What carbs for a buffalo
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- tz375
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What carbs for a buffalo
I almost gave this post a title of "best" carbs, but that left too much room for interpretation.
The question is simple - has anyone changed from early VM32 to BS40 or vice versa and if so was there any discernable difference?
I have pictures of Blueboy with what appear to be both, but I have no idea of their dates, so i don't know which came first.
I'm sure that larger flatslides would be an improvement, but that requires tilting the intakes for clearance, and I have enough other changes to do without adding that to the list if it can be avoided.
I should have said - this motor is for the street and needs to make more Hp than stock but at relatively low rpms.
The question is simple - has anyone changed from early VM32 to BS40 or vice versa and if so was there any discernable difference?
I have pictures of Blueboy with what appear to be both, but I have no idea of their dates, so i don't know which came first.
I'm sure that larger flatslides would be an improvement, but that requires tilting the intakes for clearance, and I have enough other changes to do without adding that to the list if it can be avoided.
I should have said - this motor is for the street and needs to make more Hp than stock but at relatively low rpms.
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Blueboy has 34 VMs on it. The BS40s are good carbs, but they do hesitate a bit compared to the VMs. Ed has a 72 (which happens to have a 75 engine) with the VMs and it does power wheelies! The CVs (in my experience) won't do that. They are great for touring, but if you want performance, go with the VMs.
Lane
Lane
If you stroke it more than twice; you're playing with it.
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
- tz375
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- Yeah Man, the Interstate
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I think I am about to learn something here.....
What is the difference between the VM and BS carbs? Assuming CV are the constant velocity carbs which I associate (maybe mistakenly since I have never owned a late model Buff) with '74-'77 models.
So if this is the case, (which may not be) what carbs are on the '72-'73s.
What years got what carbs?
I am slightly confused now...
What is the difference between the VM and BS carbs? Assuming CV are the constant velocity carbs which I associate (maybe mistakenly since I have never owned a late model Buff) with '74-'77 models.
So if this is the case, (which may not be) what carbs are on the '72-'73s.
What years got what carbs?
I am slightly confused now...
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Yep, what Wayne said. The CV carb Mikuni model number is BS40. And they are 40mm carbs, but they don't flow as well as the 34 VMs (round slide).
They cleared the hump using the mounts from the CV carbs, HOWEVER, some slight mods had to be done. The throats on the 34s are a lot smaller than the CVs, so you can either use mounts from a 73 model, which still have to be clamped really violently to get them to seal.
OR you get creative, and use the late-model sleeves, like so:
That's plain old PVC pipe, 1.5ID, I think, but anyway, it slid right onto the carb. I JBWelded the PVC adapters on , and used a 1/4" dremel bit to cut the groove in it. Now it fits the original sleeves perfectly.
Also notice on the first pic that I copied the vacuum port from the CV carb, and epoxied it in place. I made the hol in the carb the same size as the original vacuum port . It works great, and they've been this way for about 3 years.
Lane
They cleared the hump using the mounts from the CV carbs, HOWEVER, some slight mods had to be done. The throats on the 34s are a lot smaller than the CVs, so you can either use mounts from a 73 model, which still have to be clamped really violently to get them to seal.
OR you get creative, and use the late-model sleeves, like so:
That's plain old PVC pipe, 1.5ID, I think, but anyway, it slid right onto the carb. I JBWelded the PVC adapters on , and used a 1/4" dremel bit to cut the groove in it. Now it fits the original sleeves perfectly.
Also notice on the first pic that I copied the vacuum port from the CV carb, and epoxied it in place. I made the hol in the carb the same size as the original vacuum port . It works great, and they've been this way for about 3 years.
Lane
If you stroke it more than twice; you're playing with it.
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
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I have a set of 36mm flatslides for my project (mikuni TM), and had Eric mill the intakes flush and then angle them so the bowls miss the cases.
(the TM's don't come stock on the GT series)
I'll tell you how they run when I get those cylinders back!
(the TM's don't come stock on the GT series)
I'll tell you how they run when I get those cylinders back!
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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Do you ever have any fuel delivery problems? I've heard the vaccuum diaphragms don't pump as much as open petcocks, but was going to run them on mine anyway...rngdng wrote:
Also notice on the first pic that I copied the vacuum port from the CV carb, and epoxied it in place. I made the hol in the carb the same size as the original vacuum port . It works great, and they've been this way for about 3 years.
Lane
Arne
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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Any ideas on how these would work on a '72 T500 with pod filters and chambers?Arne wrote:I have a set of 36mm flatslides for my project (mikuni TM), and had Eric mill the intakes flush and then angle them so the bowls miss the cases.
(the TM's don't come stock on the GT series)
I'll tell you how they run when I get those cylinders back!
Should I stick to the stock 32's?
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I wouldn't hesitate to go to 34's, you'll want to think about 36's tho.GT Tim wrote:
Any ideas on how these would work on a '72 T500 with pod filters and chambers?
Should I stick to the stock 32's?
I'm taking a bit of a gamble on mine going to 36's, as with bigger carbs you lose throttle response and it makes it less 'streetable'.
The drag racers put big old carbs on but they don't necessarily care about throttle response.
This guy has some interesting things to say about carburetors and size.
http://homes.midmaine.com/~shoeman/inde ... dcarbs.htm
Note that he's writing about the reed caged RD motorcycle and not the piston ported T series, but some of it's applicable.
From what I've read about Lane's GT750 bike it runs good with 34's.
Note that flatslides are supposed to have throttle response like the next size down but wide open throttle flow like the next size up in comparison to round slide carbs, but I haven't run mine yet so I don't know that for sure (yet)
Good luck! Arne
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project