ZX11 carbs onto a ZRX 1100

[Purgeraptor]

Guess what, ZX11 40mm carbs fit the ZRX1100 head using ZX11 inlet rubbers.

Also the K&N pods for the ZRX carbs fit over the ZX11 airbox plate trumpets.

Just got to get the carbs and float heights adjusted to make it all work.

Maybe it won't, but worth a try

[Kermit Z]

Keep us updated on this

[oldogrxer]

before I got my Rex, I owned a ZX11D
The carb angle to the intake side of the head was so radically different I did'nt think these would swap. Only because of the float bowl design. Curious to see if you can get it to work. Good luck..............Ron

[KWICK]

Interesting....

[lytnin]

I thought Ytrap had made downdrafts work on his ZRX? I don't remember which carbs they were but I think he had them working.
Later == Bobby

[zrxoa1]

I just don't see how downdraft carbs can work..... that is a serious angle for the float bowl, just seems like gas would not properly get to the main jet....

Didn't Shannon use ZX9 carbs... I have also, I think, seen a few using flatslides downdrafts... I still just don't see how they can work right.

[Purgeraptor]

I think I read somewhere that Shannon used ZX9 downdrafts and got them working.
Also Ryan thought that they 'may' be made to work.
I haven't heard that anyone else has tried this and failed, so I'm going to give it a go.
The brand new carbs were quite a bargain from eBay!

The angle isn't as bad as it looks. The ZRX block/head plane is already at quite an angle off horizontal towards the ZX11 45 degrees of the 40mms.

Anyway, here's hoping, I'm having it set-up by one of the best tuners in the UK (PDQ), I'll be comparing the dyno runs on the same day between my current setup (ZRX stage 3 DJ jetted carbs with K&N Pods, Akra, ZX11 cams, Wiseco 1109 and ZX11 igniter) and with the ZX11 carbs setup too.

I'll let you know, I'm booked in at PDQ on 24th March

[Purgeraptor]

For anyone still following this thread see this link

http://zrxoa.org/forums//showthread....hreadid=105457

The CVK40 semi-down drafts DO work on a Rex with major jetting chnages, the float bowl angle is not an issue.

Clearance between tank fuel tap and left hand carb top is the only problem, but not difficult to sort.

[Purgeraptor]

Seeing as the thread linked above fell out the General forum, I'll post the power curves below.

Here's the carbs fitted:

All sorted, only had to file down the fuel tap vent stub flush with the tap body, got all of 0.5mm clearance now betwen that and the carb top, and didn't have to do anything else to the tank.

[Purgeraptor]

Just got back from PDQ to tune the carbs for the Wiseco1109 kit, ZZR1100 igniter (extra 1000 rpm different timing curve) and ZZR1100 CVK 40mm semi-downdraft carbs.

Final power and torque is 141.86bhp and 82.99 ft-lbs with the modded ZZR1100 carbs and Pods.

With the 36mm Stage 3 ZRX carbs and Pods we got 138.67bhp and 82.23 ft-lbs.

Before the Wiseco 1109 kit I got 130.66bhp and 72.60 ft-lbs (cammed Stage 3 with full Akra).

Things I've learn't:

The Wiseco kit is excellent value for money, improving power and torque everywhere from tickover to the red-line. More power and similar torque to a Stage 2 or 3 tuned 1200 with full Akra.

The ZZR1100 igniter's extra 1000rpm gives no more power than the standard ZRX igniter, as power starts to tail off at 10,500rpm. It is not worth doing as a road mod, but could be useful on track to hold a gear longer, ie at the end of a straight without having to change up and back down again (like Donnington or Brands).

The ZZR1100 carbs provide a small gain over standard ZRX carbs throughout the rev range apart from a dip between 2,500rpm and 3,500rpm. The dip low point still produces more power than the pre-Wiseco tune. It is probably worth spending extra on FCR41 flat-slides or staying with standard Stage 3 tuned ZRX carbs.

ZZR carbs fit under the fuel tank with careful filing of the fuel tap.
ZRX pull throttle cable fits the ZZR carbs but close cable is not long enough, so I left it off.

Overall i'm pleased, as purgerex has gone from 93bhp to 142bhp over the last 4 years!!!!

Big dyno chart for the anoraks HERE

Small dyno chart for the grazers below:

[Pal]

You need to connect your vacuum pipe to the tap in that third pic.
Must be where you're losing all them ponies.

[Purgeraptor]

Not going to use it, saves the weight of the rubber tube and also the tap flows more in PRIME

All the inlet vacuum stubs are bunged.

[Purgeraptor]

You must live quite near me.

Is Hampshire, UK close to UK, Hampshire

[Purgeraptor]

Had a few PMs on what is needed to do the mod, so I'll repeat here for everyone.

They're ZX11 (ZZR1100) C model carbs.

Changed the standard Keihin 155 mains to DJ200 mains.
Blocked the air corrector passageways as it was still too lean.
Raised the standard needles 0.5mm with a shim.
Idle screws 2 turns out.

Fitted full power carb tops and removed the de-icing heater plumbing.
Had to cut the ends of the rubber intake trumpets off to fit inside the K&N pods (same pods as we use for Stage 3 on the ZRX.
Had to rotate the ZZR1100 carb inlet rubbers through 180 degrees so the vacuum stubs point down otherwise they clash with the coolant log.
Also had to file off the vent stub on the rear of the petrol tap as it clashes with the top of the LHS carb cover.
Just used the ZRX 'pull' throttle cable, and junked the 'close' cable.
ZRX choke cable connects straight up, just need to screw it in to remove the extra play in the cable.

