KymcoForum.com
General => General Discussion => Topic started by: grantourismo on November 28, 2010, 12:52:37 PM
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Hey guys
just a thread what you guys or girls prefer over engine type
I personally prefer Two stroke due to the beautiful engine noise
but too bad they re being phased out and no company seem to be willing
developing the super cool direct injection two stroke
leave your comment and personal preference !
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I prefer (noise, odour) 4 stroke, but wouldn't hesitate driving a 2 stroke.
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If you're talking about the need to mix oil and gas, plus the added pollution and noise, then it's 4 stroke all the way.
-Wolf
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I have always had 4 stroke but I would give 2 stroke a try just because I ride all year and they start easy in the cold better then 4 strokes.I just dont like the idea of running a scoot off of oil and gas.Rideing a scoot is to save a little cash. rideing a 2 stroke you stell have to pay for oil to. Buy that time you can but that much gas in a car.
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I have owned several of both and 2 stroke are MUCH more powerful and responsive per cc , so for a 50cc scoot I prefer a 2 stroke . If engine size is not a concern I prefer a 4 stroke .
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I have a 4 stroke because that is what I could find in my price range in my area. If the 2 stroke had been available I would have learned to mix the oil if needed, though. I took what I could get. One day though I would like to ride that powerful Super 9S L/C 2t for sure!! :D
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Two stroke is my preference -- all else being equal. There used to be plenty of big displacement two strokes available and, believe me, they were wonderful to ride. Too bad, not any more. Smooth and extremely powerful! Some people don't like the fact there is no engine braking with a two stroke but I think it's a plus. You don't get the diving of the front end when you let off the throttle.
Once you get the two stroke bug, you start to love all their qualities.
We've discussed the reasons there are no more of the big two strokes here before. It boils down to political lobbying by HD in the 1970's.
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This pic is from Evans Ward -- a noted Kawasaki enthusiast. (http://i893.photobucket.com/albums/ac134/Hepafilter_2010/IMG_04851.jpg)
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Some people don't like the fact there is no engine braking with a two stroke but I think it's a plus. You don't get the diving of the front end when you let off the throttle.
I did not know that about the engine braking...I bet I would LOVE it! ;D
Wow...I bet I could ride that Kawasaki there in that pic...doesn't look too heavy...
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Never ridden a two stroke scooter, but had a fair number of two stroke motorcycles over the years. The big Kawasaki 750 ntriple shown a few spots above, was so powerful that they were basically unmanageble. The power was way too much for the chassis and suspension. Kawasaki also had a 500 and 350 version.The 350 that I riode was pretty fast.
Two strokes have a different set of quirks than a four stroke.Generally spark plugs don't last as long. The ones that have a metering oil pump use a cable to control it.If that cable breaks or seizes, or the pump goes out, then you are running with no lubrication. They tend to eventually plug the exhaust with carbon.The motorcycles had removeable baffles you could take out and clean. When it's time for a cleaning you'd know because the engine wouldn't run well at all.They don't generally get as good of gas mileage as a comparable four stroke.They are generally faster than a four stroke as they fire once every revolution, rather than once every other revolution as a four stroke does.
When the Suzuki X-6 Hustler and the Yamaha RD350 came out, they were humbling much bigger bikes on the streets.Both had six speeds transmissions that really helped too.
Did you know that there were large diesel two stroke engines used in freight hauling trucks?Set up properly they were absolute screamers.Engines were made by Detroit Diesel, and were used in trucks,marine applications, and generators.
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Did you know that there were large diesel two stroke engines used in freight hauling trucks?Set up properly they were absolute screamers.Engines were made by Detroit Diesel, and were used in trucks,marine applications, and generators.
WooHooooo! I did not know that...but if I had... I would have HAD to drive one! :D
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I started riding on a two stroke which was a '75 Kawasaki KE 100. Just under 200 lbs., it was a good beginner's bike, but loved to foul plugs and what was called "load up" on hills causing the engine to quit running. Next was a two stroke '76 Suzuki GT380, with none of the typical two stoke problems. It was good on plugs, had an oil injector and would rev like nuts. Downside was adjusting three sets of points since it was a triple. I wish I still had it but four strokes rule the day.
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I ride a 4T, but would like to get into the 2T realm next scoot. That Aprilia Ditech direct injection engine sounds like it is incredible, runs fast and clean because it is so efficient.
