650 ride stability - comparison to other bikes

[PGWIN]

This (NH650) is my first street of which i've put about 750 miles on it now.  I do not have a fairing and it is otherwise stock /original.

At speeds about 45 mph and certianly 50 mph to 60 mph, on the smoothest pavement i can find (which there are lots of newly paved good quality roads around here) I notice the bike seems like it has this forward / after bucking thing going on, it's not violent but it is enough that it is readily noticeable and it takes away from what I imagine would be a smoot sailing ride.

So my question is - does this sound unique to my bike or is it common on the NH 650's?  If it is common is this likely just inherent to the suspension design or could this actually be an effect of buffetting?  I know i feel buffeting going on at these speeds but that is more me getting pushed around randomly from the wind turbulence, where as this feels like a fwd / back motion.

Thanks.

[Bumblebee]

What year?

No kind of weird motion is intentionally designed into a suspension or propulsion system. Something is going on that shouldn't. Tires? Clutch slipping or out of adjustment? Forks? Suspension? Engine pulsing or carburetor related? High or low frequency forward/aft vibration?

[PGWIN]

Year -1983

The clutch doesn't slip and the engine is snooth - not pulsing.

Tires have good tread but are upwards of 10 years old.

I also notice a wobble in the bars at above 50 mph (side to side) the amount of movement if I relax the grip is small -perhaps .5 inch but it can be felt.

Perhaps it is related to this?

Things to check that are likely culprits?

[Maxx]

10 year old tires is where I would start. Then check the wheel bearings then the steering bearings.

Those tires can kill you even with plenty of tread.

[niteman]

In my limited knowledge base, I would go with the following.

- As maxx said, new tires. 10 year old rubber is no good. Rubber hardens over time and there could be dry rot that you're not noticing/haven't yet noticed. Start there ASAP.
- I was getting some funky motion at around the same speeds and also on deceleration. New wheel bearings fore and aft, new tires, and checked/tightened steering head bearings fixed it for me.

I believe, as a rule, that you should plan on changing the wheel bearings when you get new tires mounted and balanced. Also check the forks for alignment and air pressure (if that model has air adjust forks) and make sure all is even.
 

[Bumblebee]

10 year old rubber?  IMHO: Get rid of them..like now. They're effectively done even if they have zero miles on them and have never touched the ground.

Tread depth means absolutely exactly zero NOTHING when it comes to the condition of tires. Rubber gets stiff as it ages. There's a good chance you can see cracks in the rubber down between the treads and/or on the sidewalls if you go looking for them. Stiff brittle rubber will do lots of things to handling, ranging from a rougher ride, steering head wobble, generally not sticking to the ground in steep turns or braking, and are high risk for KABOOM faceplant country. They can go from no cracks and good looking to near failure in just a few miles. Some of the worst tires I've seen were zero mile older spare tires that don't make 10 miles before exploding.

Old tires may not be all the problem however they're likely a contributing factor to the front end wobble and likely the oscillations. When you change the tires, have them balanced and checked for true and round and if it has spokes, all are tightened properly.

[fishmeister]

Yessiree cowboy, this is where to start.....and could very well be your only wobbly problem.

                            That pony definitely needs new shoes.     

[PGWIN]

Ok, tires it is - it was on my list just at the top now. I'll go from there. Heading to the tire page now.

What is the rule of thumb for tire age on motorycles?  I thought I'd read motorcycle tires were good for upwards of 10 years (general rule of thumb - dependand on storage and use conditions).  RV tires tend to be about 6 yrs, tractor tires well more than 10 (granted tractor tires and rv tires may not be in the same risk category when a failure occurs).  But i alos know the tire life (degradation factor) is dependant on the stabilizers that may or may not be compounded into the rubber.

[Maxx]

4 Years is about all I personally trust.
I do have my moments 

[fishmeister]

Order them from here: http://www.americanmototire.com/catalog/

Buy only the sizes your bike calls for. Have them mounted and balanced.

Then ride safely and assured you have not made any mistakes that would threaten your life.

[Bumblebee]

Ok, tires it is - it was on my list just at the top now. I'll go from there. Heading to the tire page now.

  Correct answer.

What is the rule of thumb for tire age on motorycles?  I thought I'd read motorcycle tires were good for upwards of 10 years (general rule of thumb - dependand on storage and use conditions).  RV tires tend to be about 6 yrs, tractor tires well more than 10 (granted tractor tires and rv tires may not be in the same risk category when a failure occurs).  But i alos know the tire life (degradation factor) is dependant on the stabilizers that may or may not be compounded into the rubber.

Why would they say 10 years for motorcycles? Any justification for that number while larger mass tires that aren't as subject to environmental degradation wouldn't last as long? If anything, motorcycle tires should be changed out more often.

