Full Suspension & Big Engine Challenge

ZnsaneRyder

New Member
Nov 21, 2008
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FLORIDA
This is a challenge to build the ultimate MB. Power, speed, strength, and ability to run over things, and go off road and in water and be the ultimate 2-wheeled vehicle.

It does NOT matter where you put your engine, but you have to have the full-suspension working, because of the hard city and offroad use it may endure.


The catch, is that you gotta be bigger than 43cc. ;) 49cc-80cc, or more. Reasons are engine weight & horsepower needed to take you anywhere offroad, and still have the speed to use on the road.

I'm starting off being in the process of building a 79cc 2.5HP bike. 4-Stroke to be able to use any gas I find, no need for fuel & oil mix. I may consider a 2-stroke as well, but I'm sticking with this engine for now. It weighs 24lbs, which hopefully wont be too heavy rack-mounted with a clutch and sprockets. Harbor Freight Tools - Quality Tools at the Lowest Prices

I'm using a Staton 24-inch Plastic Tuff Wheel, but putting it on a 26 inch bike and will modify the brakes. It's the strongest big wheel without spokes that I could find for bicycles.
Motorized Bicycles Detail Page

If you have any input, or want to enter the Challenge with a full-suspension bicycle of your own, that would be great!.shft.
 
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Andyinchville1

Manufacturer/Dealer
Dec 26, 2007
502
1
18
Scottsville, VA
HI,

This sounds like a very interesting thread!

When I get some more time I am will try to make more progress on my build (the bike itself is together but the engine kit / shifter kit is not installed:

Bike is an Older GT LTS Team edition frame (full suspension), Black with red anodized parts.

I took all the other components (brakes, wheels, seat Rock shox etc..) off another mountain bike I bouhgt just for this build (FWIW, and this may help others out there in their builds, it was cheaper to buy an entire bike to pirate parts off of than to buy all the parts to build up a bare frame separately)...

I will be running one of Blue Collar's "80" cc engines and I will be running Jim and Pablo's shift kit Modified with our Red Anodized Super Sprockets.

The engine will be stock (at least initially), but I will run one of our Power Pipes....

I am going to tinker when it gets a tad warmer!

Looking forward to seeing all the pics tin this thread!

Andrew
 

rsmith

New Member
Jan 10, 2009
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England
I'll be up for this. A hardcore full sus is what I need for the trails near me. Finding a suitbale frame could be tricky though. The GT looks a good option. Rob
 

ZnsaneRyder

New Member
Nov 21, 2008
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I've been too busy & broke to work on the bike, but I've been getting a few parts for the planned build. I'm going to use the same bicycle I use now for my trailer, but make a rack-mount for the new engine.

I'd love to use my 6.5, but it's just way too massive to put on a bicycle, so I'm sticking with the 79cc 2.5HP 4-stroke engine.

I already have a #40-chain 10T clutch, and some #40 chain, and a 48T freewheel sprocket for the jackshaft. I need to get a hub for my 48T sprocket and a 24T solid sprocket for my rear plastic wheel, and need to build the rack.

It's a work in progress, may be slow, but patience is the key, as I do plan on making this a main source of transportation, and HAVE to have off-road capability.

I'll keep you posted.
 

NunyaBidness

Active Member
Jun 29, 2008
1,062
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memphis tn
The M85 has been one of the inspirations behind an idea I have been thinking on. I would like to build a frame that my 69cc chinese motor would mount in, it would be full suspension with disc brakes, a jackshaft that powered the pedal crank with a free wheel and lets me use the 6 speed bike cassette.
ahh
dreams are big sometimes
 
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trackfodder

Member
Sep 8, 2008
347
2
18
USE the 6.5. I am using a 5.5 Jiang Dong like HFT sells by another name. It does just fine with #41 chain. The bike is Monark. I am using a 3 speed hub tranny for a jackshaft. With a biggy you can use the governor for cruise control. It's nice not to have to screw around with throttle setting on hills etc. Mine ran 42 with the governor at 3100 I have since changed carbs and gone to a straight pipe. KW
 

ZnsaneRyder

New Member
Nov 21, 2008
163
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FLORIDA
USE the 6.5. I am using a 5.5 Jiang Dong like HFT sells by another name. It does just fine with #41 chain. The bike is Monark. I am using a 3 speed hub tranny for a jackshaft. With a biggy you can use the governor for cruise control. It's nice not to have to screw around with throttle setting on hills etc. Mine ran 42 with the governor at 3100 I have since changed carbs and gone to a straight pipe. KW
I like your enthusiasm!!!! How did you to mount that huge engine of yours? Pics or details? I'm open to ideas, as you can't beat the HP/$ ratio of the bigger engines! Feel free to fill us in how you are using your 5.5HP engine!!!!