Hope other manufactures were follow suit.
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Yes, let's hope KYMCO will be competitive.
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Some people don't like the fact there is no engine braking with a two stroke but I think it's a plus. You don't get the diving of the front end when you let off the throttle.
This is a prejudice that originates from old 2 stroke engines with old construction, that also had pre-mix oil and gasoline mixture.
In that case, using engine braking would cause premature wear due to inadequate lubrication of the engine during engine braking.
Almost all bikes in the past 20 years do not use pre-mix but have separate gasoline and oil tanks.
Internal friction of the engine enables engine braking and, ceteris paribus, it is determined by engine's compression ratio.
Usually Kymco's small 2 stroke engines have compression 1:7-1:8 while small 4 stroke engines have 1:8-1:9.
So, they will pretty much engine brake the same, regardless of 2 or 4 stroke composition of the engine.
Whoever drove 2 and 4 stroke motorcycles can from experience notice the same.
If you are from USA, I think you did not have 2 stroke cars in the past.
In Europe we had just a few (usually from the Eastern block) and they had special system that allowed the driver to use or not engine braking for short periods of time, in order to prevent engine damage (all such cars were pre-mix at the time, I am referring to East German Wartburg and Trabant cars).
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I ride a 4T, but would like to get into the 2T realm next scoot. That Aprilia Ditech direct injection engine sounds like it is incredible, runs fast and clean because it is so efficient.
Hope other manufactures were follow suit.
Piaggio's direct injection 2 stroke small engines are a failure of the decade. In the same time, around 2002-2003, other manufacturers also tried switching to that technology (Peugeot for example) and they all had incredible problems, engines were weaker than "regular" predecessors, the spark plug costs a lot and has to be replaced in very short intervals. Online forums are full of very disgruntled owners.
My gf has almost OEM 2 stroke Piaggio NRG 50 mc2 2 stroke from summer 2003 with 26.000 kms on it, not direct injection but normal 2 stroke engine, it drives like crazy, fully stock except lighter roller weights and clutch spring, the thing goes almost 100 km/h according to tacho and it is only a tad slower than Agility 125 in regular usage... 5.5 vs 10 hp.
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Two stroke is my preference -- all else being equal. There used to be plenty of big displacement two strokes available and, believe me, they were wonderful to ride. Too bad, not any more. Smooth and extremely powerful! Some people don't like the fact there is no engine braking with a two stroke but I think it's a plus. You don't get the diving of the front end when you let off the throttle.
Once you get the two stroke bug, you start to love all their qualities.
We've discussed the reasons there are no more of the big two strokes here before. It boils down to political lobbying by HD in the 1970's.
Kawasaki was known for their 2 stroke engines, 250 and 500 cc and they used to make them throughout 80s.
They were not deathbeds, but "deathboards". They developed the power near the top and were hard to drive. A lot of dead people driving them.
In 70s they had also 750 cc 2 stroke motorcycles.
In Europe we had many 2 stroke motorcycles, for example, Italian 125 cc engine was in a number of small off road bikes and sports bikes, it developed around 34 hp.
There was also famous Honda NSR 125 with 34 hp.
They are hard to drive because they rev very high, usually had to have 6 or even 7 gears in order to use the developed power and it is a constant struggle to drive them.
They are great if you are 15 years old and live for the thrills, as you get older, you tend to like more balanced vehicles/engines.
For that reason I do not like big thumpers or 2 cylinder engines and prefer 4 cylinder engines in motorcycles.
However, my 2000 Piaggio NRG 2 stroke with 72 cc kit that developed 10 hp is still my favourite scoot from the past. :)
It did 115+ km/h on flat road and I used to overtake cars with it on the road between cities. :)
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Did you know that there were large diesel two stroke engines used in freight hauling trucks?Set up properly they were absolute screamers.Engines were made by Detroit Diesel, and were used in trucks,marine applications, and generators.
WooHooooo! I did not know that...but if I had... I would have HAD to drive one! :D
Ships and trains also use 2 stroke engines.
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If you're talking about the need to mix oil and gas, plus the added pollution and noise, then it's 4 stroke all the way.
-Wolf
well most new carburettor has got automatic mix why do you need to mix it yourself? ??? ???
