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Author Topic: APS/Ω Gas turbine bike build  (Read 403877 times)
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RidgeRunner
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« Reply #405 on: April 06, 2014, 07:57:16 AM »

   Why not use steel for the tube clamp ballast mounts?  No gain for saving weight there and material cost savings might buy an extra beverage of choice down the road sometime grin

            Ed
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JimL
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« Reply #406 on: April 06, 2014, 09:14:55 AM »

I do not strap down the forks.  I just set up the final ride height and then limit the compression travel so I dont bottom my front fender into my streamlining.

I decided that I do not know more than the manufacturers about damping versus spring rate, so I run the forks stock at whatever the bike weight puts on them.  The engineers have already figured out what the damping should be at different compression levels, so wherever the forks are (stock) seems to work good.  That becomes very clear the first time you do hard braking on a modern sportbike and discover they keep steering well with the forks heavily loaded.

I just set up the height I want to run at, and then work on improving the aero to reduce front end lift under power.  Thats why I have to limit compression travel at low speed.  Simpler is better.

I was surprised to learn that some good research has proven that "too low" center-of-gravity near the steering head is a significant cause of high speed weave.  The report said that if the bike is not unstable at very low speed, it will weave at high speed.  I have lowered this bike twice over that last four years, and it has become much easier to push around by hand (less tendancy to flop over) and easier to drive off the line, BUT ....now it is beginning to require alternate pressure on the bars for the last two miles of a run.  It goes straight enough, at my low speeds, but it hasnt been staying exactly on the line I try for.

I suppose that explains why the sportbike engines keep getting moved higher and more forward as the bikes get faster.  This is an awkward trade off, because raising the bike makes the aero pull weight off the front wheel.  I have had the front end blow away at 150, before I started moving weight forward and lowering the bike, a few years ago.

Interesting , this trying to learn how to go faster. tongue
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Ellwood
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I do landracing on ice-Flying Kilometer in Sweden


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« Reply #407 on: April 06, 2014, 12:36:09 PM »


Hi, any idea when the first startup/run will be ? i would love to see it live.
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Mobacken Racing
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« Reply #408 on: April 06, 2014, 03:23:33 PM »

Ed: I like to work with aluminum, the difference in cost is neglectable and it wont ever rust on me so alloy it is.

JimL: The reason I need to shorten the forks is because my helmet will hit the top of the fork legs at speed position, you can see in the pic that I need to shorten them 5-6cm to get enough clearance. I´ll soon find out if the handling is affected by this, very interesting to read about your findings in this matter.

Ellwood: No idea, but I just got back from visiting the guy who will paint the frame for me so in two weeks or so it will have a nice black paint on it. I have some work cut out for me the next couple of weeks in other words, footpegs, seat, the mounts for the rear fairings and a couple of other stuff needs to be done by then.

With the frame painted and forks shortened I can start to assemble the bike again, so by the time summer arrives to the cold northern parts of Sweden it should be fairly ready for a test run. smiley

Cheers!
/Anders
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maj
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« Reply #409 on: April 06, 2014, 04:39:05 PM »

how much travel do you want ? , if you internally shorten (space them down) 50-60mm you will get your helmet clearance at your current ride height , if you take more you just get less suspension,

and if you adjust the preload up now , see how the forks react per mm  you get a better feeling of how much extra tube length to add

and you can fine tune it with the external adjuster later , also have a think about slightly heavier oil and less airgap as means of making the limited travel work as a package 
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JimL
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« Reply #410 on: April 06, 2014, 08:47:32 PM »

Anders, I am wondering how much you will have to slide them back down once your bike is up to weight?

I thought I was going to have to modify my FZR1000 forks, but after everything got stuffed in the chassis, I found it was good.  I notice that your bike is shorter front half than mine, so your position is more forward.

This might be a wait-and-see moment.

Regards, JimL
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Mobacken Racing
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« Reply #411 on: April 07, 2014, 03:05:28 PM »

maj: I haven´t given the travel lenght much thought, I know that with the current fork position the bike is level with me on it and taking 50 or so mm off the travel leaves enough I recon. Tuning them with preload and different oil viscosity should result in a decent working fork.

JimL: Hmm, food for thought there. I have the forks apart already and really need to shorten them since I cannot strike a decent riding position with the helmet hitting the fork tubes as it is now. Perhaps I should settle with 40mm to begin with and go lower later if I find it necessary. Good pointer there Jim!
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Seldom Seen Slim
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Nancy -- 201.913 mph record on a production ZX15!


