@@Jeff4559 You need venturi effect, with that stepped angle you make the carb less efficient at making the right mix across a higher band of rpm, it's actually important to keep your piston temps in range. shouldn't make a big difference unless he's going all out full throttle.
You realize that that's not how a carb works. Just increasing the size of the diameter doesn't mean that the carbs going to spray more fuel. It's a ratio between the different id's of the carb. You have to get the air to go faster through the middle bit so that way you can create a vacuum to suck the fuel in.
Opening the venturi and not the throttle bore reduces the velocity in the venturi where the main jet is, increasing the pressure in the venturi. This reduces the amount of fuel the carb introduces into the airstream, creating a lean condition. Lean in a two stroke means hotter and less power. Ultimately, a two stroke can only take in the volume of air equal to the volume of the crankcase, the carb is only to meter the air fuel mixture.
That was my thoughts as well because my car I would change the larger throttle body making inlet and flap larger for more air flow I dnt understand how u could get more air into it other wise
I know a hole will only allow so much air flow if the hole is no bigger all the way threw then its not allowing anymore air flow into the inlet of the barrel i know a thing or two about tuning two stroke barrels we only won a trophy or two on the oldest rs 125 on the track 4 times we was scrutinised 4 times we was cleared of any wrong doing never did we open one half of the carburettor without going all the way including new butterflies do you know how to tune a two stroke i think not
@@coolestguyontheplanet723 I still can't see it being a any better I like efi 😂 and it would completely stuff the venturi affect in regards to air speed and fuel delivery unless that's been addressed in another video 👍
@@williamfryar73 "he said" not sais, gotta pay attention while writing comments, also what did he say he was doing about the throttle butterfly? Because I didn't hear him say anything about what he was going to do about that.
@@BleedingWhiteKnuckles as far as the throttle butterfly, it isn’t affected.. do you have eyes? Can you see the throttle plate still perfectly mounted where it was originally? Wowwwww Rich, what a world!! Amazing right?
I like where you are going but really curiosity as other have asked, without enlarging the venturi and throttle blade area is it even letting more air in? Maybe a small increase, like putting a larger air filter on a V8 or something but using the same carb. CFM of carburetors is measured as flow through the venturi which you have not opened at all. Still awesome to experiment and try new things. 👏
The venturi is the throat he opened up. Small engine carbs have large throttle plates and small throat to regulate air flow (venturi). This isn't like replacing an air filter. It's like replacing the 600 cfm to 700cfm. Not having a smooth transition is where he screwed up. That step is slowing air down.
Just like the full build I did on my redmax bcz260 weedeater .25cc yes everyone said your crazy but carb intake was ported the cylinder was ported compression increased let me tell you its wicked for 25cc professional trimmer.
I think that's awesome that you posted this because I have done this to a Husqvarna 125l 28cc weed eater and also have done the same thing to a craftsman 25cc weed eater
know how much your head flows, that would make calculating how much you need to bore easier, too big i think will be detrimental to the venturi effect and run lean, possibly melt a piston... worst case. but again im just theorising from past engine tinkering
I wonder if you broke the edge of the venturi where it narrows- making the angle (where it gets smaller) less aggressive -if it would increase air flow?
You just made it run far far worse ! You destroyed the Venturi that is very carefully designed and machined , what are you thinking ! The ratio between Venturi and carby bore is measured in thousands of an inch to each other ! It's not just how much air it can get through, I had a 403 Oldsmobile v8 small block I put a Offenhauser Duel Quad intake manifold on , everyone said oh put two 750 CFM Holley's on it ! But I knew better I tryed it with two other 750s and it went sort of ok. Then I changed to Two 390 CFM Holley four barrel carbys, wow better response , better on off throttle , better all round and MORE power , bigger is not better. You want as higher flow of air over the Venturi as possible , and if you put a bit carby on flow of air goes down over Venturi putting the 390s on increased air speed and turbulence is hay aids fuel atomization and fuel burn,
What’s your aim? I don’t work on engine lathe’s anymore but I can appreciate your skills and execution. I guess you were looking for more flow ? What’s the results when you bore a carburetor larger than designed do you also make the jet’s larger? How do you regulate the air velocity?
