There's the 'project'...I have some OKO carbs gathering dust in the workshop somewhere and I am told they will fit very nicely onto an FZR engine (goodbye standard carbs). The FZR is pretty quick in standard trim, so it would be interesting to see how one would run with better carbs. I'm talking drag strip and not road bike.
.... and as u know , I have more than enough of the rest of the bits to carry them down the drag strip Sounds like a project for the new workshop And sounds like a good time for both of us to hone our skills in top end rebuilds
Yes, there's no point me sitting on these OKO carbs, they just physically don't fit between the frame rails of a ZXR250. I will be in touch Chief. We'll chat about the 'project' when you're back from school hols with the lad. I think @maelstrom might like to be involved, time permitting.
@GreyImport I'll go and find them and put them aside for the 'project'. They're the version with clear bowls, so they look schmick.
So they run individually and not as a "bank" .... interesting .... Ill have to find some info on them Clear bowls .... now wouldnt that make life easier! Home - OKO Motorcycle Parts and Accessories (oko-australia.com.au) oko-australia.com.au/parts-accessories/
Hey Chief, start a new thread. Call it whatever you like. So they run individually and not as a "bank" That's correct. The ZXR carbs have their throttle mechanism on the far RHS of the carbs, so even if the OKO did fit within the space provided, the throttle mechanism would need to make some kind of magical mystery tour around the tank and other bits to get to the throttle. I had thought to have 4 throttle cables merging into 2 and then merging into one; with that single cable going back to the throttle and there was no need for a 'return' cable as these carbs return themselves. On the FZR engine, it might actually be easier to connect the 4 individual carb cables to a single plate (or similar) mechanism and then have the single throttle cable going from that to the throttle. As long as you could adjust the cables to ensure they are all exactly the same 'timed length' to the plate so that they all open and shut at exactly the same time. The cable guides on the top of the carbs are movable, so you could easily point them all to a single area.
Also, the carbs I have are Taiwanese OKO carbs. There are plenty of cheap chinesium knockoffs which that link to the OKO Australia website talks about. Blair might be able to recall better than I, but I believe the Italian Polini company makes the best OKO copies. I'll have to check the original packaging, but I think mine are K101 carbs with clear bowls.
Have a good look around Aliexpress. When I built my scooter I found an alloy manifold that matched the carb and the port on the head and had the perfect curve as well. The carb is a 33mm Mikuni pumper and the port is about 30-31mm. The taper was near perfect. It'll be something for a scooter or monkey bike sort of thing. If you have a head apart make sure you check the valve spring installed height. EVERY single one I have checked has been over length. This results in reduced seat pressure leading to valve float and failure. I had my head refreshed by NZCylinders. They couldn't do it exactly how they wanted but the end result is still perfect. NZ Cylinders - Cylinder head machining
Forget the 'pod' filters, my preference is going bell mouths that merge together so they also help to hold the carbs in place and perfectly aligned. The ones below are for EFI, but they illustrate what I'm referring to. Given how many members of this forum do 3D printing these days, it wouldn't be too hard to knock a set up. I even found a sample file online.
Most of the minutia of this exercise has been covered in the "conversation" section. The plan to use the 4-1 cable setup was to establish that it was functional then a push pull setup could be done at a later date. They angle left and right, and as you can see in the picture, are a very tight fit. Any alloy manifold would have to be cut and welded to suit.
OK. I'd just fabricate something rather than try modifying anything. I've made stacks for my FZR. Looking at the fuel standoff on the dyno it seemed that the motor would need long stacks. They seemed to work fine. I also printed a set of big fat stacks for a 4A-GE engine a YT guy was messing with. They ended up being as good as his own stacks.
