Motorcycle get high emission than car.

[deafsmogtech]

Nitromethane, methanol, lube oil. That is what Google says.

The engine is very basic and functions similar to diesel (glow plug). I don't think they have valves. The burnt fuel exits through a hole in the side of the combustion chamber.

Oh, I got it. 2 strokes I believe.

 

[deafsmogtech]

I know 450cc and 250cc and what your point is?

You says the 4 stroke engine is better than 2 stroke cuz of higher RPM and more HP. Because the 4 stroke engine size is almost double than the 2 stroke. If both of the 2 and 4 stroke engine sizes are the same bore and stroke,then 2 stroke engine is a winner of the higher RPM and torque.

 

[The Highlander]

You says the 4 stroke engine is better than 2 stroke cuz of higher RPM and more HP. Because the 4 stroke engine size is almost double than the 2 stroke. If both of the 2 and 4 stroke engine sizes are the same bore and stroke,then 2 stroke engine is a winner of the higher RPM and torque.

And? I never said both engine sizes are same. Re-read up again.

 

[deafsmogtech]

I remembered I had a go kart with a McCulloch, very high RPM probably hit 14,000 RPM with full WOT. I used to tuning the A/F mixture screws in a big carburetor (kart carb) to obtaining good high RPM peak while WOT on the flat surface.

I found one link about the McCulloch kart engine. I ID'ed one engine was MC91.

 

[deafsmogtech]

And? I never said both engine sizes are same. Re-read up again.

You misunderstand. The bike with a 450cc, 4 stroke engine is outperformed a 250 cc 2 stroke engine that you mentioned in previous post. Right? Because the 2 stoke engine is small. Make sense?

 

[The Highlander]

You misunderstand. The bike with a 450cc, 4 stroke engine is outperformed a 250 cc 2 stroke engine that you mentioned in previous post. Right? Because the 2 stoke engine is small. Make sense?

What misunderstand?

You said

Originally Posted by deafsmogtech
You says the 4 stroke engine is better than 2 stroke cuz of higher RPM and more HP. Because the 4 stroke engine size is almost double than the 2 stroke. If both of the 2 and 4 stroke engine sizes are the same bore and stroke,then 2 stroke engine is a winner of the higher RPM and torque.

I knew about 4 stoke is 450cc and 2 cycle is 250cc but my point that YOU CAN'T USE 450CC WITH 2 cycle for dirt bike. Do you understand? Yes you can use 450cc with 4 cycle engine for dirt bike. So Which you want to pick 450cc with 4 cycle engine OR 250 cc with 2 cycle ? I will pick 450cc with stroke 4 over 250cc with stroke.

YOU ASKED FOR IT! MOTOCROSS ACTION'S TWO-STROKE VERSUS FOUR-STROKE SHOOTOUT: YAMAHA YZ250 VERSUS YAMAHA YZ250F | News | Motocross Action Magazine

The AMA rule forced 250cc two-strokes to compete against 450cc four-strokes. On paper it’s not that good a match, with both horsepower, torque and powerbands falling on the side of the thumper. Eventually, the factory race teams came to the realization, egged on the sales departments, that they needed to go all four-stroke, all the time.

Yes, 250cc with 2C beat 250cc with 4c but why should you pick 250 with 4cc for dirt motorcycle or motorcycle? Don't forget about EPA rules for 250ccc with 2C. I don't want to deal with EPA or other.

 

[deafsmogtech]

What misunderstand?

You said

I knew about 4 stoke is 450cc and 2 cycle is 250cc but my point that YOU CAN'T USE 450CC WITH 2 cycle for dirt bike. Do you understand? Yes you can use 450cc with 4 cycle engine for dirt bike. So Which you want to pick 450cc with 4 cycle engine OR 250 cc with 2 cycle ? I will pick 450cc with stroke 4 over 250cc with stroke.

YOU ASKED FOR IT! MOTOCROSS ACTION'S TWO-STROKE VERSUS FOUR-STROKE SHOOTOUT: YAMAHA YZ250 VERSUS YAMAHA YZ250F | News | Motocross Action Magazine



Yes, 250cc with 2C beat 250cc with 4c but why should you pick 250 with 4cc for dirt motorcycle or motorcycle? Don't forget about EPA rules for 250ccc with 2C. I don't want to deal with EPA or other.

Why you post it in first place? I know nothing about the motorcycle engines.

 

[The Highlander]

Why you post it in first place? I know nothing about the motorcycle engines.

Are you sure?

