center stand technique

[happydaze]

I was just reading another forum and found out something that I thought I would pass along because I had not heard it before.

If your XS650 has a 16" rear wheel, it's much easier to get it onto the center stand if you roll the rear wheel onto a piece of 1"x4" lumber or 3/4" plywood. The extra height in the rear gives you more leverage. This is (allegedly) because when Yamaha went from the 18" rear wheel to the 16" they did not change the height of the center stand. So, the bike sits 1" lower.

Anyway, I didn't know that. Remember to push down with your leg rather than trying to lift the bike with your arms. My '81 has a 16" rear wheel and I have never put a board under the rear wheel to get it onto the center stand. You can feel it when you're doing it right. It's all about applying leverage at the bottom.

 

[5twins]

Keeping the pivot bolts greased makes a world of difference.

 

[gggGary]

The rolling wheel radius difference between 18 and 16 is less than 1/4" because of the larger tire size on the 16's
PS a 140 tire on the stock 16" rim is overly wide and further reduces the stability of a Special.........

70s 80's era rims are really too narrow for the tires they came with stock.

 

[happydaze]

Thanks for the info about the tire height. I was wondering about that. I just took the other person at their word.

Yes, I'm seeing that 140 is wide for my wheel. Hasn't caused any problems. When it comes time for new one I'll get a more appropriate size. How does a wider tire make the bike less stable?

 

[retiredgentleman]

I was just reading another forum and found out something that I thought I would pass along because I had not heard it before.

If your XS650 has a 16" rear wheel, it's much easier to get it onto the center stand if you roll the rear wheel onto a piece of 1"x4" lumber or 3/4" plywood. The extra height in the rear gives you more leverage. This is (allegedly) because when Yamaha went from the 18" rear wheel to the 16" they did not change the height of the center stand. So, the bike sits 1" lower.

Anyway, I didn't know that. Remember to push down with your leg rather than trying to lift the bike with your arms. My '81 has a 16" rear wheel and I have never put a board under the rear wheel to get it onto the center stand. You can feel it when you're doing it right. It's all about applying leverage at the bottom.

Yes, that is a good technique to use. I first learned that method from Pamcopete about 6 or 7 years ago. I use a 2 x 6 which lifts the bike about 1.5 inches. I simply pushed down firmly on the centre stand, there's no lifting at all.

 

[retiredgentleman]

The rolling wheel radius difference between 18 and 16 is less than 1/4" because of the larger tire size on the 16's
PS a 140 tire on the stock 16" rim is overly wide and further reduces the stability of a Special.........

70s 80's era rims are really too narrow for the tires they came with stock.

I don't believe there is any difference in stability or handling, between a standard XS650 with 18 in rear, and a Special with 16 in rear.

This sounds to me like another internet myth, that gets repeated over and over. Can anyone give a factual example of this?

 

[650Skull]

Happydaze, the rear shock angle is the main cause for the Special being lower to the ground than the standards. The center stand is the same height = harder to center stand the Special over the Standard.

Your description is spot on and if coupled with 5Twins tip, its a breeze

 

[5twins]

I've ridden both Specials and Standards. The fat 16" rear on the Special makes it steer slower and it doesn't want to flick into turns as easily. It's by no means bad, just not quite as easy to throw into turns as a Standard.

 

[retiredgentleman]

I've ridden both Specials and Standards. The fat 16" rear on the Special makes it steer slower and it doesn't want to flick into turns as easily. It's by no means bad, just not quite as easy to throw into turns as a Standard.

I'll offer some real life facts about tires:
The Standard rear tire 4 in x 18 in, or about 110/90-18
the Standard front tire...............................100/90-19
So rear is 10 mm wider.

The Special rear tire ..................................130/90-16
The Special front tire..................................100/90-19
So the rear tire is 30 mm wider.

The Yamaha YZF-R1M (designed for sporty street handling) :
Rear tire is 200/55ZR17
Front tire is 120/70ZR17
So the rear tire is 80 mm wider.

A typical MotoGP full race bike uses these tires:
Rear 190/65R 16.5
Front 125/60R 16.5
So the rear tire is 65 mm wider than the front.

I think the numbers speak for themselves. It appears that Yamaha and other
racing companies, believe that a rear tire anywhere from 65 to 80 mm wider than the front promotes excellent handling characteristics.

If anyone sees an error in my thinking, please point it out to me.

 

[gggGary]

Just a guess that a lot of the race bike rear tire width has to do with delivering horse power to the ground and attempting to extend tire life while cornering in a rear wheel slide. A fair amount of the blame for that goes to the big KR when he (successfully) brought flat track techniques to Gran Prix racing. Anything on the street has more to do with posing than actual performance. Ask your tire shop how many street tires they replace because the edges are worn out compared to the center....

 

[gggGary]

Add rear weight bias to reasons for a larger rear tire. Riding two up or with a butt ton of luggage. Guess I'll be able to comment a bit on a both tires the same set up if I survive my latest wheel/tire experiment for a while.

I never really noticed much difference between the specials and standards as far as handling. And I have had some pretty nice tires on standards, the specials? Not so much.

