Vibration

[mack]

Had a good ride yesterday. My brother and I had both bikes out for a 230 mile tour. A couple spots we had a chance to open them up a bit. We both experienced vibration starting around 5K RPM. Not white knuckle time or anything but definately noticeable.
I don't think it's motor mount related and both engines are smooth a silk other wise.
Plugs are perfect. No stumble at all throughout the tach range on either. Cam witness markers are dead on.
Both sets of ignition coils gave all the proper readings.
Both bikes have new plugs and caps.
I have 404's on the SF and Battle axes' on the LH.
New front and rear wheel bearings on both.
However I've had to retorque the exhaust headers a couple times after a ride on both bikes. Was wondering if anyone has had a similar issue and was able to solve it by putting in a second set of header /exhaust washers.

[James England]

They just do that. If it's not white knuckle bad, then it's not too bad. I use spring washers on the header studs.

Is your exhaust system isolated correctly from the frame by use of rubber bushes? Or is any part of the exhaust system attached directly to the frame/mounts without any isolation?

[mack]

Mounting

Hi James, Happy Fathers day by the way.
The only contact with the frame is at the foot rests and yes the bushings were installed. The only other contact point is at the header/ exhaust flange. Was thinking the nuts bottom out before the flange is fully seated. Thought another gasket could cure it.
What ever it is, both bikes have it, so it must be something I've done; or, didn't do.
I have some family stuff today as I'm sure we all do, but I'll try to fire them up today and just hold the rpm at 5-6 k in neutral (outside) and see if it is still there. May even do a hot compression test.

[skids]

Maybe an exhaust leak under the heat shield? Specials are known for that, but it would probably cause popping on decel. The thing to determine is whether the vibration is an rpm thing or a speed thing. If it is a speed thing, there might be a tire balance issue.

[WMarshy]

Hi James, Happy Fathers day by the way.
The only contact with the frame is at the foot rests and yes the bushings were installed. The only other contact point is at the header/ exhaust flange. Was thinking the nuts bottom out before the flange is fully seated. Thought another gasket could cure it.
What ever it is, both bikes have it, so it must be something I've done; or, didn't do.
I have some family stuff today as I'm sure we all do, but I'll try to fire them up today and just hold the rpm at 5-6 k in neutral (outside) and see if it is still there. May even do a hot compression test.

I would caution against reving them up in neutral fior any length of time. IIRC the manual says not to rev over 3k in neutral... I think what you both are experiencing is just some vibration from the exhaust. I think all of these bikes have a buzz in the foot pegs and even in the bars between 4-5k rpm, its just their nature... I wouldnt get to concerned unless its more than just a buzz in that range... just my 0.02$

[James England]

Yes, definitely a buzz is usual in the 4-5 thousand band. My wonderful XS1100 caused my middle finger on my right hand to go white! Weird! And, everything about that bike was perfectly maintained and balanced etc.

Like I say, if it's not white knuckle stuff, then I really wouldn't bother.

Do your headers have the metal collars that tighten the flange onto the head? Your nuts shouldn't really bottom out when tightening

[motoman]

Might wanna pull back the front portion of rubber boot and check U-joint for hoizontal and end play...........JAT........BTW, if all is correct on these bikes there is no buzzy vibration at any particular rpm.

[mack]

Found it (hopefully)

I think I found my problem. The upper front right motor mount had a deteriorated bushing so it was metal on metal. Looked ok from a distance but once I got a good look with lighted scope it obvious. I have a spare set I got from Andreas last year so I'm going to pop them in tomorrow and see for sure. I'll get back to all with the result. I was looking through the repair forum and found one on bushings, they're not rubber. Has anyone tried this, if so how did it work for you?

[mack]

Motor mount

Just to follow up on the vibration. It was the dampener on the front upper that was the problem. Switched the uppers out yesterday and all is well now.

[GLoweVA]

This Thread got me thinking about why my right hand goes numb after about 30 mins of riding.
I'm gonna check out my mounts and see what's going on.
I just looked at that modification tech tip on the aftermarket poly bushings and for $2.50 each, for a total of 6, that's only $15 and only $5 for shipping.
I think I'll order some and see about replacing them anyway.
With almost 100K on my bike and as many oil leaks I've had over the years, I'm sure my 30year old rubber bushings are probably shot anyway.

I'll try to snap some pics of the swap so Steve can add it to the tech tip.

[rombat]

One other possibility for vibration is a carb sync setting. My XJ was running fine but my fingers would get numb after 20-30 mins. After a regular maintenance carb sync, it was off just a bit between 1-2 and 3-4, the vibration was gone.

[bikerphil]

I just looked at that modification tech tip on the aftermarket poly bushings

George, do you have a link to the bushing source? Something I may be interested in doing.

[GLoweVA]

Phil, Here it is: http://www.suspension.com/4-bar.htm
I just got off the phone with them, seems really nice and with the $5 USPS if it fits it ships box, can't beat it.
I ordered 6 #2008 that Steve posted about in the tech thread.
Should be here hopefully by Sat.

BTW, they only come in black, which is perfectly fine with me.

[bikerphil]

Thanks George.

[YamaRule]

Wheel weights!!!

I melted some wheel weights and poured the liquid lead into my handlebars. solid lead core from one end to the other and worked great. I poured a little to create a cap on the bottom end. Once it solidified I put the handle bars in a bucket of cold water to prevent discoloration while pouring the rest!