Motorsport motors these days

Wondering what type of motors do they use these days -- 2-stroke or 4-stroke.

I had a Yamaha 125 Enduro bike back in the late 60s. Man, I drooled over that thing in high school before I bought it. I had a picture from a magazine that I would just take out and look at when the teacher wasn't looking, lol. Yellow and black paint job. I thought it was really something. I rode that bike all over creation for several years. Rode some enduro races through the woods. Played on a motocross course. I had too much fun with it but it was not powerful enough really. I modded it with this and that. Put an expansion chamber exhaust on it. Wow, was that bike loud! I never did get enough power out of it to lift the front wheel at will with the motor's power alone. In those days, Penton, Bultaco, Maico, Husqvarna... those bikes did have enough power. I guess the Yamaha 125 Enduro was kind of the consumer saw of chainsaws and the other brands mentioned were like pro saws! Honda wasn't even in the mix in those days; they only had 4-stroke and they were too heavy and under-powered for the dirt bike world.

Curious what has happened in the motor wars over the past 50 years! In those days, 2-strokes ruled in dirt bikes. Seems like 2-stroke was even king then in high speed racing, not sure about that.

 

2 strokes pretty much rule in everything imo

 

Everything has gone 4 stroke per EPA...but they are now lighter high revving high power monsters...2 strokes still win cc to cc, but they have been outlawed, and the new 4 strokes scoot, so no problem, ride on!

4 stroke noises coming from snowmobiles still takes some getting used to IMO...

 

Yep, almost everything I know is 4stroke now. 450cc is the largest dirt bike commonly found. Hoping for a day when 2smoke makes a comeback, but it’s doubtful. Those smells instantly transform you back in time. There’s still a company making a V4 track bike that is simply divine. Suter : MMX 500

OMG the sounds they make are intoxicating!

 

Wow, I didn't expect these responses. This 'conversion' is just due to emissions? Oh well, probably will be all battery bikes some day.

 

Yep.
Heck, no 2 stroke mowers anymore either...and 4 stroke weedeaters are pretty common now too...not sure how chainsaws have gotten through without change, so far...

 

I was wondering that very thing -- why no 4-stroke chainsaws? I suppose it is weight? But with weedeaters, weight is also a factor, so don't get it.

I run 40:1 mix and the only reason I do is due to how many forumites run 40:1. I cannot know for sure, but those who say that 50:1 came about due to emissions concerns and EPA pressure... that makes sense to me. It might be just fine at 50:1 but I suppose it doesn't hurt a thing to run 40:1 and it might help. I suppose the negative is it's more pollution, and that is def a negative. I don't like to pollute.

If I were to become convinced 50:1 truly is fine and dandy (and I might), I would prefer to run 50:1. Not only for the environmentalist streak in me but also because 50:1 should burn cleaner and be less apt to bother me. As I have aged, I don't like exhaust/fumes.

 

BTW... 2-stroke mowers? What mowers were 2-stroke? It's probably obvious but I don't recall!

EDIT: Lawn Boy. I didn't know that. I suppose because we always had 4-strokes that I recall!

 

The only 2 stroke motors I have these days are in the chainsaw and an old Evinrude Ducktwin. I have the Stihl tiny 4 strokes in the leaf blower and trimmer. 2 stroke off road motorcycles are getting rarer every year, but hey are still being made, Beta, Gasgas, Husqvarna, KTM, I think Yamaha is the only Jap bike maker still making a 2 stoke mx bike.. There was a time when they couldn't compete with the 2 stroke of the same cc, those days are gone. I have a 250cc 4 stroke supermoto, think mx bike on street tires.. A whole lot of off road bike, atv, utv, and even snowmobile, and boat motors are 4 stroke these days.

Enjoy the sounds and smells while you can..

I miss the days when I worked around heavy equipment with Detroit Diesel 2 strokes. 6-71s, 8v-71s, even small 4-53 and 6v-53s....mmmm the smell of them warming up in the garage with smoke so thick it would almost choke you...Nothing else smelled like that... maybe older busses... I got to go start my saw...

 

In snowmobiles, 2 strokes are still king. Yes there's 4strokes, but not every company has one. Direct injection actually makes 2 strokes cleaner emissions wise than 4 strokes in certain particulates measured. Doo, cat, Yamaha all have 4 stroke options. Yamaha was the leader in 4 stroke sleds as they went all 4 stroke in like 2003. Just in the last year or two Yamaha started making a 2 stroke sled again, but it's a work machine. Simplicity's sake with that. Newer Yamaha's are basically blue colored arctic cats. All the 4 stroke cats are green and black Yamaha motored sleds.
Polaris still has all 2 stroke sleds, but they did have a couple of 4 strokes. TBH, I'm shocked that they don't offer a 4 stroke currently, as the last one was a weber 750 parallel twin in na and turbo flavors. Those turbo Polaris 750's were fast and stock at 140 hp. They were easily modded to make a lot more power with their factory Motronic fuel injection.
Polaris and doo have 850 cc parallel twins that are making serious power. Sure, Yamaha has a turbo 4 stroke that's even more power, but there's added weight with a 4 stroke. It depends what you're using it for. For me, a 120-140 hp 4 stroke in a 2up touring sled is perfect. They get great mpg, near 20 mpg in 1000-1200cc form

Now in a performance trail or mountain sled, 2 stroke all the way.

