Another thread on wishing to make motors quiet

GoldenMotor.com

bowlofsalad

New Member
Feb 3, 2013
4
0
0
Midwest USA
Hello,

I've been doing a lot of reading on various forums (here, endless sphere and others) on various options for propelling a bicycle.

Electric is extremely expensive, I wouldn't mind but the range is kind of a choker for me.

So, I am hoping to understand how to make a motor as quiet or silent as humanly possible. If I thought there was a 25cc engine for 2000-3000 dollars right now that rivaled the noise levels of an electric setup, I'd jump at it like a warrior.

With that in mind, I am looking into subaru/robin or honda 25cc engines. What I've come across thus far for making things quiet are mufflers for the intake, the exhaust, and pieces of rubber on the cooling fins.

The fanciest muffler I've come across are called vortex cherrybombs. I imagine putting one on the intake and one on the exhaust. I am sure there is some fatal flaw I am missing to these ideas.

I am sorry if this idea/question has been beaten to death, I've read many threads and the details are a bit on the light side.
 

Kioshk

Active Member
Oct 21, 2012
1,152
10
38
Connecticut
I regret I have no answer for you, but I hope you'll excuse my curiosity; why the requirement of extreme quietude? If you're willing to consider something exotic/expensive, try steam-power.
 

Mr. Minecraft

Visionary
Jan 13, 2012
349
0
0
San Diego
Welcome to the forum!

A stock HS 49cc engine is not as loud as people think. For example, last night I finished cleaning the carb in my friend's stock 4 stroke motorbike and he took it for a test ride. It was around 11:30 at night. After he got 60 feet down the street i could not hear it anymore.

And as Kioshk asked, why the need for such a quiet motor? Most of the time quiet engines will not make sufficient power to use as a commuter bike.
 

Barnfresh

Member
Sep 5, 2011
205
10
18
Nor-Cal
I'd start with a four stroke engine then look at adapting a breather/filter box and exhaust from a comprable size Honda generator. I've never heard any ICE as quite running as a Honda genny. The quietest aftermarket muffler I've ever seen (that didn't strangle power) was made back in the 70s by DiscoJet Corp and called Xdusor or Xdusor II w/spark arrestor. They were way ahead of their time and would quite a dirt bike down to something like 85db. You can still find them on eBaY once in awhile.
 

bowlofsalad

New Member
Feb 3, 2013
4
0
0
Midwest USA
Why would I want to be so quiet? I don't want the attention, and there are places I'd like to be able to go, such as various trails, where a motor wouldn't be too welcome. So there are times and places I'd like to go where the attention generated by the noise wouldn't be a good sort of attention.


This may give me an idea, honda eu1000i to a converter, converter to a controller, controller to an electric hub motor. I don't know if it is very quiet, makes me wonder how quiet a gx25 honda can be.
 

Kioshk

Active Member
Oct 21, 2012
1,152
10
38
Connecticut
I get that; there are a few locations on Long Island (bike paths/nature trails) I enjoy riding where "motorized vehicles" are prohibited. I have found inthe six-months I've been motorized bicycle riding on these trails that pedestrians and bikers are surprised to see my motorized bicycle, and some stop me to happily ask me about the kit. I make sure I ride slowly and conscientiously. When I come upon other trail-users, I slow down, pull the clutch, and pedal if necessary. Make eye-contact, smile, and give a nod. Only a ******-bag would find this behavior offensive, and I have not as yet met that ******-bag on my journies.
 

BarelyAWake

New Member
Jul 21, 2009
7,194
21
0
Maine
Electric is extremely expensive, I wouldn't mind but the range is kind of a choker for me.

So, I am hoping to understand how to make a motor as quiet or silent as humanly possible. If I thought there was a 25cc engine for 2000-3000 dollars right now that rivaled the noise levels of an electric setup, I'd jump at it like a warrior.

With that in mind, I am looking into subaru/robin or honda 25cc engines...
Doubtlessly you've considered it, but I'm curious & I wonder what distances you're thinking of...

Given the above parameters electric may not be as cost prohibitive or range limited as it initially appears, particularly given the comparative power & speeds of a 25cc. A 15ah LiFePO4 pack & a basic 1000w hub kit together costs roughly $1000 & will do approximately 25mph for 30mi completely unassisted - obv if assisted (as you'd need do w/a 25cc) the range could be far more and if you're willing & able to spend as much as "2000-3000" as mentioned above you could have an ebike of truly impressive capabilities...

