Stock S40:  Rake: 35 deg., Trail: 5.8 in.
Ryca Mod.:  Rake: 29 deg., Trail: 4.75 in.  Wheel Base: 57"

"new" Norton 961:  Rake 24.5, Trail: 3.9"  Wheelbase: 55.9"
"new" 2001 Triumph: Rake: 29 deg., Trail: 4.6", wheelbase: 58.9

All that being said:  Ryca kit definitely makes improvements over the stock S40.  However, its can be tweaked to be a little more responsive in the twisties.  Now, is it worth it?  I dunno....stocker its a pig., but I've never ridden the Ryca version.  But I've heard mixed reviews on the geometry. I guess it depends what you are used to a your riding style.

I'm curious has anyone de-raked an S40? Old Featherbed nortons were 24 deg. rake., trail:  ~ 4" (not exactly sure).  They were known for superior handling.......

Seems to me on paper the S40 (esp. in a cafe racer form); could benefit from a little quicker steering.

How do you figure that you are picking up another 4 degrees o de- rake?     I think 24.5 and 3.9 trail is optimal.   Feather beds got triumph, harley, vincent.....you name it engine swaps.  All were simular improved.

I think it can be done with a top backbone cut and down tube heat bend.

I just went out and measured my Cafe' conversion that is RYCA inspired and does use a lot of RYCA parts - but the forks are tweaked a bit as I used Suzuki RM400 fork yokes to cut back on the offset between the fork tubes and the steering head.....which may have not been a great idea as it has increased my trail.  I also installed a 1/2" spacer to cut down on the fork travel a tad and add some preload, and I dropped the fork tubes about 1.5"....the forks are dropped as far as I can go and when they bottom out the bottom fork yoke is just a tad short of hitting the fork seals.  My initial sag of the forks when in the riding position is 30mm.

When I push the bike down into the "resting" position with the bike weight, I have a fork angle of 28 degrees and a trail of 5".  This trail is more than you will have with the RYCA yokes as the stoke yokes have an offset from the steering head to the fork tubes of about 2.5" - while my yokes have an offset of only 1"....but because of the 28 degree fork angle that 1.5" offset is reduced to the approximately 1" difference between my bike and the RYCA with the stock yokes.

With the 5" of trail my bike is extremely stable and holds any line well - however the initial force from going straight to turning.....is kind of stiff.  MMRanch rode my bike and said when he went into the first turn he thought he was "trying to bend a board!  I don't think it is that bad, and I don't notice that it turns any stiffer than my ST1100 - but it is not as nimble feeling as my 250 Ninja.

I promised Gary a few weight numbers.  With my bike unloaded the front weight 154.2 pounds, the back 173.4.  When I get on the bike it is a bit hard to hold the exact same posture for both times I need to sit o the bike and move the scale from front to back, and release the jack and hold on to a ladder to balance - but with me on the bike the weight was 218.4 on the front and 280.4 on the back...which works out to be within 4 pound difference of the 175 that the scale said I weigh tonight (lots of warm clothes on).

Kris: basic and accurate.

Lots of guy merging modern sportbike front ends and wheels on old style (prior to 1980 - with 28 deg. rake) triumphs get themselves in a little bind.  There is very little offset with sportbike trees, due to the very steep rake (<23 deg. at times) of the sportbike frame.  This puts alot more trail into the ole Triumph.  so they wind up with a sportbike look that won't handle worth a crap.

I think a 24 deg. rake;  3.75-4" trail would do the Ryca justice....as long as some dive can be limited from the front stock forks so the trail doesn't shrink too much under braking.

The Harley XR 750 had 24 degrees rake and 3.75" trail.  That seems to be the winning combo for a scrambler.

As far as handling goes, the best handling bike that I ever owned was a 1973 Norton Interstate. When I picked up the Norton at the dealer in London, both tires were 4.10 x 19" Dunlop. At some point when the Dunlop tires wore out I purchased Pirelli tires and they improved handling.

Later on when the tires needed to be replaced I used Pirelli tires again, but I went with a more narrow tire on the front and a 4.10 on the rear. Handling noticeably declined.

The next tire change I used Pirelli size 4.10 on both the front and rear and the handling was absolutely great.

One other observation about the Norton, both front and rear tires wore out at the same time. I rode the Norton for over 30 years so it was easy to know what worked and what did not work. Most riding was done on two lane asphalt roads with a speed limit of 50 to 60 MPH.

Kenny G  

Thanks for the "fix" Kris on the link.

A 10 degree correction from stock (35 deg. and 5.8")  would bring him down to 25 degrees, and ~3.75 trail.     I think those would be great numbers.    under braking, those number reduce more.

The New Norton "sport" 961 has similar numbers (24.5 deg., 3.9" trail 55.9" WB)....but that's a street bike.

I think they may be have more trail (4.6") due to signifigant fork compression which will really reduce trail!   A streetbike ideally has less compression, therefore a more stable trail number.  

I'm starting to be convinced, that with the upcoming Ryca strip down, I'm going to reduce the rake another 5 degrees from the Ryca numbers.

I've got to do a little thinking on this.   A 5 or 10 deg. correction is do-able, but if "undoing" the Ryca correction, I'm not sure how the bodylines would change.   If they do, how much.

I think "mock" ups is the only way to tell.

Nah...no worries.   look at the CBR600 numbers.  The typically do not have steering dampers and don't go into a death shake at 50+ mph.
However, a damper is a good precaution!  mid 1980 sport bikes (ducati's) had them stock

real world number sample:

Typical Cruiser Dimensions (2003 Honda VTX1800)

Rake 32.0 degrees
Trail 152.0mm (6.0 inches)
Wheelbase 67.5 inches

Therefore: With a rake of 32 degrees and a trail of 152mm (6 inches) this motorcycle will be better and more stable in a straight line than turning a tight corner. The long wheelbase of 67.5 inches also assists this motorcycle again in straight line performance but will hinder it in cornering. So this motorcycle has been properly designed for it's intended purpose (touring, cruising, and highway use).



Typical Sport Bike Dimensions (2003 Honda CBR600RR)

Rake 24.0 degrees
Trail 95.0mm (3.7 inches)
Wheelbase 54.7 inches

Therefore: With a rake of 24 degrees and a trail of 95mm (3.7 inches) this motorcycle will turn much quicker and sharper than the Cruiser, but will not be as good or as stable in a straight line. The short wheelbase of 54.7 inches also assists this motorcycle again in cornering but hinders straight line stability. So this motorcycle has been properly designed for it's intended purpose (going in and out of corners at high speeds and taking twisty roads).