In general: The less a tire is used, the less it's flexed thus quicker the tire turns stiff. I've seen 8-9 year old tires last for lots of miles yet a same age or newer zero mile spare tire shreds itself shortly after being put on and brought up to speed. 10 years for any tires? No way, no how. IMHO based on real world observation, it's more like 6-7 years maximum regardless of the vehicle, tire ratings or compounds used. Anything over 7 years is a failure in progress.

Low speed tractor tires can get away with things that high speed tires can't simply due to the dynamic forces involved in typical operation. You don't see a tractor tire being put under the stress loads and flexing that a motorcycle tire goes through. I'd be ok, and have, run 12 year old tractor tires simply because they're not likely to be put under the stresses that would cause them to come apart.

BTW while a motorcycle tire self destructing is off scale extremely dangerous at best, don't believe for a moment that a RV tire isn't high risk. The next time I see and old one that exploded, I'll take a picture of it and the resulting damage. It often looks like someone put a quarter stick of dynamite in the wheel well. The tire tends to shred itself into strings that are still attached to the wheel. All that flying rubber does a lot of damage then is ejected out onto the road at high velocity along with wheel well area materials.
Don't ride near large vehicles..and stay far far away from trailers since virtually no one crosses their chains anymore and the ones that do usually have too much slack in the chains to be of any use.

[PGWIN]

Does anyone have experience with Bridgstone S11's

The OEM sizes are:
Rear 130/90/16 67H
Front 100/90/19 57H

"H" is speed rating - i'm not sure what 67 and 57 are - hardness?

Do these look to be a compatible tire?
http://www.americanmototire.com/catalog/product_info.php?manufacturers_id=296&products_id=730
http://www.americanmototire.com/catalog/product_info.php?manufacturers_id=184&products_id=723

[JordanA]

I can't comment on the Bridgestones, but I am thoroughly enjoying my Dunlop Elite III's.

[ROJ]

Both my dad's 750K and his friends 750SC run Bridgestone Spitfires and both bikes handle quite well with them. The ones on the K are well worn and still hold up strong and have plenty of grip. The SC has brand new ones and after the break-in period, the bike handles like a dream. I'm likely going to get a set of S11's when I get new tires.

[Vermontster]

My bike wears Spitfires. I have no experience with other tires, but these handle great! 

[Term]

Another vote on the Spitfires ,great tires.

[PGWIN]

Spitfires it is - for about $126 for both to the door.  Seems like a reasonable price.  Just slightly more than my bicycle tires!

How many miles roughly do you expect i can get out of these?  I'm a mild rider (corners and acceleration). Considering all variables that effect tire wear what may be the average and what might be the maximum?

[jwomack]

i had spitfires. wasn't to happy with them in the rain. not sure...why...but just wasn't

i switched to the IRC Wild Flare


for the pair was less then $200 bucks shipped to my door. i love them. there good tires in everything. had them in the rain day be for yesterday, did aw some. had them on mud today. did aw some. for the money, i give them a solid 9 outta 10 stars.....i would look into them if i was you. also i have about 1100 miles on them now, and still going strong...I'm a big guy and i was concerned about that a little bit. but they seem to stick to the road good. good enough for me to pull the front wheel (not on perpose) off the ground, with a farring hanging on the front.

[WABBMW]

PGWIN:
My motorcycle had the same exact problem as you describe.  The pogo stick / hobby horse ride, with handlebar shimmy.  The previous owner had put Kenda Challenger tires on it, and now they were 12 years old, with about 50% of the tread remaining.  The bike had set up for years.  The tires were well balanced.

I just knew it had to be the front tire, but the problem was being caused by the rear tire.  It was almost 1/8" out-of-round, and, in my opinion, was manufactured poorly.  I put Dunlop Elite III tires on and the problem has disappeared.  The rear tire is belted or reinforced, which I like.  Even though the tries are bias ply, the tread is similar to that on modern sportbike tires.  I have been very pleased with these tires.  Hope your problem also goes away.  Good luck.

[Bumblebee]

My motorcycle had the same exact problem as you describe.  The pogo stick / hobby horse ride, with handlebar shimmy.  The previous owner had put Kenda Challenger tires on it, and now they were 12 years old, with about 50% of the tread remaining.  The bike had set up for years.  The tires were well balanced.

I just knew it had to be the front tire, but the problem was being caused by the rear tire.  It was almost 1/8" out-of-round, and, in my opinion, was manufactured poorly.

12 years = severly dry rotted hard tire even if it doesn't show. BTW, tread depth is not a valid indicator of actual tire condition.

All else being equal, a hard unflexing tire will bounce around and do annoying stuff a lot more than one that flexes normally even if perfectly round and balanced.

[ExTex]

I had similar problems with my Sabre.  It was the rear shock (Sabre has only a monoshock).
It was almost frozen up.  I replaced it and the ride got much better.
So, check to see if the rear shocks are functioning.  New ones are available.

Ride safely,