Not tried to lean out the rich dip at 2.5K yet, but we did play around on the dyno, and any attempt to lean out the dip by shimming the needles or adjusting the pilot screws made the top end too lean as well. I think with lots more dyno time and different needles it can be cured, but ran out of money.

It pulls well enough through the dip, and I tend to ride above 3.5K revs anyway.

[Vincent Hill]

I have the Igniter for a ZX11 (93) are you saying that I can use that Igniter for the ZRX? Plug & Play? I had a Vance & Hines Igniter that was Programable because on my graph the power is still going "UP" when the limiter cuts in!

Great work guys! Another neat thread!

[KWICK]

Originally posted by Vincent Hill
I have the Igniter for a ZX11 (93) are you saying that I can use that Igniter for the ZRX? Plug & Play? I had a Vance & Hines Igniter that was Programable because on my graph the power is still going "UP" when the limiter cuts in!

Great work guys! Another neat thread!

The ZX11D ignitor works. The ZX11C one isn't worth the effort as it only raises the rev limit by 500 vs 1000 rpm.

I have the wiring all sorted. 480-961-0643

[c10]

Originally posted by Vincent Hill
I have the Igniter for a ZX11 (93) are you saying that I can use that Igniter for the ZRX? Plug & Play? I had a Vance & Hines Igniter that was Programable because on my graph the power is still going "UP" when the limiter cuts in!

Great work guys! Another neat thread!

[Vincent Hill]

Originally posted by c10

I have that also! I have about every ZX11 Performance Part laying on a Self and 500 is better than no hundred but 1,000 so I can rev to about 11,300 to 500 is cool for the few times I would need to There are some serious people around here!!

[SteddyTeddy]

But has anyone installed one on a 1200 or has anyone installed a ZZR box?

[KWICK]

Originally posted by SteddyTeddy
But has anyone installed one on a 1200 or has anyone installed a ZZR box?

Yup,
We've put one on a 1200, works GREAT!! Dyno before and after to follow in a week or so.

[Pal]

Originally posted by c10

You also need to wire in a few diodes to get the speedometer to work properly, Sean S and Kwick have the details. It is't simple plug in tho' you have to chop the loom a bit.

[Perko]

Originally posted by Purgeraptor
For anyone still following this thread see this link

http://zrxoa.org/forums//showthread....hreadid=105457

The CVK40 semi-down drafts DO work on a Rex with major jetting chnages, the float bowl angle is not an issue.

Clearance between tank fuel tap and left hand carb top is the only problem, but not difficult to sort.

I was looking at the carbs from Shannon's 2000 ZX9 before I sold um for Nancy and I bet they would bolt on with minimum effort .... well ..... pod mounting MAY be a lil' issue but they have the the KTRIC (or as I now call it KWICK) hook up and the spacing was right. They are 40mm and would probably flow like 38mm flat slides.
Might be somthing for you big cammed N/A guys to look into.

SS

[KWICK]

Originally posted by Perko
....the KTRIC (or as I now call it KWICK)

SS

[Vincent Hill]

Originally posted by Kwakapal
You also need to wire in a few diodes to get the speedometer to work properly, Sean S and Kwick have the details. It is't simple plug in tho' you have to chop the loom a bit.

The Dyna now sounds a lot better!

[KWICK]

Originally posted by Vincent Hill
The Dyna now sounds a lot better!

It costs about three bucks for the diodes and takes 15 minutes of soldering....it's EASY as Pepsi!

Gimme yer address and I'll mail you a set of my notes.

[SteddyTeddy]

Originally posted by Perko
I was looking at the carbs from Shannon's 2000 ZX9 before I sold um for Nancy and I bet they would bolt on with minimum effort .... well ..... pod mounting MAY be a lil' issue but they have the the KTRIC (or as I now call it KWICK) hook up and the spacing was right. They are 40mm and would probably flow like 38mm flat slides.
Might be somthing for you big cammed N/A guys to look into.

SS

I am. I am. I have a set on the way. Will be here tomorrow. Heading to the dyno Saturday morning to see where I stand now. I'll post my results as I go along.

[Perko]

Originally posted by SteddyTeddy
I am. I am. I have a set on the way. Will be here tomorrow. Heading to the dyno Saturday morning to see where I stand now. I'll post my results as I go along.

Very cool!

SS

[Purgeraptor]

Regarding the KTRIK / TPS, I wouldn't worry about losing it if you go to ZX11 carbs and igniter and pick-up rotor.
The ZX11 igniter has a slightly different advance curve to work without KTRIK.

Also, Nick at PDQ has done back to back dyno runs on a standard ZXR1100 with and without the TPS and found very little difference in power characteristics (I've not seen the curves though).

Done 250 miles now with the new mods and I must say I am very pleased, very snappy throttle response and I love the extra revs

The 'dip' in my dyno curve at 2.5K is not noticeable at all on the road.

[KWICK]

Below is a link to my dyno runs. The difference is ONLY the ZX11D box/rotor, everything else is unchanged.

The tire was rock hard and the top end power is not correct.

[Bob 37]

Sorry Pete, but I gotta call on this until I see a dyno run that actually shows a power advantage. I don't see how your tire is going to spin up at 9k as the torque is falling off, not rising. Both curves show a power drop off after 9k, it's just worse with the new igniter. Maybe I need to move to Missouri.