler does, and extends to the rear axle. It works, and allows other mufflers to be fitted as well if you want to play around - (y) :geek:
 

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Discussion Starter #9
Ron, I for sure noticed this as well especially in low RPM in 5th gear. It almost feels like something is wrong sometimes. I am also fairly confident that this is what is causing my issue with my battery cable post screws constantly backing out and now allowing the bike to power on. I now have to keep a philips screw driver with me just in case I need to tighten them down.
That rear mount is a touchy bitch. I've had it with real bad vibes at one point and currently what I'd expect as normal for the v rod. I've jumped back and forth between it and the isolator mount. While the isolator mount was always repeatable, the Aka mount seemed to produce different vibes and at different rpms between one bolt on and another. You can try to see if there's a tad of pressure misalignment in that area. Might need to slot the holes so when it all bolts up there is no force exerted to do so. Like I say, currently mine is fine but it's still a lame way to mount the exhaust. Next winter, I will do it right, now that I've found out what's taking place and how it moves.
Ron
 

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Discussion Starter #10
Honestly I think all you guys need for that Akra muffler is the Original V Rod Muffler mount it's a beefy bracket ( for the original big swept muffler ) with two rectangular ears that have rubber sleeves in them that allow the muffler to move back and forth with temperature stretch and cold shrink - I bought a brand new one off ebay for like $ 70 but you could buy a used one, rattle can paint it and replace the rubber sleeves if it needs it, just as good. Fitting the Bub7 pipe to my R was a real PIA with the mid pegs but without that bracket I would've been screwed. It took some fitting, fancy measurement templates and drilling to get the holes to line up with the frame and a bushing to set the angle but the sliding metal angle bolted right up to the bracket on the back of the muffler and it slides where ever it needs to and dampens vibration. It even has an extra round ear you can use or cut off, I just left it on for future options. I have no vibration issues whatsoever with that H-D OEM bracket and my muffler weighs probably 4X what your Akra Ti muffler does, and extends to the rear axle. It works, and allows other mufflers to be fitted as well if you want to play around - (y) :geek:
Stock is no perfect design either. Where do you think that buz comes from at 2500-3500 rpm? That actually went away with the Akra. Don't seem to have a distinct rpm rough spot now. Where they can get away with it stock is the bitch weighs a tone and less likely to develop resonant vibes and the two point mount takes out the rocking couple in the pipe. By the way, my isolation mount is in the third volume mount stock location. Sure, likely coming up with a different durometer rubber might fix it but the main thing is to tame that flexible slip fit pipe from getting into a buz . This can be felt with the had test on the heat shield going down the road. I wear gloves, by the way. Another interesting tidbit is if you feel the rear head there is next to no vibes. The front head, quite a bit more. This is how I came up with the fulcrum point at the swing arm shaft as the natural hard point, not the frame as it's currently designed to mount.
Ron
 

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Sounds good - don't know if you did it but another thing I did with my slip fit Ti DSP pipe on my WR400 was to use super high temp red RTV on all the slip joints to prevent relative undamped movement and buzzing between the parts - no it doesn't last forever but it would last until I removed the pipe for yearly engine Mx so that's plenty and that's on a jumping, bouncing dirt bike - probably last forever on a V Rod. Also you might think of another tendon that would attach to the muffler and frame location to dampen muffler harmonics. If you eliminate the ability of the muffler to resonate around a single point that will be helpful. My Bub7 pipe has absolutely no buzz or vibration at 2500 - 3500 Rpm - stock, probably since it would shed heat shield nuts - but not bad and definitely not now. One of the reasons I wanted a Revo was for the smooth almost vibration free engine. I can't even ride a older traditional H-D air head my screwed up neck with a plate in it can't handle it - hands get numb. As I've always said maintenance begets more maintenance and modifications beget more modifications. I think the swingarm mount might work but sounds like a hassle to pull off. The next time you ride it get it into the vibration and put your shoe on the muffler see if an additional mount tendon would dampen it out - that and if you haven't put red on the slip joints with maybe tighter springs should fix it with less hassle.
 

