Sturdier triple clamps

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acotrel said:
How accurate do you think Norton made the taper on the fork tubes and in the top yoke ? Was it of critical importance amongst the myriad of other production issues ? With a parallel fit, as long as the clamp is tight, there is zero movement. With the taper, there only has to be an error of a degree to create the situation where it is tight at the top and loose at the bottom and vice versa.
Click to expand...

That’s a good point Al.
 
In the past, I only ever had the taper fit yokes. These days I use a parallel fit pair off a TZ350 - they are far superior. With the taper fit type yokes , you really need to tie down the yokes to the wheel with the forks compressed, before you tighten the pinch bolts and the caps and axle . If you don't do that, you can get binding. The parallel fit type yokes are much more accurate.
 
I regard to what stanchions to use with clamped yokes I would think most 35mm stanchion from Japanese or European origin, along with their damping, could be fitted into standard Norton sliders. I've certainly seen this done with 35mm Suzuki legs and dampers. It required machining up new bushes, but from memory everything else was straightforward.
 
acotrel said:
How accurate do you think Norton made the taper on the fork tubes and in the top yoke ?
Click to expand...

Probably very accurate. I don't know about machining standards at the Villiers factory, but the tool shop at AMC was run to the highest standards. As long as the taper angle fits on both parts (steering crown and fork tube), the connection is as good as it gets.

-Knut
 
Nortoniggy said:
From an engineering perspective the taper fitting is superior to clamping the tubes. It's much easier to manufacture a clamp setup though.
Click to expand...

Normally the pinched clamp will excert pressure at a few locations along the circumference only, mostly at 90 and 180 degrees to the slot. It's not like a hose clamp which extends and shapes itself. The pinch clamp also has the disadvantage of trying to pull the clamped tube out of line. The taper is superior, providing even contact forces all way around the circumference, hence the mating member is centralized. In the ideal world, the fork crown (lower tripe tree) would have provided a tapered solution as well. For cost reasons this is not realized.

-Knut
 
acotrel said:
In the past, I only ever had the taper fit yokes. These days I use a parallel fit pair off a TZ350 - they are far superior. With the taper fit type yokes , you really need to tie down the yokes to the wheel with the forks compressed, before you tighten the pinch bolts and the caps and axle . If you don't do that, you can get binding. The parallel fit type yokes are much more accurate.
Click to expand...

In my view it's the opposite. The risk of binding should be much greater with the clamped type of yokes. You name it parallel fit - with one pinch bolt there is no guarantee that the connection of mating parts is paralell, What's worse, the upper and lower triple tree may pull the fork tube in different directions, causing fork tubes to misalign to another. In practice this is largely avoided by slotting the u/l triple tree in the same angular location and providing twin screws for clamping. Yet, the centralising effect of a tapered fit is much better.
I didn't understand your procedure of having to tie down the yokes to the wheel to avoid binding. If fork tubes are straight, of equal length and manufactured to spec there will be no risk of binding. As for taper accuracy, I see your point with third party suppliers. If in doubt, please verify there is a problem before raising the flag. Or buy from a reputable source like A-N!

-Knut
 
bsaboss said:
I regard to what stanchions to use with clamped yokes I would think most 35mm stanchion from Japanese or European origin, along with their damping, could be fitted into standard Norton sliders. I've certainly seen this done with 35mm Suzuki legs and dampers. It required machining up new bushes, but from memory everything else was straightforward.
Click to expand...
or the option of bolting on the full fork/wheel brake package,

doesn't take much to go with pinch bolt yokes if desired, or other bigger fork packages

https://www.caferacer.net/forum/project-builds/14059-triple-tree-fork-conversion-chart.html
35 MM FORKS BY MANUFACTURER

Harley 35MM
35 Harley XLH, XLCH, XLRC 1975-83; XLX & XLS 1983 only 35 mm
35 Harley XLS 1979-82 (Showa Forks) 35 mm
35 Harley Sportster with Showa forks from late 1986-87 35 mm Coarse Thread
35 Harley Sportster 1984-E86 35 mm Fine Thread
35 Harley FX & FXE 1973-76 (Kayaba Forks) 35 mm
35 Harley FX, FXE& FXEF (Showa Forks) 1976-83 35 mm
35 Harley FXS, FXB, FXSB, FXR & FXRS 1977-83 (Showa Forks) 35 mm
35 Harley FXRT & FXRD 1983-86; FXSB 1984-85; FXRS Sport Edition 1985-86 35 mm
35 Harley FXE & FXEF 1984-85; FXR 1984-86 (except FXRT, FXRD & Sport Edition) 35 mm Fine Thread
35 Harley FXR (except FXRD, FXRT & Sport Edition) with Showa forks from late 1986-87 35 mm Coarse Thread
35 Harley FXRT with Showa Fork 1987 only 35 mm
35 Harley Sportster 1973-74 (Kayaba Forks) 35 mm