My 6.5 engine is modified, and ungoverned, so it's a bit faster than stock, probably about 8HP @ 5000 RPM .wee.

The 196cc 6.5 is 38lbs, compared to the 24.8 lbs of the 79cc 2.5. I weigh only 138lbs myself. If I rack mounted the 6.5, do you think I'd be able to balance the bicycle properly? Maybe putting the gas tank lowered on the bike somewhere with a fuel pump would help the center of gravity a bit. Also, I want the engine to look smaller, so it doesn't appear to have nearly 200cc's.

My new Staton/Skyway plastic tuffwheel would handle it for sure, but I'm concerned with my safety of harnessing such a beast. However, I'm open-minded, and I REALLY love the torque of the 6.5, and I was thinking of how I'd really miss the HP by going to a smaller engine.

Heck, I may just do that, well see.
 

Egor

New Member
Jan 30, 2008
714
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Hurricane Utah
That M85 should be powered by a Morini engine. the lighter weight components from Bicycles, even the downhill stuff is not as strong as the bike the engine was intended for. Good looking outfit though. And I know there is a lot of work that has gone into the stage you are at. Good luck. Have fun, Dave
 

ZnsaneRyder

New Member
Nov 21, 2008
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Now if they just made a 4-stroke as powerful as a Morini engine.........no smoke and oil smell, no mixing, and really high RPM, that would be great.

Either way, I encourage any of you that get a big or fast engine mated to a full suspension bike that can go all terrain to make it happen! ..........And post pics of course ;)
 

jg767

New Member
May 28, 2008
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I have a 9.4 hp morini, couldn't find a suitable full suspension bike that the Morini would fit, so I bought a 29er w/front suspension forks. I'm hoping the bigger wheels will give a much smoother ride than the 26" mountain bike. The motor weighs 20 lbs. I would'nt want one any heavier. If I found a 4 stroke with the same power to weght ratio I'd consider it, but I don't think it exists! I don't mind mixing oil and gas, it's really no big deal, well worth it for the performance. BTW, all my 2 strokes run very clean, the Mitsubishi TL43 is very quiet, the Tanaka 40 is a bit loud, but it's one heck of an engine! I have a robin subaru 35, nice motor, but it only puts out 1.6hp. It WOULD be nice if they came out with a 50cc model! Maybe some day........cs..trk
 

jg767

New Member
May 28, 2008
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I looked into the custom frame from Pipelyne but by the time I bought the front forks, disc brakes,rear shock, bottom bracket,etc. I would be dropping at least 1200 bucks into it, (not counting the Morini motor). It is a great bike, especially for off roading I'm sure, but I went with a larger complete 29er, less money and more suitable for my size and riding style(strictly road)..rd.
 

Easy Rider

Santa Cruz Scooter Works
Jan 15, 2008
2,144
4
38
Nor*Cal
Pipelyne plans on selling complete bikes with good component parts but since he will be buying them in bulk, Dean will be able to offer the bike at a more reasonable price. It will be around the price of a Whizzer. A lot of R&D went into this bike and my hat goes off to Pipelyne for building a durable and low-maintenance off road motored bicycle that runs like a 125 dirtbike out on the trails but a lot lighter. The bicycle is under 70 lbs.
I'm hoping there will be an interest in off road racing in California. We have connections with a couple of race promoters that I'd like to pursue if we can get more that a handful of racers.
 

Egor

New Member
Jan 30, 2008
714
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Hurricane Utah
I think Obama just signed a bill that restricts off roading in California! That is some of the stuff the Dem's have been trying to get away with for years. Just a note I think the Two Smoke is doomed in this state, and any little engine that they can keep from running. We already can't sell any two strokes or any thing not CARB. Have fun< Dave
 

huckersteve

New Member
May 20, 2008
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Seattle
www.gohuckyourself.com
I like your enthusiasm!!!! How did you to mount that huge engine of yours? Pics or details? I'm open to ideas, as you can't beat the HP/$ ratio of the bigger engines! Feel free to fill us in how you are using your 5.5HP engine!!!!

My 6.5 engine is modified, and ungoverned, so it's a bit faster than stock, probably about 8HP @ 5000 RPM .wee.

The 196cc 6.5 is 38lbs, compared to the 24.8 lbs of the 79cc 2.5. I weigh only 138lbs myself. If I rack mounted the 6.5, do you think I'd be able to balance the bicycle properly? Maybe putting the gas tank lowered on the bike somewhere with a fuel pump would help the center of gravity a bit. Also, I want the engine to look smaller, so it doesn't appear to have nearly 200cc's.