 

[Grummer]

two strokes is MORE FUN, QUICKER and four strokes more traction , heavier and too flat in a powerband..... but if you go 500cc 2 strokes itd loose to 4 strokes because of wasted wheelspins , say 2 x rev is wheel spinning hard, as opposed to 1 in every 4 spins does a kick it give wheel, momentum, weight, surface density time to give the stroke per force to forward More grips.....then about....its about riders, and which riders are more apt in two stroke riding style or four stroke style...or even their adaptability.....

i rode husquvarnas four strokes, amazing, FAST, grippy on sandy tracks, but the two stroke is more explosive outing the berms, and easier to clutch in going half and half, then with a four stroke - when you back off, or clutch in , its more risky to fuck up the motor in a 4-stroke than a 2 stroke...simpler in parts....more durable for this sort of riding but 4-stroke is mroe durable if you ride a certain way with less clutch work AND with abilty to use engine braking.... in the tactics, two strokes there no engine braking....

so ,MY point is,
its not about 'figures' and shit, its about HOW you RIDE AND WHAT YOU PREFER.....for me
id have a much easier time with 2 strokes, maintainence-wise, riding-wise,,fun factor wise....but for say maybe enduro, id go with four strokes as steep hills.....(either down or up) a four is a big plus...it trucks and it less you do less sliding down...unless you re extraordinary with the brakes....(and suspension settings are finicky business with mulitple terrains)...
ok
I LIKE TWO STROKES Better end of story.

 

[purplecatty]

I have no idea how do they lubricate the crankcases when turning the tiny 4 cycle engines upside or downside. LawnBoy? This 2 stroke LawnBoy mower outpower than any small 4 cycle engines of the lawnmowers. I think my ex LB mower's engine was about 4HP, can be equal to 2 Briggs & Stratton engines, cuz of high torque and can cut tally grass easy. LB mower's body was made of aluminum and lightweight. I want it too bad before they are gone soon. I see they are in Midwest or Southeast. I maybe buy a good one there and bring to California. EPA? No problem, they won't bother me and LawnBoy mower.

I've seen plenty of 4 cylinder lawnboys in Kansas it's all new, Toro Pacesetters lawnmower are very popular and I even own one too (one with self-propelled).

I used to have 1971 Toro self-propelled 3.5hp lawnmower. It was one of the best mower I've ever use (belongs to my dad). It have spring crank start. Crank 3 or 4 times then hit the throttle stick full (to choke) and it'll roars to life quickly. It had "S" shape blade that can cut tallest grass with ease. It have oil filler funnel built in with cap. Just pour in oil to fill it up and screw in clear cap. Press the bottom button to fill oil till bubble stops inside funnel then it's level and full inside crankcase.. Pretty fancy mower back in Ol' day.

To get an idea how it lubricates inside of engine regardless what position are.

As for 4 cycle small engine for weed eater, blowers ect, It have 1" or 1 1/2" thin flat rod with "finger" on bottom that was bolted to bottom of piston arm so when it's oscillating, it splashes oil from bottom of crankcase perhap "finger" just 2/16" to crankcase "floor". Just like Horizontal and Vertical 4 cylinder engines, If you take apart Vertical 4 cylinder from Go Cart, Tiller ect, you'll see flat rod with "fingers" on bottom of piston arm while Horizontal engine commonly on lawnmower do not have rod with "finger" in it. Because piston oscillation splashes oil. Vertical engine can't do without flat rod with "finger". For small 4 cycle engine, It works both way regardless position you are at and still splashes oil to lubricates inside of it. I worked on small engine for many years and learned so much about it. You can steal Vertical engine's thin rod with "finger" and bolt it on bottom of piston arm on Horizontal engine and upright it with thick "L" shape bracket to use it for Go Cart. You'll have to modify carburetor tube so it'll be at level. Cap the oil filler hole with rubber cork with screw secure it. It's very possible!! Think Logically!! smile

Catty

 

[Grummer]

nah, dont ever waste time on a four stroke, as for Go-karts, get Rotax, tandem twin, 250cc 2 stroke, SERIOUS POWER!! it is FAST, thats the stuff where Formula One champions starts from. i also knew how to port, fabricate expansion chambers for these. Then i played with swingarms on 'Bucket-racers' up to 100cc thrashy for fun club racing, they can get Serious too
, either Reed valved or rotary disc valved i dont care, they both fun, rotary disc is quite mathematical lol
best four stroke for dirt racing would be Harley XR1000 for the brake-less dirt track (oval track) racing...again GP riders came from that, cuz thats' where they learnt powersliding...and SLIDING BOTH back and Front wheel!!, in other words actual 2 -wheel drifting.