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Not all two strokes are/were "peaky". Many examples of moderately tuned ones which were a pure pleasure to ride and operate. Yamaha RD 350 or 400, Suzuki GT 380[edit] and 750 just to name four.
Kawasaki and some others tuned their two stroke street bikes for near maximum hp to get people buying them. In later years those models were detuned substantially and were not so dangerous.
It could be done because two strokes are easily tuned to maximum hp without much expense. Not so for a four stroke with all the valves, seats, cams, sprokets, gears, rockers, etc.
On another point, in the USA, two strokes never presented a polution problem because they never were a significant percentage of the overall number of vehicles on the road. However, when congress was legislating them away, their alleged higher polution was used as an argument. It was BS -- only reason it was done was for US govt to give HD competing power which they had totally lost.
I can understand that in countries where scooters and motorcycles are present in high percent, polution should be considered.
By the way, if multi-cylinder two strokes were in production today, they'd surely have cdi instead of points -- some did even back in the day. ;D
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Yes, Axy, you are right. I did not mean that one cannot use engine braking on a two stroke. Of course one can. I only refer to the fact that there is no momentary sudden diving of the front end when letting off the two stroke throttle. ;D This is one thing that buggs me about four stroke performance, though it can be corrected somewhat by the inclusion of a "throttle follower". Some four stroke engines have them and must be adjusted properly or else the bike or car won't slow down as quickly as the driver expects. Edit to add: Also, I suppose fuel injection or cdi programming can reduce or eliminate this effect. My Xciting is carburated, though.
This is a different phenomenon than the optional use of a compression release mechanism for engine braking which both two and four strokes can use. Neither usually comes equiped with one, though.
If you were raised or learned to ride on a four stroke, you come to expect this momentary dive and it's nothing.
If two strokes is what you learned on, it's annoying.
I do remember when I was a child, there was one two stroke car in my little home town in Florida. Could it have been a Saab?
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I don't particularly like the way it feels when that happens on the 4 stroke. It reminds me a bit of older cars with cruise control that take that extra second to slow down when you hit the brake.
I wanna control my own cruising and stopping. ;D
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Ha! Rianna, then you might not like a two stroke cause when you let off, it's like nothing happend for a second! :D What I'm saying is I happen to like that!
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Oh, okay then. :D I imagine I would get used to it, though. I'd like to ride/drive/try everything out there possible. I couldn't count the number of cars/trucks/vans I've owned in my lifetime. When I was younger, Hoolander, I even wanted to fly a plane...until I learned the cost of flight school.
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it seems that all you bike / scooter boys do have a thing for 2 stroke ;D ;D ;D
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Internal friction of the engine enables engine braking and, ceteris paribus, it is determined by engine's compression ratio.
Usually Kymco's small 2 stroke engines have compression 1:7-1:8 while small 4 stroke engines have 1:8-1:9.
So, they will pretty much engine brake the same, regardless of 2 or 4 stroke composition of the engine.
Whoever drove 2 and 4 stroke motorcycles can from experience notice the same.
I noticed, that the additidonal friction of all those additional 4 stroke parts (camshaft & Co) make a signifikant difference. "ceteris paribus" isn't applicable.
My experience covers Yamaha Neos (50cc, 2 stroke) up to VEB Trabant P601 (599cc, 2 stroke). (And bigger scooters, but no 2 stroke motorcycles.)
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Not all two strokes are/were "peaky". Many examples of moderately tuned ones which were a pure pleasure to ride and operate. Yamaha RD 350 or 400, Suzuki GT 380[edit] and 750 just to name four.
Kawasaki and some others tuned their two stroke street bikes for near maximum hp to get people buying them. In later years those models were detuned substantially and were not so dangerous.
It could be done because two strokes are easily tuned to maximum hp without much expense. Not so for a four stroke with all the valves, seats, cams, sprokets, gears, rockers, etc.
On another point, in the USA, two strokes never presented a polution problem because they never were a significant percentage of the overall number of vehicles on the road. However, when congress was legislating them away, their alleged higher polution was used as an argument. It was BS -- only reason it was done was for US govt to give HD competing power which they had totally lost.
I can understand that in countries where scooters and motorcycles are present in high percent, polution should be considered.
By the way, if multi-cylinder two strokes were in production today, they'd surely have cdi instead of points -- some did even back in the day. ;D
HD is Harley Davidson?
