Is Four Stroke Fading Away?..

[johnnyboxer]

It's gone a bit off topic........................all this talk of GG 300's

[zippy]

It's gone a bit off topic........................all this talk of GG 300's

I think the 4 strokes "faded away"

[dgraf]

opinion only, how did they(ama manufactors etc..) come up with the fact that they are polluting more? Can't really understand it. On average I would imagine most trilas riders only get a few hours in on the weekends to ride, yet they use weedwackers blowers etc to service peoples lawns. they are running from the moment I get up till the day ends. I don't think Montesa should have stopped production of the 2t(unlike the other companies). there will always be the 2stroke 4stoke war and I don't mind what anyone rides, but saying that they are polluting more is just absurd. I have rode both, but 10200 for a stock Montesa and 12200. for a repsol is ridiculous. pretty soon the only people that can afford them will be the pro riders. I think I'm getting old(sigh).

dgraf

[tony27]

It's not the "power" (as in horsepower) as much as the torque produced by the 300, which is actually just a few cc's larger in capacity than the 280 (294 vs 272 cc's). The 300 produces torque lower in the RPM range and is not as quick-reving to a degree than the 280 (heavier piston and other minor differences) which makes it a little easier to ride with less throttle input necessary to overcome obstacles.

I had one of the few JTR370's imported into the US in 1996 and found, even with the PWK28 Keihin I put on it, easier to ride than the JTR270 in most instances. The 370 was a 338cc, high compression gentle giant that would grunt up sections that other riders had to spin their engines to get through. So, most of the time it was an easier bike to ride, for me anyway.

Jon

Thats quite a long time ago that the JTRs were around, the 370 was a tractor type grunter & the 270 was the expert level animal. Not many people got on with the 270 & the 370s were generally only used by lower grade riders who trail rode them when not competing

The modern 280s/300s are probably quite similar in their delivery although the 300 is probably slightly less snappy, compared to a bike from the 90s all newer bikes are snappy though

[telecat]

Adding to my previous remarks. Yes the 4T is probably more suited to No stop trials using current materials. However I don't believe for a minute that Tony Bou's bike uses the same materials in the engine that the production bikes do and it shows. The other problem 4T's have us that 2T's are nearly as good at no-stop as the 4T's meaning that the 4T's need a trial to be set out in a certain manner to get the advantage.

Most of the 4T engines are also very tall to accommodate the valve gear and create a engine with good "trials" characteristics. This means that they fit the frames very "cosily" and put weight higher up. As the "holy Grail" is to get weight lower down and "compacted" into as small an area as possible the 4T's are at a disadvantage on balancing and when doing the "big Steps". Again the works Montesa 4T's look like the engine is more "exotic" allowing them to use some expensive metals and composites in order to get back the design advantages of the 2T's.

Adding to that is that Bou just appears to have "clicked" with the 4RT in a way many club riders did with it. In many respects the 4RT and the other 4T's are "marmite" bikes. Either the rider can ride them well or they can't.

Edited August 16, 2010 by Telecat

[benbeta23]

Adding to my previous remarks. Yes the 4T is probably more suited to No stop trials using current materials. However I don't believe for a minute that Tony Bou's bike uses the same materials in the engine that the production bikes do and it shows. The other problem 4T's have us that 2T's are nearly as good at no-stop as the 4T's meaning that the 4T's need a trial to be set out in a certain manner to get the advantage.

Most of the 4T engines are also very tall to accommodate the valve gear and create a engine with good "trials" characteristics. This means that they fit the frames very "cosily" and put weight higher up. As the "holy Grail" is to get weight lower down and "compacted" into as small an area as possible the 4T's are at a disadvantage on balancing and when doing the "big Steps". Again the works Montesa 4T's look like the engine is more "exotic" allowing them to use some expensive metals and composites in order to get back the design advantages of the 2T's.

