Able2007

iTrader: (1)

Absolutely! I ride small bore two strokes. Always have. Tried riding a newer ktm 450 in the woods and got about a mile before I gave it back. Waaaaay too much for me. I'll stick to my 200xcw.

dewrag

mmmm you kind of have to be careful with the 250 strokes running against the 250 4 stroke deal.

In canada, all the way to the national level, you can run a 250 2 stroke in the 250 class as long as you're not a top 10 rider. Kind of stupid if you ask me. The top 10 rule was implemented after Kaven Beniot ran a 65hp 2 stroke in the 250 class and cleaned everyone out.... There are 4-8 250 2s riders on any given national gate in Canada depending on the track.

In the states as far as I know they only allow the head to head 250cc rule in the amateur ranks. Supercross and Nationals don't allow it, probably largely driven by the manufactures.

Guy named Jared Steinke hit the AMA nationals on a 125cc 2 stroke the past couple years. He puts it in the show and rides around in 35th place all day but had an INSANE following just because the thing sounded sick. I'm assuming that he would have run a 250 if the rules allowed it.... Check it out:

Blown06

iTrader: (32)

Wow, thanks for all the posts. Lots to add here so I'll do my best.

Blown06

iTrader: (32)

Yeah they are still in business. I totally get the jab about it being for dudes who can't tune.......but, in the right hands they make gobs of power.

As a side note, the Lectron stayed on Version 1.0 for about 6 months and the owner went back to the stock carb. Not because it didn't work, it just didn't fit very well onto the air box boot. If we could get a "factory dimension" Lectron, I think it would probably make more power than the stock carb. My opinion though.......I don't have any dyno proof other than my right hand and ***.

Blown06

iTrader: (32)

After reading the post above the first phrase that came to my mind was "2 stank'n" lol. That dude is what "it" is all about. In my opinion, he went out there on that 125 and absolutely killed it. That is a fact that is backed up by his fan base being bigger than some, if not all, of the top 10 riders in the 250 outdoor class.

There is no doubt that the latest 4 stroke technology has launch the 250-4 and 450-4 class motors into orbit. I mentioned that the owner of this bike has a special edition KTM 450, and while I have personally never riden it, you can just tell that it has enough power to tell everyone else to just **** off. Before he bought the KTM he had a YZ450F (I think it was a 2013 or 2014). I did have a chance to ride that bike at the track one day while I was helping him dial in a fuel/ignition map for dry/hard pack conditions and I can tell you it was the most powerful single cylinder engine I've ever experienced. It was just flat angry.

The 2 strokes power band characteristics can skew the mind of a novice rider because the hit of the power band. They may get on an a 4 stroke and say that it doesn't have the top end power of the two stroke when in fact what really is happening is that the botttom/mid of the 4 stroke is so strong, its somewhat linear transition into the upper rpms just make it seem like it doesn't have the power. The japs have long since discontinued their relentless assault on 2 stroke technology and as a result, yeah they are out out matched by the latest 4 strokes.

I bought a 2005 YZF450 brand new, did the typical mods (titanium/carbon fiber exhaust, changed cam timing, intake/filter, jetting and dropped about 30 lbs). At the time, I felt like the thing was probably making around 50 to 51 horsepower. It was a monster no doubt, but just the other day, I saw where Crower got near 53 horsepower out of a KTM 250 4 stroke. So roughly 10 years of technology now has the modified 250 4 strokes very close to stock 450 4 strokes, which is crazy awesome.

I had a 4 mil stroker banshee that was around 80-90 horsepower back when I had my YZF450 (with the mods mentioned above). In a flat out drag race in loomy conditions (lots of traction), the 450 would be within 1 bike length of the shee until about 75 mph. Problem was, the 450 was topped out in 5 gear as the shee was just getting into 4th gear. After that, it just pulled away like it was tied to a stump.

Version 2.0 for this bike is gonna be right around 265 cc's. I'm not really sure what to expect power wise, but I think we are gonna get some dyno time for it so those results should be interesting. I can tell you this though, the factory backed outdoor 450's are rumored to be in the 70-75 horsepower range. That just simply isn't going to happen on this bike.

So after all this rambling and reminiscing, 4 strokes rule the roost, however 2 strokes still win in the categories of cost of maintenance, on/off switch powerband fun and the nostalgia factor. Another thing that is cool is that I predict prices of 2 stroke bikes only have one direction to go and that is up, and the guys that can truly build these things are going away......so it will become even more of a niche market than it already is and I intend on servicing that market for years to come.

Blown06

iTrader: (32)

Interesting.

When I was building Version 1.0, I was also building an RM125 motor for another guy. It was just a simple complete split case tear down to replace any worn components and a fresh top end. In anticipation, I spent about $400 having some custom tools make especially for pressing main bearings into the jap 2 stroke bikes. You have to be very careful if using a press as the back side (or outside) of the case half is not supported properly, you can junk a case half by cracking it. Since this topic came up, I'll dedicate a post here in a few days to showcase these custom press tools I had made.

Vortec350ss

iTrader: (20)

Hah! that 2 stroke video was awesome!

Crazy watching the thumper blow past him on one of the hills though.

Able2007

iTrader: (1)

I wouldn't say 4-strokes rule the roost. Depends on what you're doing. I ride/race woods in the southeast and while a lot of folks ride 450's, only a select few can actually use them dodging trees. You have to be a special kind of window licker or just a damn good rider to wick out a big bore like that. I don't race much anymore but the last gncc I ran I entered the open class on a 125, got the holeshot and won. The 450's gave me hell in the open spots but couldn't keep up with the nimbleness of the little buck and a quarter in the tight stuff.

That 2.0 is going to be wicked. Have you contacted any magazines on the build?

dewrag

Ktm cases are magnesium, so I cringed every time I hit it. Thats largely why I did the heat/cool method putting them back in. I usually don't have the patience and never have the money to make or buy custom 1 off tools, so I end up getting primitive. Its never the way I want to do it but its the way that works.

dewrag

I can't find a decent link to it but Cosworth (the F1 guys) built some yz250fs in 2012-2013 for the euros that ran the old 5 valve motor and a carb that were insane.

- 16,500 RPM
- rumoured to be 55hp.
- I believe the power stayed on long enough that they turned it into a 3 speed.

He pulled a start on a field of factory 450s at the mx of nations that year. Now thats a bike I want to ride...... and then give back before it windows the cases!