What controls swingarm alignment?
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From: Northwest
I understand the oil thing.. I'm not sure abd out the "shear" versus "compression" thing. Compression says to me that the mount is compressing something.. As far as I can tell the VibraTech mount operates in shear just like the stock mount except that the device is round and not flat..
Does sound like you mount went bad if the motor started to sag significantly.. Did the rubber actually tear? The 6 speed bikes do seem a bit heavier than the 5 speeds.. I could see where they would eat mounts especially with a heavy exhaust system. I replace mounts on my 00 DX but the new mounts made no difference.. This is sort of getting a little OT here.. The OP's question was about alignment.
Does sound like you mount went bad if the motor started to sag significantly.. Did the rubber actually tear? The 6 speed bikes do seem a bit heavier than the 5 speeds.. I could see where they would eat mounts especially with a heavy exhaust system. I replace mounts on my 00 DX but the new mounts made no difference.. This is sort of getting a little OT here.. The OP's question was about alignment.
The stock mount has two metal mounts. One mounts to the frame, the other mounts to the engine. Fuzed between these pieces of metal is the rubber. The way it is designed, the metal plates mounted to the engine, are trying to push past(down, gravity) the single metal slug mounted to the frame. The mount is feeling a 'shear' force.
The Predator also has two metal mount assemblies, one to the frame and one to the engine, but the engine mount sits on top of the frame mount, with the rubber sandwiched in between... it is being 'compressed'.
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Extreme HDF Member
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From: NW Ohio
I think I'm sold on that! It does the job and looks clean. I can always notch the frame crossmember to allow a few degrees of adjustment if required. I strongly suspect the rear mount is far less important with regard to drivetrain alignment stability.
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From: poway
Maybe a little OT... but the front mount affects alignment and handling to a large degree.
The stock mount has two metal mounts. One mounts to the frame, the other mounts to the engine. Fuzed between these pieces of metal is the rubber. The way it is designed, the metal plates mounted to the engine, are trying to push past(down, gravity) the single metal slug mounted to the frame. The mount is feeling a 'shear' force.
The Predator also has two metal mount assemblies, one to the frame and one to the engine, but the engine mount sits on top of the frame mount, with the rubber sandwiched in between... it is being 'compressed'.
The stock mount has two metal mounts. One mounts to the frame, the other mounts to the engine. Fuzed between these pieces of metal is the rubber. The way it is designed, the metal plates mounted to the engine, are trying to push past(down, gravity) the single metal slug mounted to the frame. The mount is feeling a 'shear' force.
The Predator also has two metal mount assemblies, one to the frame and one to the engine, but the engine mount sits on top of the frame mount, with the rubber sandwiched in between... it is being 'compressed'.
Here is a pic of the vt rubber mount.. Notice that there is a bit of taper to the od and the ID spacer has the same thing but there really isn't a place where the rubber is directly compressed.. I don't see how it's any different than the stock mount which has a similar tapered shape to it.. Also when you tighten the center bolt the inner spacer does not compress anything..
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From: NW Ohio
Bwoltz, you seem to be pretty experienced in the arena. Are you saying the Vibra-Technics is inferior in some way? Do you have any suggestions for a good drivetrain mounting system? I don't mind sacrificing some isolation for good rear tire control.
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From: poway
Not saying that the VT stuff is inferior. But IMO it's not as much different than the stock mounts as some would think.. The link is good.. I do think adding a link to the front is beneficial whether you use VT or Sputhe, TrueTrack or whatever.. The back link is likely not as important as the front unless you carry a lot of weight in the back like saddle bags.. I have a 2000 FXDX and have tried both Sputhe with stock motor mount and VT. The 2000 FXDX I have is a high compression 116 that makes 125/128. It has had handling issues in the past but right now it's rock solid.. I'm currently using the Sputhe front. Rear didn't make much difference. I've read where others have had good luck with the above mounts so I would definitely give one of them a try. If you don't have vibration issues, I'd lean towards links front and back and see if they help.
Looks like your bike is a 99 WG.. If you want to get that bike handing better, you will also want to look at wheels. Stock spoked wheels with steel rims flex. You can replace the stock rims with aluminum, loose some weight and pick up stiffness. I'd add better shocks front and rear..
Tires will also make a big difference in handling.. HD/dunlop 402s are not the best tires for cornering..
Looks like your bike is a 99 WG.. If you want to get that bike handing better, you will also want to look at wheels. Stock spoked wheels with steel rims flex. You can replace the stock rims with aluminum, loose some weight and pick up stiffness. I'd add better shocks front and rear..
Tires will also make a big difference in handling.. HD/dunlop 402s are not the best tires for cornering..
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From: NW Ohio
Thanks. That's my plan. The rear is currently a 180/65-16 mounted on a 40 spoke aluminum Excel rim with stainless spokes and nipples from Buchanans. Torqued to 80-ish in-lbs with both runout measurements under .015 TIR.
When I get there, the front will be similar but with a 150-ish tire. Shocks are also on the list. Works or Ohlins. Something tunable and rebuildable.
When I get there, the front will be similar but with a 150-ish tire. Shocks are also on the list. Works or Ohlins. Something tunable and rebuildable.
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From: poway
Sounds a little like what I did except that I went with a 180/55-18 rear.. Front is 110/80-19 on a 2.5 inch rim.. Rims are aluminum RevTech with Buchanan spokes.. Use Bridgestone Exedra G850 on the rear and T30 on the front.. Tires are nice and sticky but rears only last about 2500 miles..
Elite HDF Member
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From: Northwest
Couple pics of the broken down front mount. Perhaps this shows the 'shear' that I am speaking of.
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Seasoned HDF Member
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From: poway
I understand what you are saying bit the discussion was centered around how the VT mount worked. The VT is still functions in shear.. Now which lasts longer is certainly up for discussion.. The later 06 up Dyna frames seem to be eating motor mounts.. Not sure if it's alignment or added mass to the drive train.. Exhaust weight and mounting would be a factor.
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From: Northwest
I still say the VT is in compression... but we'll agree to disagree 
Part of the issue with the stock front mount might be the stroker engine, sets up different harmonics/vibrations due to different mass/stroke length. I know trying to keep oil off the damn thing when changing filters is pretty near impossible.. and rubber/oil do not like each other.
Part of the issue with the stock front mount might be the stroker engine, sets up different harmonics/vibrations due to different mass/stroke length. I know trying to keep oil off the damn thing when changing filters is pretty near impossible.. and rubber/oil do not like each other.