Adding to that is that Bou just appears to have "clicked" with the 4RT in a way many club riders did with it. In many respects the 4RT and the other 4T's are "marmite" bikes. Either the rider can ride them well or they can't.

I'm Sorry, But who even mentioned that in the first place, Obviously Bou's bike is uncomparable to standard Monts, Doesn't take a rocket scientist to work that one out, But anyway the fact is, 2 strokes, Lighter, Easier to chuck about, 4 strokes, way more torque, More postive engine response in some ways etc.., But there both as good as each other in there own ways.

[bigfoot]

I agree with most of this except in 2009 & 2010 bike. I've ridden the bigger GGs for years now and liked the slower response and gentle power BUT my 2009 300 was an animal out of the box (probably still is). I only changed the throttle tube to a slow one and left the rest but it took my ages to get used to and I still think its too much. After probably 10 years of the 330, 320, 300 models my next one will be a 250 for sure. My mate has one and it lovely.

[telecat]

I'm Sorry, But who even mentioned that in the first place, Obviously Bou's bike is uncomparable to standard Monts, Doesn't take a rocket scientist to work that one out, But anyway the fact is, 2 strokes, Lighter, Easier to chuck about, 4 strokes, way more torque, More postive engine response in some ways etc.., But there both as good as each other in there own ways.

Actually the comparison I was making is that if they could use those materials then the bikes would be comparable as Bou has proved. I also would disagree with the comments about more torque and more positive engine response. They are merely different in the way that they "feel". Under most conditions with comparable riders The Non "Works" 2T's will be a better bet than the 4T's. The last kicker is that 2T's will "seem" quieter.

[tony27]

I'm Sorry, But who even mentioned that in the first place, Obviously Bou's bike is uncomparable to standard Monts, Doesn't take a rocket scientist to work that one out, But anyway the fact is, 2 strokes, Lighter, Easier to chuck about, 4 strokes, way more torque, More postive engine response in some ways etc.., But there both as good as each other in there own ways.

You've fallen into the classic torque versus flywheel trap, a 2T will always produce more torque than a 4T for any given capacity due to the fact they fire twice as often. A 4T needs a heavier flywheel to keep the engine turning for the revolution where the engine isn't firing which is what you feel as torque

[dgshannon]

A 4T needs a heavier flywheel to keep the engine turning for the revolution where the engine isn't firing

This produces a characteristic, that under some circonstances, is desireable. For example, off camber turns, acceleration under less than desireable traction conditions, etc.

The 4-stroke is producing drive to the wheel, with half as many power strokes. For lack of a better explaination, this means that the bike is travels further, still under power, but with less (in total) violent input pulses to the real wheel. There are half as many power pulses to disrupt traction at the rear wheel, plus the heavier flywheel better smooths out the half as many power pulses that are there. A rider that gets along well with a 4-stroke learns to be a lot less throttle happy. They learn to use that unique characteristic of the engine to do something akin to "coasting" through the obstical, more on flywheel momentum, than on engine power pulses.

The vast majority (95%+) of the guys in our club ride 4-strokes. But, the most of us are clubman level riders, with no hop and bop skills, riding in an area with a lot of loose traction off-off camber stuff, hillsides, creek beds, etc. and no real need for the quick response, violent explosion of power, that the 2-strokes are so good at. In our particular area, 2-strokes are at the disadvanage in almost every case. Except, when the 2-stroke is a vintage bike, and the heavy flywheel there makes it exhibit characteristics more like the modern 4-stroke.

[benbeta23]

Actually the comparison I was making is that if they could use those materials then the bikes would be comparable as Bou has proved. I also would disagree with the comments about more torque and more positive engine response. They are merely different in the way that they "feel". Under most conditions with comparable riders The Non "Works" 2T's will be a better bet than the 4T's. The last kicker is that 2T's will "seem" quieter.

