Issues that engines cause

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druszek206

New Member
Hi all, I'm new hear so forgive me as I'm sure this has come up but I couldn't find it by searching. If there's a big thread dedicated to this please point me in the right direction.

I have been thinking about putting a 50cc 2-stroke on a bicycle, probably hybrid bike. My ride to work would be really easy and mostly downhill, but the ride home is the opposite so I thought an engine would be a nice way to ease into the full ride. Also I was hoping it could serve as a main form of commute to and from other parts of the city where I frequent.

After visiting a few bike shops looking a for a bike in the first place, many of the technicians I spoke with said that engines completely ruin bicycles, mainly because the back-end isn't supposed to take so much torque. If anyone knows how to stop this from happening, or if it's as big an issue as the guys I spoke to made it seem your advice would be greatly appreciated.

Thanks a bunch!
 
I have a COUPLE of bikes with 10,0000 miles on them, and there has never been an issue with the frame, rear end or anything else'
 
You'll find a lot of bike shop owners/mechanics don't approve of our hobby. Many of them deal almost exclusively with the hardcore roadie types who also frown on motorized bicycles. The reaction you got is not uncommon.

As for engines ruining a bike...hogwash. You've joined a forum with over 30 thousand members, many whom ride every day, commute and put thousands of miles on their bikes.
Installed and maintained correctly there is no reason to assume that motorizing a bike will compromise it in any way.
Keep reading, use the search feature and ask when you can't find the answer.
Good luck and welcome to the forum.
Tom
 
Ok that's great to hear, do you peddle up to speed then engage the engine. These guys were probably avid bicyclists but there reactions seemed so dead-set on it being a horrible idea.
 
Starting methods vary with the type of engine you choose to install. The typical in-frame 2 stroke, commonly refered to as the 'HT' has a manual clutch. You do indeed pedal up to speed and release/engage the clutch then ride away. There are some with centrifugal clutches that rely on engine speed to engage but even those benefit from a little pedal assist.
Friction drive is another option whereby the engine drives a drum or roller that is put into contact with the tire. These normally have a rope pull start and often a centrifugal clutch. Lots of options to choose from.
Tom
 
Pedal up to a good bike cruising speed then drop the clutch. Run it at at various and don't run it don't too low.

Use 24;1 AS A STARTING MIXTURE
 
Bike shops are rarely in favor of motorized bicycles. They make their bread and butter from people who read fashion bike magazines, and who spend liberally when some bike product is hyped up, and from people who can't even change their own chain or tires. It's true that bike engines will ruin a lot of bikes. If you pay attention on this forum, there are lots of cheaper bikes, and heavier framed bikes that can take these bike engines as they were designed, to run about 20-30mph as cheap transportation.

If you want to skip all the headaches and get something that doesn't "ruin bikes", go to www.thatsdax.com and get a friction drive.
Go with thicker tubes and tires, and just remember, it's a bicycle with a boost, not a motorcycle with pedals. It matters how you think of it and how you drive it, for safety and longevity of parts.

http://motorbicycling.com/picture.php?albumid=531&pictureid=4241
picture.php






druszek206 said:
Hi all, I'm new hear so forgive me as I'm sure this has come up but I couldn't find it by searching. If there's a big thread dedicated to this please point me in the right direction.

I have been thinking about putting a 50cc 2-stroke on a bicycle, probably hybrid bike. My ride to work would be really easy and mostly downhill, but the ride home is the opposite so I thought an engine would be a nice way to ease into the full ride. Also I was hoping it could serve as a main form of commute to and from other parts of the city where I frequent.

After visiting a few bike shops looking a for a bike in the first place, many of the technicians I spoke with said that engines completely ruin bicycles, mainly because the back-end isn't supposed to take so much torque. If anyone knows how to stop this from happening, or if it's as big an issue as the guys I spoke to made it seem your advice would be greatly appreciated.

Thanks a bunch!
Click to expand...
 
