SBP help! Skyhawk GT frame with SBP crank??

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Jerrycurljuice

New Member
Apr 29, 2014
8
0
0
Germany
Hello everyone. I have been lurking around a bit and am now posting my first post. I am building my very first motored bicycle and i have decided to go with a Skyhawk GT frame. Naturally i bought a SBP HD kit from all the great reviews i keep seeing from this page. How in the world does the crank fit in the huge hole that this frame i have.. am i missing something? thanks guys (everyday there is something else preventing me to ride grrrrr) :-||
 

Jerrycurljuice

New Member
Apr 29, 2014
8
0
0
Germany
yeah i just got educated.. shows how out of the loop i am... i never even seen this type of crank before.. well the wait for the part continues
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
for the time being here is a picture of the build from a week or so ago.. far from done
You are going to leave the frame the unfinished acid bath gold and not put a finish on it?
Considering the money you are putting into it with that expensive frame, all the bike parts, and a shift kit you really owe it to yourself and the bike to put a finish on it as they really turn out well.



Just take the frame, jackshaft back frame, and all 3 of your 2-stroke engine covers up to any local auto body place and have them throw a couple of coats of paint and lacquer on it for ~$80, you'll be glad you did when it's done and you can pick any color you want ;-}

Here is a tip for installing the 3-piece bearing cups in your now empty bottom bracket 1-piece crank hole.

1. Take a 1/2 round file to the hole on each side where the press in bearing cups were and file them smooth to make the new bearing cups go in easier and straight.

2. The new threaded bearing cups are NOT the same, there is a left and right side. Some have an L or R stamped or painted on, some don't.
It is crucial you get them right.

To see which one goes on which side look at your threaded sealed bearing axle cartridge.
It looks like one piece with threads on each end but it's not.

Grab both threaded ends and twist and pull it will come apart as 2 pieces, the main piece and just a little threaded cup.
The cup that goes on the right side is reverse threads and the part the main axle parts crew into backwards on the right.

The little connecting cup piece screws in from the left once the right side is in all the way as far as it can go.

One other clue on the cups is the 3 or 4 long skinny bolts screw in from the left side cup so it has a little recess for the bolt heads and no threads, the right side has threads for the bolts to go into.

3. Since your bearing cups are threaded they have to in straight so the axle goes in straight and the bolt holes align.

I just align one hole on each cup pointing at the seat post or straight up.
Push them in as far as you can by hand then take a chunk of 2x4 and place it over the cup and whack it with a sledge hammer until it is in all the way and flush up against the bikes BB hole on both sides.

4. Gently screw in the main axle cartridge in from the right counter-clockwise.
These are extremely fine threads and easy to get miss-aligned.
I find holding the left side of the axle centered in the left hole helps you get it straight and screwed in.

It should spin in all the way with little effort with your fingers, if it feels like you need a tool then it's not threaded right.
Leave it out about an 1/8" from all the way in and get your left side piece started turning clockwise.

It should spin freely by hand as well until it meets the cartridge and has to slip around it to make a solid one piece unit again.
This is where many get it wrong.
If the bearing cups are not aligned the pieces won't cup si if you tighten it there the left side is just butted up against the crucial right side and offers no support.

With no left support for the right side of the crank axle , as soon as you through power at the right side via the freewheel dual sprocket the axle will move as only the right bearing cup is dealing with all the torque!

Now get the left side in and make sure it gets around the cartridge, then torque the right down tight with the special star socket, then tighten the left side in until it seats at the stop on the cartridge barrel itself and use the star socket on it as well.

Get it right and you have a new 3-piece crank set with sealed bearings you will never have to mess with again that will take the power transfer from your engine to your pedal side back wheel.
 

BOYGOFAST

New Member
Sep 28, 2013
124
0
0
Citrus Springs Fl.
use a steel conversion kit for the crank the not aluminum if you can avoid aluminum to mount the system to the bike frame and trim the excess weight off the kit with a bench grinder and metal cutting tools too my personal advice
 
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BOYGOFAST

New Member
Sep 28, 2013
124
0
0
Citrus Springs Fl.
first don't take a file to that soft aluminum frame use a hammer to drive bearing cups in place that's that, and don't use the aluminum conversion kit and thirdly send the sick bike deluxe parts and buy the cheapest kit it was going @about a hundred bucks a week ago and don't forget the thread locker on the final assembly that's about it
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
first don't take a file to that soft aluminum frame use a hammer to drive bearing cups in place that's that.
I have a nice sized 1/4 round file I prep all BB cavities with regards of frame material.

Hold a piece of wood between the cup and hammer.
Dead blow with an 8# slede of piece of 2x4 against the cup gives it a nice nudge in.

Note the orientation letters on the cups, there a left and right, the left side has reverse threads.

Last but far from least is lining up the bolt holes on each cup.
I just make sure a hole on each cup is at 12:00.

send the sick bike deluxe parts and buy the cheapest kit it was going @about a hundred bucks a week ago and don't forget the thread locker on the final assembly that's about it
The only price difference between the basic shift kit and HD shift kit is the cost of the freewheel sprocket bearing.

The $20 basic kit bearing is OK for lower watt electrics and stock 48cc gas engines, much more or a bad shift will rip that cheap bearing to shreds so bad you can't even get it off the right side special crank arm or get the inner sprocket off so you have to buy the whole darn thing again.

I won't use the cheapie on anything more than a 350W electric shifter.

The HD in the HD kit is the $85 freewheel bearing.
I build a lot of shifters and haven't been able to break one yet.

As far as the Deluxe kit goes, it includes most of the specialty tools you are going to need for a little than what it will cost you go back and buy them when you need them.

If you already have them don't go deluxe, just HD, but know that it can be a very expensive gamble to use the cheap freewheel bearing.