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Post by JA-Moo on Dec 2, 2012 18:30:42 GMT -5
Have a look at Nev Lush's H1B framed (essentially the same as an H1A) 750 racer for some ideas: kawtriple.com/mraxl/articles/bushwacker1.htmI believe he said it weighed 341lbs full of gas. Pay attention to the jacked up rear end, long swinger, and small offset triple clamps, that pull the front wheel back. The end result is a weight distribution/geometry/handling more in line with a modern sport bike. J Nev told me the writer got it wrong, it's a 73 or later frame.....
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Post by lc on Dec 2, 2012 18:53:49 GMT -5
Interesting! Well its got an H1B gas tank on it?.... OK, the main difference between the early H1 frame and the late frame (besides the tail end and the round rear foot peg mounts) is the frame neck angle. The later frames were raked back and subsequently fitted with a less offset triple clamp (50mm VS 58mm) to regain the trail: kawtriple.com/mraxl/modelspecs.htmlAlways figured it would not be too hard to bolt an early frame to a concrete floor (leveled at swinger pivot and plumbed at neck), cut the spine tube at the neck (and maybe the two down tubes at the neck, and use a good fitting pipe in the neck to reset the rake as desired. The spine tube gap will be about .070in. per degree of rake reduction (depending on where the remaining neck structure yields, but application of heat during the process could determine this)..... Finish by adding a welded tube splice repair to correct the now spine tube gap and re-weld the down tubes. Re-check neck for desired angle and any incorrect twist.... Any incorrect twist could be "adjusted" with a long bar in the neck prior to welding reinforcing plates (these frame necks have been noted to bend easily in the simplest of spills). Or, Jack up the rear end a couple of inches (it already has an 18in. front wheel) and it will be just fine for street use! J
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Post by seaglider on Dec 2, 2012 18:54:11 GMT -5
You guys probably have already looked at this....but I thought I'd send this link along for those who may not have found it... www.mojokawasaki.com/history/h2raninsidelook.htmlFocused mostly on engine development from back in the day...I like the part where he sez "Spectators and riders alike saw this unit wiggle violently on more than one occasion, but as long as the center of mass is pointed down the track and the thing is on its wheels, all the oscillations can do is try to frighten the rider. They didn’t." All fine and good for Yvon....I think I want this machine to be a little less interesting...embarrasing having to clean out your pants! ;D
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Post by Walms on Dec 2, 2012 20:30:45 GMT -5
Here's a link to some FEA results from a variety of braces added to stock 400 frame. What it will show you is how the bracing reduces the flexing... Whether the bike is pushed to the point that it is required, probably has allot to how hard you ride and how much you weigh. It's always worth to take a grain of salt when a 140 lb guy tells you that bracing is not required... triplescanada.proboards.com/index.cgi?board=general&action=display&thread=3111
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Post by drewski on Dec 2, 2012 21:40:30 GMT -5
Good feedback... thank you all. Does anyone think that the difference in engine weight will make any significant difference to the handling? I know whatever weight increase there is, is carried low, which certainly helps. Just curious what you all think about that. The 18" front wheel, along with the 14 1/2" shocks should help the overall handling package. I don't think we'll get too radical with the back bone tubes at this point, unless someone wants to step up to volunteer their services. We could undertake laying the shocks down to improve the suspension action and increase the rear ride height. Yes Walms, neither Don nor I have seen 140 lbs since our early teens!! ;D Right Don?!?! Gussets to prevent it from collapsing under us might be helpful! ;D
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Post by lc on Dec 2, 2012 22:06:53 GMT -5
It has been reported the 750's big heavy crank causes allot of gyroscopic effect. Hence the handling in the "twisties" is sluggish/heavy compared to the smaller engined triples.
Leo has a 750 powered 400 chassis bike. He has stated he gets beaten badly by the regular 400s in the twisties....
Otherwise the 750 in a 500 chassis is a popular conversion.....
