I have a 03 YZ250 with FMF fatty, Ti Shorty, V-Force 3 cage, geared for Cali desert along with other mods. I have a 07 YZ450 with FMF Power Core silencer, stock header.

250 2 Stroke is snappy, 450 4 stroke is torquey. You can get lazy on a 450 4 stroke more than you can on a 250 2 stroke. 450 4 stroke you can point and pull the trigger and it will tractor up anything.
Depending on where you are riding, one is going to be better than the other. If I take mine out to the local desert where I live, I will be faster on the 450 out in the open desert, but faster on the 250 in the tighter canyons.

 

Dave, thanks for that. Just what I was looking for. Info from someone that has both.

 

Also, 4 strokes are usually more difficult to start after laid down. Those 450's get-up and go!

 

I personally like both. I've ridden the CRF450R, and I have a RM250. Love the sound of that two stroke, and the smell of mixed oil. Both have great power, and like stated before. The four stroke definitely has torque, but if you get cocky on the two stroke it'll put you on your a$$ quick as hell.

 

What type of riding do you do? Do you race? I have both and can give you a good idea on what youll want based on what your wanting to do. I race AMA A class AKA Pro Class. Iv ben on both bikes. I like my 2-stroke best. Even tough the entire class is almost all Thumpers now. Im way faster on my 2-stroke. Ill ride the 4-stroke if its going to rain that day or if its a sand track. Only time i have ever lost to a 4-stroke is from a mistake i made on a track.

One thing people dont take into account when they get a thumper is the costs that come with it. If you blow up a thumper your talking thousands of dollars to fix. Blow up a 2-stroke a few hundred to fix and less time to rebuild the engine. The aftermarket Pipes cost an arm and a leg. There almost the cost of a system for the R1 now.

The new EFI thumpers are a joke. If have to do all of my own work to the bike. Rebuilding, Upkeep, engine modding, everything. The cost that comes with EFI is not justified to privateers unless you have factory support or really deep pockets. Having to spend 2 to 3 grand just so i can tune my bike is retarded. That money can be better spent on suspension and Tire and wheel combos. I have ridden a EFI bike. They dont come close to a properly tuned carb.

 

One thing people dont take into account when they get a thumper is the costs that come with it. If you blow up a thumper your talking thousands of dollars to fix. Blow up a 2-stroke a few hundred to fix and less time to rebuild the engine. The aftermarket Pipes cost an arm and a leg. There almost the cost of a system for the R1 now.

:stpd:

 

if you are just a weekend rider you will like the 450 better but like mentioned above it will make you a lazy rider:lol....

 

I didn't see it mentioned, the 4 stroke will engine brake. 2 strokes not so much.

 

the four stroke engine is better then the 2 stroke engine...as long as you do the proper maintenance such as oil changes and air filter cleaning....I have never blowen up a four stroke engine but I have blowen up a 2 storke engine

 

I would say go with the 4-stroke but you need to keep in mind the costs that come with it. As Jonrone mentioned earlier they do have a good amount if engine break. If you have an extra 1k you can fix this by buying a back torque slipper clutch from Henson racing. Then you will be able to adjust how much engine break is there when you let off the throttle.

Be for you go all out and go buying one of thies bikes. Ask your friends that ride 4-strokes if you can take there bike for a spin and see if you like them. On 4-strokes it easier to find traction. Yes its a fact you will get lazy riding them. Hondas have a bad habit if the valve clearance needing adjusting all the time.

If you do buy one. The varry first thing you should do is buy a scotts reusable oil filter. Will save you lots of money in the long run sense you have to change the oil on thumpers like mad. Another thing to buy is a air/fuel screw so its not a pain to adjust. If you dont know how to tune a bike then you have no reason being on a 4-stroke. 4-strokes have accelerator pumps and can be a biotch to tune sometimes.

Yeah i know what you mean buy getting the bike loaded up. Only ever happens to me when im out on the track with little kids riding. I dont want to scar them or throw a crap load of dirt in there face. If there going through a section ware they become unseen by other rider. I fallow them so the other riders see me and slow down be for for they come up on the little dude that Putin along. I know from experance what its like to get landed on at that age. but that one was my fault.

 

Phuck it.....say hello to my little friend! Thump thump, bitches!

 

Nice!

I bought this last week:

<edit> I dumped it once on a wicked hill last weekend and the hot start lever was a god send. I read that the 05 and older were not as easy to start. This bike fires right up, though.

My old dirt bike was a Husaberg FC400 and the left foot kick suited my left leggedness. Kicking right still feels funny to me, but it starts.

