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Discussion Starter #1
I was hoping to find some real life experience responses or links to such from you guys about the EX500 engine. I am doing some research before I begin swapping a high revving, freeway speed motor in one of my projects. I’m looking at the EX250/500 engines, because they have been around forever, can rev, are good around town or freeway and are relatively compact/light. My best info for the EX250 has come from here:

http://www.eurospares.com/ex2501.htm

According to weights taken from this guy, the 250 engine is approximately 90 lbs. I have not really found anything worthwhile about the EX500 engine. What I have found is the EX500 is about 388 lbs, where the EX250 is 304 lbs according to kaw’s website. Rumor has it that the 500 engine can be swapped into the 250 frame with extensive mods. I have also read that the two engines are the “same design” with different internals, but without someone claiming first hand knowledge, I think it is still rumor. I have found several 500 engines for close to the same price as a 250.

I really want to use a 500 for the midrange power over the 250, but my design criteria limits me to something the same size and weight of the 250. So my question is, does anyone know how much the EX500 engine weighs and how much bigger is it than the EX250?

My guess is that they are close and the rumors above are true, because the whole point of swapping the 500 motor in an EX250 must be the 84 lb difference is mostly in the frame and bodywork. Otherwise, why wouldn’t someone just buy an EX500 if the final result weighs the same! I just need some good info or links to confirm it and I will finally be able to sleep (and build)! Thanks.
 

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Interesting ideas. I hope somebody here can help you out.
 

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Discussion Starter #3
MrSciTrek said:
Interesting ideas. I hope somebody here can halp you out.
Thanks, I was afraid that everybody would try and suggest all of the other engines I could use as they do on other forums. There is always some other direction to go, but you'll never know which is one suits better until you do both! This is a very good forum and I have been impressed with the cut and dry facts on other threads I've read. I hope someone answers too and others can easily find this thread for future searches.
 

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Discussion Starter #5
Royson said:
I'm curious, what is the project?
Basically, I'm looking to build a board tracker with decent power to weight and an engine with endurance. The Kaw’s 500 motor has been around so long and it just seems well suited for my idea, useage and budget.
 

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Inherent in Pull's originol post "My guess is that they are close and the rumors above are true, because the whole point of swapping the 500 motor in an EX250 must be the 84 lb difference is mostly in the frame and bodywork. Otherwise, why wouldn’t someone just buy an EX500 if the final result weighs the same! I just need some good info or links to confirm it and I will finally be able to sleep (and build)! Thanks."


The above is the Conrumdrum of all Motorcycle designs. Want more power in your tiddler? Ok lets stuff the big ol v8 in thar. Overkill? ok but as a MFG that has to follow good engineering Princapils even a modest power increase in the originol design will require additional stregnthing. This adds weight and reduces the gain of the originol Idea.
You have till recentlly had to make the same decisions when buying a bike. For aproximantlly the same prefoormance , that 900 1220 big boy that weigh 560 lbs. or the little 500cc twin at just under 400.

My point is that your going to find it hard to gain any real advantage with an engine swap other than the novelty.

That Said I stuffed a neat little Porche Super 90 into a 60 VW bug that was a big improvment. But the bug was way overbuilt for heavy handed Germas.



FOG
 

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I have both an EX250 and an EX500 sitting here at home. But wouldn't have the slightest clue as to how much each engine weighs. :(
 

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Bathroom scales... oughta weigh them pretty close.
 

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Looks like I'm bringing this thread back from the dead.

I'm looking for a fairly accurate weight for the ex500 engine. My university is considering using one in our FSAE car but first we need a good idea of how much it weighs. I have found info stating that it weighs 115 pounds but I don't know how complete it was or if it was wet. I am assuming that is wet with carbs and exhaust, maybe even cooling, otherwise its kind of a pig as our F4i in long block form weighs 115.

I'm sure other people are curious about this too.

Thanks in advance.
 

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I believe the 250 motor has the timing chain on the side, while the 500 runs it down the middle. So it's not just a scaled down 500.

Doh.. yeah old thread
 

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Forbin said:
404namenotfound said:
Looks like I'm bringing this thread back from the dead.

I'm looking for a fairly accurate weight for the ex500 engine. My university is considering using one in our FSAE car but first we need a good idea of how much it weighs. I have found info stating that it weighs 115 pounds but I don't know how complete it was or if it was wet. I am assuming that is wet with carbs and exhaust, maybe even cooling, otherwise its kind of a pig as our F4i in long block form weighs 115.

I'm sure other people are curious about this too.

Thanks in advance.
I can guarantee the power to weight ratio of the 600F4i motor is far superior to the EX500. The intake restrictor may complicate matters, but my money is still on the 600 maintaining its lead, especially if you can make custom camshafts. Furthermore, the EX500 motor is nowhere close to capable of the 85kW power limit.

It should also be noted that the EX500's engine was originally designed and built for the 454LTD, aka EN454 (later, the 500LTD, aka EN500). A cruiser. Kawasaki merely stuck in some hotter cams for the EX500 and stuck it in a different frame.
That's good to know that it started out as a mild engine. It doesn't have much left to pull out of it does it?

The power to weight ratio of the F4i is better than the ex can ever hope to be, we make about 90 horsepower (67kw) and a big flat torque curve with our 130lb f4i (wet w/ intake). The thing is we don't get use all the power the F4i can make, the tracks are designed to keep the cars around 35-40mph. The car spends over half the time at low throttle negotiating corners and only weighs 430 pounds. We are almost never power limited. Personally I still like the idea of using a sport bike motor because its easy but I'm looking for conclusive evidence to prove that its the "right" choice. If I can say it weighs X and is capable of Y power I can run some calculations and plug it into our lap sim and have a good idea of how it compares to a sport bike engine.
 

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Quite a few teams do well with off road and dual sport singles the CRF450x and WR450 are common choices. The team that won the Michigan competition last year is rumored to only be developing 48 horsepower with a naturally aspirated single, their car did also weigh about 350 pounds. Now their car was "underpowered" but they still won with a car that was excellent in every other way. Without boring you with too much detail the way this competition is set up a car that would be outright slow on any real road course can place well or even win. This is due to the tracks being so tight, 10% of the points are from efficiency, and almost 40% of the points come from "static" events where the team's work is judged as this is a university & SAE sponsored engineering project after all.

The Aprilia motors look like a sweet setup but they are expensive and have been trouble for the teams that have run them. They have a bad reputation for being very sensitive to tuning and having dramatic failures.

I appreciate everyone's input on other engines but I have spent a lot of time looking into this and the conclusion that I have come to is every other twin has some major drawback to it, and I can't find a good triple. The EX is starting to look a lot like the other twins I have found. I am just curious about the weight so I can quantify its performance.
 

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If its any help i have an ex500 engine sitting here on my workbench and i was able to pick it up off the floor and put it on my rolling table so approx 100 pounds plus or minus a few.

It felt just like the 100 lb flour sacks i used to haul in the pizza shop in new york i worked at as my first job in life at age 15. The place was called Southdown Kitchen, in Huntington, NY and we had the best pizza around!
 
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