 

[deafsmogtech]

I've seen plenty of 4 cylinder lawnboys in Kansas it's all new, Toro Pacesetters lawnmower are very popular and I even own one too (one with self-propelled).

I used to have 1971 Toro self-propelled 3.5hp lawnmower. It was one of the best mower I've ever use (belongs to my dad). It have spring crank start. Crank 3 or 4 times then hit the throttle stick full (to choke) and it'll roars to life quickly. It had "S" shape blade that can cut tallest grass with ease. It have oil filler funnel built in with cap. Just pour in oil to fill it up and screw in clear cap. Press the bottom button to fill oil till bubble stops inside funnel then it's level and full inside crankcase.. Pretty fancy mower back in Ol' day.

To get an idea how it lubricates inside of engine regardless what position are.

As for 4 cycle small engine for weed eater, blowers ect, It have 1" or 1 1/2" thin flat rod with "finger" on bottom that was bolted to bottom of piston arm so when it's oscillating, it splashes oil from bottom of crankcase perhap "finger" just 2/16" to crankcase "floor". Just like Horizontal and Vertical 4 cylinder engines, If you take apart Vertical 4 cylinder from Go Cart, Tiller ect, you'll see flat rod with "fingers" on bottom of piston arm while Horizontal engine commonly on lawnmower do not have rod with "finger" in it. Because piston oscillation splashes oil. Vertical engine can't do without flat rod with "finger". For small 4 cycle engine, It works both way regardless position you are at and still splashes oil to lubricates inside of it. I worked on small engine for many years and learned so much about it. You can steal Vertical engine's thin rod with "finger" and bolt it on bottom of piston arm on Horizontal engine and upright it with thick "L" shape bracket to use it for Go Cart. You'll have to modify carburetor tube so it'll be at level. Cap the oil filler hole with rubber cork with screw secure it. It's very possible!! Think Logically!! smile

Catty

Sound like you already teared down a newer tiny 4 stroke engine like weed eater? Did you?

 

[deafsmogtech]

nah, dont ever waste time on a four stroke, as for Go-karts, get Rotax, tandem twin, 250cc 2 stroke, SERIOUS POWER!! it is FAST, thats the stuff where Formula One champions starts from. i also knew how to port, fabricate expansion chambers for these. Then i played with swingarms on 'Bucket-racers' up to 100cc thrashy for fun club racing, they can get Serious too
, either Reed valved or rotary disc valved i dont care, they both fun, rotary disc is quite mathematical lol
best four stroke for dirt racing would be Harley XR1000 for the brake-less dirt track (oval track) racing...again GP riders came from that, cuz thats' where they learnt powersliding...and SLIDING BOTH back and Front wheel!!, in other words actual 2 -wheel drifting.

Is "Fabricate expansion chambers" referring to the intake manifold? or Exhaust pipe/muffler?
I never see the word "Rotary Disc Valve" before.... what kind of the engine? Yamaha KT100?

 

[Grummer]

expansion chambers is those bulging curvey pipes that you see on two strokes, Motocross and Formula 1 bikes (500GP back then now 2 strokes 'banned', thanks to bullshit politics).
so, these are 'exhaust pipes"/muffler....it is designed in w main ways (mostly a combination of..) tuned lengths (four strokes also have this as 'extractors" that is extracting spent charges for the next combustion cycle...whereas the 2 stroke 'expansion chambers' is not only the length but also timing to send back shock waves to "plug" in the exhaust port to prevent the next-coming fresh charges from being wasted, to maximise the potential to toward te next 2-stroke combustion cycle. (remember 4 strokes goes 4 entire strokes/2 spins of the crank to complete the intake/compress/fire/expell of air/fuel charges where as 2 strokes is effectively done at Every SINGLE full spin of a crank. Not only the 'every' sometimes engineers will exploit this to triple , even quabruple the power strokes for every 360 degrees turns of a crank. (now thats why striaght 6, v8's are "powerful" becuase it is balanced into doing as MUCH POWER per Rev of a crank...

let go back to the exhaust pipe shall we?

