Motor Vehicle Maintenance & Repair Stack Exchange
Motor Vehicle Maintenance & Repair Stack Exchange

Questions tagged [two-stroke]

A type of internal combustion engine where all of the cycles of combustion occur in one 360 rotation of the crankshaft.

A type of internal combustion engine where all of the cycles of combustion occur in one 360 rotation of the crankshaft.

There are several types of two stroke engines that include:

  • Piston controlled inlet port
  • Reed inlet valve
  • Rotary inlet valve
  • Cross flow scavenged
  • Uniflow scavenged
  • Stepped piston engine

The image below is type piston controlled inlet port where the piston skirt controls the timing of the port inlet flow.

Image of a two-cycle or two stroke engine

enter image description here

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Why do two-stroke engine exhaust pipes look so strange?

Two stroke gasoline engine exhaust pipes are shaped strange. They expand into a wide diameter and then shrink down to a very small diameter where the exhaust gasses emerge into the environment. - Why are they shaped in such a strange way? - What is…
DucatiKiller
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What is happening when a two-stroke engine is said to be "four-stroking"?

Many years ago, I was involved in a hobby of building and flying model aircraft. The aircraft used alcohol-fueled 2-stroke engines with glow plug ignitions. When these engines ran rich (and always at idle), they produced a distinctively different…
Anthony X
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What makes two-stroke engines less fuel-efficient than four-strokes?

It is a commonly-held belief that two-stroke engines are less fuel-efficient than four-stroke engines, and some example BSFC figures appear to confirm this as well. But what is it that causes two-strokes to be less fuel-efficient? I used to believe…
Zaid
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Does the air screw only affect the pilot jet?

I have a 2 stroke motorcycle, it's Kawasaki KR150. When I try to do some jetting on its carburetor (it's Keihin PWL26), I saw that there's an air screw. So now I've been wondering about this air screw on 2 stroke motorcycle carburetor, since I'm a…
edwin
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Brake Specific Fuel Consumption of 2-stroke vs 4-stroke

How much fuel do various types of engines burn per power output? I'm especially interested in naturally aspirated piston engines, and comparing two-stroke to four-stroke. The wikipedia article gives the value for several specific engines, but…
user3092
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Starting a 2 stroke jet boat after several years

The parents in law gave me a jet boat, it hasn't been started in 5 years. The boat resided in NH on a trailer on their yard for 5 years, so it has seen freezing temperatures frequently. From what I understand, 6 years ago the boat ran fine at the…
Calvin
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What are the problems in building 2 stroke engines with a large displacement?

I understand (from preliminary research) that when engine gets bigger, with a higher displacement that it is practically not possible to have a two stroke engine. What are the implications in building a higher cc two stroke engines?
BraveNinja
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Is it okay to run aviation fuel (100 low-lead) in a dirt bike?

I'm wondering if it will be okay to run 100 octane low-lead aviation fuel in my 2007 RM250 motocross bike (two-stroke). Half of the people I've asked say yes, while the other half say no. Will it be okay to run aviation fuel in this high RPM…
hgwhittle
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Carb. Rebuild or Adjustment?

Just put a rebuilt 2 stroke and brand new Mikuni SBN carburetor in my jet boat. Got her running no problem the first couple times, now it seems I can't get any gas into the carburetor from the primer bulb. The primer gets very firm and I am…
Calvin
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Can I dilute 2-stroke gas and run it in my riding mower to get rid of it?

Over the winter I needed a chainsaw, I mixed a gallon of gas for it and unfortunately it just refused to start which gave me the motivation to purchase an electric chainsaw which did the job wonderfully. Problem is, now I have a gallon of two-stroke…
Sidney
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Two-stroke dirt bike piston running into spark plug

Recently, I submitted a post on here regarding a broken ground electrode on the spark plug of my 2005 Suzuki RM125: Bottom piece of spark plug broke off in motorcycle engine Well, I found out what caused this. The piston is traveling too high in the…
hgwhittle
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Honda R8X-S heat seize

I've got a Honda R8X that heat seizes when I'm riding it when it goes over 40mph. The lad I got it off said he had it re-bored and that it was run in. Will I need to re-bore this again or is there some thing that not been done right?
Richard
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Two-Stroke Diesel Engine - Do they use forced induction on them?

As I have indicated before, I'm very diesel ignorant. I just know the basics, very basics. In a two-stroke diesel engine using forced induction seems necessary but at the same time I see challenges. In motorcycles, which I have more knowledge in,…
DucatiKiller
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Two-Stroke vs. Four-Stroke Diesel Engines - What is most commonly used in heavy vehicles?

I am not well versed in diesel engines. To prove my point, I've learned in the last month that a two-stroke diesel engine actually exists. My Question. What kind of diesel engine (four-stroke or two-stroke) is most commonly used in heavy vehicles…
DucatiKiller
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No compression on my two stroke

I was recently riding racing my Honda 250R (1986) (informally), and, all of a sudden, the engine quit completely. I tried letting out the clutch in second gear (push starting) with my momentum, but although the engine turned over freely, there was…
Cullub
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