I do not think that 2 stroke engines were in the same market niche as HDs.
Japanese motorcycles killed off HD in 60s/70s, not small 2 stroke engines.
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I noticed, that the additidonal friction of all those additional 4 stroke parts (camshaft & Co) make a signifikant difference. "ceteris paribus" isn't applicable.
My experience covers Yamaha Neos (50cc, 2 stroke) up to VEB Trabant P601 (599cc, 2 stroke). (And bigger scooters, but no 2 stroke motorcycles.)
They do, in terms of somewhat higher compression ratio, as I already said in my previos message.
Both Neos and Trabi had 7.5:1, similar 4 stroke engines nowadays have 9:1 - 11:1.
Divide those numbers and you will see how much more there is engine braking with 4 strokers. 20-45 % more, in fact.
But claiming that 2 stroke engines do not brake with engine is not correct.
No special magic there.
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Yes, Axy, you are right. I did not mean that one cannot use engine braking on a two stroke. Of course one can. I only refer to the fact that there is no momentary sudden diving of the front end when letting off the two stroke throttle. ;D
I do remember when I was a child, there was one two stroke car in my little home town in Florida. Could it have been a Saab?
It could have been Saab, maybe this one: http://en.wikipedia.org/wiki/Saab_96 (http://en.wikipedia.org/wiki/Saab_96)
There was just one in my city when I was a child. Very rare machine (except in Sweden, probably).
Regarding nose dive... you will experience that with 4 strokes ONLY with large displacement thumpers (1 cyl, >400 cc) and especially with 2-cyl bikes.
This problem can be compounded with short first three gears. For example, if you drove any 650 cc 2-cyl bike like SV650 or even worse, Suzuki TL1000 or Aprilia Falco 1000 that all have 2 cyl, they have high compression and big pistons and tend to brake HAAAAARDDD when you back off the throttle.
The big ones also want to lock rear wheel if you are not very careful when downshifting from 4->3 and 3->2, especially on poor surfaces. Many people fell off their bikes that were 1000 cc and 2 cyl. Today similar bikes exist too, for example, Tuono 1000 series, but they are a bit more mellow.
This phenomenon is even more evident in one and 2 cyl "supermotard" bikes like KTM Duke or Husabergs that have 60-70 hp, very short gears and low top speed. I never liked those bikes.
However, you will never experience such sudden deceleration driving 4-cyl 4-stroke bikes, even on beasts with 1000 or 1400 cc. Never, ever, they are very smooth. There are drivers that like one and two cyl bikes and those that like smoothness of 4 cyl bikes, I am in the latter group.
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A few more things about 2 stroke engines.
1. They are simple, easy to performance-mod: for 50-100 EUR you can double the power just by changing the piston and cylinder and ramping up the displacement for 50 % and almost double the power; the problem is that these aftermarket parts are of low quality, tend to last less than 10.000 kms and the crankshaft usually dies too because it is not suited for 100 % more power. The crankshaft costs usually three times the price of the cyl+piston.
2. Spark plugs tend to last 5000 kms compared to 4strokers where they are great even after 10000 kms
3. 2 strokers usually have oil pump that is almost always powered by a small toothed belt that is "very OEM" and there are no alternative replacements; you already guess that these tiny belts has to be replaced when the variator belt is replaced and this doubles the maintenance cost. They are also prone to breaking, and if they do, the engine does not get oil in mixture and it locks up -> major problem. Very rarely, and in older scoots, the oil pump is sprocket powered.
4. 2 strokers are simple, but very sensitive to tweaking (carbs, air, exhaust). Exhausts tend to clog up because the engine runs much hotter than in 4 strokers and in a number of scoots, the exhaust has to be torn apart and cleaned even in intervals as short ast 3-5.000 kms. Ask any Italian 2 stroke high performance scoot owner. This also causes some major costs because mechanics usually do not want to mess with tearing apart the exhaust and welding it back and want to replace it with a new one that costs 250-300 EUR. A LOT OF MONEY.
5. 2 strokers are not that reliable when there are temperature extremes and tend to overheat more easily than 4 strokers. The only case when I saw the bike overheating was with (liquid cooled!) 2 strokers. Never with 4-strokers, regardless of outside temperature and load on the bike.