J
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Post by seaglider on Dec 2, 2012 22:29:47 GMT -5
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Post by drewski on Dec 2, 2012 22:34:06 GMT -5
It has been reported the 750's big heavy crank causes allot of gyroscopic effect. Hence the handling in the "twisties" is sluggish/heavy compared to the smaller engined triples. Leo has a 750 powered 400 chassis bike. He has stated he gets beaten badly by the regular 400s in the twisties.... Otherwise the 750 in a 500 chassis is a popular conversion..... J Ya, I guess it's the quick right/left/right transitions in roadracing that would be most affected by that gyroscopic effect. I figure with some thoughtfully added frame bracing, small/simple improvements in the front end geometry, rear suspension improvements, attention to swing arm bushings and head stock bearings, properly built and trued wheels and some good rubber, we should be off to a super start with this thing.
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Post by drewski on Dec 2, 2012 22:39:05 GMT -5
Haha! LOVE it!! Not sure about the "racing" part. We could substitute "moto" or "special"? "Sea & Ski Special" Still need work?
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Post by seaglider on Dec 2, 2012 22:46:39 GMT -5
I have the rights to the Logo ;D so I can always change it..... I didn't take the "racing" part seriously....maybe others would...so let's think about it.... I liked it enough to change my avatar....HA!
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Post by seaglider on Dec 2, 2012 23:16:11 GMT -5
It has been reported the 750's big heavy crank causes allot of gyroscopic effect. Hence the handling in the "twisties" is sluggish/heavy compared to the smaller engined triples. Leo has a 750 powered 400 chassis bike. He has stated he gets beaten badly by the regular 400s in the twisties.... Otherwise the 750 in a 500 chassis is a popular conversion..... J Ya, I guess it's the quick right/left/right transitions in roadracing that would be most affected by that gyroscopic effect. I figure with some thoughtfully added frame bracing, small/simple improvements in the front end geometry, rear suspension improvements, attention to swing arm bushings and head stock bearings, properly built and trued wheels and some good rubber, we should be off to a super start with this thing. Agreed....and yes I was proabably 13 when I passed 140....just thinking about setting sag in the suspension....HA!....if it's set so I don't bottom out you'll be finding it a little stiff Haven't weighed myself for a long time but I'm north of 220 that's for sure....may need some new springs in those forks!! ;D
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Post by seaglider on Dec 3, 2012 8:45:32 GMT -5
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Post by pipe welder on Dec 3, 2012 21:32:29 GMT -5
Don't know why but "Sea & Ski" reminded me of the Boa Ski Snowmobiles we had at Manley's back in the day. A blast from the past. ;D As for frame bracing that Seasmoker, I learned my tig welding skills doing frame bracing with Ross Sully Metal Specialties on race bikes back in the 70's. I think you guys are on the right track. If I had a welder I'd do it up for ya. But the welder's on my list that I just mailed to the North Pole. ;D
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Post by seaglider on Dec 3, 2012 22:10:55 GMT -5
Don't know why but "Sea & Ski" reminded me of the Boa Ski Snowmobiles we had at Manley's back in the day. A blast from the past. ;D As for frame bracing that Seasmoker, I learned my tig welding skills doing frame bracing with Ross Sully Metal Specialties on race bikes back in the 70's. I think you guys are on the right track. If I had a welder I'd do it up for ya. But the welder's on my list that I just mailed to the North Pole. ;D Saw a few Boa Ski's up in Sudbury when Drewski and I were living up there back in the late 60's....cool! Hey here's hoping Santa is good to you!! We'd be pleased to have you work on the first Sea n Ski Moto production!! ;D ;D
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Post by drewski on Dec 5, 2012 14:01:11 GMT -5
Lovin' the logo Don! Man... Boa Ski!! I hafta dig deep into the memory archives to remember those!! Looks like we have welders "lining up" for the new year! Thanks Dave and Jim!! Either one would do a great job!! Certainly well above and beyond my skill level!! Haha!
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