Recent Topics
Mobile 1 0W40 19.98 @ amazon & Walmart
by Pajero
11/24/17 10:12 PM
German Scrabble Anyone?
by StevieC
11/24/17 09:40 PM
Remington?
by bigj_16
11/24/17 09:26 PM
Oil Filter Effect on Pressure
by bunnspecial
11/24/17 09:19 PM
Rotela T4 -> now without API SM ?
by Yannick
11/24/17 09:12 PM
Uh yeah, Pizza!
by StevieC
11/24/17 08:59 PM
MotorGuard M100 install on Triton V10
by A310
11/24/17 08:58 PM
Using cheaper filters at shorter intervals
by izz
11/24/17 08:56 PM
3" vs 4" casters
by JHZR2
11/24/17 07:26 PM
2001 4.6 misfire on one cylinder
by terry274
11/24/17 07:01 PM
Buying a house! Hard to find a non hoa area.
by motor_oil_madman
11/24/17 07:00 PM
Best Dextron Vl brand for overheating conditions
by 911Hunter
11/24/17 06:33 PM
Engine Damage from Starting Fluid?
by StevieC
11/24/17 05:50 PM
Opinions on bubble balancers.
by ram_man
11/24/17 05:41 PM
FYI: EPA on "Waste Oil"
by bunnspecial
11/24/17 05:39 PM
Small Hobby project :)
by maverickfhs
11/24/17 04:40 PM
Castrol (3 varieties) $2/qt, O'Reilly Auto
by D60
11/24/17 04:36 PM
F1 safety article
by Whitewolf
11/24/17 04:30 PM
Maxlife in Transmissions Calling for Dexron VI?
by mphilleo
11/24/17 04:29 PM
Replaced bulbs in Mag Lites
by tig1
11/24/17 03:16 PM
Newest Members
BobStirratt, CajunLariat, knead2no, izz, Heema
63494 Registered Users
Who's Online
52 registered (A310, 911Hunter, anndel, 4WD, 2strokeNorthstar, AVB, 3 invisible), 1275 Guests and 14 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
63494 Members
66 Forums
274270 Topics
4559143 Posts

Max Online: 3590 @ 01/24/17 08:07 PM
Donate to BITOG
Page 1 of 2 1 2 >
Topic Options
#4331598 - 02/16/17 11:33 PM The best explanation on how a 2-cycle engine works
Merkava_4 Online   content


Registered: 01/30/07
Posts: 17061
Loc: Clovis, CA
THIS is it!

I've always wanted to understand how they work, but until now, never had the right explanation.

Top
#4331615 - 02/17/17 12:39 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
Ducked Offline


Registered: 10/25/12
Posts: 3144
Loc: Taiwan
I think they're like the Bumble Bee is supposed to be. Impossible.


Edited by Ducked (02/17/17 12:39 AM)

Top
#4331650 - 02/17/17 05:00 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
ZeeOSix Offline


Registered: 07/22/10
Posts: 15287
Loc: PNW
This is a pretty good explanation.

https://youtu.be/hV3LImCslpo?t=45s

Next engine to ponder is the Wankel.

Top
#4331664 - 02/17/17 05:42 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
Panzerman Offline


Registered: 12/16/06
Posts: 3998
Loc: Port Orange, Florida
Truly a light power producing motor. Stupid simple. Produces about 1.5 times the power of the same size four stroke and will run at any angle. I love em, unfortunately environmentalists/ EPA doesn't and they really don't like people like me that encase themselves in smoke. I once argued with a shop teacher in high school because he said two stroke longetivety is shorter than a four stroke. I disagree. Run good oil, at a rich ratio and a two stroke will run as long as a four stroke in the same service.
_________________________

2006 Dodge Ram 2500 Hemi 4x4
2016 Dodge Challenger Scat Pack

Top
#4331698 - 02/17/17 07:00 AM Re: The best explanation on how a 2-cycle engine works [Re: Panzerman]
JetStar Offline


Registered: 10/02/08
Posts: 1504
Loc: Flatlands of Indiana
And they really make a lot more power with one of these;
https://en.wikipedia.org/wiki/Expansion_chamber
_________________________
My weakness is I love all motorcycles regardless of brand
2016 Suzuki DR650
2015 Road Glide
2007 Yamaha FZ1
1978 Suzuki GS1000 (now 1085)

Top
#4331731 - 02/17/17 07:48 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
RedOakRanch Offline


Registered: 11/10/13
Posts: 759
Loc: Central Coast California
I have always loved the simplicity. I think of them as a pressurized crank area on the down stroke (piston becomes a super charger), then from the bottom of the cylinder the fresh mix pushes out the exhaust. Rinse and repeat.
_________________________
1994 Ford Crown Vic 202k-Castrol GTX 10w30 since new!
2005 Chevy 1500 Crewcab 4X4 175k-BC 0w30 $2/qt
2016 Outback 2.5 Limited 42k-PP 0w20 $2/qt

Top
#4331792 - 02/17/17 09:11 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
CT8 Offline


Registered: 10/09/14
Posts: 9487
Loc: Idaho
I miss the tow stroke motorcycles.