 

nice bikes guys:thumbup

 

I can't see the pictures here at work, but I am sure they are stellar. I'll check it out when I get home. As you can see below in my sig, that is my 450.

 

Dave, post a bigger pic. I like what I can see of that sticker kit. Looks like you have some coin in that beast.

 

Dave, post a bigger pic. I like what I can see of that sticker kit. Looks like you have some coin in that beast.

Couple shots out riding a few weeks ago: :flex:
And 1 of my 2 stroker:thumbup

 

Its funny...back when i rode motocross it was nothing but 2 strokes and now all the 4 strokes have come out. What is weird though is that it takes like a 450cc 4 stroke to equal the power of a 250cc 2 stroke and even then im not sure. 2 stroke 250's and 500's are no freakin joke man.........

I'd take any spanking new fuel injected 450cc 4 stroker and put it against my old 1990 CR500 any day and just laugh.

But hey, 4 strokes are "green" and green is in.

 

it takes like a 450cc 4 stroke to equal the power of a 250cc 2 stroke and even then im not sure.

I thought this, too, but I am not sure it's true. Hey Dave, is this fact? If so, what's the benefit of a 4s...the TQ?

 

 

If the CR500 is beating by that little of a margin, the 250 would get left. That's truth.

 

The 09 YZ450 has 46.5 HP and the 09 YZ250 2 stroke has 45 HP. So horsepower is pretty much the same, but the 4 stroke has way more torque. The 2 stroke has more snap.

 

Two strokes concentrate their power in a more narrow RPM range....much peakier.

My old CRF 500 dyno'd at 64.9 HP (a trypical number for those bikes) and it was insane. Im talking digging a 4-6 inch trench in the dirt with the rear wheel through every gear while the font tire stayed off the ground for the most part. The R1 is the closest thing i can get to that feeling on the street and thats why i got one!

 

Go 4 stroke or go home. (unless we are talking about weed wackers and chain saw's) LOL

 

Added a couple new parts...

 

How the hell do you get that bike so clean? It looks brand new. Here I thought I was doing a good job on mine...

 

R-acer, how are you liking that seat?

I bought some ASV levers for my wifes LTZ400 and now I need some for my YZ, they are awesome!

Quick question for the 450F owners, what kind of range do you have with the stock tank? I am signed up for a 35 mile poker run week after next. I bought 3 1l fuel bottles to take with me just in case. But it sure would be nice to know if the 1.8 gallon tank will make it or not.

 

R-acer, how are you liking that seat?

I bought some ASV levers for my wifes LTZ400 and now I need some for my YZ, they are awesome!

Quick question for the 450F owners, what kind of range do you have with the stock tank? I am signed up for a 35 mile poker run week after next. I bought 3 1l fuel bottles to take with me just in case. But it sure would be nice to know if the 1.8 gallon tank will make it or not.

Fz1squid - Depending on the terrain you should be able to make the 35 miles on the stock tank. I still have the stocker on mine and I ride out in the So Cal deserts. I would recommend taking one 1 liter bottle with you just for piece of mind. A trick from back in the day, after filling with gas, put a piece of duct tape over the opening and screw the cap down over it. Helps seal and not leak fuel down your leg or in your backpack. :thumbup
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The trouble folks have blowing up 4 strokes is related to years of riding 2 strokes, and expecting to simply get on and ride without any changes to riding style or habits. You cannot ride a 4 stroke like a 2 stroke and expect it to survive long. If you never had a 2 stroke, you probably will never have a problem with your 4 stroke. I had one customer that kept blowing up his 4 strokes. I went to the races with him, and sure enough, he was running it like his old 2 stroke. Once I got him to bring his rpms down a bit and use the torque a bit more - his motors lasted the rest of the season.

In theory, a 2 stroke can rev higher and faster because it does not have to move (reciprocate) a valve train. If you have a flat torque curve from idle to redline, this means more horsepower up top... So, two strokes can make more horsepower for a given displacement. The trade off is that they are weak down low by comparison.

 

:corn

 

I was riding my son's 2 stroke yesterday, and while it was fun, I missed the "power everywhere" of my 4 stroke. The 4 strokes just tractors through everything.
It has the power to pull off some serious jumps from a short distance where you would have had to had a good run on a 2 stroke.

 

That means I'll be able to do those big hill climbs now that dont have much room to get speed :rock

 

4 strokes do the riding for you. They basically brake for you with the engine. I get a lot less arm pump on 4's.

 

oh and the 4 stroke low end torque is just a myth. the illusion of torque you are feeling is just the huge amount of rotating mass of a 450cc four stoke compared to a light weight 250cc 2 stroke engine. compare a 450cc 2 stroke to a 450cc 4 stroke and see where the low end torque really is.