"How to make the Yamaha XS11 Handle" article

[Mike F]

Hi All
In the "How to make the Yamaha XS11 Handle" it refers to using a number 52 drill on the front fork damper rod. Can anyone give me the metric equivalent of it, please?
Keep revving
Mike F

[JP]

Mike, I've come to believe that most (maybe all - I don't know) of the info in that article is outdated. Progressive springs weren't available for our bikes back then and many of the "remedies" and references are obsolete.

What exactly is it that you're trying to accomplish?

[Mike F]

Hi JP
I figured that all that adding air to the forks was increasing springing rate, which is what's happening when you add progressive springs. I've got progressive springs already and have a spare set of damper rods so I thought I'd have a go at drilling them out as per the article and see what difference it makes.
Keep revving

[JP]

It's my impression that adding air is just adding preload which is different than progressive springs. I suppose if the forks were made of rubber then it might be progressive as there would be the difference between the compressive range of air and the expansive range of the rubber.

Of course with rubber forks you would probably have new "handling problems."

[Jerry]

#52 drill:

1.6129 mm
.0635 inches.

Source: wwforum.com\faqs_articles/drillchart.html

[Mike F]

Thanks Jerry
Keep revving

[Mike F]

Hi Jerry
Yes, I suppose if you think about it, it makes sense. Sometimes it has felt as if I've got rubber forks.
Keep revving

[Mike F]

Hi JP
Sorry I got your name wrong - seems like when I type one fingered - I only use one brain cell.
Keep revving

[JP]

Think nothing of it my friend.

[strom]

OK.. what aftermarket progressive springs would fit on a 78E?
Damn.. almost forgot to check out my ZX springs... but I guess they're too soft, since the ZX was bout 210kg and the yam is more like 270kg...

LP

[JP]

Well, they're called progressive springs from Progressive Suspension. They're the only ones I know.