Top
#4331801 - 02/17/17 09:17 AM Re: The best explanation on how a 2-cycle engine works [Re: CT8]
HerrStig Offline


Registered: 08/24/11
Posts: 9560
Loc: Boston, MA
Originally Posted By: CT8
I miss the tow stroke motorcycles.
AKA "crop dusters".

Top
#4331803 - 02/17/17 09:19 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
HerrStig Offline


Registered: 08/24/11
Posts: 9560
Loc: Boston, MA
Even with a fancy exhaust and reed valves instead of ports there isn't a lot of low end torque to be had.

Top
#4331807 - 02/17/17 09:21 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
beanoil Offline


Registered: 10/17/04
Posts: 2790
Loc: Midwest, Illinois
Love the 2 stroke. Light, instant power, very tune-able with exhaust, reed tension, port size and position in the cylinder. And simple. When my boy raced MX, if needed, we could install the spare piston, rings, and cylinder between races. Tuning for short straights and supercross style jumps was done with different pipes and silencer lengths, and race fuels. EPA killed them because of the unburnt hydrocarbon emissions.
Lots more info in Two Stroke Tuning by A. Graham Bell.
https://www.amazon.com/Two-Stroke-Performance-Tuning-Bell/dp/1859606199
One of my best memories is a long ride on a Suzuki GT380, an in line 3 cylinder two stroke.


Edited by beanoil (02/17/17 09:24 AM)
_________________________
beanoil: Tough under heat, real dirty afterwards.

Top
#4331839 - 02/17/17 09:48 AM Re: The best explanation on how a 2-cycle engine works [Re: HerrStig]
Cujet Offline


Registered: 02/15/03
Posts: 6526
Loc: Jupiter, Florida
Originally Posted By: HerrStig
Even with a fancy exhaust and reed valves instead of ports there isn't a lot of low end torque to be had.


You might be surprised at the dyno curves of big bore 2 stroke dirt bikes. 500cc two strokes make a bunch more low end than a comparable 4 stroke. It's a mistake to think that a well designed 2 stroke engine has less low end torque. What really happens is that 125cc two strokes produce almost as much peak power as 250cc 4 strokes. When comparing the two, the 125 falls very short on low end.

Better to compare by displacement.




Edited by Cujet (02/17/17 09:50 AM)
_________________________

Top
#4331862 - 02/17/17 10:12 AM Re: The best explanation on how a 2-cycle engine works [Re: HerrStig]
IndyIan Offline


Registered: 09/23/08
Posts: 8449
Loc: Ontario, Canada
Originally Posted By: HerrStig
Even with a fancy exhaust and reed valves instead of ports there isn't a lot of low end torque to be had.

Normally they aren't tuned for low end torque, but could be. I think also the fact that 2 stokes fire twice as often tends to make people think they are revving higher than they are, compared to 4 stroke.
I used to ride an '84 IT200 (2T) and my buddy had an XR200 (4T) and even off idle my bike was quicker, got a much quicker once on the pipe. The XR would rev out more though, and in the woods the XR had nice and smooth power.
_________________________
07 Focus ZXW, 5spd manual, 190km VWB 5W30
06 CRV, 5 spd auto AWD, 298km M1 EP 5W30

Top
#4331891 - 02/17/17 10:51 AM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
DoubleWasp Offline


Registered: 05/21/12
Posts: 4606
Loc: Fort Lauderdale, FL
I love 2-stroke outboards. A lot of 4 strokes are just a mess. Lot less to go wrong on a 2.
_________________________
07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
07 Ram 3500 4x4 / Cummins 6.7 /DBL7349
17 Maserati GranTurismo Cabrio

Top
#4331912 - 02/17/17 11:19 AM Re: The best explanation on how a 2-cycle engine works [Re: DoubleWasp]
SteveSRT8 Offline


Registered: 10/10/08
Posts: 18607
Loc: Sunny Florida
Originally Posted By: DoubleWasp
I love 2-stroke outboards. A lot of 4 strokes are just a mess. Lot less to go wrong on a 2.


I don't care what the peanut gallery says, my 2 stroke outboards came out of the hole much quicker than comparable 4 strokers do. My old Polaris jetski would absolutely throw you off if you weren't pretty strong and holding on well when we took off.

Love me a couple strokes...
_________________________
"In a democracy, dissent is an act of faith."
J. William Fulbright
Best ET-12.79 @ 111 mph
4340 pounds, Street tires
Just like we go to Publix

Top
#4332044 - 02/17/17 01:32 PM Re: The best explanation on how a 2-cycle engine works [Re: Merkava_4]
Kawiguy454 Offline


Registered: 06/01/15
Posts: 532
Loc: Arizona
I had 2 Yamaha RD350's that would scream on the street a Yamaha IT465 enduro that had boatloads of torque. Yes a 2stroke can be made for low end torque as the IT465 was exactly that. All the magic happens in the exhaust as the expansion chamber is tuned to use the moving hot gasses volume to PULL in the fresh fuel charge. The misconception of peaky horsepower IMO came from dirt bikes that were always run on the ragged edge around a track.

Top
Page 1 of 2 1 2 >