[SvtBullet]

My first post here so please bear with me,

I recently picked up a 2011 b5 here in Ca. Mostly been riding v twins with a wide tire on the rear. So on my commute I hit about 5 miles  of the concrete rain grooves on the freeway. The first time I almost shit my pants and slowed down to 55 in the slow lane. I'm currently running the dunlop k70s F/R. Is there anything I can do to reduce the wobble?

Any recommendations on tires?

[Blairio]

Is this about the speed you were travelling at, or the surface you were travelling on?

In other words, does the bike wobble at speed on any surface, or just the rutted concrete of the freeway?

Also, what pressure are you running your tyres at?

[SvtBullet]

It was wobbling at 75 as well at 55. It was a bit less at 55. I'm currently running 27f/29r. Only noticed it on the rutted concrete freeway. Otherwise it rides just fine.

[Blairio]

Normally I would start with the basics. Is everything tight - swing arm, steering head bearings, axles? However, if the bike is fine on any other surface it could be some weird interaction between the concrete and the tyre. I guess it would be worth experimenting with different tyre pressures. That wouldn't cost anything.

 We don't have much concrete 'topping' on our roads here in the UK, it is mostly asphalt. However, when the asphalt is stripped off to be replaced, the concrete underneath is revealed, and it is horrible to ride on.

[suitcasejefferson]

Those ribbed front tires are a nightmare on rain grooves, but they sure look good. Switching to a different front tire will help. I have noticed a wobble on a few different bikes, and always discovered the tires were underinflated. It is safe to inflate the tires to the pressure molded into the sidewall, even though this is often referred to as "max" pressure. There is a wide safety margin built in. If you are looking for comfort, you need something besides an Enfield.

[Richard230]

In 1972 I swore off the K70 when California started grinding rain grooves into their pavement. The grooves caused my Triumph Bonneville's Dunflop K70 tires to feel like they were going in three different directions at once while riding over them. However, it didn't take long for other tire manufacturers to design different tire treads that would handle rain grooves much better.  Since then CA no longer seems to use the original deep rain groove design and is using either a brush finish on concrete pavement or a rougher surface on asphalt pavement. That has resulted in little movement from my Avon Speedmaster II tires. You might need to change your tires to a more modern tread design to banish the rain groove shimmy, although you could try altering the tire pressure a bit and see if that helps. (But I don't think it will.) Perhaps the installation of a universal steering damper might help, too. 

[Bulletman]

Oh Boy!!! The wobble story surfaces again.
I have a C5 and had nightmares riding the CAlifornia grooved roads.. so I just left the state of California ... just kidding.. I was using the Dunlop BattleAx tires at many different tire pressures, never could really stop the wobble completely..I was very carefull when I rode on the grooved roads..just recently about 2 weeks ago I changed my front rim to a 19” from the original 18” and it made a huge difference, the handling Has drastically changed as well, I’m also using the K70’s front and rear as well 3.5 front 4 rear.
Only one time a few days ago did I feel the wobble , I was doing 88 MPH .... YES !! 88 MPH on my C5 2011.... Thank you GHG and the freeway road to San Jose was grooved when I felt a slight wobble where I promptly slowed down and switched lanes.. since then I’ve not had any issues. Hope this helps.

[Arizoni]

SvtBullet

As others have mentioned, you can try reducing the tire pressures.

I know it sounds weird but RE suggests in the Bullet Owners Manual that riders riding single use a front tire pressure of 18 psi.  (Yes, I typed eighteen psi). 
They also say the rear tire pressure for riding single should be 28 psi.

(For riding two-up they recommend 20 psi front, 30 psi rear.)

I don't know if the lower tire pressures will keep the tire from trying to follow those terrible rain grooves but it might.

I do know, I just got my front tire replaced with a Dunlop K70 and the guy who mounted it for me inflated it to 35 psi.

The first time I rode the bike after getting the front tire back in place my RE seemed to want to twitch sideways every time I turned a corner.  The whole bike felt unstable.

