two stroke vs four stroke

[Irish John]

Sparky the Mitsu comes with a Staton rear mount I know and I don't know of a Tanaka frame mount kit. Have you ever considered buying youself a Suzuki GSX 1000cc because it would probably fulfull your desire for wot travelling and spare you the heartache of busted small motors lying all over your garage.

 

[sparky]

What does a transmission have to do with engine RPMS and reliability. 9000 RPMs is 9000 RPMs, regardless of what the engine is coupled to.

I was about to reply to this that Nascar riders don't stay at 9000 rpm the whole time because they're shifting... but then I realized that Nascar isn't a drag race. Perhaps too early in the morning for me... or too late at night... whichever.

Sparky the Mitsu comes with a Staton rear mount I know and I don't know of a Tanaka frame mount kit. Have you ever considered buying youself a Suzuki GSX 1000cc because it would probably fulfull your desire for wot travelling and spare you the heartache of busted small motors lying all over your garage.

Mitsu comes with Staton and Dimension Edge, while the Tanaka comes with GEBE. And who wants a frame mount anyway?

As for the 1000cc recommendation... no thanks! I know what I want, and what I want is a rear-mounted and chain-driven 33cc engine with a dual freewheel on a set of double wall alloy rim... and a thumb throttle to boot. Just so happens that I already know I'm a 2-stroke person before even putting the 4-stroke on. I love the lighter weight, the higher rpms (who needs torque when you've got pedals?), the ringy ding ding sound, the smell of castor oil, the mixing of the gas, and especially the peace of mind from worrying about changing oil or adjusting valve lifters. 4-strokes are good for the environment... and that's about it, IMHO.

As for busted engines in my garage, there's only one. And it busted because I didn't use Loctite. Now with second Loctited engine, I haven't even attempted to tighten any bolts on my bike since last year (other than brakes). Not the best idea, but whatever... I've been averaging 30 mph, nearly nonstop, with no problems so far. My only problem is a very touchy carb, which isn't even that much of a problem because there's one single adjustment screw to control the flow of gas. It's a pretty decent Tanaka rip off with crappy metal and threading, and it gets the job done [with Loctite].

 

[Warner]

I guess it depends on what you're in to.
Myself, I like being able to fire up the 4 stroke at 6:30am on a Sunday morning to cruise down to the diner for breakfast. I wouldn't do that with a 2 cycle.
I guess stealth is more appealing to me than noise and smoke.

I'm assuming you are talking about the Happy Time type two strokes, because my Mitsubishi 2 stroke is super quiet and stealthy. I think that as people discuss the 2 stroke vs 4 stroke topic, it's important not to automatically think that 2 stroke = chinese made, Happy Time engine. While those ARE 2 strokes, they are not what I am talking about when I say 2 stroke.

Warner

 

[Irish John]

Mitsu comes with Staton and Dimension Edge, while the Tanaka comes with GEBE. And who wants a frame mount anyway?
.

I'm a frame-mount guy because I like the balance and the frame is the best place for an engine for a multitude of reasons and then I can have panniers at the back for carrying stuff. I was thinking of Tecumseh when I wrote Tanaka. I don't think I'd like a Tanaka unless I had proof they weren't made in China. I do like the reliability of the rear mounted motors because I insist upon reliability before all else.
I have terrible trouble getting people to accept the Huasheng motor against the Honda even though the HS costs about $500 less than the Honda (that's $350 in price and $150 labour to rig up the Honda carby and change the governor set up. I tell people the HS is a very good motor because it is a very good rip-off of a Honda but they turn up their noses at anything Chinese.
I'd have thought the price difference would sway them towards the HS but it doesn't. I'd like to build a Franco Morini frame-mounted rig one day that I would just use for speed on a track.

 

[Warner]

ohhhhhhhhhhhh sparky -- think we got you !!!

let's not forget about good old Nascar
they run those big 4-strokes all day long


as we ride those things

Sure they do....and they get rebuilt after each race. I'd bet my Mitsu engine against a nascar engine at wide open throttle any day....let's run them both wide open and see which one blows up first. I don't think comparing a nascar engine to a weed wacker engine is a great comparison.

I do agree that both the quality 2 stroke and 4 stroke engines are reliable enough. They both have the same engine life ratings, and both typically outlive those ratings (I believe they are rated for 600 hours). Having said that, I'd bet money on the Mitsu 2 stroke in the test that Sparky suggested where you run them both wide open until one of them pukes. There are a LOT more wear items on the 4 stroke to consider with the mechanical valvetrain.

