That does help hdgzr, thanks a lot. I'll have to reevaluate whether to keep the shims or try this solution.

 

I own a sweet 2006 streetbob and the front rubber motor mount was "blown out", and was resulting in an annyoying "oscillating" vibration at low RPM's that I could REALLY feel through the handle bars and saddle. So tonight I parked the bike upright by shimming the jiffy stand with a 2x4 block of wood, placed a floor jack under the motor casing to take the weight of the motor off the front motor mount, undid the two front allen bolts and DAM... the snubber pulled back (without the motor shifting back whatsoever) resulting in a full 1/4" gap between the snubber and front frame mount!! No wonder the front mount was "blown out"!!

I then removed and replaced the mount with a brand new one, bolting the two bolts to the T-bracket first, still a full 1/4" gap!! I installed enough washers to take up the space and torqued everything down to spec. I fired it up and took it for a spin... WOW, A HUGE DIFFERENCE, and no more annoying "oscillating" vibration. I contend that stretching that snubber forward prematurely "blows out" the mount.

 

Is this the place where there's supposed to be a .040 gap? And I'm assuming you take a file to the rubber to make a gap if there isn't any.

 

From your post it sounds as though you may not understand the symtoms, and the fix for this vibration. You are not trying to create a gap and there is no specification for the gap that appears when the front engine mount bolts are loosened with the engine supported. Certainly no need to file anything either. You are essentially shimming the front motor mount to the frame, so the mount is in a relaxed state when bolted up to the front cross member. The mount becomes (pre) stressed when installing the bolts, stretching the mount rubber...causing excessive vibration and shortening the life of the rubber mount. I would recommend if you do this procedure you just go ahead and replace the front mount anyway. If you currently have excessive vibration the mount is likely fataigued and collapsed already. Doing this procedure with a collapsed mount will not yeild the best results, and may make things worse. It's easy to tell just by looking at the mount to see if it's collapsed. It's collapsed if the tip of the rubber mount is contacting (bottomed out on) the aluminum upper mount bracket.

Check out the two links below, good pictures and information.

http://spotks.blogspot.com/

http://www.*****************/forums/ha...materials.html

Tech23

 

Well I changed mine up yet again. Since I changed to the stock exhaust off a fatbob I lost most all my vibration. Even took out the washers. Runs smooth without the washers, runs smooth with them as well. The pipes that I had were most of the problem. I'm just going to ride like this now until I get some slipons or buy all new exhaust.

 

Does anybody read the TECH literature from HD? There is suppose to be a small gap of .03" (1/32") with the rear wheel off the ground by lifting the frame - NOT BY LIFTING UNDER THE ENGINE OR TRANNY. That is the wrong way to diagnose the mount gap. Also many aftermarket exhaust systems cause vibration. The OEM system was designed with a certain length and weight to reduce vibration. A lighter weight or shorter length exhaust can cause more vibration.

 

I've already performed the motor mount shimming and I understand the theory although I didn't see the amazing improvement some here found. As you read the most recent posts there is a piece of technical advice from Harley that speaks to checking the front motor mount for a certain amount of clearance. The terminology of the advice is a little unclear to me and my picture is trying to get confirmation about how a person checks the mount and obtains the proper clearance (gap, I think the recommended gap is .030 not the .040 I said before).

My picture shows my bike with the tires on the ground. Harley recommends checking the mount with the bike raised by the frame. Would this actually make a difference? Seems to me the motor/frame relationship is the same either way. The process of loosening the rear mounts and running the motor briefly probably requires the rear wheel off the ground but I don't understand why it's necessary simply to check the front motor mount gap.

 

Dale, did you have excessive vibration? If not, than as I stated earlier to someone else who stated the same thing as you, this isn't for you. This isn't something to do "just because". You do it for a specific reason.

 

Correct me if I'm wrong, but I think we're talking about two different vibration symptoms and two different fixes for the problem.

In my instance, and the reason for my original post, was according to the HD Tech, my front isolater had "settled" during break-in...and filing down the top portion of the rubber isolater (or snubber) was the cure to remove the frame to engine mount contact. The front isolater was removed and inspected by both the Tech and the Service Manager while I watched, and it did not appear to be damaged. Thus it was filed down to achieve the desired clearance and reinstalled.

Using washers or shims to remove the gap that exists between the frame and the front of the isolater when the front mounting bolts are loosened is a completely different issue.

Or am I just totally phucked (get's by the "IT" police this way) up?

 

Yes that's the way I see it.
Today I went out and did mine because I felt if the frame is puling the mount forward, in time that pressure could damage the rubber mount. I had about 3/16" gap. As long as the Weather holds out I should get about 150 miles on her tomorrow. My bike has always had a stronger vib around 4200-4800 rpm rest of the time she seems pretty good. I will up date how it went.