Project "Rigged"

[Snarky]

I had originally bought this Mongoose Detour about 3 or 4 years ago with the intention of motorizing it. However it never happened. I ended up buying an XT255 instead, before progressing to bigger and better bikes. I still have always wanted a motorized bicycle for some reason, because it would be "fun".

I ordered a kit from pretty much the first retailer I found that wasn't "shady shady" imo and a week later I find myself putting it together. This is a 49cc rear mounted kit, with a 4 stroke honda-like motor.

This frame does not particularly lend itself to motorizing. There is zero possibility of a central mounted motor with this design, so you are left with the rear option only. Further more the kit intends for you to mount one support to the seat. Which is all well and good aside from the fact that the rear suspension moves.

My first goal was with this bike was to get it working as quickly as possible with the minimum amount of effort or expense associated with it. I wanted the bike built and running in one evening. I wanted to only use things around my house as parts. And I wanted to avoid busting out power tools.

First problem: Rear suspension lock down. I took the rear coil spring off and apart, and removed the spring. Then I took an old maglight and cut a chunk out of it. I reassembled the rear 'shock' with this maglight spacer in place. This solidified the suspension. Eventually I'm going to fabricate a bracket to move the horizontal support bracket to the rear swing arm, but not tonight!

Second problem: I'm missing a throttle cable. It might come tomorrow, it might not, but I wanted this bike running tonight! I removed the brake cable off another bike, added a chunk of copper tube to tighten up the length, crimped a barrel connector on the end of the cable, and put into place. I tested it and it's a bit rough, but it worked fairly well. Hopefully the cable will come tomorrow. If not, I'll email the vendor.

 

[young grease monkey]

.I've had those kind of situations a lot, really anxious to get 'er done. That's when I break stuff! Try not to permanently modify things when jerry-rigging a temporary setup. Nice looking build! I admire your mcgyver skills lol. Most 4 stroke clones are at least decent, can't go wrong with them. I would put a solid piece of metal where the shock was. That piece of tube will only stop down movement.

 

[wayne z]

Looks like your gear ratio is going to be way too high to be useable. You may not be able to get up enough power or speed to get the clutch to lock up at all.

I built a bike with that engine and a 3:1 gearbox, driving a 56 tooth wheel sprocket, and my gearing was still too tall. My clutch wouldn't stop slipping until about 22 mph.

 

[Snarky]

Here's the rest of my thread I couldn't post last night. But there was nothing really dramatic here.

That was pretty much it with technical side tracks. The sprocket
centered itself hub-centrically without needing measurement. The
tensioner just seems to 'work' despite an off angle.

I have no particular chain issues. It went together rapidly and
without drama. I think after I remount the horizontal stabilizing
bracket from the seat to the swingarm, I'll see about locktighting
everything down, and then work on a muffler (although the bike is
really quiet I don't like that it exits near me).

I might also weld up some better vertical brackets, though I do like
the adjustability of the all-thread rods.

I'm also waiting on lighting.

.I've had those kind of situations a lot, really anxious to get 'er done. That's when I break stuff! Try not to permanently modify things when jerry-rigging a temporary setup. Nice looking build! I admire your mcgyver skills lol. Most 4 stroke clones are at least decent, can't go wrong with them. I would put a solid piece of metal where the shock was. That piece of tube will only stop down movement.

I tried to make sure everything was reversible. The coilspring is reinstallable with two bolts and a nut, and the throttle cable slips right out.The coilover is adjustable, and the retaining ring is adjusted so there is no up movement from the "shock".

Looks like your gear ratio is going to be way too high to be useable. You may not be able to get up enough power or speed to get the clutch to lock up at all.

I built a bike with that engine and a 3:1 gearbox, driving a 56 tooth wheel sprocket, and my gearing was still too tall. My clutch wouldn't stop slipping until about 22 mph.

I haven't had any problem with it yet. However, I'm really light weight. I'm about 134# and the bike is aluminum and fairly light, so if the clutch is slipping, I can't really tell because it always moves me well. The bike will push through grass on low range, and then go faster than I want on pavement. I'll experiment with it more though. I'll put some of my bigger friends on it and see if the clutch/gearing can handle them. I can always get different sprockets for the gearbox at TSC.

 

[Snarky]

I drove this death trap to my shop which is about a mile a way and back. I had a few problems coming back with chain slippage, because the tensioner loosened up. I also had to locktight the horizontal bracket because the backing nut kept loosening. Still waiting on the mail for the throttle cable.

So far, so good. The 4 stroke starts on the first pull, and the kill switch is super effective.

Here's video of it operational.

http://youtu.be/gXaP1DubXB0