The undebatable advantages of a 2 stoke are: More power per cc, less weight, and greater simplicity (no adjusting valves or changing oil).

The advantages of the 4 stroke could be: No mixing fuel, quieter in most cases, and fewer emissions.



Warner

 

[Warner]

I'm a frame-mount guy because I like the balance and the frame is the best place for an engine for a multitude of reasons and then I can have panniers at the back for carrying stuff.

As far as balance, you are definitely correct. Once moving, the rack mounts are as easy to ride as a regular bicycle, but you CAN feel that weight up high at walking speeds. As far as mounting panniers....no problem with a rack mount...you just have to be mildly creative. Here are some photos of my ride:

http://i224.photobucket.com/albums/dd265/warners_photos/MAB28.jpg

http://i224.photobucket.com/albums/dd265/warners_photos/MAB34.jpg

http://i224.photobucket.com/albums/dd265/warners_photos/MAB21.jpg

http://i224.photobucket.com/albums/dd265/warners_photos/MAB17.jpg

http://i224.photobucket.com/albums/dd265/warners_photos/MAB18.jpg


Warner

 

[arceeguy]

Since when is running WOT for extended periods of time an indicator of whether a particular engine technology is superior?

Would I "max out" a Happy Time engine for more than a few minutes at a time? Heck no! But, they will run for a loooong time just cruising around. I wouldn't have any problem riding a Vespa 2 stroke scooter WOT for hours on end.

I have a Chinese knockoff of a Honda CT-70 Trail Cub, I "ride that thing" all over the place as long as the speed limit on the road is not over 50. It has a 110cc 4 stroke engine, and 4 speed transmission. It's like driving an old VW Bug, accelerate through the gears and go WOT for the rest of the way. My speed will vary from 50-60 depending on the terrain. I think the CDI has a rev limiter as I cannot exceed about 63 going down hill. I don't worry about blowing it up. It is a very good copy of a Honda, like the HuaSheng engine. But once again, whether it is a 2 stroke or 4 stroke makes no difference.

 

[duivendyk]

Potentially 2 strokes are quite reliable because of the inherent simplicity, any weakness is in the con rod & crank bearings.They also tend to get revd higher which explains their high specific output.4 strokes are more complicated,in either case the quality of construction is really the key.Which is louder depends on the exhaust system.My old Yamaha 2 stroke is less noisy than a Harley for instance.

 

[Waterfowl]

2-stroke!

The "rumor" wasn't that 2-strokes last longer, but that 2-strokes last longer IF ran WOT for hours at a time. 4-strokes aren't designed to be ran at WOT speeds for more than 20~30 min at a time, whereas 2-strokes are designed to be run WOT all day every day until they go kaput.

If you really want to compare 2-stroke to 4-stroke reliability, then don't even consider the Crappy Times engines. Now... how many Mitsu or Tanaka 2-strokes have you heard of with problems? That's what I thought.

A 2-stroke motors inherent design calls for routine piston ring replacement and cyclinder boring to maintain compression. The cylinders can be only bored so much so many times. After this the cyclinder has to be thrown away. Its common for any 2-stoke to have consistent cyclinder wear which leads to this maintenance.

These are just facts. It does not matter who makes the 2-stroke. They will all need replacement rings and cyclinder boring after a certain amount of hours.

4-strokes are made for reliability. 4-strokes are the choice for most applications that requires a workhorse. They are not designed to have the rings replaced after a short time to maintain compression.

Before the recent implement of 4-strokes, motorcross racers had to change their piston rings after every race. Every time. Not changing their rings they lose power and would have to bore their engine sooner to maintain their compression.

The argument can be made for power, look and affordability. But as far as reliability its not even close. 4-strokes last longer period.

Ask an actual engine builder who deals with 2-stroke and 4-stroke rebuilds. He will laugh at the notion that a 2-stroke even comes close to 4-stroke reliability.

 

[Warner]

Since when is running WOT for extended periods of time an indicator of whether a particular engine technology is superior?

Well, since that is how these particular engines generally end up getting used in the application that we are using them in, I can't think of a better way to compare them. The manufacturers (of the quality engines) give both the 2 strokes and the 4 strokes the same engine life rating in hours. Is there a better way that could be used to determine reliability and/or engine technology? If we were using these engines like an automobile (or even motorcycle) engine gets used, then this would not be a great comparison as their rpm's vary to a great degree. I know that when I am on my bike, it's generally at wide open throttle and cruising around 30mph. Others may use them differently I suppose....

Warner