6-1/2″ WIDE REAR RACING SLICK

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jseng1

jseng1

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When we were chasing faster Ducatis around Willow springs in the mid 1980s I saw my friend Fred Eiker in the pits with a hack saw cutting away the side of his new racing slick so it would clear the chain. Time was short and a race was coming up so he was desperate. The Ducs (starting with Tony Guest) were running wider slicks than we could fit into our narrow Commando, Feathrebed and Seeley swing arms and some very fast riders were leaving us behind. Something had to be done. I was bringing out my space frame about this time so I made allowance for the same wide slick that Tony Guest was using. To make it work I had to mill off the chain side of the tranny mounts, add spacers to the opposite side to stagger the tranny over and go to a 520 chain. The motor and engine plates were also slightly staggered. With the 6-1/2" wide slick I was able to achieve extreme lean angles and drag my leg all the way down to the ankle. You can make out the wide slicks (blued all the way to the edge from overheating) in the photo below

6-1/2″ WIDE REAR RACING SLICK
 
TomU said:
You should have used magnesium wheels
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Apart from being 40 years too late, I like suggestions like that.....but only when they come from someone prepared to gift the funding.....

If that is you, I have several motorcycle projects you might like to hear about :)
 
I was always a dollar short. It had a close ratio 4 speed and desperately needed a 5 speed. It needed dual ft brakes, And yes it needed magnesium wheels so I could use the latest tubless radial tires. It did get those things (plus 920cc) when Ken Canaga took owrenship. Then it went on to place in a BOTT national at Willow Springs in 1990 with Rob Tuluie riding.

6-1/2″ WIDE REAR RACING SLICK
 
Anybody ever ride that around Laguna Seca for grins?

According to what I read a few minutes ago AMA BOTT was dominated by Ducati. The lack of competition from other marques is apparently what killed BOTT. Getting on the podium with a Norton is impressive.
 
Schwany said:
Anybody ever ride that around Laguna Seca for grins?

According to what I read a few minutes ago AMA BOTT was dominated by Ducati. The lack of competition from other marques is apparently what killed BOTT. Getting on the podium with a Norton is impressive.
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I remember watching BOTTs at Loudon, Kawasaki EX500's (baby Ninja's) were riding RINGS around, airheads, sportsters, guzzis....
 
jseng1 said:
I was always a dollar short. It had a close ratio 4 speed and desperately needed a 5 speed. It needed dual ft brakes, And yes it needed magnesium wheels so I could use the latest tubless radial tires. It did get those things (plus 920cc) when Ken Canaga took owrenship. Then it went on to place in a BOTT national at Willow Springs in 1990 with Rob Tuluie riding.

6-1/2″ WIDE REAR RACING SLICK
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When I originally built my 850 Rickman in '75/'76 I built a close ratio 4 speed Manx in an old AMC case, using a ball race in place of the kick start with a bush in it.

Like you, I always thought a 5 speed would have been better, but on balance it wouldn't have been.

Two things, the 4 speeds were exactly the same ratios as the top 4 in a 5 speed

We did push starts, and I pushed off in first whilst the 5 speeders used 2nd, so in the same gear.

The only place it lost out was at a circuit that had a hairpin that demanded the 1st in a 5 speed, most of the guys using 5 speeds actually never used first!

The 5 Speed boxes failed regularly, this was well before outriggers were popular.

I didn't take the outer cover off my box for 4 seasons. I saved a lot of expense and got more finishes. You probably did too.
 
The close ratio 4 speed I used was achieved by swapping out a couple gears. It did not have the same ratios as the top 4 gears of a 5 speed. Again - I was too poor to afford what I really needed. Yes it was stronger than a 5 speed and the ratios were closer than a stock 4 speed - but it was overgeared off the line and coming out of the turns. See below:

6-1/2″ WIDE REAR RACING SLICK



Schwany - I did race it at Laguna Seca BOTT around 1985 against the likes of Marco Lucchinelli (Ducati). I can't remember but think I was running around 7th place when the Boyer leads failed and I dropped out. The bike was a twin shock at the time as shown below. Note the window in the fuel tank and the steep angle of the velocity stacks.

6-1/2″ WIDE REAR RACING SLICK
 
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jseng1 said:
The close ratio 4 speed I used was achieved by swapping out a couple gears. It did not have the same ratios as the top 4 gears of a 5 speed. Again - I was too poor to afford what I really needed. Yes it was stronger than a 5 speed and the ratios were closer than a stock 4 speed - but it was overgeared off the line and coming out of the turns.
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I may have been better placed than you being both in the UK and the '70s rather than '80s, not only because we had push starts, but because I bought 8 gears from Quaife, for the princely sum of £80 delivered.

Manx ratios, and not the Daytona set with a low first that was designed to work with a kickstart. The standard Quaife 5 speed used exactly these ratios for 2nd, 3rd, 4th and 5th.

I remember holding the gears in my hands and contemplating the £10 a piece set as if it was gold, that was a lot of money to me in a bike that cost £1200 to build with mostly new parts, largest used part was the gearbox case.

Then I had to get a new Commando long mainshaft and a layshaft which was modified to fit in the ball race and get a bearing mounting made for the inner cover.
 
Steep angle on the intake manifolds is an understatement. Wow!!?

I like the swing arm bracing. I should do that on my P11, but I can't ride quick enough to get much out of it other than finally getting around to doing it 30 years too late. lol
 
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