Honda 35MM
35 Honda CR-80R (87-95)
35 Honda CR-125M "Elsinore" (76)
35 Honda CR-125M "Elsinore" (77-78)
35 Honda NX-125 (88-90)
35 Honda XR-200R (81-83)
35 Honda CL72 "Scrambler 250"
35 Honda CR-250M/M1 "Elsinore" (73, 75-76)
35 Honda MR-250 "Elsinore" (76)
35 Honda VTR-250 "Interceptor VTR" (88-90)
35 Honda XL-250 "Motosport 250" (72, 74-76)
35 Honda XL-250S (78-80 To 5204066)
35 Honda XL-250S (80 From 5204067 - 81)
35 Honda XR-250 (79-80)
35 Honda CL77 "Scrambler 305"
35 Honda SL-350 "Motosport 350" (72)
35 Honda XL-350 (74-78)
35 Honda CL-450 "Scrambler" (69-72)
35 Honda CB-450 (70-74)
35 Honda CB-500 "500 Four" (71-73)
35 Honda CX-500C "Custom" (81-82)
35 Honda GB-500 (89-90)
35 Honda GL-500/I (81-82)
35 Honda XL-500S (79-80 To 5104835)
35 Honda XL-500S (80- 81)
35 Honda CB-550 "550 Four K" (74-78)
35 Honda CB-650 (79-80)
35 Honda CB-650 (81-82)
35 Honda CB-650C (80 To 2009951)
35 Honda CB-750K (69)
35 Honda CB-750 "750 Four" (70, 72)
35 Honda CB-750A "750 Hondamatic" (76-78)
35 Honda CB-750C "Custom" (80-82)
35 Honda CB-750F "Super Sport" (75-78)
35 Honda CB-750F (79-80)
35 Honda CBX (79-80)

Kawasaki 35MM
35 Kawasaki KX-80 G1/G2 (86-87)
35 Kawasaki KX-80 L1-L3/N1-N3 (88-90)
35 Kawasaki KE-175D1-D4 (80-83)
35 Kawasaki EX-250E1/E2 "Ninja" (86-87)
35 Kawasaki KE-250B1-B3 (77-79)
35 Kawasaki KZ-550H1/H2 "GP" (82-83)
35 Kawasaki ZX-550A1-A3 "GPz" (84-86)


Suzuki 35MM
35 Suzuki RM-80 K/L/M/N/P (89-93)
35 Suzuki RM-80 R/S/T/V/W/X/Y/K1 (94-01)
35 Suzuki RM-100 N/T/X (79-81)
35 Suzuki DR-125 G/H/J (86-88)
35 Suzuki DR-125 SER/SES/SET (94-96)
35 Suzuki RM-125 M/A (75-76)
35 Suzuki SP-125 G/H/J (86-88)
35 Suzuki DR-200 G/H/J (86-88)
35 Suzuki DR-200 SET/SEV/SEW/SEX/SEY/SEK1/SEK2/SK3 (96-03)
35 Suzuki RL-250 L/M "Exacta" (74-75)
35 Suzuki SP-250 Z/D/F (82-83, 85)
35 Suzuki TS-250 1 "Savage" (69)
35 Suzuki TS-250 B/C/N (77-79)
35 Suzuki GN-400 T/XT/XX/TX/TZ (80-82)
35 Suzuki TM-400 K/L/M "Cyclone" (73-75)
35 Suzuki GS-450 LD (83)
35 Suzuki GS-450 LF/LG/LH/LJ (85-88)
35 Suzuki GT-500 A/B "Titan" (76-77)
35 Suzuki RE-5M, A
35 Suzuki GS-550 LX/ LZ (81-82)
35 Suzuki GS-550 B/C/EC (77-78)
35 Suzuki GS-550 LN/LT (79-80)
35 Suzuki GS-550 LG (86)
35 Suzuki GT-550 J/K "Indy" (72-73)
35 Suzuki GT-550 K (KAYABA)/ L (73-74)
35 Suzuki GR-650 D/XD "Tempter" (83)
35 Suzuki GS-650 EX/EZ(81-82)
35 Suzuki GS-650 GLX/GLZ/GLD(81-83)
35 Suzuki GS-750 B/C/EC (77-78)
35 Suzuki GS-750 EX/EZ (81-82)
35 Suzuki GS-750 LT/LX (80-81)
35 Suzuki GS-750 TZ/TD (82-83)
35 Suzuki GT-750 J/K/L/M/A/B "Lemans" (72-77)