Please know I've nothing against gasbikes, I've a couple myself lol - but there's something about electrics that can corrupt the most hardcore petrol-head & I wonder if it's exactly what you've said you want, a motor "as quiet or silent as humanly possible" and as you'd be happy with a 25cc, I suspect electrics may not be as unattractive as presented.

Electrics do seem "extremely expensive", the initial investment can seem overwhelming at first, particularly the batteries - but as with anything some shopping around can yield significant savings, kit batts vs custom, branded motors vs generics etc. Contrary to general impressions, "custom" packs are actually far more cost effective (ping etc) & as brushless electric motors are wonderfully simple, you needn't fear generics as much as you would w/gas engines. It seems much disappointment seems to stem from "sticker shock" (cost of branded full kits, factory batts included) and the false economy of trying to scrimp on the investment of batteries, trying to use SLAs instead of LiFePO4s and the unfortunate results.

It starts to get questionable which is "better or worse" in expense, reliability & range should compromises be made in the quest for silence - modifying a tiny gas motor to be silent as possible means you've "unlimited" range but comparatively little assist, adding a tow-along generator to an electric negates the silence, simplicity and a significant amount of "savings" and due to the added weight, makes pedaling less effective.

Every bike is a compromise, what you're willing to settle for can only be decided by you ofc... but I just though you may wish to reexamine what you want vs what it costs vs what you'll actually get for your pennies ;)

An example of my own electric preconceptions being resoundingly disproved, I never thought for a moment I'd be satisfied with an ebike & yet: http://motorbicycling.com/showthread.php?t=40663

Jus' some thoughts :)
 
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bowlofsalad

New Member
Feb 3, 2013
4
0
0
Midwest USA
I have and am heavily leaning towards electric setups. I was hopeful someone here would pop up and say something I've never heard before. I've looked around tremendously, it seems not many on gas motors care much for the stealth aspect so not much research has gone into it.

Indeed, a decent electric setup can be had for under 1000, or less. But I am really looking for quality stuff in every piece, so it seems most of the totals I come to are over 1500. I am still a little lost on the BMS aspects, mostly on what to do for a BMS. This is meant to say, no BMS and just use something like a celllog8 to monitor voltage of charge and discharge (not newbie friendly, I am a newbie), use a BMS with something like a celllog8, or rely solely on the BMS. Some people call a BMS a battery murdering system, meaning they think using no BMS (being the BMS) is the only way to go.

I read you bought from ping, how has your setup been treating you so far? I am sort of balancing between ping's lifepo4 and various a123 batteries. Though, I am not sure I fully understand a123, a123 sometimes seems like a general term like lipo, even though they mean something very specific.

I definitely want to ride with range in mind for the most part. I have a recumbent bicycle, and I plan on going a lot slower than most seem to, extending the range.

Outside of ping for battery, I am considering at least two other places.

http://em3ev.com/store/index.php?route=product/product&path=35&product_id=106

http://www.osnpower.com/ < this place doesn't seem to list pricing or too much specific, but some people seem to speak highly of the place, I don't really know. Lots and lots of people speak highly of ping though.

How do you charge your batteries? Where do you charge them? Some people think any of these batteries are a fire risk, it is with that that I realized that if you were actually scared of the batteries exploding or catching on fire, that putting them in a fireplace or a old fridge (outside) to charge would be the way to go. Beyond safety, temperature is a concern I have for charging batteries. I am guessing it gets plenty cold in all parts of maine, is the temperature an issue for you concerning charging?

I don't know if you've ever heard of ebikes.ca but they seem to be highly spoken of in tandem with ping. They have an interesting calculator, http://www.ebikes.ca/simulator/ I've played with it a fair bit, I am sure there are infinite variables that would change the range you'd get, but some of the calculations are very interesting with just a 48v20ah battery.

The reason I'd be so happy to pay 2000 for a silent 25cc motor is solely because of the refueling aspect, even 2000 dollars on batteries would still have a limit, be it a crazy limit. Perhaps the weight would be a bit much as well.

I wish people wouldn't mind the gas motor, but they do/would, and so does the law (in some of the places I like to ride and go).
 

BarelyAWake

New Member
Jul 21, 2009
7,194
21
0
Maine
Indeed, a decent electric setup can be had for under 1000, or less. But I am really looking for quality stuff in every piece, so it seems most of the totals I come to are over 1500. I am still a little lost on the BMS aspects, mostly on what to do for a BMS. This is meant to say, no BMS and just use something like a celllog8 to monitor voltage of charge and discharge (not newbie friendly, I am a newbie), use a BMS with something like a celllog8, or rely solely on the BMS. Some people call a BMS a battery murdering system, meaning they think using no BMS (being the BMS) is the only way to go.
I fail to see how a properly matched battery management system would do anything other than maintain each individual cell, charge & discharge as it was designed... I can see the possibility of folks attempting to alter, "upgrade" or do away with it altogether in an attempt for greater preformance & being disgruntled with the results however. Given the investment and the reliability of LiFePO4 provided only it's not subject to charge/discharge irregularities, I'd hafta vote BMS.

