Author Topic: Wacky inventions  (Read 54992 times)

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Offline John Orchard

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Re: Wacky inventions
« Reply #180 on: August 30, 2011, 04:12:13 pm »
With the increasing popularity of Vinduros those Skunk kits may have some relevance to those that love or have Pre 75 bikes. Get some extra travel for those events and help save the kidneys. Easy to put back to stock when needed. 


Aren't vinduro riders restricted to 4" at the rear in pre 75?
Johnny O - Tahition_Red factory rider.

Swiss

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Re: Wacky inventions
« Reply #181 on: August 31, 2011, 09:49:29 am »
Shoot, my shocks had 4.7" of travel in '74!  So much for Vintage!  As it was built back then it wouldn't even be able to compete in a Vintage class!  Not everyone was riding "box stock" factory stuff!

Swiss

Offline firko

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Re: Wacky inventions
« Reply #182 on: August 31, 2011, 10:27:12 am »
Quote
And the cost was about 1/2 of what the "name brand" shocks went for, and all high quality chrome moly parts.  Charlie Curnutt said he was making a fair profit on his products and couldn't figure out why the competition was charging so much for lower quality materials in their products!
I've got a couple of pairs of Curnutts that had been fitted to bikes I'd imported and must agree with Swiss that they're pretty good quality. In the seventies just about every desert racer had Curnutts on their bikes. I pulled a pair apart and found them to be very similar to Works Performance in design. Rebuild kits are still available somewhere online.
'68 Yamaha DT1 enduro, '69 Yamaha 'DT1 from Hell' '69 DT1'Dunger from Hell, '69 Cheney Yamaha 360, 70 Maico 350 (2 off), '68 Hindall Ducati 250, Hindall RT2MX, Hindall YZ250a , Cycle Factory RT2MX flat tracker, Yamaha 1T250J, Maico 250 trials, '71, Boyd and Stellings TM400, Shell OW72,750 Yamaha

Swiss

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Re: Wacky inventions
« Reply #183 on: August 31, 2011, 03:57:04 pm »
Firko, On my Curnutts I went to a Works style spring limiter with dual springs and small travel limit rings above the dividing collar.  That allows some tuning of the spring rate through the travel.  It will start out fairly soft (two different rated springs are always softer than either by itself) and when the travel limiter stops the short spring travel, it uses only the stiffer long spring.  Works Performance did this with I think as many as 3 different springs stacked together to control the progressive spring rate through the travel.  They had some "Trick name" for it but I don't remember what they called it back in the day!  The collar between the upper and lower springs is nylon, and keeps the springs from "ringing" on the shock body also, like the full length Curnutt springs had a tendency to do.  I remember guys spraying chain lube and WD-40 and such on their springs to try keeping them quiet.  Charlie used 4130 tubing for the shock body and the best quality springs that he could get so they tended to last pretty well.  People now say that they don't have a sophistocated damping system, but they ARE Period!  And there are still people pushing up and down on them and saying that they are too soft until they actually ride with them!  You can't test them with a push compression test!

Swiss

Offline firko

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Re: Wacky inventions
« Reply #184 on: August 31, 2011, 09:45:12 pm »
Thanks for that Swiss...I've got a rebuilt pair of 14" Curnutts on my TM250 but as that bike's about to get chopped up to make it into a flat tracker using shorter shocks so I might just use them on my race DT1 which needs 14'' shocks. What springs did you use for the two spring conversion Swiss? Do you have a photo of the conversion? I've got a few different rate Works and Yamaha springs for the two spring set up so I'll see if they will fit. I had Curnutts on my 360 Husky Auto back in the day and remember how soft they felt when static. It's only when you get going that their magic comes alive. They're a plain looking shock but it's surprising that they usually work better than the shiny shocks with all of the gizmos.

Speaking of which.....I've been doing a stocktake and rearanging my shed to make room for more bikes and while ferretting around I've uncovered five pairs of Arnacos. One pair are leftovers from the seventies when I had them on one of my Maicos, two sets are NOS off eBay and two more sets are second hand sets I've bought over the years for the mythical 'future project'. I've decided I'm going to build up a couple of sets for my projects to match the pair I have on my Cheney Yamaha. They're unbelievably high tech for 1973/4 with clicker external dampening adjustment and a simple but effective preload adjustment.
It looked as if Arnaco shocks would set the pace for shock development back in 1973 but an inbuilt seal failure problem seemed to end the Arnaco run before they could capture the market. They're close to as good as anything available today except for their unreliability problem but I've got a smart engineer looking at the feasibility of adding a second o-ring seal the see if that works in keeping the oil in and air out. If it does work it's going to save me some money on modern shocks for my bikes.
'68 Yamaha DT1 enduro, '69 Yamaha 'DT1 from Hell' '69 DT1'Dunger from Hell, '69 Cheney Yamaha 360, 70 Maico 350 (2 off), '68 Hindall Ducati 250, Hindall RT2MX, Hindall YZ250a , Cycle Factory RT2MX flat tracker, Yamaha 1T250J, Maico 250 trials, '71, Boyd and Stellings TM400, Shell OW72,750 Yamaha

Swiss

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Re: Wacky inventions
« Reply #185 on: August 31, 2011, 10:02:29 pm »
Here is a photo from the early '90s.  Shows the shocks with an aluminum sleeve on the body for length, and the dual springs with the spacer/sleeve.  I will see if I can get a photo of one of the shocks by itself.  I will have to check my notes and see if I have info on where I got the springs.  I got 3 pairs of shocks from Charlie over the '70s and had various springs. 



Swiss

My current 2 pairs of Curnutts are 5.5" travel and 5.9" travel.  The old SL125 had the early 4.7" travel shocks.  I bought the 5.5" travel shocks for the XL350 build in '74, finished the bike in '75 (first build).  I don't see in my notes where I got the shorter springs from, may have been with the later 5.9" shocks from Charlie? 
« Last Edit: September 01, 2011, 12:57:00 am by Swiss »

mx250

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Re: Wacky inventions
« Reply #186 on: September 14, 2011, 11:15:09 am »
http://www.ebay.com.au/itm/Vintage-Style-Pentagon-Grips-Honda-Mini-trail-Suzuki-/320705764035?pt=AU_Motorcycle_Parts_Accessories&hash=item4aab8d9ac3  ;) :D.

Although others considered these whacky I had a pair and quite liked them 8) - they conform to the clenched hand well.

Hmmmmm, maybe,  - do you guys promise not to point and laugh :P.

Offline Canam370

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Re: Wacky inventions
« Reply #187 on: September 14, 2011, 11:20:17 am »
Didn't Preston Petty do these style of grips too?
WANTED. Canams;all models,complete or parts.SWM stuff too!

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Offline dkupf

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Re: Wacky inventions
« Reply #188 on: September 14, 2011, 07:22:42 pm »
« Last Edit: September 14, 2011, 07:31:37 pm by dkupf »
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