Hello All.

I did a very quick check to see the flow rates of the injectors on the GSXR-1000 K5/6 ITB's, and I was a but perplexed as to why a 180bhp bike needed that much fuel! We did a 15 second test and both inner and outer bank injectors flowed just a tad over 80ml. That's 320cc per minute, and there are 8 of these.

I have been scouring the internet for days to find some infor on these injectors, I just can't find anything at all.

These are the injectors.


Keihin Injectors

I know I flow tested them, but I'd be really happy to know what the official specs of these injectors are, unless I unwittingly bought an intake with upgraded injectors.

I did some research a few years ago, the injectors I had were Grey primary, and brown secondary, the greys were specified as 270cc/min, and the browns 540. I can't remember the K designation, but the bodies were in pairs.

I didn't have my GSXR1000 long enough to really thrash it before it was written off in a SMIDSY, but the R1 I replaced it with could easily drop into the teens per gallon on the twisties with constant accelerating and breaking.

What I cannot understand is why have two models of an injector that flow the same quantity of fuel? From the picture you can see that they have different part numbers. During the flow testing we noticed that the TB21 had better atomisation (and a higher impedance) than the TA25 model.

Could be the spray patterns are different wide angle close to the valve, and narrow further up the venture to save the spray hitting the body wall.

If the bike uses sequential injection then you need high injector flow rates to complete an injection event in the required time at high RPM, much higher than the power output of the engine would suggest.

As an extreme example, the the last of the original mini's used a port injection system. This required some tricky injection timing to minimise charge robbing and used two 480cc injectors on an engine making 62bhp!

quote:

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Originally posted by r1_pete
Could be the spray patterns are different wide angle close to the valve, and narrow further up the venture to save the spray hitting the body wall.

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Aha! Now it makes a lot of sense! Well yes the bike has staged injection and it also had secondary butterflies, that I removed. I suppose sequential injection is all the rage on superbikes now that sooner or later they too will be required to meet emission laws.

Well then, I am still a happy bunny, as I got myself 2 sets of 320cc's for my MX-5 engine.

quote:

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Originally posted by MikeRJ
If the bike uses sequential injection then you need high injector flow rates to complete an injection event in the required time at high RPM, much higher than the power output of the engine would suggest.

As an extreme example, the the last of the original mini's used a port injection system. This required some tricky injection timing to minimise charge robbing and used two 480cc injectors on an engine making 62bhp!

quote:

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Originally posted by r1_pete
Could be the spray patterns are different wide angle close to the valve, and narrow further up the venture to save the spray hitting the body wall.

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Almost certainly. "Shower" injectors normally have a narrower spray pattern.

[Edited on 9/4/15 by MikeRJ]

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Over the last few years i've collected 24 of those injectors from 750 and 1000gsxr's. From what i have seen the numbers you see are batch numbers rather than part numbers and there are many other letters/numbers used too. They all come out with the same flow when i have tested them (inner/outer or just one bank on some 750 tb's). As i said on the other thread i found them all to be 270cc/min at 3 bar (tested for the full minute) but the exact flow doesn't matter any way if they're being mapped on another engine.

Ian

Just gone through my bag of those injectors, and i have them with markings of;- UC23 BBE, UD24 BBE, SD05 ABE, SD05 BAE, RA13 BBE and TA27 BAE. When i tested them they were all the same flow/min.

Ian

I did the same as you Ian when I fitted GSXR throttle bodies to my ZZR 1100. At 3 bar I got near enough the same.