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Discussion Starter #12
Sounds good - don't know if you did it but another thing I did with my slip fit Ti DSP pipe on my WR400 was to use super high temp red RTV on all the slip joints to prevent relative undamped movement and buzzing between the parts - no it doesn't last forever but it would last until I removed the pipe for yearly engine Mx so that's plenty and that's on a jumping, bouncing dirt bike - probably last forever on a V Rod. Also you might think of another tendon that would attach to the muffler and frame location to dampen muffler harmonics. If you eliminate the ability of the muffler to resonate around a single point that will be helpful. My Bub7 pipe has absolutely no buzz or vibration at 2500 - 3500 Rpm - stock, probably since it would shed heat shield nuts - but not bad and definitely not now. One of the reasons I wanted a Revo was for the smooth almost vibration free engine. I can't even ride a older traditional H-D air head my screwed up neck with a plate in it can't handle it - hands get numb. As I've always said maintenance begets more maintenance and modifications beget more modifications. I think the swingarm mount might work but sounds like a hassle to pull off. The next time you ride it get it into the vibration and put your shoe on the muffler see if an additional mount tendon would dampen it out - that and if you haven't put red on the slip joints with maybe tighter springs should fix it with less hassle.
I hate vibration too. While it'ts not bad it can be improved. Most vibes on a vrod are related to the interaction of the engine and exhaust. I did do fillet seals with the high temp for tuning purposes only. Slips are coated with nickle anti- seize. In your job , you probably use mouse milk. I didn't have any laying around. LOL.
Ron
 

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Yea, in normal aircraft operations the nickel anti-seize ( or our favorite Mouse Milk liquid ) is the way to go but maybe not on M/C slip joints as it allows lubricated movement between the two head pipes and mid pipe to muffler.. The head pipes on my Bub 7 2-1 pipe are welded together and allow no relative movement. The Red RTV application process I used on my off road race bike was cleaning the inside of the one larger pipe, the outside of the one smaller pipe in both ends and muffler inlet then coating all with a nice even coat of high temp RTV and sliding them together, and quickly installing and snugging down the head pipe/mid pipe/muffler mounts so the RTV sets up in position - after a few hours or so of initial curing I'd start the engine for 10 seconds a few times and heat cycle cure it. The RTV allows the pipes to move a bit in relation to each other but it's more like stretching the RTV and it's still damping any real excessive movement that results in vibration. It works. The exhaust pipe acts more like one assembly instead of 3 parts that resonate. Also that Akro muffler may set up it's own vibratory situation trying to muffle the extensive Revo exhaust volume by reversing it internally, and it's got a relatively small outlet diameter - building up back pressure. I've always dreamed of taking the Akro head & mid pipe and putting a longer straight thru 2 1/2" muffler on it with a larger 3.5 " outlet - like a V&H big twin Pro pipe muffler ( second choice the short V Rod Comp pipe muffler ) I think it would be the ultimate Revo power, sound & and appearance pipe - not cheap, but the best.
 

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Discussion Starter #14 (Edited)
Yea, in normal aircraft operations the nickel anti-seize ( or our favorite Mouse Milk liquid ) is the way to go but maybe not on M/C slip joints as it allows lubricated movement between the two head pipes and mid pipe to muffler.. The head pipes on my Bub 7 2-1 pipe are welded together and allow no relative movement. The Red RTV application process I used on my off road race bike was cleaning the inside of the one larger pipe, the outside of the one smaller pipe in both ends and muffler inlet then coating all with a nice even coat of high temp RTV and sliding them together, and quickly installing and snugging down the head pipe/mid pipe/muffler mounts so the RTV sets up in position - after a few hours or so of initial curing I'd start the engine for 10 seconds a few times and heat cycle cure it. The RTV allows the pipes to move a bit in relation to each other but it's more like stretching the RTV and it's still damping any real excessive movement that results in vibration. It works. The exhaust pipe acts more like one assembly instead of 3 parts that resonate. Also that Akro muffler may set up it's own vibratory situation trying to muffle the extensive Revo exhaust volume by reversing it internally, and it's got a relatively small outlet diameter - building up back pressure. I've always dreamed of taking the Akro head & mid pipe and putting a longer straight thru 2 1/2" muffler on it with a larger 3.5 " outlet - like a V&H big twin Pro pipe muffler ( second choice the short V Rod Comp pipe muffler ) I think it would be the ultimate Revo power, sound & and appearance pipe - not cheap, but the best.
The Akra can itself is somewhat misleading. The core is only slightly bigger then the collector. Most of it is packing between that and the outer shell. You can drive miles and the can is only warm. Takes forever to heat up. As for the vibes, the hard point mount is behind the rear engine fulcrum. This sets up a collector and head pipe buz. In this pic, you an get a rough idea what I'm talking about. Yellow is the Akra hard mount location. Green is engine motion, more or less. Red is the result acting on the pipes. Orange is where it should be mounted as in back of engine hard point, which happens to be the swing arm shaft. Two point needed to have an anti rotation effect on the swing arm shaft. Ok, so my show and tell sucks but I think it's step in explaining it. This system is very light and won't dampen the engine vibe effect like a system with more mass.
Ron
 