So, where do you get jets for these things. I actually have a couple stils, but also have a polond sitting around that I was told needed a new carb, it starts and runs but if shut off, it won't start again. May try opening everything up on it
That's a pretty big and sudden step, doesn't that cause all sorts of problems with airflow/turbulence where it opens up! Sudden steps in carbs are never good, slopes all the way surely!
Please help me! My dr200 sat since 2007 but now runs, for a few minutes. Coil terminal to terminal about 6ohms, terminal to plug 23kohms. Float bowl height good. Rebuilt carb. Valve clearance. New plug. In-line fuel filter. Has good power when it runs, then just slowly dies and bogs on the throttle input. New battery and bike seems to be charging and always start Easily when cold with no or half choke quickly I have no freaking idea why it will not run more than a few minutes 😭😭
Curious as well, is it like when my neighbor bored out his 250cc Yamaha and holy crap the difference in power, if I recall correctly, it was like a 500cc, this was way back in 85, I was 21 and it was scary powerful.
Its commendable if you as a human being are able to spend every last second bettering this planet… But the fact that you’re here just like the rest of us letting some steam off enjoying some good ol youtube shorts + the comment section gives me feeling you may not be practicing what you preach
Hell yeah freed up .0025 hp!
That .0025 is a lot when you only make .050 of a hp😂
He didn’t show it run so it probably never did again
@@FreddyFunderbunz stihl are pretty good at what they do
🤣
round out the inner edge to make the air accelerate properly and have torbulence in the right way. nice work
May help in a performance scale but it isn’t necessary for a standard application
@@Jeff4559 You need venturi effect, with that stepped angle you make the carb less efficient at making the right mix across a higher band of rpm, it's actually important to keep your piston temps in range. shouldn't make a big difference unless he's going all out full throttle.
It will sacrifice mid range torque and if gets pulled even a little off top rpm it will bog.
@@engenhokas69 No, you do not want venturi for this application.
@@engenhokas69 lmao you have no clue wtf you are talking about.
That square edge in the ventury is choking flow to about the same as stock you want to radius them like the factory did.
It looks like his first day with a lathe. At least he put his big boy panties on a gave it a try even if it was an epic fail.
it stills gets the exact same cfm flow. you didnt open the most narrow part
that narrow bit is the venturi, it's how the carburetor draws fuel outta the bowl
if he bored that out, the carb wouldn't work anymore bruh
@@jimjam742 it can be bored out .0035" to increase cfm flow. If you put more fuel without putting more air youre just wasting gas.
You realize that that's not how a carb works. Just increasing the size of the diameter doesn't mean that the carbs going to spray more fuel. It's a ratio between the different id's of the carb. You have to get the air to go faster through the middle bit so that way you can create a vacuum to suck the fuel in.
It would be interesting if he would show the engine running with that carburetor. Would like to see what kind of difference it made. 🤔
Opening the venturi and not the throttle bore reduces the velocity in the venturi where the main jet is, increasing the pressure in the venturi. This reduces the amount of fuel the carb introduces into the airstream, creating a lean condition. Lean in a two stroke means hotter and less power. Ultimately, a two stroke can only take in the volume of air equal to the volume of the crankcase, the carb is only to meter the air fuel mixture.
IMO the carb is no bigger it wont allow anymore air through now than it did before
That was my thoughts as well because my car I would change the larger throttle body making inlet and flap larger for more air flow I dnt understand how u could get more air into it other wise
y'all even know how a venturi works?
I know a hole will only allow so much air flow if the hole is no bigger all the way threw then its not allowing anymore air flow into the inlet of the barrel i know a thing or two about tuning two stroke barrels we only won a trophy or two on the oldest rs 125 on the track 4 times we was scrutinised 4 times we was cleared of any wrong doing never did we open one half of the carburettor without going all the way including new butterflies do you know how to tune a two stroke i think not
I'm a mechanic and can't see how this will help anything . I would really love an explanation to how this helps ?
