Getting ready for new season: Performance and comfort mods

MikeO

I posted this in another thread:

I thought all belts had Kevlar in them - the aftermarket ones are advertised as 'Kevlar belts' in order to sell them.
From experience - the Piaggio belts last much longer than the am ones (as do the Honda ones in the X9250sl maxis) and show signs of wear, unlike the am ones which usually fail with little or no warning.

_________________
Mike - Riding on the right - riding for pleasure!

'09 Silverwing 600 - 'The Winged Express' - Delta Blue, ABS, Heated Grips, Laminar Lip, Utopia rider's backrest, Givi pillion backrest & E52 Topbox, Cortech Super Mini Tank Bag as a tunnel-bag, Starcom Digital Comms System.

www.x9ownersclub.co.uk - for all Maxi-Riders who want to RIDE!

"All that is necessary for the triumph of evil is that good men do nothing."
Edmund Burke

mickey

Cosmic_Jumper wrote:

Mikey take another look at that YouTube video you posted. You can see the belt flapping away while the Variator & Driven Pulleys are 'changing' gears.

Yep. I noticed that. And that's what convinced me that there is no magic solution to belt slap except to keep everything clean and sliding freely. I can't imagine why kevlar would have anything to do with the amount of slack in the belt.

I suspect the reason people are reporting "no more belt slap" with the Kevlars is they clean everything up when they change the belt. That's what solves the problem.

I'll find out soon enough, because with only 4K on my machine I don't think I'll change the belt right away. I'll just make the mechanical changes I want and spiff everything up.

mickey

MikeO wrote:

I posted this in another thread:

I thought all belts had Kevlar in them - the aftermarket ones are advertised as 'Kevlar belts' in order to sell them.
From experience - the Piaggio belts last much longer than the am ones (as do the Honda ones in the X9250sl maxis) and show signs of wear, unlike the am ones which usually fail with little or no warning.

Ran into a similar issue with VW TDI cam drive belts. They also have to drive the high-pressure diesel pump, which puts a huge amount of stress on the belt. OEM belts were lasting 40K, tops. Gates came out with an 80K "kevlar" belt. Our assumption was that the OEM belt didn't have kevlar reinforcement, but we don't actually KNOW that for a fact. The Gates belt might just be a better product, that's all.

If a Gates is available for the Swing I'll buy one. They are the best of the best. You just have to know the dimensions of the belt and see if they have one in their catalog. Honda probably just picked one "off the shelf" when they designed the bike.

buddy19520

mickey wrote:

Cosmic_Jumper wrote:

Mikey

There is nothing wrong with Honda's SWing belt. I believe that it does have kevlar in it.

The belt does have direction arrows on it. And even though there is no information about the belt orientation in the shop manual, you'll get belt slap if the belt is put on with the arrows pointing contrary to direction of rotation.

Hope this helps

Tim

Mine slaps, and that complaint seems to be almost universal after a few thousand miles. I can't imagine Honda put them all in backwards.

It occurs to me that "belt slap" really shouldn't have anything to do with the belt itself. Kevlar makes it last longer, but it's not like a non-Kevlar belt would stretch like a rubber band. Belt slap is probably caused by a tendency by the CVT transmission not to take up slack properly. Probably gummed up with dust, grease and gunk.

That's what my "slightly better than clueless" logic is telling me, anyway. I need to take another look at diagrams of the drive system. You've got the clutch up front and the variator in the rear, but what uses up the extra slack as the variator does its thing? Is there a third pulley with a spring? That would be the "belt slap" culprit, I'd imagine.

An idea came to me that I don't think I have seen asked/answered anywhere else - if you were to install a stronger contra spring (the big one on the clutch) AND heavier weights, would it keep additional tension on the belt and stop the belt slap?

Anyone try it before?

Philip

mickey

I would imagine so, but you want to be careful getting them too far away from the stock settings.

I've never thought of that before. All the belt-slap discussion centers around which belt to use, but changing the tension isn't discussed in that context. More tension would raise the frequency of the oscillation, like tightening a guitar string. The amplitude should decrease, though, so the belt will be less apt to strike the plastic cover. That's my guess, anyway.

mickey

OK.....

Stronger "big spring" wants to keep the driven pulley squeezed together, and resists changing to higher gear. It counteracts the effects of heavier rollers. The stock rollers are already as heavy as you'll find. So you'll have a slower runup through the "gears." Kind of like having lighter rollers. As you decelerate the driven pulley will tend to go back into "low gear" more quickly.....

Oh, hell. I give up. Try it and let us know.

buddy19520

I think it would act the same as putting lighter rollers in the variator.

It seems that the belt is always under tension from the variable centrifugal force from the rollers in the variator (trying to press the variator together) being resisted by a static pressure from the contra spring in the clutch. By putting lighter rollers in, the contra spring in the rear becomes comparatively stronger, keeping the driven pulley pressed together, giving it a lower gear ratio. Usually, we put in lighter variator weights to allow the contra spring (I think that is what the big spring in the clutch is called) to keep the driven pulley pressed together - its just a lot easier to change variator weights than a clutch spring.

I would guess that, if you put a softer contra spring in the rear and lighter variator weights in the front, the machine would act the same as a stock machine, with the exception of a lot of slop in the belt. That is why I think that heavier weights and contra spring might get rid of belt slap. When I rode a mountain bike and we would get chain slap, we just took out a couple of links. A shorter chain was under more tension and didn't slap.

I don't really know! I'm just a theoretical guy. Besides, I already put in a J Costa and it got rid of most of the slap.

Philip

_________________
Philip
2003 Swing with GIVI and GIVI, Kuryaken, J Costa, Blinky LED taillight, Wallyworld el cheapo driving lights, AirHawk, Laminar Lip

The Scootist · Subject: Belt Slap?? Mon Mar 01, 2010 10:59 am

Belt Slap?? What is that?? (grinning) I don't have any since I installed the J Costa...

_________________
2007 Silverwing - "Growler" - with 17,000 miles and counting; Givi windshield, Givi top case with back rest, K&N air filter in a drilled air box, Leo Vince Exhaust, J Costa variator, HyperPro Springs, and Oxford heated grips. All I need now is a power commander, and a nitrous kit with a blower...

Or maybe a Kawasaki Concours 1400 with ABS...

or an ST1300...

Let's ride...