Carb suggestions?

DeadPixel

DeadPixel

Member
#1
#1
What size carb do you guys recommend? I might order a carb on Monday for my build. Big bore 208cc clone, CL1 high torque cam, stock ratio rocker, 18cc head with 26mm intake vavle, will have about 9.0+ compression, GXV 160 flywheel with probably a +4* key and a billet rod. Its only a 5,500 RPM+ motor. I am thinking a .650 Ruing with the choke still installed or should I get a .625? I still want the choke on the motor if possible. Also should I run the Ruing or a Keihen? The Ruing is only $45 and the Keihen is around $70+

Will I notice any power from a larger carb on this motor?
I am going to be modifying every thing on the motor so figured I should probably address the carburetor too.

I have what I think is a stock bore Ruing right now that came on my BSP motor. It has a .038" main and a .022 low speed jet. I also have a GX140 emulsion tube but it is not installed. Should I just use the stock Ruing and play with it or is there some power in me buying a slightly bored carb?
 
DeadPixel

DeadPixel

Member
#3
#3
Thanks but sticking to a clone carb on this build. Just wondering if the larger bore will make more power on my build. Also don't want to loose too much bottom end and still want a choke. Not sure if I should use a .625, .650 or just stick to my carb that came on the BSP motor. When I build the BSP it will get a mikuni. Going to do a high RPM motor on that one.
 
KMC3420

KMC3420

Member
#4
#4
I have been listening to Jody @ ARC racing, he has several videos, and he said the typical way he chooses a carb, on a modified motor, is to measure your intake valve, and have the carb venturi to measure 1-2 MM smaller than your intake valve. His explanation was very thorough as to why, but you can check out his video if you need the facts. If your running a 26MM IN valve than your carb should have a 24MM venturi. Of course this is a on a modded motor, you will have the larger bore 208CC. I would make a phone call to NR or Jody and tell him what you got, see what carb he recommends versus just throwing a carb at it. ***I just wanted to put a disclaimer on here, not sure how heavily modded of a motor he was referring to.
 
Last edited:
ole4

ole4

#5
#5
+1 on 22 Chikuni. I've used them even on stock Tecumseh Hs50's they run great and the same jetting (130 main) works for all I have used them on. From stock to modded. The have a oval slide area that is narrow but tall giving greater granularity to the throttle. They also have an enrichening device for starting. Tim Isky sells the aircleaner adapter and carb for 95 bucks but his adapter is not curved and it does not have the cable. If you are set on using the clone carb yes the larger the bore the more power you will make. Even a stock head outflows those carbs.
 
DeadPixel

DeadPixel

Member
#7
#7
Ya pretty stuck on using the clone carb. So get the .650 then? I might be doing a 24mm mikuni on the next build as it will probably get a ported head with 27mm intake valve. This build I decided to do a mix match of clone parts. The motor is only going on a Colman CT200u that's going to be a quick trail rig. The next build will be for an American flyer 215 and will be built for pavement and for top speed.
 
DeadPixel

DeadPixel

Member
#8
#8
ole4 said:
22mm chikuni on a tec
Click to expand...
That's a nice bike. I need to put a few hundred away so if I come across something I want to restore I can swoop it up. I need to find some one who has a few stashed in a barn . My brother in-laws do landscaping and come across cars and trucks all the time that people some times just give away or let go super cheep so I have them on the look out for mini bikes and motors.
 
L

Latent

Active Member
#9
#9
They make the .650 and .670 carbs specifically for stock appearing go-kart racing classes. Why would you want to put that on a mini bike when mini bikes have no special classes needed to run stock appearing carbs? Makes no sense to me. Your better off just rejetting the stock clone carb and saving your money. Only other logical answer would be to buy the 22mm mikuni kit when you have enough money if you want bang for your buck. I wouldn't throw away money at a .650 or a .670 bored out clone carb. Just my honest opinion.
 
DeadPixel

DeadPixel

Member
#10
#10
Latent said:
They make the .650 and .670 carbs specifically for stock appearing go-kart racing classes. Why would you want to put that on a mini bike when mini bikes have no special classes needed to run stock appearing carbs? Makes no sense to me. Your better off just rejetting the stock clone carb and saving your money. Only other logical answer would be to buy the 22mm mikuni kit when you have enough money if you want bang for your buck. I wouldn't throw away money at a .650 or a .670 bored out clone carb. Just my honest opinion.
Click to expand...
Ya I totally hear ya. The mikuni will have better throttle response, make more power and looks a lot better. The build so far has been a mix of Honda and clone factory performance parts and just want to stick to the theme on the motor. Think it is cool to have a mix of stock and modified stock parts to make a performance motor. Only parts that did not start out as a stock part is the connecting rod, the molly push rods, air filter and header. Well and I will probably put head studs and stronger side cover bolts on the motor.
 
You must log in or register to reply here.
Top