Yesterday was a rainy day and I was able to work on a project that I have been wanting to try for a while.

My Cafe' bike steering is really light, and you can wiggle the bars and the bike will quickly shimmy in response.  I have only had one tank slapper in the 16,000 plus miles I have ridden it - a pavement hump at a bridge threw the bike up in the air and me off the seat at 70mph, and when I landed on the front wheel the forks began to shake from side to side for half a second.  The loose steering is likely a combination of the steeper fork angle caused by lowering the forks 2" and raising the back 2", going to a larger 18" rear wheel and a smaller 18" front wheel with a small 90/90-18 front tire.  I have gotten used to riding the bike this way and the light steering touch doesn't bother me - but it is a bit scary to folks who ride it for the first time.

I wanted to see if a steering damper would help to settle the steering down a bit.  I took the damper off my F800 BMW and it seemed like it could work - so I watched eBay for a while and waited for a reasonably priced one to come along......after about 6 months I finally was able to get one that was priced acceptably and in good shape.

The pivot point on the forks is the hole on the left side that was previously used to mount the brake line on the stock bike.  The hole was tapped for a 6mm screw - I drilled and enlarged it to an 8x1.25 screw size to match the steering damper.

I began the process of making the mount by drawing a cardboard template that was approximately the shape I needed, then I cut up a block of aluminum to the rough shape/size.  The aluminum was likely a bit thicker than I needed - but at this point I wasn't sure how far the pivot point for the damper needed to be away from the frame for clearance.

I was able to get the piece turned down without hurting myself, the lathe or the work piece.  I did have to put masking tape on the flat piece of the part while I was cutting on it - the flat surfaces would reflect the light and cause a very distracting "strobe light" effect and it was hard to keep my eyes focused on the area I was cutting.

Once I had the other two holes drilled properly in the frame I removed the mount and drilled/countersunk the holes and then tapped the frame for the screws, and installed the spacers/seals on the damper.

Very cool stuff Dave.
Good idea

Nice work Dave!

I was able to get the cleaned up and powder coated this morning, and then I put it back on the bike and went for a ride.

The damper has settled the steering down a little bit - it is still a very easy steering bike.  If you jiggle the bars while riding - the bike responds quickly and it jiggles as well.

I don't remember the bike being this jiggly when I had the Bridgestone Battlax BT45 tires on the bike.....either in the 90/90-18 or 100/80-18 sizes.  It turns out that the BT45 has a design that helps bikes that are unsettled become more stable in a straight line....which is really the only place my bike feels it could be better.  The newer BT46 version also has this benefit according to Ryan at Fortnine.


The reason I stopped using the BT45 is that the tread on the sides has little blocks that wear unevenly when leaned over, and they become pretty noisy as the tire wears and you lean into a corner.  When I took them off I put on a pair of Michelin Pilot Sport Active tires.....and that is when the twitchy steering became noticeable (I also put on a set of waaay too stiff rear shocks at the same time....and that also contributed to the poor handling).

With the steering damper, the better rear shocks and the Avon Road Rider tires the bike is doing much better and I will have no issues riding it the rest of the year to wear these tires out.  Then I likely will go back to a set of the Bridgestone BT46 tires.

That's a beautiful installation Dave.  Looks like it rolled off the assembly line with that damper.  I really like the job you did.

Respect.  

How are you cutting up your aluminum stock?  I use a ten-inch chop saw with a plywood blade (carbide).  Been doin it for years.  I even lobbed off a 4" diameter slice of 6061.  What are you using to chop off those big chunks?

DragBikeMike wrote on 06/13/23 at 18:11:14:



I have a very nice metal band saw that I use to cut my parts with.  I was lucky enough to find it many years ago and bought it from a man in his  80's who spent his days rebuilding Bridgeport milling machines.  He used a fork lift to pickup and move everything as he was no longer strong enough to lift heavy things.

The "Hack" that I used in making this piece is using a Forstner bit to countersink the screw holes in the aluminum.  Amazingly the Forstner bits work incredibly well with a normal drill press in aluminum.  I first drill a small pilot hole to allow the sharp point of the Forstner bit to have a path to travel....as the point has no cutting ability and doesn't need that when used in wood.  I drill at a pretty low speed and don't use a lubricant, and it cuts incredibly well and the hole is clean.  The bit and work piece don't get hot.  After I drill the counterunk hole with the Forstner I then drill the hole for the screw through the smaller pilot hole.