Yamaha 35MM
35 Yamaha YZ-100 G/H (80-81)
35 Yamaha IT-125 H (81)
35 Yamaha RT-180A/B/C (90-93)
35 Yamaha XT-200 J/K/KC (82-83)
35 Yamaha XT-250 G/H/J/K/KC (80-83)
35 Yamaha TZ-250 C/D/E (76-78)
35 Yamaha TZ-250 F (79)
35 Yamaha RZ-350 L/N/NC/NCII (84-85)
35 Yamaha TZ-350 /C/D/E (72-78)
35 Yamaha XS-400 J/K "Maxim" (82-83)
35 Yamaha SR-500 E/F/G/H (78-81)
35 Yamaha XS-500 C/D/E (76-78)
35 Yamaha XJ-550 RH/RJ/RK "Seca" (81-83)
35 Yamaha XZ-550 RJ/RK "Vision" (82-83)
35 Yamaha XS-650 D/E/F/2F (77-79)
35 Yamaha XS-650 SE/SF/SG/SH/SJ (78-82)
35 Yamaha TX-750/A (73-74)
35 Yamaha XS-750 D (77)
 
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Good discussion.
All my bikes currently have pinch clamps. It is not difficult to keep the forks parallel. I understand how a well made taper may provide more contact area in some applications but the clamping area from two pinch bolts per triple clamp is larger.

Normally the pinched clamp will excert pressure at a few locations along the circumference only, mostly at 90 and 180 degrees to the slot. It's not like a hose clamp which extends and shapes itself.
Click to expand...
If the machining is well done why would this occur?
or the option of bolting on the full fork/wheel brake package,
Click to expand...
Two benefits- a 38 mm or 40mm fork is stiffer, and there are cartridge forks available. Having grafted a few front ends on bikes, finding a triple clamp with similar rake and trail is essential. I also like the ability to raise the fork legs to modify the steering
 
Pete Komarek said:
Good discussion.
All my bikes currently have pinch clamps. It is not difficult to keep the forks parallel. I understand how a well made taper may provide more contact area in some applications but the clamping area from two pinch bolts per triple clamp is larger.
Click to expand...

Only because the twin bolt yoke is thicker than a single bolt yoke, nothing to do with it being parallel. You could do the same on a tapered top yoke by making the taper a shallower angle so the yoke can be thicker.
 
mdt-son said:
Probably very accurate. I don't know about machining standards at the Villiers factory, but the tool shop at AMC was run to the highest standards. As long as the taper angle fits on both parts (steering crown and fork tube), the connection is as good as it gets.

-Knut
Click to expand...

Once when the Norton factory was being moved, they found they could not get the required precision with one milling machine. Somebody forgot to bring the board which was propped against it to steady the machining head.
 
Pete Komarek said:
Good discussion.
All my bikes currently have pinch clamps. It is not difficult to keep the forks parallel. I understand how a well made taper may provide more contact area in some applications but the clamping area from two pinch bolts per triple clamp is larger.

If the machining is well done why would this occur?
Two benefits- a 38 mm or 40mm fork is stiffer, and there are cartridge forks available. Having grafted a few front ends on bikes, finding a triple clamp with similar rake and trail is essential. I also like the ability to raise the fork legs to modify the steering
Click to expand...

A common move to adjust the bike's handling is to change the position of the fork yokes, up and down the sliders. With a Manx, you cannot do that and it is not usually necessary - but if you change the motor and thus the weight distribution, you can stuff the handling with no way back.
 
