Hello - building kit bike to Triumph Bicycle

bdavanza

New Member
Nov 19, 2008
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oak cliff tx
Hello
I picked up a kit on ebay, supposed 80cc kit from powerkingshop. I build/fix restore Triumph motorcycles and I have a cool 3 speed Triumph Bicycle, I think made by Raleigh and want to make it a baby Triumph.
The motor seems to fit the frame fairly well but the Sturmey Archer 3 speed hub looks way too big for the sprocket to fit onto. I could use some help and advice in the is area. I cut the rubber gasket to get it on the inside of the spokes and it does not fit all the way around the hub. I have considered changing this to a coaster brake hub for the rear, as I have a hub, spokes and a rim but I'm not very experienced with truing wheels. One other problem I have is the gas cap does not want to come off the tank. I think I can get that solved though. I have searched the forum for Sturmey Archer / 3speed etc info and I haven't found much. Any advice/help/etc appreciated. Here are some pics of my mock up.
Thanks
-Ben
 

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bdavanza

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Nov 19, 2008
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oak cliff tx
Thanks for the input, The coaster brake will reduce some of the cables, levers, etc. and allow me to save the 3 speed in case I want to restore this bike.
-Ben
 

bdavanza

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Nov 19, 2008
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With regards to my crank arms, they are the 3 piece type that clamp around the shaft. They are aluminum. Do you think it can be bent, in a dogleg fashion, to clear the motor, or do you think there are off set crank arms available for this type of bike?
-Ben
 

bobmcmillen11

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Sep 9, 2008
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Rather than bend or buy new crankarms, I would try to find a longer spindle. Cottered cranksets aren't very popular at the moment, but a real bike shop should have a good assortment of them. Should be dirt cheap. You could also make one out of round stock, and replace the loose balls and cups with roller bearings.
 

2door

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Sep 15, 2008
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A couple of things: 1st, I'd love to have a Triumph decal like that one on your tank. That's too cool.
I tried to find Sturmey Archer parts a couple of years ago and found plenty in England. There are collectors of those old 3 speed hubs but are willing to part with them but they're proud of them so expect to pay top dollar. I agree with the idea to replace the rear wheel, save your original, and find a good coaster brake hub.
I've not had to deal with the extended crank arms so I'd listen to the advice from the guys who have on that point.
It is a good looking bike, thanks for sharing and welcome to the forum. Don't hesitate to ask all the questions you want. We're all here to help and have fun.
Tom
 

bdavanza

New Member
Nov 19, 2008
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oak cliff tx

bdavanza

New Member
Nov 19, 2008
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oak cliff tx
I thought the crank arms were aluminum, but after trying to remove a cotter pin I have discovered they are steel. The pin would not come out, even after applying penetrating oil, heat, and much hammering. Any suggestions out there? I got a coaster brake wheel assembled and trued (slight dishing in the rim but l/r barely any play) and would like to keep moving on this project.
I also noticed it's difficult to get the sprocket straight on the spokes, it has too much run out for my taste. SO...
I am planning to
Bend the coaster brake arm out a bit
Use countersunk fasteners for the sprocket
Perhaps bend the crank arm out a (dogleg) to clear the motor
please any suggestions or advice
Also
I've read that the best and truest sprocket setup is from a disc brake style hub. In my old english 3 speed this would be odd looking. Is anyone selling pre fab'd coaster brake wheels/hubs that take sprockets on both sides?
Or at least a flange that could be tig welded to a coaster brake hub?
Thanks in advance
-Ben
 

xPosTech

The Old Master Motorized Bicycle Builder
Oct 23, 2008
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SETexas
If I were building that bike I think I would put a SBP shifter kit on it and keep the S-A 3 speed. Harris Cyclery has parts and replacements for S-A hubs (even 8 speed).

You would still need to replace the BB spindle. Take a look at Sheldon's cottered crank page.

From your seat post back your bike would remain stock.

Ted
 

bdavanza

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Nov 19, 2008
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oak cliff tx
xpostech
Thanks for the advice.
I had looked into the shifter kit, but the 200 bones is more than the whole engine kit cost. I have yet to ride one of these kits and I hate to sink in more money than I would get out of it as far as riding goes. I have a lot of motorcycles to ride...
I have the rear wheel figured out now, so it's a matter of replacing/changing etc the crank. I have a C clamp I modified to be a valve spring compressor, hopefully that will allow me to get the cotters out. Sheldon's page is helpful.
If the bike is as fun as I hope it will be to ride, the shifter kit could be very cool. My S/A 3 speed is only engaging 1st and 2nd at the moment, so I'd be looking at rebuilding that or finding a nexus hub. I have a nexus 3 on one bike and a 7 on another, they work great!
-Ben
 

bdavanza

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Nov 19, 2008
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oak cliff tx
Update-
I got a longer spindle at a local bike shop, and it just fits perfect! for some reason the spindle was only slightly longer on the side where the clearance was ok, but about 1/2" longer on the side where I needed it most. Getting those cotter pins out was ****, though. If I had to do it again, I would strip the bike down to the frame, put it on a bench and whale on it in the vice.
I found a coaster brake hub that fits the sprocket, but I realized it's 36 spoke and my wheels are 40 spoke. UGH. It would be nice to have the same rims front and back. Ok so I also was given a british coaster brake hub, a Perry, which looks very nice, and is 40 spoke, but the sprocket hole is too small. I have been enlarging the hole by hand, using a metal file, grinding stone, etc, but I'm making this hole out of round faster than I'm making it bigger. Lining it up with the sprocket, even if it did fit around, the bolts hit spokes. This must be because of the extra 4 spokes on the wheel.
UGH. At least the crank fits!
-Ben
 

bdavanza

New Member
Nov 19, 2008
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oak cliff tx
The Triumph Runs!

Well today was the day, my Triumph breathed it first breath of pre mix and air..
I finally got a similar looking rim and laced it to a coaster brake hub, got the sprocket to fit and figured out how to get the chain relatively aligned. It's a good thing these chains are so forgiving! The tensioner is crap but I can live with it for now. One of the cottered cranks came loose immediately, you really have to whack those things with the hammer!
Anyway, it runs now and all my neighbors had to check it out. fun.
I imagine it would be much more interesting with balloon tires, a few gears and some suspension, but I like what I built. Sorry the pics are from my phone, I'll do it better justice later on.
 

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TimsBikes

New Member
Jul 1, 2010
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CT
Hey,
I am also building a Triumph motorized bike. I pulled its really rusty frame out of a dumpster and built it up with a Robinhood. I have run into a problem though. The bolt pattern on the gear is too small. Even the rubber spacer is not enough to take up the space between the hub and the gear. Did you run into this problem and if so how did you fix it?

Tim
 

bdavanza

New Member
Nov 19, 2008
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oak cliff tx
Timsbikes:
I had to ditch the 3 speed hub and wheel for the same reasons. I went with a simple coaster brake hub and a similar looking rim. Coaster brake because I wanted to have it act as much as my motorcycles, with a foot brake, right hand brake (swapped levers) and a left hand clutch. This also meant 2 less cables to mess with. The bike runs well but with skinny tires it's a little rough and squirrely, but I knew it would be. It is fun to ride.
 

TimsBikes

New Member
Jul 1, 2010
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CT
ok. yeah I tried a ten speed and that was too big. I can't find a one speed 26X 1 3/8 wheel right now. Do you really need to pedal start or can you just push off? I am thinking about using a front wheel or something.

Tim