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G The Voice of Reason
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RhynoCZ |
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RhynoCZ Super Spammer
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stevo as b4 |
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stevo as b4 World Chat Champion
Joined: 17 Jul 2003 Karma :
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Posted: 09:01 - 03 Sep 2017 Post subject: |
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I don't knock anyone for trying to follow the two stroke road into its dead end, and it's only companies like KTM who do still sell probably nearly 50% of bikes as two strokes, who be able to get away with trying to eek out a bit more time with them.
They are popular, and this TPI system just let's them get euro 4, while keeping decent engine characteristics and drivability.
I head they've been testing and developing direct injection systems, but the compromises these systems entail in terms of weight, size, cost complexity and limits on performance, mean it's not deemed worth while to roll out, until they really have to.
Personally I think DI two stroke bikes won't see much light of day, as there's so many issues with making it work, and keeping the benefits of a two stroke engine. Also the next more stringent round of emissions legislation, will probably mean that spraying any oil into an engine and burning it, will be unacceptable and a no no.
That's when two strokes will roll over and they'll turn the lights out and shut the door. Non crankcase compression will make two strokes advantages nullified and mean there's no reason to develop anything else.
Four strokes havnt got forever, but at least cleaning them up is easy to do comparatively and gives them more time. |
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RhynoCZ |
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RhynoCZ Super Spammer
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Posted: 09:18 - 03 Sep 2017 Post subject: |
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stevo as b4 wrote: | Also the next more stringent round of emissions legislation, will probably mean that spraying any oil into an engine and burning it, will be unacceptable and a no no. |
This is an interesting point. But, I do not think this will be the issue.
Most of the car manufacturers today run their engines with oil losing lubrication system, reducing the internal friction of their engines, which leads to better fuel economy = less harmful substances in the exhaust gases.
The issue could be the durability test.
EURO 5 spec:
2020 (E4 2016)
CO: 1.00g/km (E4 1.14g/km)
Hydrocarbons: 0.10g/km (E4 0.17g/km)
NOx: 0.06g/km (E4 0.09g/km)
SHED test: yes (E4 yes)
OBD: yes (OBD2) (E4 OBD1)
Durability test: Lifetime (E4 20,000km)
*SHED test = Sealed Housing for Evaporative Determination; evaporation of fuel.
*Durability test = to ensure that motorcycles remain emissions-compliant even as they get older. ____________________ '87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI; MZ 150 ETZ, '98 Mercedes-Benz w210 E200 Kompressor |
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G The Voice of Reason
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thx1138 |
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thx1138 World Chat Champion
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Posted: 00:37 - 04 Sep 2017 Post subject: |
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and two stroke dirt bikes are just more fun |
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stevo as b4 World Chat Champion
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G The Voice of Reason
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stevo as b4 World Chat Champion
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Posted: 21:48 - 04 Sep 2017 Post subject: |
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Well I'm a bit light on actual modern two stroke experience tbh. Think it was a 15min session on a 2003 KX125, a few stints on WR200's and KDX200's that sums it up.
I haven't ridden any really recent thumpers either, things like WR250F, and a DRZ 400 are the most recent.
But yeah for a few reasons, if I was going to get really serious into MX and race most weekends looking for a result or two, I'd be going four stroke. Justifying that because I ain't ridden MX for years, was never very good at it even as a kid, and also alot of proper tracks these days have gone alot more supercross'y in layout. If consistent lap times on a slightly easier to ride to my limits thumper were what I was after, then why wouldn't I take every little advantage I could get?
Of course It would assume that I could afford four stroke maintenance costs, but then I bet most mature riders that buy them can afford their keep, and arnt bothered about a few extra kg either.
Not sure how I'd feel riding a four stroke trials bike though, I think that would be quite weird to get used of.
Oh and my original point was that neither four in two stroke always excels in every off road discipline. E.g you wouldn't really want a two stroke desert racer or Dakar bike. |
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G The Voice of Reason
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Posted: 23:08 - 04 Sep 2017 Post subject: |
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Always fancied an EXP-2 .
Definitely worth getting a go on a modern 250 or 300 2 stroke enduro, as I've probably said before. Very different to what you're used to I'd say.
I'd like to try out the new KTM350 4 stroke. However, I wouldn't be surprised if one of the above enduro bikes would be better for the begginer rider on a motocross track, still.
4 stroke trials very similar to 2 stroke I'd say - you don't lose much of the low down grunt of the 2 stroke for the slightly higher revs in my experience.
But I'm far from skilled enough to comment. |
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thx1138 World Chat Champion
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Posted: 23:18 - 04 Sep 2017 Post subject: |
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all I know is I'm a crap rider, I point my Beta at things I can't do on my Honda, snatch the throttle and get over them |
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G The Voice of Reason
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Old Thread Alert!
The last post was made 6 years, 207 days ago. Instead of replying here, would creating a new thread be more useful? |
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