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« Reply #412 on: April 08, 2014, 04:06:37 PM »

Anders:  Forgive me, but even for those from countries other than USA I tend to take my station as the comma cop seriously.  In your line "... travel leaves enough I recon. Tuning them with..." - - recon should be spelled "reckon", I believe.  Your command of the American version of English is outstanding, and that's why I'm pointing out such a minor error.  You're the envy of lots of Swedes -- and many Yankees, too.
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Jon E. Wennerberg
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grumm441
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« Reply #413 on: April 08, 2014, 05:02:27 PM »

Anders:  Forgive me, but even for those from countries other than USA I tend to take my station as the comma cop seriously.  In your line "... travel leaves enough I recon. Tuning them with..." - - recon should be spelled "reckon", I believe.  Your command of the American version of English is outstanding, and that's why I'm pointing out such a minor error.  You're the envy of lots of Swedes -- and many Yankees, too.

Jon, it's good that you have time to proof read some of us foriegn folks posts. I didn't realise (English spelling) that you spelled
length differently over on your side of the planet. Or did you miss that one  evil
G
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Chief Motorcycle Steward Dry Lakes Racers Australia Inc
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Seldom Seen Slim
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« Reply #414 on: April 08, 2014, 05:50:20 PM »

I do use the British version for many words that include a "z" - such as "realise".  I do that on purpose just to mess with the minds of the readers.

As for "length" -- hunh?  I missed that one.  Where'd I do it? huh
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Jon E. Wennerberg
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Mobacken Racing
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« Reply #415 on: April 09, 2014, 01:13:54 AM »

Anders:  Forgive me, but even for those from countries other than USA I tend to take my station as the comma cop seriously.  In your line "... travel leaves enough I recon. Tuning them with..." - - recon should be spelled "reckon", I believe.  Your command of the American version of English is outstanding, and that's why I'm pointing out such a minor error.  You're the envy of lots of Swedes -- and many Yankees, too.

No problems, thanks for pointing that out. I am fairly good at writing English but I am terrible at speaking it, I blame the school plus myself for spending all money on workshop projects instead of travelling around like many do.

I read a lot of English and American fantasy so that is probably where I´ve picked up most of it, you can´t avoid learning something while digging through 20.000-ish pages of Steven Erikson´s "Malazan Book of the Fallen". smiley

A busy weekend coming up for me, my family heads off to my mother-in-law tonight so I will have almost a week to myself where most of it will be spent in the workshop getting the bike frame ready for painting. I also have to make the seat and a set of adjustable foot pegs so a couple of project updates should drop in over the next couple of days.

Cheers!
/Anders
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grumm441
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« Reply #416 on: April 09, 2014, 04:13:39 AM »

maj: I haven´t given the travel lenght much thought, I know that with the current fork position the bike is level with me on it and taking 50 or so mm off the travel leaves enough I recon. Tuning them with preload and different oil viscosity should result in a decent working fork.


Jon, I don't want to go on at length about it
Anders, I struggle with writing, but I struggle even harder with being understood when I am in the USA.
They seem to think I'm from the south
G
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Stainless1
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« Reply #417 on: April 09, 2014, 08:22:57 AM »

G... You are from the south!

Anders, I would ask SSS about his command of languages other than English.... If'n he wants it all in perfect English he should install a spellin' and grammar program. 

I knew what you meant and that is all that is important when communicating. 
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Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.
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« Reply #418 on: April 09, 2014, 09:41:26 AM »

Anders and G. Slim just likes to as we Yanks say "pull your chain" cheers
G, Don't you live in south Texas? grin
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John Gowetski, red hat @ 221.183 MPH MSA Lakester, Bockscar #1000 60 ci normally aspirated w/N20
Seldom Seen Slim
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« Reply #419 on: April 09, 2014, 10:06:34 AM »

All right, I did mean it.  A while back Lars -- the Dane - made a minor mistake with his English, and when I commented (PM) on it he thanked me a couple of times for helping him learn our language better.  And keeping that in mind - is why I offered a spelling check for Anders.  It's not like I'd give you You or Stainless, JB -- you two deserve a round of abuse - just on general principles, you understand.
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Jon E. Wennerberg
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 Skandia, Michigan
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