faffi Posted April 5, 2018 Share Posted April 5, 2018 Air gap will not have any measurable impact on ride until forks are compressed quite a bit, but oil viscosity has a real impact at all times. Link to comment Share on other sites More sharing options...
shinyribs Posted April 5, 2018 Author Share Posted April 5, 2018 6 hours ago, faffi said: Air gap will not have any measurable impact on ride until forks are compressed quite a bit, but oil viscosity has a real impact at all times. That's kinda where my head is at. I'm happy with the action of the fork now, so maybe I better leave the viscosity alone. I've slammed some pretty hard pot holes and still have 1" of unused travel, so maybe air gap is the answer. Link to comment Share on other sites More sharing options...
faffi Posted April 5, 2018 Share Posted April 5, 2018 I test the spring/air gap by doing an emergency stop - with ABS you can go to the absolute limit - over a ripply or bumpy surface. I want about 1/4 of an inch of travel left for huge bumps during a hard stop. Link to comment Share on other sites More sharing options...
Beemer Posted April 5, 2018 Share Posted April 5, 2018 Mystery solved, good job, shinyribs! Beemer Link to comment Share on other sites More sharing options...
rick Posted April 5, 2018 Share Posted April 5, 2018 1 hour ago, shinyribs said: That's kinda where my head is at. I'm happy with the action of the fork now, so maybe I better leave the viscosity alone. I've slammed some pretty hard pot holes and still have 1" of unused travel, so maybe air gap is the answer. Better to have a theoretical inch left over than to bottom hard - that's when tires get flatted and wheels destroyed. Still trying to get my head around why having the back pointed a bit askew caused your bars to move about. I could sure live w/o knowing if it was mine and that fixed it. 😉 Kinda wonder if you were unconsciously compensating (with a bit of body movement) for the bike wanting to track off a straight line. Link to comment Share on other sites More sharing options...
shinyribs Posted May 4, 2018 Author Share Posted May 4, 2018 On 4/5/2018 at 9:27 AM, Beemer said: Mystery solved, good job, shinyribs! False alarm! I thought the wobble was fixed, but a few days later I noticed it again. It was funny how it would come and go, but over the past couple weeks it became more persistent. I've been putting off posting here until I truly had a solid solution, and now I think I do. I've been over the forks, stem bearings, wheel alignment,etc over and over...just can't find anything wrong. I was staring at the bike up on the lift, scratching my head over it all, when the tread pattern of the Conti Motion caught my eye. I don't know how to explain it in text, but the tread has a very slight overlap directly at the centerline of the tire. I had a suspicion that it could cause the tire to wander/flutter around. I called a buddy who I knew had recently put a pair of Conti Motions on his VFR and told him what was going on. He said his bike recently started doing the exact same thing ( after owning it for 60k miles) and he had been inspecting his bike for an issue, too. Of course, he found nothing wrong with his bike either. I think we're on the hunt now. I just spooned on a new rear tire after wearing out my rear Conti Motion in just under 2k miles, and it's looking like the front tire will only ake to to about 3k max. I'm gonna pick up front tire soon and see if that's my issue. If I can positively prove this tire is making my bars wobble I am going to contact Continental about it, and the extremely fast tire wear, and see what they have to say about it. I googled "Conti Motion front tire handlebar shaking" and actually got several hits, some as much as 4 years old. This apparently is an ongoing issue. Link to comment Share on other sites More sharing options...
rick Posted May 4, 2018 Share Posted May 4, 2018 A front tire on its way to its end can cause this. Some tires seem to be more of a problem than others as well as some bikes being more sensitive to it. But this is one of the reasons why track schools want you to show up with new rubber. Between potholes and braking forces, front tires take a beating. Cords get fatigued, if not damaged. When this happens, the result is poor handling. These loose ball stem bearings found on bikes today are sorta hard to diagnose by feel (assuming there's no race damage and they are not loose to the point of clunking). It might not hurt to loosen up the top clamps and go thru the manual's procedure for setting that stem bearing's torque. Might not hurt to pull the wheel and allow the them to drop down enough to get some new grease on both bearings while yer at it - especially if the bike has seen a lot of rain. Link to comment Share on other sites More sharing options...
shinyribs Posted May 4, 2018 Author Share Posted May 4, 2018 I did service the stem bearings, actually. Initial inspection showed no problems, but I was overly cautious with the wobble issue I was having. I didn't like the look of the factory grease, so that all got flushed out and repacked with my favorite flavor. No signs of brindling in the races like you mentioned before. I checked the forks for straightness, checked the rims were running true, verified there were no warped rotors... anything I could think of. No issues anywhere. The fact that my buddies VFR suddenly picked up the same wobbly bars when he put Conti Motions on ( his are brand new), coupled with several reports of the same thing online, tells me this is a legit issue with these particular tires. And I'll not sure mileage has much to with it, although it does feel apparent to me that it gets worse with mileage. I might be wrong, but I think it's simply a issue of a bad tread design. I'll try to get a picture of what I'm seeing this evening. I think the tire is "hunting" down the road due to how the tread overlaps. Link to comment Share on other sites More sharing options...
