Mikuni 22mm vs arc .625 carb

[Davis]

I have a mild built predator hemi and it seems the stock carb can't flow enuf to get it to its full potential.

 

[KMC3420]

I vote clone carb versus the Mikuni for ease of installation. The mikuni requires a different intake and throttle cable for installation. No doubt the Mikuni flows more air/fuel, but the clone carb will be a bolt on deal in your case. Not sure your engine specifics but plenty of guys on here that could help you better with jetting than myself.

 

[Davis]

It's a mild built motor just billet rod and flywheel 275 cam #26 springs no governor open air cleaner and stage one pipe 38 main jet with stock head and valves.

 

[KMC3420]

My predator is very similar to your build, head is milled though. I have this carb: Carburetor, Ru*ing (Chinese 6.5), Bored & Blueprinted, .650 (16.5mm), Gas and the throttle response is good with the jets that came with it and idles just fine.

 

[Davis]

My predator is very similar to your build, head is milled though. I have this carb: Carburetor, Ru*ing (Chinese 6.5), Bored & Blueprinted, .650 (16.5mm), Gas and the throttle response is good with the jets that that came with it and idles just fine.

Thanks for the link what kinda rpm are you getting outta that one?

 

[KMC3420]

Thanks for the link what kinda rpm are you getting outta that one?

I do not have a tach, but I have had it hammered a few times and the carb/motor did just fine. My limiting factor revving is my cam, its a mod 2: Camshaft, Dyno Cams Mod 2 - GX200 (GX160), 6.5 Chinese OHV, & 212 Predator It just doesn't rev like my black mamba Sr does.

 

[Davis]

I do not have a tach, but I have had it hammered a few times and the carb/motor did just fine. My limiting factor revving is my cam, its a mod 2: Camshaft, Dyno Cams Mod 2 - GX200 (GX160), 6.5 Chinese OHV, & 212 Predator It just doesn't rev like my black mamba Sr does.

I have the 275 welded lobe clone cam from OldMiniBikes.

 

[KMC3420]

I have the 275 welded lobe clone cam from OldMiniBikes.

Looks like a pretty decent cam, and 275 Lift always gets thrown around for max lift on a hemi head motor, never had a hemi head, just a hemi bottom end. I would say the .650 bored carb would be a great choice for your motor. You can buy larger ones that flow more, but you will pay for them.

 

[Davis]

Looks like a pretty decent cam, and 275 Lift always gets thrown around for max lift on a hemi head motor, never had a hemi head, just a hemi bottom end. I would say the .650 bored carb would be a great choice for your motor. You can buy larger ones that flow more, but you will pay for them.

I think you may be right as I live at around 7000ft elevation so the air up here ain't that great. What does this carb do for bottom end power?

 

[KMC3420]

I think you may be right as I live at around 7000ft elevation so the air up here ain't that great. What does this carb do for bottom end power?

It pulls all through the rpm range pretty strong. More so on the low end. I'm geared 6:1. Your cam has more lift and duration so it will help you just the same. I thought your cam showed 108LSA so it is focused on mid range, you can always gain more low end with gearing if needed.

 

[Davis]

It pulls all through the rpm range pretty strong. More so on the low end. I'm geared 6:1. Your cam has more lift and duration so it will help you just the same. I thought your cam showed 108LSA so it is focused on mid range, you can always gain more low end with gearing if needed.

Does this carb have a choke I can't see it in the pic and it doesn't say anything about it in the description.

 

[KMC3420]

Does this carb have a choke I can't see it in the pic and it doesn't say anything about it in the description.

Yes this carb does have a choke. I can get you a picture of mine if you need it.

 

[Davis]

Yes this carb does have a choke. I can get you a picture of mine if you need it.

I kinda wonder if I have other problems beyond just carb because according to the jackshaft and gearing mph chart I'm only gettin between
6100-6300 rpm outta it now do you think in just changing the carb it will do closer to 7000rpm?

 

[KMC3420]

I kinda wonder if I have other problems beyond just carb because according to the jackshaft and gearing mph chart I'm only gettin between
6100-6300 rpm outta it now do you think in just changing the carb it will do closer to 7000rpm?

More Air,more fuel, more power. I don't see why not. Which gearing calculator are you using?

 

[Davis]

More Air,more fuel, more power. I don't see why not. Which gearing calculator are you using?

Bmi carts.

 

[KMC3420]

Bmi carts.

Which calculator, I assume the MPH calculator? The ones I saw allow you to manipulate the engine RPM unless you know your top speed and doing backwards math to determine engine RPM. Do you have a tach?

 

[Davis]

Which calculator, I assume the MPH calculator? The ones I saw allow you to manipulate the engine RPM unless you know your top speed and doing backwards math to determine engine RPM. Do you have a tach?

No tach going off of gearing and mph.

 

[KMC3420]

No tach going off of gearing and mph.

What is your gearing? Jackshaft? I have a calculator i found on here that I want to verify your numbers with.
I need:
Clutch gear teeth count:
Jackshaft in teeth count
Jackshaft out teeth count
Axle sprocket number of teeth.
Wheel diameter.

I will see if your RPM and mine match. Isnt your cam a 7000 RPM max cam?

 

[Davis]

What is your gearing? Jackshaft? I have a calculator i found on here that I want to verify your numbers with.
I need:
Clutch gear teeth count:
Jackshaft in teeth count
Jackshaft out teeth count
Axle sprocket number of teeth.
Wheel diameter.

I will see if your RPM and mine match. Isnt your cam a 7000 RPM max cam?

12t clutch 13t jackshaft input 12t jackshaft output 60t final and the tires are general 5.30/4.50/6

 

[KMC3420]

Please see the below image. It shows your final gearing at 5.4:1 and max speed of 50 MPH with a 15" rear tire @ 6100 RPM's. I forgot to ask what your max speed is you were running? Once you give me that, I will change the RPM until i get to your speed.