(This is crazy heavy mounted in that location for off road use)

My new Staton/Skyway plastic tuffwheel would handle it for sure, but I'm concerned with my safety of harnessing such a beast. However, I'm open-minded, and I REALLY love the torque of the 6.5, and I was thinking of how I'd really miss the HP by going to a smaller engine. (You have Pedals, AND a motor!)

Heck, I may just do that, well see.
As a Downhiller and freerider (MTB) myself, I just want to bring up a couple of points regarding your proposed build. The Skyway mag you are planning on using is, at any given diameter (20', 24', or 26') VASTLY less stiff and strong than a spoked wheel alternative. This is a fact, and has been proven over and over again by everybody from ten year old kids jumping plywood jumps in abandoned lots, to pro BMX riders who never use them as a primary wheel, except in a few cases of tech oriented riders who don't go too crazy on jumps, and then only EVER as a front wheel. The skyway mag looks Tuff, and IS cool, but it's NOT a good wheel for off-road riding at all. In addition, the braking surface it provides for a rim brake is vastly inferior to metal rims for pad contact friction and in the wet will sound horrible and work even worse than it sounds. It's also important to note that a 24" rim will feel vastly less smooth rolling over uneven terrain than a 26" wheel, and lowers your final drive gear ratio noticeably as well. (Hence the rising popularity of 29" MTB's lauded for their smooth rolling characteristics and inertial qualities). Do yourself a favor and forget the skyway mag- it will cost you weight and certainly performance on a number of levels.

Also- there's a reason you don't want a 6.5hp motor chilling on the rear rack of an MTB- aside from the obvious (I would think) concern of screwing the balance point of the bike up to the point of making it handle like a wheeled turd, especially in off camber, uneven, and uphill terrain, there are very few racks made than can handle the weight of that motor, in this application. What I mean by that is- a rack that is rated to hold even 40-50lbs on pavement will quickly fail when taken off road for even comparatively mild backroads riding. Take an average fire road or forest service access road (never mind the legal implications of taking an unlicensed, non spark arrestor equipped rig on these types of roads) the average randonneur or adventure cyclist routinely breaks rack support struts just from the gentle rippling road surface of these gravel byways. Now you'll probably tell me you're going to fab up your own rack that is way stronger than the off the shelf products- and that's fine. That still doesn't address the issue of an absurd center of gravity and the complete inability to EVER bunny hop the bike over even very small irregularities in the trail, something any mountain biker must do numerous times a day on an average trail ride if they're really getting it done out there. This motor (rack mount) will also have further to fall in the event of a crash, will be tenuously mounted to a fragile rack that will likely damage the bike on it's way to failure, and most certainly leave you stranded just when you've gone further into the back country than you've ever ranged before.

I'm not poo poo-ing the idea of an off road capable MB, but I do believe there are some things that true off road riding will bring to light very quickly should you proceed with your build as planned. I would advocate the use of a steel framed hardtail bike, with a decent front suspension setup, and disc brakes front and rear. A suspension seatpost is fine if you just HAVE to have rear suspension of some kind. (At your stated weight of 136lbs this is totally elective IMHO) Also- I believe that a MB ridden in the woods will do well on fire roads and also smoother singletrack trails, but probably not hold up very well long term in truly rugged trail riding scenarios. I've seen handlebars snap in half out there, forks let go of wheels, frames cracked, stems shattered, wheels taco'd, the works. This is why lightweight trail bikes from the major manufacturers are all vastly heavier weight than even the beefiest DH bikes built to run under human power only. Check out Sikk MX, or FX Bikes to see two more good examples of featherweight class trail bikes that are rugged enough to be jumped, and CRASHED- and still have a chance of getting you home. You will see thoughtful application of some DH bike technologies and components backed up by a lot of motorcross derived technology in wheels and frame especially. Without exception, these bikes and any others I've ever seen for off road use utilize an in-frame motor mounting architecture. This is both for protection of the very important motor, but also for a safe and functional center of gravity.

If your goal is to access your fave fishing or camping spot, or a distant peak off in the hills, and you're willing to do it at a safe and sane rate of speed, I think you'll get there smiling. If on the other hand you're envisioning jumping culverts, fording streams, and riding skinnies out there, well, I guess all I can say to that is- Pics or it didn't happen! ;)

Don't let me rain on the parade, I'm just bringing a little pure MTB rider's ethic to the criteria I think a bike like that ought to be held to if expected to work..