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Hmmm I get no vibes at thoes rpm ranges with the slipons. Now when I get up around 5 or 6 maybe some.I know when its cold I feel it more until it warms. Seems like I feel some vibrations when I ride on different road surfaces. And yes I to notice the front cylinder feels like it vibrates . The rear not. I did not know if this was normal or a tune was bad. (Spark plugs did not show any issues tho). Guess we can probably see why they used them factory mufflers. A lot of r&d and this is probably what they knew.
 

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Discussion Starter #16
Hmmm I get no vibes at thoes rpm ranges with the slipons. Now when I get up around 5 or 6 maybe some.I know when its cold I feel it more until it warms. Seems like I feel some vibrations when I ride on different road surfaces. And yes I to notice the front cylinder feels like it vibrates . The rear not. I did not know if this was normal or a tune was bad. (Spark plugs did not show any issues tho). Guess we can probably see why they used them factory mufflers. A lot of r&d and this is probably what they knew.
Rear of engine is a bit more captured in the mount and front has less restraint, which is why when you place your hand on the cyls you can feel the difference. I noticed the same effect when I had the stock and slip ons. It was always a tad more vibration the first few miles in the ride. Then it got a bit smoother. Don't notice it with the Akra so figured it must be as the rubber mounting in the stock system, once it heated up, it must have gotten softer or all the expansion of the pipes made it firmer. Not sure which but did notice a vibe change from cold to hot. Pretty sure it wasn't the tune.
Ron
 

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Yea, up to operating temperature engines always run better and more vibration free, funny Ron most guys have a mirror or camera taped on their shoe for looking you know where but with us - it's the raw underbelly of the beautiful Miss V Rod, her exhaust pipe out to see in all it's glory ! :ROFLMAO: In any event yea I see your point - and think about it that whole mid pipe is supported only by spring pressure pulling the pieces together - fine for a race bike but not for what should be an almost vibration free street bike. Again I would ride it & get it in the vibratory mode, put a shoe on the aft side of the muffler and see if it dampens vibration. IF it does I'd fab up a tendon that would attach to one rivet location on the back side of the muffler cap with a small angled bracket and go down to the aft bolt on your mount to the frame. Include a rubber isolator mount at the bottom mount location or mid way up the tendon, or like my old Can-Am dirt bike had rubber mounts that were about the diameter of a quarter, an inch long with a threaded stud coming out of each end - used on gas tank & exhaust pipe mounts - something like that could screw into a threaded I.D. shaft that would attach to the muffler & frame mount brackets with the rubber mount half way up to the muffler, it would dampen vibration from the head pipes thru the mid pipe to the muffler - while installing that you could clean & RTV those slip joints and I can't imagine any really noticeable vibration after that.
 

