A rider ...

[pd]

I guess it might be a bit easier if someone could simply post a pic of the MT1 carb inlet with the choke wide open .
I'd really appreciate it . Thanks in advance .

[admin]

I guess it might be a bit easier if someone could simply post a pic of the MT1 carb inlet with the choke wide open .
I'd really appreciate it . Thanks in advance .

The reason I haven't posted it, is because I'm not certain, but I think it is 7/8".  Do NOT take this as gospel.

[pd]

Thanks for that , Rick .

But , there may be a misunderstanding of what I mean by venturi . I mean the 'neck down' about half way through the carb , between the choke plate and the throttle plate . That is the portion that helps meter and determine air flow .   
7/8" would be about the size of the initial inlet immediately after the air filter .

[pd]

Giovanni Battista Venturi, an 18th century Italian physicist, didn't give a rip about carburetors, but his discovery is what makes carburetion possible. He learned that when fluid flows through a constricted space, it creates a low-pressure, high-velocity area at the constriction. This is precisely what happens in a carburetor's venturi, allowing air and fuel to be drawn into the motor.

[Ricks]

I am well versed in venturi's principle, as I spent years running a drag car with both down draft  and side draft weber and dellorto carburetors.   .    I don't have an extra mt1d sitting on the shelf to go measure, and I do not want to pull the one off my bike, as it is a pain in the ass. 

[oil-lamp]

Pd I will be at home after four me thinks I've got a mt1 that is off plus a couple more. I will check them all and post the findings. 

[pd]

Rick ,
So , you like the smell of 'nitrous' in the morning ?

I didn't mean to offend anyone . Simply clarify what I meant and maybe help educate a fellow or two .

And , Thanks , Reese .

[pd]

Here's a pic to show the difference between the venturis of the MT9 on the right and the MT48 .
You can easily see the 48 is nearly twice as 'open' .

[Ricks]

Can't offend me, I'm too dumb to notice! Lol.     No nitrous,  just Turbochargers.

I do have a Carpenter Cushman replacement carb which I will measure tomorrow.  These are made for 4 stroke engines, but can be modified for our 2 strokes by drilling additional holes in the metering rod, like the original.  Wayne has told me he has had Great success using these carbs, which are available for $100 and can be had with the fuel inlet on the top, like a stock MT1D.

[kjwiley]

Interesting!! What is trying to be accomplished? Are you trying to use a different carburetor or increase the Venturi to gain performance?

Ken

[oil-lamp]

Ok pd of the five on hand mt1d has a 5/8 opening, the mt33a has a 1/2 opening, and the mt56a has a 5/8 opening also. But the mt56a and the mt33a has its vent come out in the venturl to where the mt1d vents under the carb. Don't know if it makes any difference but they are there. Hope this helps.

[oil-lamp]

Sorry for the size I thought my camera was still set for the smaller size. My bad.

[pd]

Good you have a sense of humor , Rick .

That Carpenter carb info will be a nice addition to the knowledge bank .

The MT48 carb I have came off a Cushman model C ( 4 stroke ) . I haven't had that one apart ,yet , but I'll note the metering when I do .

Ken ,
Simply trying to expand possibilities .
I don't have an OEM MT1 carb . I do have an MT9 and an MT48 . If one of these will work nicely , I'll use it . If not , we'll be the wiser .
I'm just trying to gain knowledge about these carbs so I can make an educated guess at which one or the other or both should do the best job on my motor and in the process add to the collective information on this site and about our bikes . If a performance gain happens , it'll be icing on the cake .

[pd]

Thanks , again , Reese .

The first pic is of the MT33 and the second is the MT1 ?

[kjwiley]

Thanks for clarifying. I was a little confused. I enjoy reading and seeing your progress.

Ken