what size performance carby can i get for my chinese 80cc

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chieflets

Guest
#1
Hi lads,

I want to improve my carby i measured other day roughtly 17mm carby i want to get more airflow to it is there any bigger carbys that will bolt in as a replacement like 21 o 26mm carby

Chieflets
 


U

unlv1200

Guest
#2
New style larger carb

I have the grubee new style carb on my bike. It is nice because you can adjust the choke.

The inside openneing measured about 25mm without the ring to fit it to the size intake that came with the kit. This shoulld probably do what your're looking for.

One dealer sells it here http://skyhawkcanada.com/catalogue.html#parts

B
 
C

chieflets

Guest
#3
I have the carby with small 29mm black box with 3 air breathers atm not the old with white cover is that what ur saying i need.

I love to get a an expansion chamber exhuast muffler for the motor that grubee makes anyone know where i can get one from

Chieflets
 
G

gone_fishin

Guest
#5
well, after my intake gasket fiasco...i realized someone has to come up with a better manifold, the "circlular" intake just doesn't do the "rectangular" port justice :(
 
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gone_fishin

Guest
#7
looks like cookie missed on the link, that wasn't me...

what i was talking about was maybe someone's improving the intake first would make more sense. the port on my 70 is nicely shaped (ellipsical/rectangular) and very clean, but the primitive round-pipe intake has to be a bottle-neck.
 
C

chieflets

Guest
#8
maybe u miss understood me,

my carby is fine ports match up manifold and cylinder head no probs there just asking for bigger carby with bigger diam for more inflow


my exhuast on cylinder head is reqtangle and my grubee stainless exhuast is round port and so is gasket witch in return restritct the flow of the exhuast.

we need a expansion chamber exhuast to make improvements and also flange that matches the cylinder head for 80cc 48 cc no problem the port is round for exhuast.

Chieflets
 
G

gone_fishin

Guest
#9
so you feel your 80 can utilize more fuel...check :)

my thinking was along the lines of better utilizing the fuel the stock carb already provides. i agree that an expansion chamber would surely help, but i also think the intake flow (on my "howell" 70) could be much improved with a better-matched flange/shape.
 
S

Saabsonettguy

Guest
#10
What does the port map on these engines look like? If the carb is indeed 17mm at the venturi then it should be plenty adequate with the stock muffler and stock cylinder porting. You don't really want your engine to be over carbureted. I really need to get a used motor just to pull apart and check out.
What type of speeds are you getting with the 80cc cylinder and 17mm carb?
 
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chieflets

Guest
#11
Iam getting 46km max speed on flat with 69kg person on it.

The motor definetly needs a matching exhuast flange it is restricting airflow...... might visit a muffler place 2morrow ans see if they can custom fabricate one
 
C

chieflets

Guest
#12
k,

worked it out getting custom rectangle flanged made up then getting a pocket rocket bike expansion chamber muffler that i need to do a cut and reweld that will be the exhuast side of things should get some decent power & torque around mid range rpm .

For the carby going to use stainless steel manifold and put washer on the mixture screw to make it sit lower and also drill out slighly larger the carby not the jets but actual carby.

will let u guys know when i have completed it


Chieflets
 
U

uncle_punk13

Guest
#13
I am working on (too many things at once) adapting the intake and carb. from my 69 Honda 70 to my 80cc...
There's also enough material on the intake pipe that I should be able to match the ports.
We'll see how it goes. The hard part will be the aluminum welding, I'll probably farm that out...
Rif
 
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gone_fishin

Guest
#14
rif, i've had pretty good luck in the past with car-manifolds using any ole piece of aluminum i had and sorta 'low-heat brazing' it. too much heat gets messy, but with practice you can get a fairly decent flow.
 
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uncle_punk13

Guest
#15
Good call!
I'll give it a whirl. The intake on the ol' honda 'snout foward' engines curves to a 90, but in the wrong direction, I wanna make mine go out to the side rather than upright.
This should not be too difficult, and, like i said, there's plenty of material on these to play with, so with a little cutting, milling, and brazing, we should have somnething that uses a carb I'm really partial to, and should be pretty closely "matched" to the engine. I can jet appropriately if needed. This will also allow me to utilize a better, or at least snazzier, air cleaner.
Again, thanks for the tip on the low heat brazing.
Rif
 
P

psuggmog

Guest
#16
Rif, it is entirely possible the weld aluminium with an oxy-acetylene torch(or oxy-hydrogen), but you need the correct flux. Some skilled race car builders prefer this metod of welding for tank fabrication over heliac welding.
 
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uncle_punk13

Guest
#17
I've read that. I may give it a go, it's not like I don't have a few of these intakes to mess about with from various parts bikes I've scrounged up...
BTW- are you going to the annual old bike swap this year?
I'm trying to get the local folks together for this and possible a motoredbikes.com moto cruise after...
Rif
 
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psuggmog

Guest
#18
I'd really like to, but it depends on cash on hand( it cost about $50 from Whidbey to Seattle roundtrip for ferry fare and fuel unless I came by motorbike,(then it would be hard to haul junk home unless I used a bike trailer)), and any schedule conflicts. Do you know the date yet? Last time I checked the website the 2006 info was still up.
 

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