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Discussion Starter #18
Yea, up to operating temperature engines always run better and more vibration free, funny Ron most guys have a mirror or camera taped on their shoe for looking you know where but with us - it's the raw underbelly of the beautiful Miss V Rod, her exhaust pipe out to see in all it's glory ! :ROFLMAO: In any event yea I see your point - and think about it that whole mid pipe is supported only by spring pressure pulling the pieces together - fine for a race bike but not for what should be an almost vibration free street bike. Again I would ride it & get it in the vibratory mode, put a shoe on the aft side of the muffler and see if it dampens vibration. IF it does I'd fab up a tendon that would attach to one rivet location on the back side of the muffler cap with a small angled bracket and go down to the aft bolt on your mount to the frame. Include a rubber isolator mount at the bottom mount location or mid way up the tendon, or like my old Can-Am dirt bike had rubber mounts that were about the diameter of a quarter, an inch long with a threaded stud coming out of each end - used on gas tank & exhaust pipe mounts - something like that could screw into a threaded I.D. shaft that would attach to the muffler & frame mount brackets with the rubber mount half way up to the muffler, it would dampen vibration from the head pipes thru the mid pipe to the muffler - while installing that you could clean & RTV those slip joints and I can't imagine any really noticeable vibration after that.
I'm a firm believer rubber mounting , now that I've built and tested the mount isn't the way to go in this application. Too short and light. Hard mount to the back of engine, as in swing arm shaft is. It can then move with the engine and not be constrained with the rigid frame mount. Of course this is a custom one off deal for me next winter. Went for a decent ride today and it didn't feel all that bad but there is room for improvement. Not sure what packing is in that muffler but I want to insulate my house with it. After 40 miles, I could still put my hand on the muffler. It was between warm and slightly hot. Not enough to burn skin. It also took 1000kms for the packing stink to go away. Really rank smelly shit is its/was. Love the exhaust otherwise. I can see why they came up with the mount as it is . Mostly to make it work with the Muscle footpeg assembly as well as it working for the DX. That and there is no user friendly spot on the engine to hard mount. On the big twins, they mount it to the trans to keep the head pipes from cracking and the rest of the overhang to the rear is rubber supported. Since there's no real overhang on the Akra, rear of engine for collector and muffler hard point only makes the most sense.
Ron
 

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I agree with all that Ron except the muffler hard point - my thought is if the engine moves up & down slightly on the fwd end the muffler has to be able to pivot and/or slide ( like the OEM bracket allows ) since it's effectively aft of the swingarm pivot - it has to be able to go a little fwd & a little aft, a little up & a little down with the engine movement. I never really appreciated the H-D OEM mount being a sliding rubber mount until we had this discussion and I thought about this. All I can say is it works great with a Bub7 2-1 and really the only difference is my head pipes are welded solid together at the collector, not a loosey goosey spring tension loaded 3 piece race style system plus the muffler. The OEM muffler slider bracket allows fwd & aft movement even a little up & down to keep pivot pressure on the muffler down when the engine moves & vibrates. If you hard mount the muffler any pressure on the mid pipe with engine lift and fall will pass stress and possibly vibration onto the hard mount and into the bike frame. I think your current rubber mount may be fine with the swingarm pivot bracket you are thinking about making for the collector. (y) :geek:
 

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Discussion Starter #20 (Edited)
I agree with all that Ron except the muffler hard point - my thought is if the engine moves up & down slightly on the fwd end the muffler has to be able to pivot and/or slide ( like the OEM bracket allows ) since it's effectively aft of the swingarm pivot - it has to be able to go a little fwd & a little aft, a little up & a little down with the engine movement. I never really appreciated the H-D OEM mount being a sliding rubber mount until we had this discussion and I thought about this. All I can say is it works great with a Bub7 2-1 and really the only difference is my head pipes are welded solid together at the collector, not a loosey goosey spring tension loaded 3 piece race style system plus the muffler. The OEM muffler slider bracket allows fwd & aft movement even a little up & down to keep pivot pressure on the muffler down when the engine moves & vibrates. If you hard mount the muffler any pressure on the mid pipe with engine lift and fall will pass stress and possibly vibration onto the hard mount and into the bike frame. I think your current rubber mount may be fine with the swingarm pivot bracket you are thinking about making for the collector. (y) :geek:
I will eventually go about building the mount and find out. The main issue is being restrained to the oem location with a hard mount the collector and head pipes get into a small vertical oscillation at the head pipe area.. With my previous rubber mount this was amplified as the the muffler and collector moved in a vertical vibe also. Less likely to do this if restrained at the back of engine ( swing arm shaft) since the engine and exhaust will be moving at the same rates. The system is very light and should follow the engine.
Ron
 
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