2 strokes's pipes (modern ones (not chainsaws you'd Never see it on that as their powerband is zero or everything so narrow it is entirely ported. But for motorcycles ridability is paramount over outright brute output to do this
they need to broaden the powerband. It is done hundreds of ways. Principally, it is achieved with alot of engineering in related to the use od expanision chambers
So many limitations are inherented with 2 strokes becuase of the port's dimensions. it is effectively a 'loose pump' engine design, working best in certain speeds and the rest is just pumping, almost misfiring, barely noticable but at that 'excess ineffecient pumping stages' (one would say below powerband, at idle, close to redline past the useful power-generating curves aka the torque curves' is where its not making power just wasting fuel.
expansion chamber is a poor name but used to conventionally refer to the 'use of expanding hot gases from the 2 stroke's exhausts' comes out EXPLOSIVELY from the the rapid movement of the pistion inside the cylindar, it had little to do with 'pressure' like you might find with 4 strokes's mechanical means of trapping with valves. 2 stroke dont have valve just holes "ports".
the exploding phemonena is like ear-popping , "not the sounding -like' but engine behaving ina way such like...
some clever scientist engneer took the idea that if its a balloon which 'matches the exploding gases from the output hole' and have it to 'blow back' (not the gases but the shockwaves) would hole the output hole SHUT a bit longer....so the piston lifts the fresh charge past the output towards the burning chamber (where the spark plugs are)..all this equals to more power and 'mixing 2-3 or 4 different kinds of 2 stroke engines into ONE single cylindar mould. Yes i said Mould, my own words.you see , in the 2 stroke design, there is transfer ports which 'carries the fresh from compression at the crankshaft side to the over above the piston side, (pistion crown, above the rings).
Hard to explain all this but transfer ports are subjected to various designs also, like 5 ports, 6 or 8 ports, small or big, or the top-side (above piston) is the position high or just below the exhausts.. if high, the transfer is slow, if low the transfer is quick but the efficency is always a problem.

Expansion chambers as made a huge differences....

oh the angles of the muffler side of the chambers decides how 'wide' the effective working range. That is the steeper is will be sharper, more narrower in range of it improvement, shallower might mean less use of the shock waves...also it had to work well with the transfers....grinding transfers helps so much, then get too narrow....then pipes helps it back...the curves and retain the power gained from grinding transfers....
these are just showing how tedious, time consuming of experimentations.
Again Rotary valves is tedious, but more straight forward but more limited in what can be done..
Rotary valves is for the inlets.
Reed valves is for the inlets as well.
Expansion chamber is that snake-like welding funnying looking 2 stroke exhaust pipes.
Often times it is 'funny looking' and often get riddled with strange routing of the pipes and welding traces....thats' because Motorcycle racing is unlike Go kart racing, riders and bikes are subjected to extreme movement problems, cornering low, jumping high bikes landing with forks and back suspension bottoming out....etc etc and Heat, that burns the riders legs is another one too....

That is fabricated on a number of ways, lengths, angles of the expanding, and angles of the (forgot the name of it, last time read the book on this was 20 years ago)...but the closing angle is right before the 'stinger' which is the narrow pipes that leaks out the gases, and left over shockwaves, and works to 'breathe the engine' the expansion chamber pipes itself is more like a working part of the 2 stroke performance engine in itself, its not a 'exhaust' it is a NON Mechanical MEANS to deal with the NON mechanical 'loss' of exhaust pressure controlling appartus that the 4 -strokes engine design enjoys. (4 strokes works alot on with CAMs.....which is timing...duration to open/shut//similarly the rotary valves' approach to decide its duration is done this way also but its whole thinking is entirely different as crank frequency as concept is totally different.

So, there Expansion chamber is shockwave-exploiting device which to alter the "results/personality" that would otherwise be restricted by the actual design of that 2 stroke engine set down by solely the port of the cylinder's chambers in both crankcase pressure and the cylinder head/in between transfers compromises that plagued its balances between 'grabbing as much from the carbs' and 'getting as much from the crank' across the rev range....

simple engines, it is not. but a fascinating one that provokes us to think pass the mechanical problems, it is the more fluid, dynamic we dont 'see' , that is the shockwaves and how we exploit it.

That's the beauty of expansion chambers.

 

[Grummer]

rotary valves is usually found on engine with low-hanging carbs that is more on the side of the engine because it is usually fixated on the crank or next to it with another gear running it. RG400-RG500 are famous to use Rotary valves. Google Suzuki RG500 road bikes, heaps of that in England...few left in NZ..

Yes KT -100 (just googled it, yes!)

 

[Grummer]

heres some pics...

actual disc valves

typical 2 stroke crank design (note it got thick barrel with thin gap where conrod goes thru to piston? - that's is to pressurise the fresh charge to 'push up thru the transfer ports in cylinder

bascially how you spot a disc valved engine..

another example, which will be similar to water cooling ones (RG400-500, 70-80's GP bikes all had those or reed valves)

 

[Grummer]

here's an excellent link..
How Two-Stroke Expansion Chambers Work, and Why You Should Care.