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Funny thing about the typical bicycle tech is they tend not to be motorheads ;)

On the "posh" end for a bike shop, my LBS is fortunately still very welcoming & ofc very skilled when it comes to bicycle stuff... but none of them are really familiar with the long term complexities of motorization & use - which given a moment's thought makes perfect sense as they are after all pedal only bicycle mechanics *shrug* but as there's a lot of crossover, they're great guys w/no ill will and a lot of interest - we've spent hours on end discussing exactly this topic... good thing their boss is equally as interested in the "component testing & frame load" resulting from my motorization habits heh

Much has been made of engines "ruining" bicycles - but after years and thousands of miles riding I've learned it's not that the engine (2hp/50cc/30mph or thereabouts) puts any undue loads on the bicycle, but the frequency of the loads - the increase in speed and reduction of physical effort by the rider resulting in far more mileage & all the wear & tear that comes with those miles.

"mainly because the back-end isn't supposed to take so much torque"

pshaw lol - the torque load of your average 50cc two stroke is equal to or even less then the peak torque of an accomplished pedaler, it's not the torque of the motor - but the repeated "high speed" impact load that can lead to the eventual failure of the upper chainstays on the very cheapest of the box store bikes, the constant pounding of "rough" road conditions, cracks, potholes & bumps at a constant 25-30mph (which is still equal to or less than the impact loads of downhill riders). This is far more a consideration than the relatively insignificant torque load of the motor itself and even a slightly higher quality bicycle than the $80 wallyworld specials has no problem at all dealing with the constant impact loads - but I do very much recommend examining the quality of the welds before motorizing any bicycle.

"Issues that engines cause"

Are more often issues of the builder - engine installation & maintenance aside, a minimum of 2x the speed & 4x the distances traveled results in a far more frequent need for routine maintenance of the bicycle's components regardless of the type/brand/cost of the bicycle... oddly, this seems to come as a surprise for some first time builders.

However, it's simplicity itself - a mere matter of checking the bike before you ride, remembering to repack all the bearings on a new bike then periodic lubrication & adjustment of the bearings & chain, brake and cable adjustment & spinning the wheels from time to time to establish they're still true & undamaged... it's the same as any bicycle would need, just more frequent as you're racking up the miles far far faster than just about any pedaler.

The greatest "issues" by far are simply the builder trying to save a few bucks, negligence & cutting corners - spend the extra $100 to get a slightly better frame & replace the cheesy single wall rims with even a budget set of double walls and all's well :D
 
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I agree. The wheels are the real weak-point on many cheap-bikes. Besides, you can get lots of good bikes off Craigslist and Ebay, that were "high end" just a decade ago, now garage-saled for pennies-on-the-dollar.

A good chromoly rigid fork mtn bike ought to serve very well as a platform for a budget MB. Frames from the 80's and 90's often had large main triangles as well, which simplifies installation.

I'm still a friction drive fan, though. pretty much any bike, even a BMX, can be fitted with one, and you never have to worry about chains or left-hand wheel cogs again.
 
I agree with everyone.

The problem isn't engines that cause issues for the bikes, it's that people (even I) buy cheap bikes and motorize them. If you buy a $75 bike from Walmart, don't be upset the motor beats it up.. I bought a 100 bike, been riding it with a motor for a few months, and it rides great.

The only advice I'd give you is get a Mannic Mechanic hub adapter, and get a rear sprocket with 44-50 teeth. This will make it very easy for you to go up hills. Sometimes without starting to pedal at all.

And, to start the motor is pretty easy (and fun, I think). You put the choke on, you pedal up to 5-8 MPH, then dump the clutch. Then you take the choke off and give it gas...

To me, that's probably the hardest on your bike. Dumping the clutch is very hard on the hub. And also very hard on the spokes. At least the Manic Mechanic hub adapter makes it easier on everything... But, it's 80 bucks, but very very well worth it.
 
I agree, the Manic Mechanic hub adapter (or really any direct hub clamp) makes everything that much better. Hub adapter, a strong frame, double walled rims, and a lot of attention to detail. I'm amazed my $120 aluminum frame has lasted so long (it's a really beefy mountain bike frame though).
 
the biggest issue buying a $150 motor kit putting it on a $75 walmart bicycle and thinking you can ride it like a $10,000 crotch rocket
 
Ibedayank said:
the biggest issue buying a $150 motor kit putting it on a $75 walmart bicycle and thinking you can ride it like a $10,000 crotch rocket
Click to expand...

So true..

Let's see how fast this thing can go. I'm aiming for 45 MPH, even though my bike will surely fall apart after 25MPH, since I only paid 80 bucks for it, lol..
 
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