OzVMX Forum
Marque Remarks => Spaniards (Bultaco, Ossa, Montesa etc) => Topic started by: TooFastTim on May 13, 2013, 06:38:39 pm
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(https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-prn1/486466_3985594130457_1226814723_n.jpg)
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Must have spent all his money on that fancy linkage and had none left for a new tyre ???
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So you noticed that too ;D
Bill, Bulto played with the parallelogram suspension for a few years but eventually gave up on it.
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What are the percieved advantages of the system
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Constant chain tension with long travel suspension.
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Not to mention the chain is on the other side! WTF?
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Also pipe is I think on wrong side and there is some weird sprocket cover happening with the drive somehow switched to the other side. Also something going on with the kickstart. Who belongs to this thing? Tell us more please. J
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Not to mention the chain is on the other side! WTF?
Good point. I hadn't noticed. But if you look carefully it uses a cross-over shaft where the s/arm pivot would be.
Jerry, the exhaust is on the same side as the later (MK11 and 12) pursangs.It seems hand made and a pretty good job too.
This seems to be a very good home made example and I have recently, seen a pic of the factory version. When I find it I'll post it.
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Same bike. Other side:
(https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-frc3/430022_289662967761563_1647120299_n.jpg)
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Nice work Tim it's got me stuffed why all the trouble to shift the drive to the other side not to mention the extra weight. Where did you find the photo? J
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Just noticed its a right shift version too. J
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it's got me stuffed why all the trouble to shift the drive to the other side
Just guessing but perhaps it's to take advantage of some sort of torque reaction? ???
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The main chain is on the RH side because there is a lay shaft that is driven from its LH end from the usual gearbox output sprocket. The main chain drive is on the RH end of the layshaft because it is neater to do it that way with the other chain on the LH end.
The funny cover seen on the LH side is enclosing the first chain and the LH end of the layshaft.
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Yeah but why? What's the advantage? J
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Model # 171 /172, Pic outa the { Historia de la Pursang} book may even be the same bike .
(http://i1260.photobucket.com/albums/ii576/KAB171/bulp_zps2625b3d2.jpeg) (http://s1260.photobucket.com/user/KAB171/media/bulp_zps2625b3d2.jpeg.html)
(http://i1260.photobucket.com/albums/ii576/KAB171/bulp1_zps60d7d5d1.jpeg) (http://s1260.photobucket.com/user/KAB171/media/bulp1_zps60d7d5d1.jpeg.html)
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Thanks Kev I think I get it now. It's all about the chain tension. You were all over it Tim, I'm just a slow learner! J
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It wasn't just to keep constant chain tension. It was to overcome chain torque reaction & supposedly give more drive. Kawasaki tried it too (called Fubar system) in both MX & RR. Duhamel was said to like it for RR (or at least think it had potential). Weinert didn't - couldn't wheelie readily. I think the story was some yanky entrepreneur (perhaps more cynically called a con-man?) made all sorts of claims & Bultaco bought the rights but couldn't get it to work to any advantage.
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Kawasaki tried it too (called Fubar system) in both MX & RR. Duhamel was said to like it for RR (or at least think it had potential).
Oh yeah. Now I remember Kawasakis efforts.
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What does fubar stand for? J
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Fuct up beyond all recognition
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Ah of course, thank you Bill
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Looks like it's designed to allow the front drive sprocket to be as close to the swingarm point as possible, to overcome the problems created by longer travel and a front sprocket situated a long way from swingarm pivot.
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What about the shock length, are they the worlds longest? Can someone smarter than me (anyone, that is) work out from the drum/wheel diameter how long they are?
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A single shock version made it into the mtb world years later http://www.google.com.au/url?sa=i&source=images&cd=&cad=rja&docid=7rn6TzZx04LwBM&tbnid=eqgDXhzBvODY1M:&ved=0CAgQjRwwAA&url=http%3A%2F%2Fvulkanlandbiker.at%2Fgallery%2FMeine-Bikes-(Trikes)%2FSchwinn_Straight_8%3Ffull%3D1&ei=eOmWUbvZMaWgige_rAE&psig=AFQjCNE12x1KehjlRpRE2Kpl24bAKYKqIA&ust=1368931064876106
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(http://i1112.photobucket.com/albums/k495/firko2/k17_zps9b612666.jpg) (http://s1112.photobucket.com/user/firko2/media/k17_zps9b612666.jpg.html)
"Fu-Bar" parallelogram rear suspension and frame as used by Yvon Duhamel at Laguna Seca in 1975.
(http://i1112.photobucket.com/albums/k495/firko2/guzzirearend_zps90563523.jpg) (http://s1112.photobucket.com/user/firko2/media/guzzirearend_zps90563523.jpg.html)
1946 Moto Guzzi Dondalino with parallelogram rear suspension similar to the Gilera Saturno design.
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I don't see a parallelogram on the Moto Guzzi Dondalino but I do see reduced unsprung weight.
Also I can see how it would stop wheelies, should work for road racing.
cheers pancho.
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To be honest I don't see how the Gilera back end works at all, there is 2 mounting points to the frame each side but no pivots at the axle end or is the lower mount not connected to the frame & instead to a sprung loaded plate under the engine?
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Just looked at the Bultaco interesting thing even the front fork legs are from a Matador or Sherpa. My MK9 250 i raced back then had a high pipe the same as that one i got it from Frasers at Newstead, Brisbane,