I don't think in one way the 4t's need to be up to the standards of Bou's bike to be comparable to 2T's & Normal 4T's will never be like Bou's Bike because his bike is a Factory secret and for no one else to know What special Parts it has on, I mean in my opinion the 2T's are better for Indoor stuff where the lightness and the top end power is a big issue, & are a very good 'Tight Section' bike, where they are good to 'flick about' But on the Hillclimb's I'm sorry but the 4T would make the 2T look crap, I Know these top UK lads like Dabill & Wiggy can get them to do anything & I'm not saying the 2T's can't do hillclimbs But that's when the 4T can really shine, They have better bottom end grunt. Also as Cabestany said, The 2T's can do some things better than the 4T, & the 4T can do some things better than the 2T, which is true But I think It is very unfair to say That if the 4T's aren't up to the standard's of Bou's bike that they aren't in the same League as 2T's because that is very much Untrue & Totally Wrong to say.

Edited August 17, 2010 by GasGasben

[rockyrider]

Having never ridden the 4t offroad, I still like the instantaneous of a 2t, that's just me.....

[telecat]

I don't think in one way the 4t's need to be up to the standards of Bou's bike to be comparable to 2T's & Normal 4T's will never be like Bou's Bike because his bike is a Factory secret and for no one else to know What special Parts it has on, I mean in my opinion the 2T's are better for Indoor stuff where the lightness and the top end power is a big issue, & are a very good 'Tight Section' bike, where they are good to 'flick about' But on the Hillclimb's I'm sorry but the 4T would make the 2T look crap, I Know these top UK lads like Dabill & Wiggy can get them to do anything & I'm not saying the 2T's can't do hillclimbs But that's when the 4T can really shine, They have better bottom end grunt. Also as Cabestany said, The 2T's can do some things better than the 4T, & the 4T can do some things better than the 2T, which is true But I think It is very unfair to say That if the 4T's aren't up to the standard's of Bou's bike that they aren't in the same League as 2T's because that is very much Untrue & Totally Wrong to say.

As others have pointed out you seem to misunderstand the way Torque is generated and how 4T's compensate for the lesser "firing" times. The Fewer times they "fire" in the cycle makes them "good" in the slippy stuff although it can be compensated for by the 2T's very effectively. As for hill climbs I haven't seen any advantage of 4T's over 2T. Generally that's down to gear selection and rider ability. My Take on it is that a 2T "recovers" better up a hill. As both "lose" revs the best riders get the back wheel off the ground to get the engine back into it's torque band. A 2T does this better.

[benbeta23]

- Two-stroke engines don't live as long as four-stroke engines. The lack of a dedicated lubrication system means that the parts of a two-stroke engine wear-out faster. Two-stroke engines require a mix of oil in with the gas to lubricate the crankshaft, connecting rod and cylinder walls.

- Two-stroke oil can be expensive. Mixing ratio is about 4 ounces per gallon of gas: burning about a gallon of oil every 1,000 miles.

- Two-stroke engines do not use fuel efficiently, yielding fewer miles per gallon.

- Two-stroke engines produce more pollution.

From:

-- The combustion of the oil in the gas. The oil makes all two-stroke engines smoky to some extent, and a badly worn two-stroke engine can emit more oily smoke.

-- Each time a new mix of air/fuel is loaded into the combustion chamber, part of it leaks out through the exhaust port.

just found a few bits of information of Disadvantages of 2T's which is all very true.

I'm sorry but when you own a GasGas I really don't think your in the position to talk about How much better 2T's are, When your radiator is cracked and your airbox is always full of water, & when the bike has completly had it, In another 5 years time the 4T will still be running strong. Then you can tell me how much better a 2T is, Trust me when you see an Evo 4T fly up a hill then you will seriously know what 4T's are about, Until then if you havn't experienced a new 4T I'm sorry but you can't judge them, No matter what you say the 4T's have more Bottom End Torque than a 2T does, But a 2T has more top end power. I no the Torque of 2T's & 4T's is generated differently as you say but 4T has more bottom end Torque.

