ZX9R Carb Dilemma - Megajolt (TPS vs MAP)

[Tatey]

Well it turns out the carbs I originally bought and got my custom ali manifold made for are NOT ZX9R carbs but are in fact ZX6R carbs, I remembered that I went for ZX6R carbs as they could be had for a lot less money but will still give the same performance.

I also got a few replies on Locost, with one suggesting to use welding tips drilled out to 4mm as they are an M6 thread and are available very cheaply, so this is what I'm going to do, I think I have a few of these in the garage so I will try and do this tomorrow and will post my results.

This does mean though that I have a set of ZX9R E carbs with the built in TPS that would be perfect for someone if they would like them for £90 + postage.

[Tatey]

I've now implemented the new welding tip vacuum take offs and drilled out the welding tips to 2.5mm, I will see how this goes as it may turn out that they need to be slightly bigger, but the restriction should hopefully act as a damper.

[Stot]

Are there not vaccum connectors on the top of the carbs just in front of the butterfly valve?

This is what I used when I put bike carbs on my Jester back in '98. They are usually used to connect carb balancers to.

My biggest problem was that if you connect them all together you dont get a constant vacuum down the pipe as they would suck from each other. I had to make up check valves for each line so they would only suck from atmosphere rather than the other manifold branches, that was for a servo mind you not a MAP sensor.

Cheers
Stot

[Tatey]

Stot, my ZX6R carbs unfortunately don't have vacuum connections, I know that more modern carbs did, some even had vacuum connections with TPS sensors.

[flyerncle]

It might pay you to use a vac resovoir to stop pulses from each cylinder giving you false feedback,TDI vw have them,black plastic ball in front of the block.

[baz-r]

you may find that you quickly lose all vac above 10% throttle and a using tps based system will be best

[snapper]

you may find that you quickly lose all vac above 10% throttle and a using tps based system will be best

I'm curious, why would you loose vac signal at 10%?
I've not seen that on my setup using Megajolt log data.
I'm concerned this thread is becoming one based on supposition and not fact
Both systems have been proved to work if well setup
The vac problem has not been reported on other sites save the inclusion of a box or manifold to suppres pulsing.
TPS needs mapping as its a calculation based on revs and throttle opening not a measurement as MAP is
Lets talk more about what we have found and not we think we may find