I read you bought from ping, how has your setup been treating you so far? I am sort of balancing between ping's lifepo4 and various a123 batteries. Though, I am not sure I fully understand a123, a123 sometimes seems like a general term like lipo, even though they mean something very specific.
I've had no cause for complaint whatsoever with the ping battery or their customer service, however I've not ordered or had experience with another battery retailer so I can't compare or recommend an alternative. A123 Systems, Inc. seems to be a manufacturer of batteries rather than a specific product, so folks are maybe just using the business brand as the name for the product (band-aid vs adhesive bandage)? *shrug*

I definitely want to ride with range in mind for the most part. I have a recumbent bicycle, and I plan on going a lot slower than most seem to, extending the range.
Recumbents & range? You might find this abomination interesting: http://motorbicycling.com/showthread.php?t=24210 but in all honesty I can't recommend it as it's complex, expensive & completely unproven in both design & function lol

You should defo post up some pics of your 'bent build in Tandems, Trikes and Recumbents when ya get a chance BTW, it'd be great to see another (^)

How do you charge your batteries? Where do you charge them? Some people think any of these batteries are a fire risk, it is with that that I realized that if you were actually scared of the batteries exploding or catching on fire, that putting them in a fireplace or a old fridge (outside) to charge would be the way to go. Beyond safety, temperature is a concern I have for charging batteries. I am guessing it gets plenty cold in all parts of maine, is the temperature an issue for you concerning charging?
I've just a small 2a charger that came w/the battery pack, I should prolly get a 5a but I've not bothered as it works well enough - but as I do bring it with me on longer wanderabouts to plug in wherever there's an available outlet whilst I have a coffee/lunch/whatever, a faster charger would obv be better. Li-ion (lithium iron phosphate) batteries are roughly equivalent to the preformance capabilities of the LiFePO4 batteries but are somewhat less expensive, the trade off being Li-ion may suffer thermal runaway (fire, very exciting) whereas LiFePO4s are considered very stable... I prefer stability over savings, but that too is up to the builder heh

Cold hasn't been an issue while charging or operating so far as LiFePO4 batteries are comparatively tolerant of temperature extremes, most say they're fine from -4 F to 150 F (-20C to +70C) & I've operated mine in even colder conditions than that successfully (daily driver/commuter), but obv that's taking a chance on getting stranded - of a greater concern is the BMS itself as if it senses a voltage drop due to extreme cold it could shut down everything, some BMS being more sensitive than others naturally.


I should mention that although I use my ebike as an all season commuter & thus have racked up few thousand miles (between 3 & 4000 so far), it is however the only ebike I've had - which means I'm not qualified or experienced enough to make comparative judgments or alternate recommendations. I've been amazed by how easily my ebike has usurped my gasbike's use completely, impressed by it's absolute reliability & have become addicted to it's sweet silence... but I couldn't say it's better or worse than any other setup as I've only had the one.

I would strongly suggest comparison shopping, paying less attention to branded names than specifications & reviews - if they don't offer such, it's a bad sign lol ;)
 

BigBlue

Member
Nov 29, 2011
781
0
16
California
I've looked around tremendously, it seems not many on gas motors care much for the stealth aspect so not much research has gone into it.
Speaking for myself, I have no need for a stealth gas engine since I try and respect the laws that prohibit me from riding on trails that are meant for walkers, bicycles (non-motorized), horses and joggers. I enjoy the hobby of riding a motorized bicycle and try to operate it in a responsible manner, so that the government doesn't have a reason to limit my hobby.

I would hope the rest of the motorized bicycle would think the same way and realize how their actions can have an effect on the whole motorized bicycling community. That is why I always suggest people follow their state laws when operating a motorized bicycles - Have the proper licensing, registration, helmet, lights, operate within the speed limit and ride only where the law allows. The motorized bicycle community doesn't have a lobby to look after our interest like the motorcycle community does. Because of the lack of a lobby, it is easy for the government to limit our hobby.

An electric powered bicycle would be a good choice if you are interested in having a minimal noise impact. Someday I hope to build one myself, but want to wait a few more years till battery technology improves.

Good Luck,

Chris
AKA: BigBlue