Rear rack mount for Solo210 engine on a New Mongoose bike

JohnnyRocket

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can someone with a rear rack mount kit please give me a hand with a few questions, I want to build a rear mount, the weight of the whole setup will probably end up being around 33 pounds, mounted as close in front of the rear axle as I can get it (towards the seat). the setup will be a 3hp 4 stroke, honda gx100, a 3:1 v belt reduction with a tensioner acting as a manual clutch to tighten the belt, and a 4.4 to 1 drive downwards to the rear wheel. What can I expect handling wise, bearing in the mind the top speed will only be about 23 mph, and what are the common problems with mounting a chain and tensioner from the rear rack jackshaft down the rear wheel. Thanks
I,ve gotta Solo210 engine laying around and a New Mongoose bike which I am never going to be a peddling’ . . . I bought a seat post mounted bike rack, lined it up and drilled a couple holes. . . Looks pretty good - With some re-enforcement it should work well. I plan to start out using a chain & a centrifugal clutch then move on to a belt driven system if it duzz’nt wurk out. You mentioned that there is a gear reduction on your engine, U may want-2 remove that 2-gain more speed. Wow - I,m just now seeing this Stanton fella’s post and that’s about the same idea that I’ve got. Yeah - - - The Solo 210 that I’ve got is rated at about 15 horse & w/o the gear reduction should make that Mongoose of mine a real animal . . .
 
Here's some pics that might help. SidewinderJerry might have 1 of these to give you ideas. Be careful he bites.

I do have the inside drive 18.75\1 gearbox but mine goes to a shift kit on the crank; not to the left side of the wheel.
 
can someone with a rear rack mount kit please give me a hand with a few questions, I want to build a rear mount, the weight of the whole setup will probably end up being around 33 pounds, mounted as close in front of the rear axle as I can get it (towards the seat). the setup will be a 3hp 4 stroke, honda gx100, a 3:1 v belt reduction with a tensioner acting as a manual clutch to tighten the belt, and a 4.4 to 1 drive downwards to the rear wheel. What can I expect handling wise, bearing in the mind the top speed will only be about 23 mph, and what are the common problems with mounting a chain and tensioner from the rear rack jackshaft down the rear wheel. Thanks
One should always start a build with the engine specs.
Here's your engine specs:

Here are some specifications for the Honda GX100 engine:
  • Engine type: Air-cooled, 4-stroke, OHC, single cylinder
  • Bore and stroke: 56 x 40 mm
  • Displacement: 98 cm3
  • Compression ratio: 8.5:1
  • Net power: 2.1 kW (2.8 HP) at 3,600 rpm
  • Continuous rated power: 1.7 kW (2.3 HP) at 3,600 rpm
  • Maximum torque: 5.7 Nm (0.58 kgfm) at 3,600 rpm
  • Fuel type: Unleaded gasoline
  • Fuel tank capacity: 1.2 liters
  • Fuel consumption: 0.88 L/h at 3,600 rpm
  • Oil capacity: 0.4 liters
  • Carburetor: Horizontal type butterfly valve
  • Ignition system: Transistorized magneto ignition
  • Starting system: Recoil starter
  • Lubrication system: Forced splash
  • Governor system: Centrifugal mechanical
  • Air cleaner: Dual element type
  • Dimensions: 254 x 316 x 290 mm
  • Dry weight: 10.6 kg
  • Equipped weight: 11.6 kg

    In order to do 23 mph on 26" wheels you'll need a reduction of 12.12\1. I'm assuming you're using some kind of reduction box coming off of it with a chain or belt drive to complete what's needed to get the 13.2\1 reduction for a speed of 21 mph on 26" wheels; 22 mph on 27.5" wheels; and 23 mph on 29" wheels.
As for handling you won't even notice a difference between a rear rack mount vs a mid-frame mount. Though I do suggest putting a long kick stand on your bike since it'll be top heavy.

Here's a picture of my long kick stand. I also have a hanger under the tool box for it when riding.

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I

I,ve gotta Solo210 engine laying around and a New Mongoose bike which I am never going to be a peddling’ . . . I bought a seat post mounted bike rack, lined it up and drilled a couple holes. . . Looks pretty good - With some re-enforcement it should work well. I plan to start out using a chain & a centrifugal clutch then move on to a belt driven system if it duzz’nt wurk out. You mentioned that there is a gear reduction on your engine, U may want-2 remove that 2-gain more speed. Wow - I,m just now seeing this Stanton fella’s post and that’s about the same idea that I’ve got. Yeah - - - The Solo 210 that I’ve got is rated at about 15 horse & w/o the gear reduction should make that Mongoose of mine a real animal . . .
Ok if you just bought a new Mongoose bike, it'd be a safe assumption you don't want to sell it.

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Let's start with the engine specs.

Technical Specifications
EngineSolo 210 cc
Power20 hp @ 6000 rpm
Thrust125 lbs
CoolingAir
CarbBing or Walbro
ExhaustResonator (tuned)
StarterManual or Electric
Propeller2-Blade Scimitar
Diameter48"
Weight58 lbs.
Tank2.5 gallon, optional 4.5 gallon
Cage4 part aluminium, single or double ring


As you can see you're talking about adding 58 lbs over the rear wheel. A Mongoose bike is a terrible choice to do this with. Then you're talking about this frame/bicycle rack withstanding the force generated by a 20 hp engine.

Now let's get on the subject of what could propel a bike along the ground. The rear wheel can't do 6000 rpm so you need reduction in order to generate enough torque to propel the bike. If you could actually make a 26" wheel turn 6000 rpm you'd be doing 464 mph. To do that kind of speed it'll take a lot more than 20 hp.