It's called not thinking it through and creating turbulence with the sharp edge, must be more work to be done.
Venturi effects on the cylinder side. That is the part he opened up. That will increase something (low pressure) = higher volume
@@coolestguyontheplanet723 I still can't see it being a any better I like efi 😂 and it would completely stuff the venturi affect in regards to air speed and fuel delivery unless that's been addressed in another video 👍
So now what do ya do about bigger throttle and choke butterflys John.
He sais he doesnt run the choke butterflys listen closely
@@williamfryar73 "he said" not sais, gotta pay attention while writing comments, also what did he say he was doing about the throttle butterfly? Because I didn't hear him say anything about what he was going to do about that.
@@BleedingWhiteKnuckles as far as the throttle butterfly, it isn’t affected.. do you have eyes? Can you see the throttle plate still perfectly mounted where it was originally? Wowwwww Rich, what a world!! Amazing right?
Warning, dain bramage detected.
Butterfly is on inside, bore is on the outside
And it did absolutely nothing, it's still the same diameter on the inside and you didn't change any of the parts that matter.
This was an old school trick done to VW back in the 70s.
With the sharp corners your creating an Eddie which will constrict your air flow. Probably was better off leaving it be.
I got a brother named Eddie he could restrict airflow by hitting me in the throat.... Ain't it just ain't it 😎 creating less horsepower in me.......
and now to hear ot run!
Oh running a little lean now? take her up about 20 steps
I applaud your courage. After all, it’s only money
looks like a carb for two stroke engines like lawnmowers chainsaws string trimmers ect
I hope this is for a chainsaw and you consider experimenting with ram tuning and velocity stacks.
No guts, no glory.
You should bevel the inner opening to reduce turbulence
Can you please explain how this is beneficial?
Just destroyed a carburator.
No venturi and probably flowing less air
I like where you are going but really curiosity as other have asked, without enlarging the venturi and throttle blade area is it even letting more air in? Maybe a small increase, like putting a larger air filter on a V8 or something but using the same carb. CFM of carburetors is measured as flow through the venturi which you have not opened at all. Still awesome to experiment and try new things. 👏
The venturi is the throat he opened up. Small engine carbs have large throttle plates and small throat to regulate air flow (venturi). This isn't like replacing an air filter. It's like replacing the 600 cfm to 700cfm. Not having a smooth transition is where he screwed up. That step is slowing air down.
Sweet job now two Nos injection points and maybe turbo
That's a properly bored out carb!! 💪
Just like the full build I did on my redmax bcz260 weedeater .25cc yes everyone said your crazy but carb intake was ported the cylinder was ported compression increased let me tell you its wicked for 25cc professional trimmer.
I think that's awesome that you posted this because I have done this to a Husqvarna 125l 28cc weed eater and also have done the same thing to a craftsman 25cc weed eater
I bigger carb only improves performance if the rest of the system was also capable of grater flow.
know how much your head flows, that would make calculating how much you need to bore easier, too big i think will be detrimental to the venturi effect and run lean, possibly melt a piston... worst case. but again im just theorising from past engine tinkering
The head doesn't flow anything. The ports in the jug do. Its a 2t
Better step up the main and pilot jet now. Gonna lean that little engine out!
Good hobby brother
Yes john!!
More gas more air means more gooo. Pop pap pap pap. Maybe too much.
I wonder if you broke the edge of the venturi where it narrows- making the angle (where it gets smaller) less aggressive -if it would increase air flow?