Edited August 18, 2010 by GasGasben

[telecat]

- Two-stroke engines don't live as long as four-stroke engines. The lack of a dedicated lubrication system means that the parts of a two-stroke engine wear-out faster. Two-stroke engines require a mix of oil in with the gas to lubricate the crankshaft, connecting rod and cylinder walls.

- Two-stroke oil can be expensive. Mixing ratio is about 4 ounces per gallon of gas: burning about a gallon of oil every 1,000 miles.

- Two-stroke engines do not use fuel efficiently, yielding fewer miles per gallon.

- Two-stroke engines produce more pollution.

From:

-- The combustion of the oil in the gas. The oil makes all two-stroke engines smoky to some extent, and a badly worn two-stroke engine can emit more oily smoke.

-- Each time a new mix of air/fuel is loaded into the combustion chamber, part of it leaks out through the exhaust port.

just found a few bits of information of Disadvantages of 2T's which is all very true.

I'm sorry but when you own a GasGas I really don't think your in the position to talk about How much better 2T's are, When your radiator is cracked and your airbox is always full of water, & when the bike has completly had it, In another 5 years time the 4T will still be running strong. Then you can tell me how much better a 2T is, Trust me when you see an Evo 4T fly up a hill then you will seriously know what 4T's are about, Until then if you havn't experienced a new 4T I'm sorry but you can't judge them, No matter what you say the 4T's have more Bottom End Torque than a 2T does, But a 2T has more top end power. I no the Torque of 2T's & 4T's is generated differently as you say but 4T has more bottom end Torque.

With regard to the 2T points

2T engines CAN live as long as 4T's if looked after. Don't forget that the Oil is in the petrol and lubricates any part it comes into contact with whereas 4T's lubricate from the crank(generally), meaning that the engine has to move to lubricate. In both cases Modern oils mean that neither is at a disadvantage.

2T does consume oil no doubt and it can be relatively expensive. But it is minuscule in the running costs of the engine.

Under 500cc A two stroke is very economical. Don't forget that most 4T's under this level are not performance engines, those that are show very little difference in MPG.

Pollution, Modern 2T's using modern oils have very little difference to 4T's. Even California doesn't ban 2T engines. Yes they are worse again over 500CC but nobody produces those today. If you are looking for the worst polluters when it comes to particulates look at diesel. Japan will not allow Many Diesel cars due to this.

All Worn engines will smoke 2T or 4T.

You repeated yourself on your next point.

As for Gas Gas Versus Beta reliability that's another matter and basically it's down to the fact that these are competition machines. I could regale you with details of some Beta faults I have come across but to honest all the Trials makes have faults. The MONTESA is a well built machine. I still see plenty of the 315R's out there competing against new Machines. However they are not the only story and in competition 4T's are as likely to be damaged and in some circumstances it is liable to be more expensive to fix.

As for seeing 4T's flying up hills I again stick to what I said earlier.

There a natural break point at which current 2T's start to lose against 4T's. Above 500cc's 4T's are more powerful, more economical, easier to control and more reliable than 2T's where the combustion method basically cannot be controlled to the degree that a 4T can. Under that point a 4T is at a disadvantage especially as they are more expensive to produce.

As an example in the 70's and 80's the GT550 Suzuki and Kawasaki KH500 Triples were great bikes. The 750cc models were always more trouble and were replaced by 4T's as the 80's went on.

As road Bikes Under 500cc then yes such as the Aprilia RS machines are pains in the neck to maintain due to the fact they are usually tuned up to within an inch of their lives. However most bikes at that level aren't and I don't see any difference in the number of 70's and eighties 2T's and 4T's that have survived to today. The factor's on their survival are more to do with desirability (Yamaha RD350LC's, FS1E's, Fantic Cabarello, Honda SS50), than the stroke of their engine.