Skyhawk Frame Build

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S1xties

New Member
Feb 24, 2012
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Bozeman, MT
So, I am going to build a motorized bike using one of the skyhawk frames, with the built-in gastank. I'm pretty excited, because I think it will look pretty nice. I've already ordered a frame and 66cc motor, and picked up a newer whizzer fork off of the ebay.

These first parts came in this week, so I did a mockup:


The wheels are NOT what I'll use - they were just stuff I already had laying around the house, so I used them in the picture.

Here are some of my goals for this bike, as I build it up (not really in any order):
-Disk brakes
-Shift Kit
-Internal Hub (not sure what will work with discs)
-Big, fat tires (24x3s)

There's some other stuff too (like handlebars & a seat!), but I think these are the tricky issues for now.

Let me know what you think! Does it look doable, or am I crazy? (wait... don't answer that last part... I know I'm crazy already)
 
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S1xties

New Member
Feb 24, 2012
8
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0
Bozeman, MT
Thanks for the encouragement guys.

Bill - it is the aluminum frame. I picked it up from Gasbike.net, along with a new motor for this build. The price on the fork seemed resonable, but shipping was killer - it came from Tiawan

I've been looking into what it will take to mount disc brakes on this bike over the last day or so. I think the front will be pretty straight forward: grind off the whizzer bracket, and fab/weld my own to match IS specs. The rear has me worried though...

I'm thinking I'll either make some kind of slotted mount to weld onto the frame (not my bike - found this example through google image):


Or I'll make some kind of slider (also a borrowed image):


Any thoughts? I think for now, I'll focus on the wheels. Then, maybe I'll have a better idea what I'm looking at in terms of spacing, and if I'll have room for something crazy like the sliders.
 
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S1xties

New Member
Feb 24, 2012
8
0
0
Bozeman, MT
So, I'm looking for advice now... dealing with brakes and hubs.

I think I've narrowed things down to the following options for rear hub & brakes (keeping in mind that I'd like to run a SBP Shift Kit too):

Sturmey Archer XL-RD3 (Internal drum brake)
SRAM i-Motion 3 w/ Avid BB7 Disc brakes
Shimano Nexus Inter-3 w/ Avid BB7 Disc brakes

I guess I've got a few questions:
Can anyone compare the braking power of the SA Drums vs. the Avid Discs?
Do any of these three specific hubs have a good/bad track record?

Reviews that I've found of the brakes all seem good, but I haven't really found anything that compares them. Likewise, I've seen some threads with folks using internal hubs with a shift kit... but has anyone managed to push one past its limits yet?

If these important criteria don't help me decide, I guess it'll be up to cosmetics/cost/ability!
 
Dogtown Burner

Dogtown Burner

New Member
Sep 15, 2011
349
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Los Angeles
S1xties said:
So, I'm looking for advice now... dealing with brakes and hubs.

I think I've narrowed things down to the following options for rear hub & brakes (keeping in mind that I'd like to run a SBP Shift Kit too):

Sturmey Archer XL-RD3 (Internal drum brake)
SRAM i-Motion 3 w/ Avid BB7 Disc brakes
Shimano Nexus Inter-3 w/ Avid BB7 Disc brakes

I guess I've got a few questions:
Can anyone compare the braking power of the SA Drums vs. the Avid Discs?
Do any of these three specific hubs have a good/bad track record?

Reviews that I've found of the brakes all seem good, but I haven't really found anything that compares them. Likewise, I've seen some threads with folks using internal hubs with a shift kit... but has anyone managed to push one past its limits yet?

If these important criteria don't help me decide, I guess it'll be up to cosmetics/cost/ability!
Click to expand...