You just made it run far far worse ! You destroyed the Venturi that is very carefully designed and machined , what are you thinking ! The ratio between Venturi and carby bore is measured in thousands of an inch to each other ! It's not just how much air it can get through, I had a 403 Oldsmobile v8 small block I put a Offenhauser Duel Quad intake manifold on , everyone said oh put two 750 CFM Holley's on it ! But I knew better I tryed it with two other 750s and it went sort of ok. Then I changed to Two 390 CFM Holley four barrel carbys, wow better response , better on off throttle , better all round and MORE power , bigger is not better. You want as higher flow of air over the Venturi as possible , and if you put a bit carby on flow of air goes down over Venturi putting the 390s on increased air speed and turbulence is hay aids fuel atomization and fuel burn,
What you do to input. you must do to output!!!
Okay, but you didn't increase the size of the throat. So you didn't improve it in meaningful way.
You didn't have to resize the jet? And plus how much more power are you gaining, I always ran pretty much stock everything had no problems
You should have rounded the edge of the lip for less turbulence!
Wow that’s going to scream when put back together and installed!
What’s your aim? I don’t work on engine lathe’s anymore but I can appreciate your skills and execution. I guess you were looking for more flow ?
What’s the results when you bore a carburetor larger than designed do you also make the jet’s larger?
How do you regulate the air velocity?
Maybe it will sound different now
Wow!!!!!
Narrowing that power band while adding a tiny little bit of power...
84 and 084 is a low RPM chainsaw do it on a 066 or a 660 those are the highest RPM chainsaws that still makes
Pretty sure its cracked. Very end of short, 1-2oclockish. Where another metal of some sort was machine down. Check it out. Right? Wrong?
So, where do you get jets for these things. I actually have a couple stils, but also have a polond sitting around that I was told needed a new carb, it starts and runs but if shut off, it won't start again. May try opening everything up on it
But does it work ,,!!! 🤔
That's a pretty big and sudden step, doesn't that cause all sorts of problems with airflow/turbulence where it opens up! Sudden steps in carbs are never good, slopes all the way surely!
Please help me! My dr200 sat since 2007 but now runs, for a few minutes. Coil terminal to terminal about 6ohms, terminal to plug 23kohms. Float bowl height good. Rebuilt carb. Valve clearance. New plug. In-line fuel filter. Has good power when it runs, then just slowly dies and bogs on the throttle input. New battery and bike seems to be charging and always start Easily when cold with no or half choke quickly
I have no freaking idea why it will not run more than a few minutes 😭😭
Sounds to me like the ignition coil
Obviously needs a new flux capacitor
@@diychad7268 agreed, funny how they got hot and start leaking that current
if its not the coil. check for air leakage.
I believe I can get plenty of those carbs all day long. Chinese made but same shit. Does the same thing
But does it work???
So you throated it and made it harder to tune and flow worse then stock.
So talk is cheep , looks are decieving .
DID IT WORK TO YOUR EXSPECTATIONS?.
got a part number on that boring bar?
How’s it run???
Why?
How does it run now?
You sound like Morty if he became a mechanic fab
Kick-ass
Who said anything about saving a planet
Save the planets not the issue right now it's building a chainsaw
@@brianduca2958 🤣🤣🤣😭
it's a lawnmower carb, not rocket science..
Yeah only bore one side not the ventury not the inlet side! I cant believe how stupid people are! He just ruined a perfectly good carb
Do you gain anything from this?
I wondered what it did also?
More air and more fuel more power
@@rivermonstersaustralia2743 execpt the venturi is the same size.
Curious as well, is it like when my neighbor bored out his 250cc Yamaha and holy crap the difference in power, if I recall correctly, it was like a 500cc, this was way back in 85, I was 21 and it was scary powerful.
Post flow numbers or get TFO here. Homosexual.
Looks lk km enthe venturi is the stock size. Did you bore it off camera? Because i cant see it being beneficial if not.
Is this supposed to be English?
You did nothing, you might want to do some research on how a carb works.
no hp gain what so ever
Wonder how much better it runs
🙊
Insane what people use their free time for... not bettering the planet
Its commendable if you as a human being are able to spend every last second bettering this planet… But the fact that you’re here just like the rest of us letting some steam off enjoying some good ol youtube shorts + the comment section gives me feeling you may not be practicing what you preach