[RB]

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Ok I ride all time with my throttle lock on and my hands off the bars and never a problem. I have a newer Dunlop 404F on the front, had it on for 6 mos. now. Tire pressure at 41. Today when I was getting up to spreed at 40MPH accelerating in 3rd gear. I lock it down to button up my shirt and the the damn thing immediately started to shake violently. I mean I thought I was going down luckily I grabbed a hold and it calmed right down. I tried it again while at speed 40MPH and it didn't shake violently but not a smooth as it's been in the past. I haven't changed anything. One day smooth as silk and now it's not.

Any ideas??

Tire lloks perfect, no cupping, etc. the road was smooth no snakes or other issues.

 

[agnogel]

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hi RB by any chance have you chequed the rear tire seen this happen before with low pressure in the rear or have you lost one of the balance weights on the front

 

[chris in va]

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41 seems a little high to me. IIRC more like 36.

Check all the usual stuff like axle bolts, play in the wheel/fork bearings etc.

 

[Hatchetman]

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I would drop your pressure to around 37/38 in front @ 40/41 rear. Double check your suspension pressure. Look for cracks in your front wheel, I hd that happen once years ago & it caused a shimmy. Make sure your front calipers are released.

 

[goldtop]

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The affect of sitting up to button shifted the weight hence the problem did't occur so severely second time when you rightly didn't let go! chances are this is the first time you have done this. do the above but thats the cause of the problem.

 

[83GoldWinger]

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chris in va wrote:

41 seems a little high to me. IIRC more like 36.

.

:waving:41 psi is the correct pressureif the bike isloaded but can be run as low as 32 psi. Pressure for the rear tire is 40-41 psi. This info can be found on the Dunlop site.

What pressure you run is determined by thetire manufacturer and it varies from one brand to the other. I have Avon Venoms front & rear on my '83 Interstateand Avon's recommended pressure is: front-40 psi, rear-44 psi and that is what I keep them at. I have over 10,000 miles on these tires and they show very little wear and the bike handles great.

 

[Riding Oregon]

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I had a similar problem a few years ago. As I hit 35mph the front wheel would shake pretty good until I hit about 40 mph then it went away, especially if the handle bars were not being held firmly. Turns out the tire plys had given away without any external evidence until I was riding in really hot weather and a bubble formed on the tread and it had to be replaced. It took me about 4 years to discover the cause.

 

[RB]

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Interesting..both tires are new but still it could be..I guess.

 

[Riding Oregon]

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Just something to think about.

Both tires having the same problem is unusual so I would eliminate all other sources.

Too bad we can't just try another tire.