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Posted by tj
- June 03, 2021, 11:23:20 AMJust a thought...rear suspension setting.
Maybe it's worth a look and adjustment.
My rear shocks are set at 13lbs with the dampener at 3. (I'm 225lbs)
Posted by tj
- June 03, 2021, 10:18:12 AMQuote from: gwilki on June 03, 2021, 09:07:46 AMSounds like the weight is within reason on both wheels (assuming it is in the correct area).I apologize JT for my bad math skills. The rear wheel has 1.375oz/39grams on it, not 2.375oz.
Even if your runout both axi and rad on both wheels is within spec, I think it is still worth looking into...mismatched tires (front to rear) and the rear tire not being a "match" for the bike. Too far off what is suggested by the tire manufacturer and the FSM.
Posted by gwilki
- June 03, 2021, 09:50:18 AMTks, Troll. I'll add that to my list of possible causes. The list is getting much longer than I had anticipated. It will keep me off the streets. 
Posted by Troll
- June 03, 2021, 09:33:00 AMHad a thought this morning about your issue. Seeing the age and the amount of time it's sat idle, I might think about a stiff u-joint causing the problem. http://www.vulcangadgets.com/files/ujoint.html
Posted by gwilki
- June 03, 2021, 09:07:46 AMI apologize JT for my bad math skills. The rear wheel has 1.375oz/39grams on it, not 2.375oz.
Posted by tj
- June 03, 2021, 07:10:11 AMQuote from: gwilki on June 02, 2021, 19:57:22 PMA few things come to mind...After a ride today, I started to think that maybe the issue is coming from the rear tire/wheel. TJ described my issue as like horse bucking. That's a better description that a handlebar vibration.
Since my last post, I've found the following:
The front tire is a Shinko SR777 bias ply. The front wheel has 1/2 oz of weight on it.
I have yet to measure the run out on the front wheel.The rear tire is a Dunlop Cruise Max bias ply. The rear wheel has 2 3/8 oz of weight on it. The rear wheel is out by about .030" axial, well within the spec. This measurement is with the wheel on the bike. I have yet to measure the radial. I will likely need to remove the wheel to get a radial run out measurement.
One thing that I am going to take up with Dunlop is that they say that the Cruise Max is not a match for my bike. The size is right, so I want to find out why they say that.
Having almost 70 grams of weight on the rear wheel IMHO is a lot of weight. If the "balance dot" is opposite the valve stem and the wheel weights are 180 away from the stem (assuming the weights are in the same spot)...then there is not much else you can do about it.
Your tires being mismatched (front to rear) will not help the situation. Some say you can mismatch tires with no ill effects. IIRC a few Ducatis came from the factory with mismatched tires...I don't think it's a good idea here and it may be compounding your issues.
If the manufacturer doesn't list the cruisemax as a match for the bike...construction and behavior may be different enough to not be a "match" (belted bias ply vs bias ply etc).
Too many things are not quite right with that rear tire...
Posted by gwilki
- June 02, 2021, 19:57:22 PMAfter a ride today, I started to think that maybe the issue is coming from the rear tire/wheel. TJ described my issue as like horse bucking. That's a better description that a handlebar vibration.
Since my last post, I've found the following:
The front tire is a Shinko SR777 bias ply. The front wheel has 1/2 oz of weight on it.
I have yet to measure the run out on the front wheel.
The rear tire is a Dunlop Cruise Max bias ply. The rear wheel has 2 3/8 oz of weight on it. The rear wheel is out by about .030" axial, well within the spec. This measurement is with the wheel on the bike. I have yet to measure the radial. I will likely need to remove the wheel to get a radial run out measurement.
One thing that I am going to take up with Dunlop is that they say that the Cruise Max is not a match for my bike. The size is right, so I want to find out why they say that.
Posted by gwilki
- June 01, 2021, 15:40:39 PMTires are Shinko. I have dial gauges so I can check the run out. I have a large wood turning lathe that I can mount the wheels on and check them that way.
I'll check how much weight is on each wheel and report back.
Tks, TJ
Posted by tj
- June 01, 2021, 14:27:12 PMQuote from: gwilki on June 01, 2021, 14:05:57 PM26-65 INCH/lbs from FSM.Do you bother to torque them? I'm assuming that, since you use an open end wrench, that you do not.
Posted by tj
- June 01, 2021, 14:24:08 PMQuote from: gwilki on June 01, 2021, 11:51:34 AMI would start here.All advice is welcome.
Check both wheels for runout.
From the FSM - With tires installed, service limits are 2mm axial (side to side) and 1.5mm radial (up and down). Standard is 0.8mm both axial and radial.
Check how much weight is on the wheel.
There is a note in the FSM. More than 90grams should not be used...I think that's about 3oz. Whenever I balance a tire (static), I start to get concerned around 2oz...especially if it's on the front.
What kind of tire is it?
I've had bad luck with the Michelin commanders. My issues showed up at 60-80km/h. I would have sworn the front wheel was the problem. Turns out the rear was out of round...sometimes you just can't tell.
Posted by gwilki
- June 01, 2021, 14:05:57 PMDo you bother to torque them? I'm assuming that, since you use an open end wrench, that you do not.
Posted by Tim
- June 01, 2021, 13:57:53 PM1/4" wrench works well to tighten the spokes. 
Posted by gwilki
- June 01, 2021, 13:26:54 PMKaw Canada mentioned the same thing, Tim. I'm going to at least do the ping test later today. Thank you.
Posted by Tim
- June 01, 2021, 12:44:50 PMI just got new tires and was riding yesterday when I got a flat rear. Took it home and it turns out I hit a nail and the tube is bad. While I was looking at everything on the stand I checked the spokes too - many lose ones! I used to do the sound test (tap each one with a wrench and if it made a ping it was good) but far better to tighten each one to know for sure.
I wonder if your spokes are loose.
Posted by gwilki
- June 01, 2021, 11:51:34 AMTks for that, Mittico. All advice is welcome.