Yo Sixties! mine came on tuesday night, and it looks like the build race is on! you and me buddy. I'm so excited I could S***! so, in trying to help I can offer this: I have 160mm BB7's on 3 bikes and I love them. they are lightweight and functional with no hydro fluid to bug you; no bleeding, weight, etc... although I did have a guy at a bike shop keep asking me when I was going to get some real brakes....and they do heat up in santa monica every-block-a-stop sign ****, but they work, and without much complaining. that being said, I am going to ante up to the 230mm rear disc for this bike and shine the whole drum thing. one hardly even uses the rear brakes on a bike anyway. ever check out a GSXR? double fronts and a puny rear disc. so I'm choosing to keep the weight down and do no rear drum. I like the 2nd pic you posted. that mount looks like a tad overkill but on the right track for sure. i'm curious where ya found it!
I know Norm built a coupla sweet Felts with 8 speed shimano internals and the shift kit. looked like a nightmare up close. i mean, excellent work by him but a LOT of work. LOT of work. oh and did i say, LOT of work? lol
anyway I'm stuck in the creative aspect of which front end to use. the fellas at pistonbikes suggested a solid fork for the track, but I like the cushion of my monark II's. theyre pretty darned stiff, (and maybe those guys have only seen first gen monarks). these new ones are almost so stiff that I didnt notice a difference from the stock solid fork. the gas cap still flew off at 30mph over that ol bump on my street. but theyre still heavy as a tank; a panzer that is.
I see that you are going solid triple-tree from the x-mas morning carpet/cat photo. looks like it'll be a cool bike for sure. keep us updated, and I will start a thread when I get back home this week!

DT
 
Dogtown Burner

Dogtown Burner

New Member
Sep 15, 2011
349
3
0
Los Angeles
S1xties said:
Thanks for the encouragement guys.

Bill - it is the aluminum frame. I picked it up from Gasbike.net, along with a new motor for this build. The price on the fork seemed resonable, but shipping was killer - it came from Tiawan

I've been looking into what it will take to mount disc brakes on this bike over the last day or so. I think the front will be pretty straight forward: grind off the whizzer bracket, and fab/weld my own to match IS specs. The rear has me worried though...

I'm thinking I'll either make some kind of slotted mount to weld onto the frame (not my bike - found this example through google image):


Or I'll make some kind of slider (also a borrowed image):


Any thoughts? I think for now, I'll focus on the wheels. Then, maybe I'll have a better idea what I'm looking at in terms of spacing, and if I'll have room for something crazy like the sliders.
Click to expand...
where'd you find that 2nd image sliding caliper mount?! love it.wee.
 
S

S1xties

New Member
Feb 24, 2012
8
0
0
Bozeman, MT
Burner -
Sorry I didn't catch your reply sooner! I don't remember the website where I borrowed the image, but that style dropout is called a 'slider.' Run a google image search for 'sliding dropouts', and you'll find a TON of examples. The only problem I see with them is the hassle. Most of the dropouts I've found are blanks ready for frame-builders.


I guess I should also make an update on my progress! I finally settled on running drum brakes. It wound up being cheaper, and follows a KISS approach, rather than over complicating the build.

I'm going to use the following to build up my wheels:
Sturmey XL-FDD front hub (bigger drum brake & dynamo)
Sturmey X-RD3 rear hub (smaller drum brake & 3-speed internal)
12ga spokes
Alex DX32 Rims
Fatti-O 24x3 tires



I have all of the supplies but the spokes sitting in my living room, waiting to be put together, and making it hard to focus on anything else! I mounted one of the Fatti-Os on a rim last night because I just couldn't wait to see it, and it looks like it should fit in the frame without having to modify the rear stays.

I want to paint the hub shells and rims red before I build the wheels, to get a look something like these wheels (borrowed pic):


I've also got to figure out how to make the narrow dynamo hub fit the super-wide (140mm) spacing on the Whizzer fork. I have a couple ideas for spacers, but I'm still mulling them over.

Also - if anyone who has more experience would be willing to double check my spoke length calculations, that would be super helpful. I think I'm on the right track with them, but I haven't ever built a wheel before, so I'm a little apprehensive.
 
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S1xties

New Member
Feb 24, 2012
8
0
0
Bozeman, MT
Just a quick update - I've finally got my wheels built up, and the bike is starting to come together. I still need to figure out how to mount the front wheel (The hub has 110mm OLD, and the fork dropouts are spaced at 140mm), which I think will involve welding on some custom dropouts on the fork.

Anyway, I mocked things up last night, and took a picture:
 
MotoMagz

MotoMagz

Well-Known Member
Aug 2, 2010
1,817
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Michigan
what size axle does the fork take if it is 10mm you can get new longer 10mm axle drill a few spacers out inside the hub and you are good to go.Scotto did this and so did I with the K10 forks.If you want a longer 9mm axle and new bearings for that hub let me know in a pm cuz I got them.
 
MotoMagz

MotoMagz

Well-Known Member
Aug 2, 2010
1,817
1,154
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Michigan
Shoot I thought it was the 90 drum only.If it does not have a special axle you could use the parts I have.If it does you might hve to do some work to the forks instead.Let me know if you tear it open ...and whats inside.
 
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