 

[retiredgentleman]

Yes, of course, the wider rear tire on the Special was a marketing design, to increase sales, and it worked. It also gave the rear tire a load carrying rating of 615 lbs., which is real nice for 2 persons and lots of gear.

My point is that the Special rear tire being 30 mm wider than the front, does not decrease its handling ability. In fact as seen on modern street/racing bikes, it's a desirable feature.
As an example, if you get into an emergency braking situation, its good to know that the wider rear tire has a larger patch touching the road preventing the back end from coming around on you.

 

[NONclow]

I think the numbers speak for themselves. It appears that Yamaha and other
racing companies, believe that a rear tire anywhere from 65 to 80 mm wider than the front promotes excellent handling characteristics.

If anyone sees an error in my thinking, please point it out to me.

Not trying any errors RG, but way to compare our 32+ year old classics to current frontline ELECTRONIC warriors pushing modern tire compounds farther than ever.

Hijack over. My 'stand technique has markedly improved......with time..........

 

[retiredgentleman]

Not trying any errors RG, but way to compare our 32+ year old classics to current frontline ELECTRONIC warriors pushing modern tire compounds farther than ever.

Hijack over. My 'stand technique has markedly improved......with time..........

Absolutely, rubber compounds have improved hugely. That means modern race bike tires have much better grip on payment, and could use a narrower tire on the rear but they don't.They like to have more rubber on the road to prevent the rear from sliding out. All I'm saying is that if wide tires in the rear reduced handling, modern racing type bikes would not use them.

 

[5twins]

I think you probably have to look at the whole package. I'll bet the rake and trail on a modern sport bike's front end is set up differently than on our bikes. It is probably set up to quicken steering and compensate for those modern fat tires.

 

[NONclow]

......Ask your tire shop how many street tires they replace because the edges are worn out compared to the center....

I go through at least one set of tires a season with my backwards Ninja. 16" front and 18" rear. By the time the rear is smooth down the middle, the front has two 1" wide bare strips each side of center. I resist the temptation to overinflate it to get more mileage.....Damn quicker steering at the expense of tire life...

I'll go with gggGary on the power application reason. Narrower rear tires decrease handling by decreasing traction. Taller or shorter would affect lean-in though (the Ninja is pretty front heavy...).

 

[retiredgentleman]

I think you probably have to look at the whole package. I'll bet the rake and trail on a modern sport bike's front end is set up differently than on our bikes. It is probably set up to quicken steering and compensate for those modern fat tires.

5twins..............yes I agree, the whole package of handling is very complex, with very many factors to take into consideration. Rake and trail would be at the top of the list concerning how a bike handles.

If you just compare a Special to a Standard, They both have the same rake, 27 degrees, and I'd say the trail is also identical. I believe there's no difference in handling between the 2 types.

I've never driven an XS650 Standard, but I drove an XS500C for 13 years, which I believe had the same wheels/tires as the XS650 Standard. It handled corners just the same as my XS650 Special.

 

[gggGary]

An interesting if slightly dated article on tires. It really does cover a lot of the common tire, rim conundrums.
https://www.motointernational.com/blog/news-and-events/post/sharing-daves-ol-tech-articles-episode-3

I'll throw in that if taken to extremes fat rear tires definitely have a negative effect on handling. 300? stupid wide. Guy was riding with some buds and he was really sweating getting that thing around corners. There may have been lots of factors but it sure looked like the front rear alignment in the transition to the lean changed so much that handling was atrocious But I feel the greatest sin commonly committed is levering wider tires on stock rims.

The 86-89 Yamaha Radian 600 runs 16"s front and rear its' possible they would swap on to an XS....
Tire size (front) 110/90-16-59H
Tire size (rear) 130/90-16 67H


It would be interesting to lever some low profile scooter rubber on those rims bolted to an XS, get you the slammed look and maybe handle pretty well, 'til bits start dragging anyways. Would probably work for the inseam challenged.

YAMAHA YX 600 (86-91) (Radian)
Front Rim Size: 2.50x16
Rear Rim Size: 3.00x16

Recommended Front Tire: K591 , size 100/90-16, 30 PSI
Recommended Rear Tire: K591 , size 130/90-16, 32 PSI

OE Replacement Front Tire: K355F, size 110/90H16, 30 PSI
OE Replacement Rear Tire: K355 , size 130/90H16, 32 PSI
Recommended Front Tire: ME330 , size 100/90-16
Recommended Rear Tire: ME550 , size 130/90-16

 

[TwoManyXS1Bs]

...I'll throw in that if taken to extremes fat rear tires definitely have a negative effect on handling...

Ditto! Lean angle must increase, to keep CG over the tire's contact patch.
It would be like having your airplane's lift center shift to the side during a banked turn.
Boat buoyancy depends on this to avoid capsizing.
So, a fat tire gives you that boatlike feel...

 

[gggGary]

On the special rear shock top location, this may help.

A special frame section on top of a standard section,



note the mount moves forward AND down resulting in little difference in the stance of the bike. Theoretically the increased angle would result in slightly softer action if the springs remain the same...