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Home made U-flow Success!

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Discussion starter · #24 ·
firepower354 said:
Doesn't look any more tortuous than the front-facing intake manifolds:confused:
Click to expand...


You confuse me. lol, what is that pic all about anyways? Idk what a gnarly welded case has to do with this but I would like to haha.



So you guys are saying that since the filter is on top it is going to have to suck air more and work harder to get air? Man I really wish I had a shock to test ride this daymn thing! Either way, I can get rid of that vertical curve and have it going horizontal like a uflow





Thanks meatball!
 
#25 ·
TwoBros-OneTen said:
You confuse me. lol, what is that pic all about anyways? Idk what a gnarly welded case has to do with this but I would like to haha.



So you guys are saying that since the filter is on top it is going to have to suck air more and work harder to get air? Man I really wish I had a shock to test ride this daymn thing! Either way, I can get rid of that vertical curve and have it going horizontal like a uflow





Thanks meatball!
Click to expand...


yeah no probs, but the picture of the welded cases is cutting off the peice that sticks up off the crank side then you can have a backward facing intake like on 50s
 
#26 ·
if the straw is the same diameter, then what's the difference if it is 4" long, or 9" long? you should experiment with that theory using plastic straw to drink something.

if the diameter is reduced, then it would be more restrictive, yeah. if it's kept the same, it should be ok.
 
#27 ·
coolaaaa said:
if the straw is the same diameter, then what's the difference if it is 4" long, or 9" long? you should experiment with that theory using plastic straw to drink something.

if the diameter is reduced, then it would be more restrictive, yeah. if it's kept the same, it should be ok.
Click to expand...


It will still take more force to move the air the same distance. It might not take that much more force but it id enough to make a difference.
 
#30 ·
TwoBros-OneTen said:
These are all good theories, but the ultimate test is just riding it and feeling if it works better. If my carb doesn't get all choked up at havasu and start shutting off then I'm good!
Click to expand...




Once you've ridden it with the modification, you'll have to update us as to how well it's worked.
 
#31 ·
a certain amount of "dead" air space is good to have for improved bottom end, it allows the jetting to react quicker, notice that almost all real motocross bikes have a larger airspace after their airfilter and before the carb.

But as Dood mentioned , depending the amount of air your engine consumes at high speed it very well could hinder topend.

larger engine will suffer much more from this kind of mod than smaller ones.
 
#32 ·
carmstrong137 said:
yeah no probs, but the picture of the welded cases is cutting off the peice that sticks up off the crank side then you can have a backward facing intake like on 50s
Click to expand...


not trying to change the subject but i would like some more info on that mod. are you also modifing the neck for the carb and spinning the carb around? if so is the stock throttle cable long enough?
 
#33 ·
It's called physics.....



An engine is an airpump. The more air you can get into a cylinder, the more power you can make. This doesn't mean make everything big because you will lose velocity of the intake charge.

Air is elastic. It's molucules can be stretched.

Making an intake track longer can aid in low end torque because you are restricting thus increasing the velocity of the air coming in to the cylinder at lower rpm's but when your engine is in a higher rev range, this choking down of the intake track ( ie length or size ) can and will be a restriction and hurt your higher rev power capabilities.
 
Discussion starter · #34 ·
dood said:
It's called physics.....



An engine is an airpump. The more air you can get into a cylinder, the more power you can make. This doesn't mean make everything big because you will lose velocity of the intake charge.

Air is elastic. It's molucules can be stretched.

Making an intake track longer can aid in low end torque because you are restricting thus increasing the velocity of the air coming in to the cylinder at lower rpm's but when your engine is in a higher rev range, this choking down of the intake track ( ie length or size ) can and will be a restriction and hurt your higher rev power capabilities.
Click to expand...




BOOM! I think you nailed it right on the head there. So...maybe I'm not so confident in my design anymore lol but we will see. This is just annoying that I don't have a shock now...
 
#35 ·
TwoBros-OneTen said:
BOOM! I think you nailed it right on the head there. So...maybe I'm not so confident in my design anymore lol but we will see. This is just annoying that I don't have a shock now...
Click to expand...


I'm not knocking your design at all. In fact I think it's great that people are being creative and making things on their own vs waiting for big dollar companies to make stuff and take your money.



I've worked for alot of those companies until I openned my own shop and have done ALOT OF TESTING. I'm not saying I know it all. I'm just giving you my knowledge of what I have learned and found. Based on what I see with your pics, you'll prolly find that your bike has better throttle response and will be easier to ride but when it comes to the top end power, it'll be a little low but who cares as long as you are happy with the results of your build.



Thumbs up brotha....
 
Discussion starter · #37 ·
thanks for all the props guys! I was bored and I found this pipe in my garage that looked like it had the perfect bend for my stocker haha so I rigged it up with what I had in the garage and it looks awesome, no trimming involved. It is a little small, but its about the same as the carb and filter. I rode it around and it definitely has a leak because there is only one clamp connecting to the carb so I need to get a two clamp rubber dealy for that.



Round 2

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Image




My favorite part is that they are both color matched..
 
Discussion starter · #38 ·
thanks for all the props guys! I was bored and I found this pipe in my garage that looked like it had the perfect bend for my stocker haha so I rigged it up with what I had in the garage and it looks awesome, no trimming involved. It is a little small, but its about the same as the carb and filter. I rode it around and it definitely has a leak because there is only one clamp connecting to the carb so I need to get a two clamp rubber dealy for that. I like where this one puts the filter, but they are both unique to the carbs and motor setups, as well as where the fender sits on 110 forks vs. 65.



Round 2

Image


Image


Image
 
#39 ·
Dood is pretty spot on with his extremely simplified explaination. I happen agree, I'd rather backyard something and get slightly worse results than pay to buy someone elses product. The result is I have built a lot of crap. ;)



the big problem most of you guys are going to have is not using a big enough tube for your intake. The real life difference in HP when we are extending the intake tract is pretty minimal. But using too small a tube WILL make a huge difference.



think of it like this.. Go get a coffee stirrer and a straw from McDonalds. take a huge breath and blow through them. Your motor is doing this in reverse. Which is better?



When building these intakes, it may not seem like much. But think about it. The stock carb is.. what.. 18mm? And an Mikuni is what.. 24mm? 6 mm may not seem like much, but it's a 25% difference! That's HUGE!



Equally.. air when in motion follows a principle called fluid dynamics.. and.. well.. it's freaking complicated. Use a bigger tube!
 
Discussion starter · #40 ·
haha I knew someone would say that about ^^ that one, but like I said I made the whole thing from scratch at home and wanted to try it out, the tube is just the perfect bend to not hit the front fender, and I haven't measured it, but it seems like the exact same size as the carb.
 
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