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'98/'99 ZX6R is my guess.
 

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Nope - Blades have different lids on them.
I initially placed them as GSXR ones but the stacks weren't right.
Then I realised I have a '98 ZX6R :)
 

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Now to determine what the engine is and why they decided to use downdraft carbs on what appear to be horizontal intakes:)
 

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Discussion Starter #8
They are 98 zxr jets drilled to 1.65 mm methinks.
The engine is a 2l Ford Sierra Pinto (done up a bit)
And just bolted on using tig welded manifold. The
only thing connected is the accelerator cable and fuel line.
Thanks to all
 

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If you know what the jet sizes are how come you had to ask what the carbs were?
I'm looking to fit bike carbs to my car.
1300cc and 6000rpm so I'm looking at 600cc carbs as well - half the capacity at twice the revs so breathing should be similar.
For a car I'm leaning towards the smaller carbs to retain midrange but I'm also an experimenter so I might try some bigger ones as well.
I don't want to run downdrafts though as I have horizontal intake tracts anyway. Seems wasteful to build a chicane into the intake tract and it's much easier to fit the bike intake manifolds to the engine and simply pop the carbs into them just as if they were going onto the bike engine.
The ports of the engine are 250mm across the outside centres (929 throttle bodies are 240mm for comparison) so it should be as simple as cutting a piece of 10mm aluminium plate to fit the bolt pattern of the head, cut the ports through it and screw the bike intake manifolds into the plate.
That's my plan anyway :)
 

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Discussion Starter #10
"If you know what the jet sizes are how come you had to ask what the carbs were?"
I was sold them by a chap who was the business partner of someone who worked on the mechanical side of his business he said they were fireblade carbs (dont think he knew much more than me) he also quoted the jet size which look about right on the vernier scale.
All in all though I am impressed with the performance.
Plan sounds good Larry
 

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I knew there had to be a simple explanation :)
How have you fitted them to the head?
Was it running the stock intake manifold and carby before?
For measuring jets a large needle works well.
Coat it liberally with texta then gently rotate it in the jet to mark a contact ring which you can then measure with a mic with very good accuracy.
 

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Discussion Starter #12
The manifold was custom built and carbs are attached with short sections of silicone hose and 2 jubilee clips on each runner.
 

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Did you choose to run downdrafts for a specific reason rather than mount them lower down?
 

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The carbs you're running sit above the intake ports and flow air downwards rather than horizontally.
They're designed for a head that has straight intake tracts and thus require the carbs to be canted over to flow into them. This dictates having the float bowls at an angle so you can't run them on a horizontal-tract head unless you fabricate angled intake manifolds as you have.
With horizontal carbs your airflow would go into the port and only curve once as it enters the chamber.
Running the downdrafts means the airflow has to curve twice in opposite directions as it enters the port and again as it enters the chamber.
 

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Discussion Starter #16
I think its because i dont have much room for any other positioning.
As I said they do work well, apart from a flat spluttering spot if i give it too much gas from rolling slowly along in 3rd or 4th.

Thanks.
Andi
 

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I'm sure they work fine :)
Is it a road or race car?
 
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