6. 2 strokers have twice as much strokes as 4 strokers in a unit of time, they tend to achieve higher revs, develop power higher. They consume TWICE AS MUCH as 4 strokers and develop TWICE AS MUCH POWER per cubic centimeter of engine. (an average 50cc 2 stroke engine has 5 hp, 4 stroke has 2.5 hp; average 50 cc 4 stroke will consume 2 l/100 km, average 50 cc 2 stroke will consume 3.5-4 l/100 km).
125 cc 2 stroke`s 35 hp average consumption is 5.5-6 liters: the same as 750 cc 4 stroke bike with 100 hp.
As you get higher with displacement and power it gets worse.
7. They are very basic and not too durable: 2 stroke engine with 30.000 kms is quite old engine and you can expect 40.000 km only with high quality brands/materials, while 4 stroke engines can last twice that without problems.
8. They do not have valves and camshaft, but have very problematic intake valve ("intake louvre") that tends to get stuck or even break and enter the cylinder freezing it and damaging it permanently.
9. There is no maintenance of engine itself, no valve adjusting, no camshaft chain to be checked or replaced, when it dies, you rebuild it, but usually everything else dies around the engine except the engine itself.
I already said that if I had to drive 50 cc for some reason, I would buy ONLY 2 stroke because I am too heavy for 4 stroke 50 cc that is too low powered (or I am too heavy, or the hills are too steep, choose yourselves...)
In all other cases - only 4 stroke engines...
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it seems that all you bike / scooter boys do have a thing for 2 stroke
Hahaha! Wait 'til i tell blue...I'm not a scooter mom anymore, I'm a scooter boy. ???
:D
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HD is Harley Davidson?
I do not think that 2 stroke engines were in the same market niche as HDs.
Japanese motorcycles killed off HD in 60s/70s, not small 2 stroke engines.
Yes, Harley Davidson. :D Of the big 4 Japanese manufacturers, Yamaha, Suzuki, and Kawasaki were making large 2 stroke street bikes in increasing numbers in early 70's and they were selling well. Those, plus Hondas, were the final threat which would have killed Harley.
In general, yes, 2 strokes do not last as long as 4 strokes. But that is true mostly for smaller engines or cheaply manufactured ones. Even so, Harley Davidson's were so antiquated and of such poor quality by the 70's you could expect them to turn into junk at same rate as any Japanese bike, 2 or 4 stroke. Not to mention their performance and handling was dismal in comparison.
We really don't know how the comparison between large multi cylinder 2 versus 4 stroke would be like today --if 2 stroke had been continually improved by market forces over the last 30 years as 4 stroke has.
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Yes, Harley Davidson. :D Of the big 4 Japanese manufacturers, Yamaha, Suzuki, and Kawasaki were making large 2 stroke street bikes in increasing numbers in early 70's and they were selling well. Those, plus Hondas, were the final threat which would have killed Harley.
In general, yes, 2 strokes do not last as long as 4 strokes. But that is true mostly for smaller engines or cheaply manufactured ones. Even so, Harley Davidson's were so antiquated and of such poor quality by the 70's you could expect them to turn into junk at same rate as any Japanese bike, 2 or 4 stroke. Not to mention their performance and handling was dismal in comparison.
We really don't know how the comparison between large multi cylinder 2 versus 4 stroke would be like today --if 2 stroke had been continually improved by market forces over the last 30 years as 4 stroke has.
6-7 years ago many car manufacturers claimed that the future is in high tech 2 stroke engines.
However, nobody has followed up on those claims and instead they have developed efficient and powerful small displacement turbo gasoline engines (1400 cc, 170 hp - VW, Alfa Romeo...)
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;D See, politics in action! ;D
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Hi,
I'm new to both Kymco as well as this forum. I've recently purchased a 2001 B&W125cc. I was wondering, what should I look at, mechanically, to make sure everythings working as it should be. Dont get me wrong, she goes, very well, but as it is 2nd hand, I'm just wondering what I should look at/have checked out for some "peace-of-mind"?
Please let me know?
Thanks
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Yes, Harley Davidson. :D Of the big 4 Japanese manufacturers, Yamaha, Suzuki, and Kawasaki were making large 2 stroke street bikes in increasing numbers in early 70's and they were selling well. Those, plus Hondas, were the final threat which would have killed Harley.
In general, yes, 2 strokes do not last as long as 4 strokes.
my daddy's 18 year old 2 stroke still goes ...
