Got Carbs!

pete.v · Mar 16, 2011

Got my carbs yesterday. I am not sure of intentions for a balance pipe like on the Amal manifolds? I see that there are bosses to be drilled but not sure of the need. I have seen pictures with and without this tube on Jim web site. I will email him and see what he says.

Kinda funky on how to rig up fuel lines. I don't really like the up, over, around, and through method that I've seen. Not alot of space here. I heated the top of the hose to bend it down to the carb so they wouldn't kink right there.

Go ahead and judge, but not on the patina.

Report on the running to follow..........and the future of old setups.

Lurker828 · Mar 16, 2011

I *really* like your fuel line routing -- that center leg is a perfect location for a single, unobtrusive in-line fuel filter.

-wgm

BrianK · Mar 16, 2011

I have similar fuel-line routing to my Keihin FCRs, with, yes, a little Pingel sintered-metal fuel filter inline just after the joining of the two down lines from the petcocks. Works well.

Carbonfibre · Mar 16, 2011

You will find that the OKO carbs work an awful lot better than Amal, and if your OE carbs were worn, then they will transform your bike. For applications where fuel hoses are likely to get quite hot, its a good idea to use hoses with braided outers, along the same lines as brake hoses.

highdesert · Mar 16, 2011

I have had my flat slides from Jim since last fall and no balance tube between them is necessary.
They are spectacular, idle like a rock, and flow strong all through the range.
No balance tube.
However, I did find from examining both spark plugs coloration that I did have to fiddle a little with my jetting to get them to perfectly match. They probably would have "worked" just fine if I had left them as Jim sent them jetted to me, but one carb flowed richer than the other and so had to change needle position and slow jet to get them to perfectly color the same. Very easy to do by the way, and I am very, very happy with mine.
They are are huge improvement over both my prior single 34 Mikuni and my Amal 32s.

pete.v · Mar 16, 2011

highdesert said:
However, I did find from examining both spark plugs coloration that I did have to fiddle a little with my jetting to get them to perfectly match. They probably would have "worked" just fine if I had left them as Jim sent them jetted to me, but one carb flowed richer than the other and so had to change needle position and slow jet to get them to perfectly color the same. Very easy to do by the way, and I am very, very happy with mine.
They are are huge improvement over both my prior single 34 Mikuni and my Amal 32s.

I am finding that the left carb is rich and the right lean and am not able to sink up a good idle as of yet. Both have a 142 main and 38 pilot. Needle is in second from the top notch on both. How does this compare to yours and what numbers worked for you?

AussieCombat · Mar 16, 2011

Gotta say they look good, nice and neat, parallel. Is there room for the original air filter plate once the filters are on. ?..AC.

pete.v · Mar 16, 2011

AussieCombat said:
Gotta say they look good, nice and neat, parallel. Is there room for the original air filter plate once the filters are on. ?..AC.

They say there is room and it is shown on Jims web site but I do not have the plate installed so I cannot affirm the claim.

click · Mar 17, 2011

Hi,

Really neat plumbing job, where did you get all your fuel fittings + fuel pipe, is it Tygon?

Thanks in advance

Kevin

Carbonfibre · Mar 17, 2011

Its well worth checking fuel level on OKO carbs before making any other changes, as this will make a difference to the running, and may mean there is no need to alter jetting.

highdesert · Mar 17, 2011

Pvisseriii,

I have sent you a PM regarding the carb settings.

Check your forum mail?

pete.v · Mar 17, 2011

highdesert said:
Pvisseriii,

I have sent you a PM regarding the carb settings.

Check your forum mail?

You mean within the last 5 minutes cause i responded to the last one regarding air screw settings both by forum mail and email.

pete.v · Mar 17, 2011

click said:
Hi,

Really neat plumbing job, where did you get all your fuel fittings + fuel pipe, is it Tygon?

Thanks in advance

Kevin

The fuel line is off a spool at the local dirt bike parts store. The fitting are PEC tee's, some kind off new plumbing fitting, and under $2 a piece compared to 1/4" brass tee from the hardware store for $7 each. The PEC fitting are a bugger to fit in the 1/4" line but it's a good seal and a closer proximity to the bend.

bpatton · Mar 17, 2011

pvisseriii said:
The fuel line is off a spool at the local dirt bike parts store. The fitting are PEC tee's, some kind off new plumbing fitting, and under $2 a piece compared to 1/4" brass tee from the hardware store for $7 each. The PEC fitting are a bugger to fit in the 1/4" line but it's a good seal and a closer proximity to the bend.

How about the 90deg fittings that go to the petcocks?

geo46er · Mar 17, 2011

Hi Pvisseriii and highdesert,
I am wondering why Jim did not drill and tap his manifolds for a hose barb (not a difficult thing to do even now) to run a balance tube or more importantly become a vacuum port in order to hook up a vacuum carb synch tool. While it is possible to come close doing it by eye or other mechanical means vacuum is the most accurate. It could be that with a proper vacuum synch your seeming mixture differences may disappear.

GB

hayabusaman0 · Mar 17, 2011

HI All, I looked up OKO carbs on e-bay & there some round filters for sale, I have been looking for 2 round filters to fit inside the shemozzzles on my Norvil. Does anyone know if they will flow enough air etc?

Thanks in advance, Paul.

pete.v · Mar 17, 2011

bpatton said:
pvisseriii said:

The fuel line is off a spool at the local dirt bike parts store. The fitting are PEC tee's, some kind off new plumbing fitting, and under $2 a piece compared to 1/4" brass tee from the hardware store for $7 each. The PEC fitting are a bugger to fit in the 1/4" line but it's a good seal and a closer proximity to the bend.

Click to expand...

How about the 90deg fittings that go to the petcocks?

Rocky Point Cycle
http://www.rockypointcycle.com/Merchant ... y_Code=N12

Carbonfibre · Mar 17, 2011

hayabusaman0 said:
HI All, I looked up OKO carbs on e-bay & there some round filters for sale, I have been looking for 2 round filters to fit inside the shemozzzles on my Norvil. Does anyone know if they will flow enough air etc?

Thanks in advance, Paul.

Pretty much any of the after-market pod type filters will flow enough air, but best to choose a foam type rather than cotton/gauze, and try to avoid having the type of filter that has a chrome end cap thats quite close to carb bell mouth. However a properly designed air box, with a foam element will improve running considerably over any of the pod type filters.

hayabusaman0 · Mar 19, 2011

Hi Carbonfibre, only thing to do I think & that is put a std airbox on, but i think they are rarer than rocking horse poo!

Carbonfibre · Mar 19, 2011

If thats the case, then why not design a more effective modern type air-box, and manufacture it in GRP? Use of pod type filters, does not provide anywhere near as good performance as a properly designed and made air box, and a proper air-box in conjunction with a pair of OKO flat slides, will result in far better running, as well as much improved power and rideability.

Got Carbs!

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