Dirt bikes, most are 4 strokes now. There's ktm, Yamaha, and husqvarna dirt bikes that are 2 stroke, but most are 4 stroke. 250 and 450cc essentially have taken the place of 125 and 250cc 2 strokes. Those 450's are high strung. They need a lot more maintenance than 4 strokes typically need. Valves need adjustment on those way more frequently than normal 4 strokes.

Outboard motors used to be 2 stroke dominated. Not any more. Evinrude was shuttered this year and they were the big proponent of 2 strokes with the etec technology that is used in their ( bombardier skidoo) snowmobiles. Honda, Yamaha and mercury are all 4 stroke except maybe some smaller engines? There's Suzuki too, but I think those are really mostly tohatsu outboards.

 

Man, I had no idea that there was still that many 2 smokes still being made...I thought they were mandated all done 15-20 years ago...

 

4 stroke engines do not rev high enough for chainsaw use. They would have to come up with some kind of gearing to get the chain speed up to the same level as a 2 stroke and then the weight factor.

On weed eaters they are heavier with the 4 stroke engines and the weed eater head has some gears in it to bump up the speed, but the speed is not as critical on a weed eater as a chain saw.

The other problem with 4 stroke engines is that they do have a crankcase with oil in it and you cannot go around tilting those things in any direction you want without having issues with the crankcase oil.

Remember chainsaws rev anywhere from 12000 to 14000 rpm's depending on the make, model, and year they were made.

 

Meh...4 strokes will rev past that...15-18,000 is not that uncommon in the motorcycle world...Honda made a lil 250 that was good for 19,000.

 

You will never get a 4 stroke weed eater to come remotely close to those high tech motorcycle engines. The cost would be out of control.

 

No, not banned but as I read with sleds, it was that the manufacturers had to have enough "clean" engines to offset the dirty ones. For Polaris, the dirty ones are the fan cooled 550 2 stroke twins. Those are at least reed valve inducted, but still dirty and old tech compared to the semi direct injection of the higher tech higher performance 2 strokes.

Skidoo offers 4 strokes in 600cc twin that are like 60 hp. A 900 triple NA, a 1200 triple at like 130 hp, and a 900 triple that is turbo'd making 150 hp or so. Their 2 strokes go from a new 600 cc low hp (85) efi, all the way to a turbo'd 850 cc twin with 165hp. So skidoo has options based on what you want 2 or 4 stroke.

Yamaha has a few, mostly 4 strokes. Aside from that 1 work sled with a 540 cc fan cooled reed valve twin, they go from a youth sled all the way to the turbo 3 cylinder 1000cc with 200 hp.

Yamaha use the cat chassis. In return, cat gets Yamaha 4 stroke engines to drop in. Cat ended the relationship with Suzuki that used to make all cats engines from 1984 when arctic cat re entered the business after a couple year absence from bankruptcy, all the way until a couple years ago. So Arctic Cat (now owned by Textron corp after more financial issues) offers 2 and 4 strokes.

In the sled biz, it's different strokes, for different folks.

Elsewhere in power sports, it's almost all 4 strokes.

Somehow chainsaws have kept with 2 stroke. Probably mostly because you can't mask actual weight on a hand held tool with Electric power steering like they do on sleds and ATVs.

 

The new Kawasaki zx25r 4 cylinder( 250 cc) is 17,000 rpm and 50-60 hp. Cost is expected to be~11k not cheap, but
The 400cc ninja twin goes to 12000 rpm and it's about $5k.
Heck, my old 1000cc vtwin does 10,500 rpm.

So the rpm isn't an issue, weight of the engine and different angles needing to be run are due a 4stroke chainsaw.

 

Horkn, why do snowmobiles need such power? Is it just like anything else, they go faster? People don't 'need' 300hp bassboats that go 80mph. Crazy stuff! I know nothing about snowmobiles. I guess some people actually do some work with them? Like pull sleds of firewood, lol?

 

You guys ever take a part a 4 stroke engine like they use on weed eaters There are more plastic pieces in those thing then you can shake a stick at.
Once again they would not even come close to doing like 13000 RPM's without exploding.
Do not get me wrong I am not saying all 4 stroke engines cannot do high RPM's. What I am saying the ones that they have for weed eaters and such will not.
Not all 4 strokes are created equal.

 

"Rolling" resistance is high.

That too

 

There's fun sleds, and work sleds. Some cross between. Guys like to climb up mountains with those turbo 200 hp beasts. For recreational trail riding, a 120 hp fairly low weight 2 stroke will get people in more trouble than they can get out of. That's what my Polaris xc600sp was, except I know how to ride. A sled like that will do well over 100mph, and 0-60 was stupid fast. The dates we use the most is a 97 hp 600 cc 2 stroke old tech Yamaha 2 up. With the longer track and all that touring stuff, it goes about 85 mph on a very good day and it gets crap mpg. It's a little slow for my taste, but it's super reliable and very comfortable. It handles pretty well, which is all it really needs to do.

Do people really need a 300 hp turbo'd trail sled? No, but they are fun.