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Hi, K125BW, I realize there isn't an actual BW125 section, but you may post your question under the Bet & Win 150 section stating that yours is a 125 if you like. "Peace-of-mind" is a good thing. :)
Congratulations on your new scoot!
And welcome to the forum!!
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Ships and trains also use 2 stroke engines.
Do you happen to know what airplanes use, axy? :)
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Bigger airplanes use a gas engine (no "strokes", only rotating parts and constant flame).
Smaller planes usually 4 stroke, very small planes (ultra light or uncrewed) often 2 stroke.
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Thank you, ts1. I was wondering about that.
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Weed eaters, motorized hedge trimmers = 2 stroke. Model airplanes too. Those have something called a "glow plug" instead of spark plug. It's on all the time -- no need for timing at all. ;D Small ones will fit easily in your pocket. Fuel tank the size of an aspirin bottle.
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Hoolander...who gonna ride something that small? Speedy Gonzalez?? :D
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Har har! ;D Oh yea and chain saws of course! And those little engines you can bolt to your bicycle.
Kid stuff aside for a moment though. If you want to see probably the most awsome two stroke bike ever made, do a search for Kenny Robert's Yamaha OW-31. There were a few versions, one for road race, one for flat track. I had the pleasure of witnessing Mr. Roberts win the Daytona 200 on this bike. Left all other riders looking like snails. Four cylinder, water cooled, I don't remember the displacement -- perhaps around 1000 or 1200cc. Edit: ok I'm reading it's a 750.
Rules changes left it out of the running after a couple years. I believe it would still beat anything on the racetrack today.
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Wow...that must have been something to see. They have a pic of it on Google Images. That's really cool! 8)
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Whoa! Where'd you find that second one? Check out that bike! If his feet were behind him instead of under him he would laying down. That's just awesome. I love the way that windshield curves like that. And I think he's got that front tire off the ground too. That's only a 750? I bet you had a great time at the track that day!!
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I would urge you, Rianna, and everybody to go to a road race sometime. Preferably in Europe or Asia! Ha! Anywhere close is good though. He's in the true racing position there -- notice he's not leaning on the handlebars like you see so many crotch rocket riders doing. I think Mr. Roberts was one road racer who didn't like wearing the big racing boots. Notice his footwear in the picture. He was the best there ever was and probably ever will be. Of course there were and are plenty of other great riders too.
OW-31 was the engine designation. The road race bike was called a TZ-750
In the 1970's and early 80's, if you showed up at the track with anything but a 2 stroke, you could count on last place. Once the OW-31 came out, you could forget winning on anything else. Harley's lobbying and such eventually got the rules changed in their favor and the two strokes were history. Watching a road race in the USA after that was never the same.
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I would thoroughly enjoy going to one. I doubt I will ever make it to Europe or Asia. I see what you mean about not leaning on the handlebars. His posture is set properly to take care of business. I'm sure it takes practice and skill to perform like he did. And he sure had some beautiful bikes!
It's a shame that when politicians get involved things get ruined like this. I didn't know the story about how HD was behind it until now. I can understand now the anger it stirred up. Thank you, Hoolander for sharing the pics!!
Oh, and I like them boots! ;D
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Yep. I'm sorry I can't credit the photos. I just snatched em off the web. I should probably take em down shortly once the regulars have had a chance to view.
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Weed eaters, motorized hedge trimmers = 2 stroke. Model airplanes too. Those have something called a "glow plug" instead of spark plug. It's on all the time -- no need for timing at all. ;D Small ones will fit easily in your pocket. Fuel tank the size of an aspirin bottle.
I think you got something wrong.
Glow plugs are not in engines instead of spark plugs and do not work "all the time".
Glow plugs are used in diesel engines to pre-heat the area of the engine where diesel is injected when the engine is cold in order to avoid thermal diffusion. They are typically turned off after a few seconds in newer and 10-15 seconds in very old diesel engines.
They are not used in gasoline engines and especially not in very small displacement engines.
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In the 1970's and early 80's, if you showed up at the track with anything but a 2 stroke, you could count on last place. Once the OW-31 came out, you could forget winning on anything else. Harley's lobbying and such eventually got the rules changed in their favor and the two strokes were history. Watching a road race in the USA after that was never the same.
I think that this bike had around 90 hp, very low by the current standards.