I had a carrier made for my Norton crank to accept a splined single-row JAWA speedway sprocket. The machine shop measured the taper on a standard sprocket and made the carrier. I was amazed at how good the fit was. I expected problems when doing that.
 
acotrel said:
Once when the Norton factory was being moved, they found they could not get the required precision with one milling machine. Somebody forgot to bring the board which was propped against it to steady the machining head.
Click to expand...

Yeah, it's nice folklore. In another version it's a lathe. Most likely neither is true. The Matchless factory had invested heavily in new tooling during the second half of the 50's and I doubt they had any use for clapped-out tooling from Birmingham, save for the jigs.

-Knut
 
Pete Komarek said:
I understand how a well made taper may provide more contact area in some applications but the clamping area from two pinch bolts per triple clamp is larger.
Click to expand...

Excuse me Peter, but that's an unsubstantiated statement. Bring up some numbers please, and let's compare equal size of fork tubes.

In a previous entry I wrote:
Normally the pinched clamp will excert pressure at a few locations along the circumference only, mostly at 90 and 180 degrees to the slot. It's not like a hose clamp which extends and shapes itself.

Pete Komarek said:
If the machining is well done why would this occur?
Click to expand...

Because triple trees are made of thick steel or aluminum plates which do not deform equally around the circumference. Essentially it's a piece of a curved cantilever bar pressing at some high spots against the solid plate opposite. The deformation charactersitic is quite different to a hose clamp. The only reason the japs make forks like this is cost of manufacture. The slotted clamp has no technical merits.

-Knut
 
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If you were manufacturing a bike with the tapered top fork yoke, how would you get the handling right first time, if you could not raise or lower the fork yokes on the staunchions ? I have only ever ridden one near-standard Manx and a couple of Tritons. But Cromie and Rex McCandless got the Featherbed Manx handling so right and Tritons usually fall short of the mark. These days most Manx Nortons have been modified, but for anyone who is really into bikes - a ride on a very original one around a race circuit, would be worth paying for.
 
kommando said:
Only because the twin bolt yoke is thicker than a single bolt yoke, nothing to do with it being parallel. You could do the same on a tapered top yoke by making the taper a shallower angle so the yoke can be thicker.
Click to expand...
Of course but we are comparing the Norton top triple to various parallel triples.
 
I measured my various triple clamps (35mm) to compare against the Norton- twisted the front end while holding the front wheel with my knees

Norton-top triple thickness at the clamping area-7/8", bottom-1 1/4"-Little twisting deflection- maybe 1/2"
Betor forks-two pinch bolts, both 1 1/4"-similar twisting deflection
Moto Guzzi- one pinch, top 1", bottom 1/14"- less than the two above
BMW-one pinch (aftermarket) 1/14", bottom 1"- twisted 3/4-1"
CZ- two pinch bolts, both 1/12"- twisted 1/2"
One part of the equation not mentioned is the front axle. The bikes with thinner axles will twist more ie. the Moto Guzzi has the thickest axle. The Norton's axle is much thicker than the BMW's and the CZ's.

Obviously this merely a comparison,not a scientific evaluation. I do not see a great benefit to switching to larger parallel clamps unless I was grafting on a stiffer front end.
 
I can think of one very good reason to use the parallel type - they are much more versatile. With the taper type, there is no way to adjust a bikes handling which is not extremely expensive. With the paralleltype, you can undo the pinchbolts are raise and lower them to alter the bike's trail. Evenwhen I have been able to twist the taper type, it has never affected my bike's feel when ridden fast.
 
Fork yokes and frame rake are a black art. The only person I have read about who has done a lot of experimentation is Tony Foale. He managed to make some generalisations about the design limits. He said the ends of the usable range are stable and self-steering. A friend of mine has made lots of yokes for various people, however the offset is always very similar to the original yoke for the particular bike. In Australia a lot of guys convert road bikes for historic racing. Most of them tend to take the wide line in corners where the genuine racers take a tighter line. Making fork yokes is expensive and if you get it wrong the result can be a nasty crash. What I have on my Seeley, I found mostly by accident. Some guys on this forum have said it probably suits my riding style, however I don't have a style. I ride the bike to the limit and adjust to it. The way my bike is currently set up, it self-steers a lot to tighten it's line, when gassed hard coming around corners. It means I have to know how much it will turn and anticipate where I want to be after I have left the corner. I really like it. It allows me to be extremely aggressive. If you did it with a superbike, it would probably kill you.
 
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