Premium Member norcal616 Posted May 4, 2018 Premium Member Share Posted May 4, 2018 Would be nice to "rotate" the tires like we do with automobiles... unless the motorcycle tire is non-directional... I noticed on all my tires the clutch side wears a tad more than the other side... mainly due to road surface lvl...center of road is higher than outside edge to help drain water... 2015 fz-07- Hordpower Edition...2015 fj-09- 120whp- Graves Exhaust w/Woolich Race Kit- tuned by 2WDW Link to comment Share on other sites More sharing options...
rick Posted May 4, 2018 Share Posted May 4, 2018 1 hour ago, shinyribs said: I might be wrong, but I think it's simply a issue of a bad tread design. I'll try to get a picture of what I'm seeing this evening. I think the tire is "hunting" down the road due to how the tread overlaps. Back when front tires had grooves that ran around the circumference of the tire, those rain grooves would cause the front to follow imperfections in the road surface - rain grooves cut in concrete caused motorcycles will stitch all over the place. The absolute worst was crossing a metal grate bridge. Talk about deodorant failure! Even one tread groove down the center of the tire can cause this. The old Continental RB2 comes to mind https://www.revzilla.com/motorcycle/continental-rb2k112-classic-tires Most modern radials aren't treaded like this anymore - though the problem still can happen a bit - metal grate bridges are still no fun, but it's no where near as bad. It could very well be the tread pattern. Throw in some uneven wear from road camber and maybe even some internal damage that you cannot see - well, a new tire & brand will be well worth spending money on. Link to comment Share on other sites More sharing options...
shinyribs Posted May 4, 2018 Author Share Posted May 4, 2018 Yeah, I had a front Shinko Raven at one point that had the continuous center rib like to described. That the was constantly hunting. But I also had a Avon Speed master that was a completely ribbed tire and it was rock solid. Two totally different chassis, though. I've been been across a grated bridge. None of this in my area, but they sound absolutely awful. Link to comment Share on other sites More sharing options...
rick Posted May 4, 2018 Share Posted May 4, 2018 Worst one of those open grate bridges I've ever been across was somewhere in the CatsKills, back in '81 on the R90/6 in my avatar.. It was raining, so the steel was even more slick than usual and worse yet, the bridge was arched. We crossed it one bike at a time. Dang, that was just no fun. Falling on a surface like that would be like falling on a cheese grater. Link to comment Share on other sites More sharing options...
shinyribs Posted May 4, 2018 Author Share Posted May 4, 2018 My post above was supposed to say I've never across a grated bridge.Reading your post just now physically made me cringe. Bleh Link to comment Share on other sites More sharing options...
rick Posted May 4, 2018 Share Posted May 4, 2018 There's definitely a speed limit on these surfaces - and it's pretty slow. With the bike darting all over the place, ya have to try and relax and not fight it. this is pretty typical - yer mostly riding on air, but every diagonal joint causes the tires to hunt and peck. And don't look down if yer afraid of heights, lol. Link to comment Share on other sites More sharing options...
r1limited Posted May 4, 2018 Share Posted May 4, 2018 8 minutes ago, rick said: There's definitely a speed limit on these surfaces - and it's pretty slow. With the bike darting all over the place, ya have to try and relax and not fight it. this is pretty typical - yer mostly riding on air, but every diagonal joint causes the tires to hunt and peck. And don't look down if yer afraid of heights, lol. And the problem going over that is? OK I get wet and or icy cold, but treat like riding in sand, be like spagetti and da gas constent “Laws that forbid the carrying of arms disarm only those who are neither inclined nor determined to commit crimes.” --Thomas Jefferson quoting Cesare Beccaria Link to comment Share on other sites More sharing options...
Premium Member norcal616 Posted May 4, 2018 Premium Member Share Posted May 4, 2018 also roads that get "stripped" by them big ole glorified sod cutters leaves behind that fine comb looking grooves... 2015 fz-07- Hordpower Edition...2015 fj-09- 120whp- Graves Exhaust w/Woolich Race Kit- tuned by 2WDW Link to comment Share on other sites More sharing options...
shinyribs Posted May 4, 2018 Author Share Posted May 4, 2018 Wobble is 100% confirmed dead now. Put a Pilot Power 3 up front and she's solid as a rock again. So solid, in fact, that the groundhog that I just ran over while I had my hands in my lap while doing 65 mph didn't even veer the bike off course. Good job, Yamaha! People probably think I make this stuff up... A couple days ago I put on a new Shinko 009 rear. Like mentioned before, I hate the front 009, but I do like the rear. Very stable, smooth rolling tire. Slow to warm up, so I run it a couple lbs lower than normal. Seems to work well. Curious to see the mileage I'll get out of these. Looking at my records the Conti Motion rear had a little over 4/32's tread depth when new. The 009 has 9/32! That's a lotta rubber to work with. I'm glad to see these tires pair together well with their profiles. Very stable while cornering and changes directions easily and predictably. To early to say much about aggressive riding, but I did drag a peg on accident, so they're definitely adequate. Here's hoping they last... Good riddance, Conti Motions. Link to comment Share on other sites More sharing options...
r1limited Posted May 4, 2018 Share Posted May 4, 2018 5 minutes ago, shinyribs said: Conti Motions. Bar Wobble Conti Motions. Bar Wobble Conti Motions. Bar Wobble Conti Motions. Bar Wobble Conti Motions. Just saying “Laws that forbid the carrying of arms disarm only those who are neither inclined nor determined to commit crimes.” --Thomas Jefferson quoting Cesare Beccaria Link to comment Share on other sites More sharing options...
shinyribs Posted May 4, 2018 Author Share Posted May 4, 2018 Well said! So far 3 out of 4 guys running these tires have bar wobble. One guy on a Ducati SBK says his bike is solid, but that bike runs a stabilizer. Trying to get him to disconnect it and see what happens. Link to comment Share on other sites More sharing options...
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