Times have greatly changed.
There are two world famous race tracks near my town, both 10 kms from the very center. World moto GP was driven on them too - from WWII to 70s on the first and throughout 70s and 80s on the second.
This is Preluk:
(http://www.cavle.hr/Slike/2008/09/17/7520824.JPG)
This is Grobnik:
http://www.grobnik.hr/History.en.html (http://www.grobnik.hr/History.en.html)
I spent the time between 1993 and 2000 going almost daily towards Preluk and driving during the night, learning to understeer, oversteer, take corners along the proper line etc... but with my car, not bike.
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My, My! You have EVERYTHING within 10kms of your house, axy! So they still race with 2t engines in your country then. axy?
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My, My! You have EVERYTHING within 10kms of your house, axy! So they still race with 2t engines in your country then. axy?
I am not that much into moto championships.
However, I know that currently, in the world moto championship there are the following classes:
1. MotoGP, max. 800 cc, 2 stroke is not allowed
2. Moto2, all race with 600 cc 4 stroke Honda engines
3. Moto 125, 80-125 cc, 2 stroke is allowed (in fact, I think ALL are 2 stroke)
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These small 2 stroke model airplane engines I speak of do indeed run on glow plugs only. You connect a battery to it while cranking. Once the engine starts, disconnect the battery and the glow plug continues to glow due to being a hot spot in the combustion chamber. The model is then launched and flys with no engine electronics whatsoever. The engine runs till out of gas. I used to fly them when I was a boy.
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Compare:
the 1974 TZ700 and the 2000 R7 Superbike
Wheelbase 56.28" 56"
Weight 345 lbs 356 lbs
Front Tire 3.25 x 18 3.5 x 17
Rear Tire 3.5 x 18 6 x 17
Horsepower 145 173
from: Superbike Planet.com
Also: http://www.motorcycleshopper.com/articles/tz-750.htm (http://www.motorcycleshopper.com/articles/tz-750.htm)
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Compare:
the 1974 TZ700 and the 2000 R7 Superbike
Wheelbase 56.28" 56"
Weight 345 lbs 356 lbs
Front Tire 3.25 x 18 3.5 x 17
Rear Tire 3.5 x 18 6 x 17
Horsepower 145 173
from: Superbike Planet.com
Also: http://www.motorcycleshopper.com/articles/tz-750.htm (http://www.motorcycleshopper.com/articles/tz-750.htm)
To compare 2 stroke and 4 stroke engines, you should at least double the displacement of 4 stroke engine.
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These small 2 stroke model airplane engines I speak of do indeed run on glow plugs only. You connect a battery to it while cranking. Once the engine starts, disconnect the battery and the glow plug continues to glow due to being a hot spot in the combustion chamber. The model is then launched and flys with no engine electronics whatsoever. The engine runs till out of gas. I used to fly them when I was a boy.
I've checked and you are right, these plugs for RC models are called glow plugs, even though this term is not exactly correct.
However, "real" glow plugs are used in diesel engines as I have explained.
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Well, this has been an interesting diversion of a discussion. ;) I would like to say that I do like the feeling of a dependable 4 stroke under me in my daily riding. But I wouldn't mind a big FUN 2 stroke to play on. ;D
I got a few details about the big Yamaha wrong. OW-31 was the FACTORY works racers. TZ-750 was the production model available for sale to independant racers. To a layperson like me they appear much the same but surely were not. Both were dominant over just about everything else for about 9 years, though.
Also, I oversimplify by accusing only Harley Davidson of affecting rules changes. Other factors were probably involved. One being that all the bikes (even non-Yamaha) were getting just too fast for the tracks. Same as NASCARs of the same era which were getting above 220 mph on the big tracks. NASCAR knew they would have to do something or there would start to be massive deadly crashes in the future so they put in severe limits on engines. Perhaps the cycle racing sanctioning bodies thought the same about the future of unrestricted 2 strokes. Maybe I'll research all this in detail someday. :D
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Well I have thoroughly enjoyed this whole thread, including the diversions, and have learned a few things too. I do think I would enjoy the 2 stroke and maybe I will have the chance to find out someday.
Yes, there probably were many factors involved, but it's still a shame. If nothing else on the track could touch them for 9 years you know they had something good going on. It would have been nice if there was a better or different solution put in place.