When I dropped my front tire pressure back to 24 psi, everything returned to normal.
While the 24 psi worked for me, remember, I live in Phoenix and we don't have those damn deep rain grooves cut into our streets and freeways.
Since you do have them, give the lower 18 psi pressure a try.  It might fix the problem and if it doesn't, a three minute stop to increase the pressure to something a bit higher is cheap.

PS:  Back in the 1950's, recommended tire pressures on many of the mid sized British motorcycles like the Royal Enfield Bullets were often down in the 17-19 psi range.
The tubed tires can be quite happy at those low pressures.

[SvtBullet]

Yeah I've been doing some research and lowering the front to 22 to 25 psi is recommended. As far as the wobble goes, its recommended to just clench your butthole and loosen your grip on handlebars and ride them out. It's only a part of my commute and I vary which bike to ride so it should work out. I'm thinking about trying the shinko 705s after I wear through the k70s.

[wildbill]

a few years back when I had my b5 I thought it was a far better bike to ride than a c5 and I had no troubles what-so-ever.
well apart from one puncture.
back on a c5 I put a set of k70's to try the old style period look. the first thing I noticed it sat a tad higher and the ride didn't appear anywhere near as stable.
I bet your problem is tyre related and i'd be very surprised if you had a wobbly b5

[gashousegorilla]

   What Arizoni said... ^^^

   These ain't "modern" bikes .  They don't weigh as much for the the most part , and the frames are not as stiff.  They call for tire pressures like you would find on old bikes.   If put modern tires on these bike with low profile sidewalls .. AND .. jack the pressure up to in the front.  You will have little contact patch in the front and your front end will fell lite.   At high speeds and depending on your own weight and body size... the bike will weave.  VERY unnerving to say the least ! 
 With the Dunlop K70's ... even with skinny 3.25 front and 3.5 rears.  I run 18 psi front and 26-28 psi rear.     And the bike is rock solid into the 90's MPH.     If the pressure is raised ? ... stability goes out the window at high speeds .    Same goes for the Avon Road riders on these bikes BTW.    I have been running these pressures for  8 or 9 years now .  Any problems ?  Nope.

 

Oh Boy!!! The wobble story surfaces again.
I have a C5 and had nightmares riding the CAlifornia grooved roads.. so I just left the state of California ... just kidding.. I was using the Dunlop BattleAx tires at many different tire pressures, never could really stop the wobble completely..I was very carefull when I rode on the grooved roads..just recently about 2 weeks ago I changed my front rim to a 19” from the original 18” and it made a huge difference, the handling Has drastically changed as well, I’m also using the K70’s front and rear as well 3.5 front 4 rear.
Only one time a few days ago did I feel the wobble , I was doing 88 MPH .... YES !! 88 MPH on my C5 2011.... Thank you GHG and the freeway road to San Jose was grooved when I felt a slight wobble where I promptly slowed down and switched lanes.. since then I’ve not had any issues. Hope this helps.

  Hell... that's just basically a stock bike with a bit of tuning brother.  Wait till we get busy this winter   .   

[axman88]

High speed wobble has been discussed in a few threads, but this thread, although old, is appropriately titled.

As a rider of a more limited machines, I'll don't expect to ever experience this first hand, but here's a short video illustrating the phenomenon:
https://youtu.be/mzx21j3dnKs

[GlennF]

The original Z1 900 Kawasaki's back in the 70s were notorious for it if you fitted the wrong sort of tires or your tires were worn or incorrectly inflated.

What is interesting here is its a B5 whereas most wobble complaints on UCE bikes were from C5 owners not B5.

[axman88]

The bike in the video I posted a link to was a Yamaha R6.

The OP was saying a B5, but with K70s plus on rain grooves.  The only thing wobblier than rain grooves in my experience is trying to ride across a bridge with steel grate surfaces on a windy day.  I keep an adult diaper in my saddlebag just for situations like that.

[Carlsberg Wordsworth]

So here's a question then without wanting to hijack too much. What speeds are people adjusting too when cornering etc when running the low(er) pressures?

Whilst we might not be talking knee/peg down speed, is it just a more sure footed pleasant constant speed?

[majstevetrevor]

Seems to me it is the bias ply.