It's not my intention to put you down but you need to ask more questions, rather than trying to give answers/advice. Especially answers you gave unwittingly, which can get another inexperienced newbie hurt. A rear bicycle rack was never intended for the purposes of mounting an engine. Telling Toby to not use a 3\1 reduction box with the 10t\44t means instead of 13.2\1 the reduction would be only 4.4\1. If it was functionally possible the speed would be 63 mph on 26" wheels at 3600 engine rpm. This isn't going to happen with only 2.8 hp.

To make the Solo engine work you'll need a 3\1 reduction box, a centrifugal clutch and a 10t/32t sprockets. For a total reduction of 9.6\1. We'll also be willing to help you with the necessities to build a safe bike to put it on. This setup could give you a speed of 48 mph on 26" wheels at 6000 engine rpm.
 
So U’r sayin’ - - - 1st of all I don’t want anyone 2b hurt by doing as I suggest. I’m just throwing shiz out there - It will b Ur idea’s that make the final product. When something works 4 me - I’ll tell you & vice versa. Rite now I’m not so savvy on gear ratios & all however, I remember when I was a kid I had a 3 & a half horse Brigg’s Mini Bike & a centrifugal clutch running straight off the shaft & it went 30 - 35 mph. That being sed I would only assume that given more HP we’d gain more speed. It sounds as if you’re suggesting that I should add back the gear reduction unit 2 that Solo 210 of mine. Hmm… That would change things jussa little - - - 2 things come to mind if I did it that way. The reducer pulley that was on it Is a Triple Belt type - so - Perhaps I could use 2 belts 2 run the reduction pulley & the outer 1 to run a cheesy rag joint drive pulley on the rear wheel… Or - I could (since the belts run flush with the top of their slot) just touch them to the back tire for a friction drive…OR - I could bolt that puppy on-2 that seatPost bikeRack ded-cen & bolt the ParaMotor Propeller back onto it. As U can see I’m looking 2 get out of the this cheap or with a minimum of purchase’s, using what I’ve got. I’ve also gotta pair of BraNew Zenoah G-25’s w/ reduction which I haven’t designated yet. They came as part of the package when I purchased a pair of DK Beat ParaMotor’s. The ParaMotor’s engines were also BraNew & I believe the Zenoah’s were given by Japanese company Daichi Kosho as a replacement for the failing original DK-472 twin which was short lived & discontinued. That’s another story. PS. I wanted to note that the Solo 210 of mine has a Tillotson HR-191 carburetor.
 
So U’r sayin’ - - - 1st of all I don’t want anyone 2b hurt by doing as I suggest. I’m just throwing shiz out there - It will b Ur idea’s that make the final product. When something works 4 me - I’ll tell you & vice versa. Rite now I’m not so savvy on gear ratios & all however, I remember when I was a kid I had a 3 & a half horse Brigg’s Mini Bike & a centrifugal clutch running straight off the shaft & it went 30 - 35 mph. That being sed I would only assume that given more HP we’d gain more speed. It sounds as if you’re suggesting that I should add back the gear reduction unit 2 that Solo 210 of mine. Hmm… That would change things jussa little - - - 2 things come to mind if I did it that way. The reducer pulley that was on it Is a Triple Belt type - so - Perhaps I could use 2 belts 2 run the reduction pulley & the outer 1 to run a cheesy rag joint drive pulley on the rear wheel… Or - I could (since the belts run flush with the top of their slot) just touch them to the back tire for a friction drive…OR - I could bolt that puppy on-2 that seatPost bikeRack ded-cen & bolt the ParaMotor Propeller back onto it. As U can see I’m looking 2 get out of the this cheap or with a minimum of purchase’s, using what I’ve got. I’ve also gotta pair of BraNew Zenoah G-25’s w/ reduction which I haven’t designated yet. They came as part of the package when I purchased a pair of DK Beat ParaMotor’s. The ParaMotor’s engines were also BraNew & I believe the Zenoah’s were given by Japanese company Daichi Kosho as a replacement for the failing original DK-472 twin which was short lived & discontinued. That’s another story. PS. I wanted to note that the Solo 210 of mine has a Tillotson HR-191 carburetor.
No offense, but this post is hard to follow. You should really start your own post explaining the parts you have and what you want them to do.

From what I got you have a paramotor you want to motorize a bike with. There was a video posted on here a while back where a fellow strapped one to the back of a bicycle with the propellers and went 50+. If I can find that post I'll post a link here. A direct drive to the wheel probably isn't the best option as those engines only make power in higher rpms, and you would need a lot of gear reduction, rendering most of your horse power unusable.
 
Cooling is a huge issue on engines used for aircraft. Heat seizing while flying is a real and not uncommon problem for aircraft of all sizes. its been discussed over the years but the consensus is that because of how much cooling and how many custom parts would be necessary, its better to sell the aircraft engine and use an engine more suited to the task.

5-7 heaven did a lot with high revving 2 strokes. Used 4.5hp zenoahs on bikes, had a build with 2 engines. A lot of stuff.
 
58lbs, 20hp? He needs a m/c. Frame, components won't stand up to that.
Especially, a Mongoose frame which is notorious for having weak welds. There was also the mention of using a bicycle rear rack to mount the engine on along with putting a rag joint on the rear wheel. If that wasn't bad enough then there was the idea of removing the reduction box and just using a centrifugal clutch connected to the rear wheel; for less than a 6\1 reduction. The engine turns 6000 rpm.
 
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