Hey Bonz! ZRX qustion

[HalfCentury]

What are your thoughts about ZRX1100 vs ZRX1200?

What about the carbs on a ZRX1100 vs the carbs on a ZRX1200?

[Bonz]

Sorry I didn't see this sooner! Oh man, I love my ZRX 1200.

ZRX 1100, 1999-2000. Based on the exact engine as the ZX11 (fastest production bike for over a decade), detuned for the ZRX "for mid range power". 1052 cc, cast iron cylinder liners, 96 hp and 72 ft/lbs in stock form with stock exhaust. 170/60/17 rear tire, 120/70/17 front tire.

ZRX 1200, 2001-2005. ZZR1200 is based on this engine, (faster yet than the ZX11) 1164cc, Nikasil plated cylinders, 112 hp and 80 ft/lbs in stock form with stock exhaust. 180/55/17 rear tire, 120/70/17 front tire.

-Stock carbs are the same Keihin 36mm, both bikes can be upgraded to the ZX 11 Keihin 40mm carbs. On a 1200 it's good for 8-12 hp and 7-9 ft/lbs. I did most of the development of that conversion in terms of a plug-and-play set up that can be repeated.

-Guys say the 1100 feels slightly more light on its feet changing direction with the slightly narrower rear tire.

-For easily upgraded bolt-on performance, either one really needs an aftermarket header/exhaust can and jet kit which ups the 1100 to 118 hp and 75 ft/lbs. The 1200 improves to 130 hp and 85 ft/lbs. All aftermarket header systems and slip-on cans are interchangeable between the two bikes. Heck for strong low end and midrange, more so with the 1200 when set up as described above.

Then you get into swapping cams and pistons in from a ZX11 (for ZRX1100) or ZZR1200 (ZRX1200) which bumps CR from stock of 10.0:1 up to 11.0:1, or adding high compression pistons from JE or Wiseco (12.5:1). Because of the small amount of cam overlap with stock cams, when increasing compression to 12.5:1 you really need to swap in the cams as well otherwise the dynamic compression ratio go sky high and premium fuel won't even keep the thing from knocking and pinging. Swapping in the ZX11 or ZZR1200 Pistons without cams is rarely done although it probably would be OK on dynamic compression ratio.

Then you get into the handling department where both of them have many aftermarket options for shocks and fork upgrades.

Without going into all the modifications mine has, it's putting down close to 150 hp at the rear wheel and near 90 foot pounds of torque. Everything was a bolt on other than swapping in the ZZR1200 pistons and pulling the base gasket. And I average 53 miles per gallon in every day riding.

[HalfCentury]

All good to know items. Thanks for sharing. I am scheduled to look at one on Monday. If its a runner, I will probably buy it.

[Bonz]

Tell me what you know about it so far. Been ridden or sitting for a while? What year, 1100 or 1200, any exhaust modifications, pods instead of airbox etc. Price? Is there a craigslist link, etc?

Do you know the name of the seller he might be on the ZRX forum.

[Bonz]

HalfCentury, what's the word?

[HalfCentury]

Hi Bonz

The bike has been purchased. It was the best possible situation. The owner is the original purchaser. He was a mechanic. He kept the bike running well. He drove it all the time and kept up maintenance. He did not belong to any online ZRX organization.

2000 ZRX1100 in green. 72,000 miles.

There are extras, a Corbin saddle, Yoshi muffler, exrtra bikini fairing with some light rash from a drop.

The gas gauge in inoperative. It will need to be repaired.

I will be thrilled to fire this baby up and ride it.

[Bonz]

Excellent! Is it just the Yosh muffler on the stock header or the Yosh header too?

[HalfCentury]

I thing that the header pipe is stock. Will check with PO to make sure. Here are pictures.

[Bonz]

Beautiful bike! Welcome to the club!

I think it's the stock header from the right side picture. Can you post one up from bike level from the right side? I can tell easily if I have a clear shot of the collector area.

Are you contemplating any modifications to it? In all the ways the XS1100 does not really respond/gain from engine/exhaust modifications, the ZRX makes up for it in spades!

Pick up an aftermarket header for the CRX to go with your Yosh can. The stock double wall header is hugely restrictive. You'll uncork 20 hp and a handful of ft/lbs. The ZRX forum has a fantastic for sale section and you could pick one up at a really good price.

WWW.ZRXOA.org is the owners forum, and with 13,790 members that are extremely active you will learn so much about your bike and how to maintain it regardless if you keep it stock or want to modify it. I am BonzRexster on the forum.

[HalfCentury]

Which header would you recommend? Does a less restrictive header require re-jetting of the carbs?

[Bonz]

It's hard to go wrong with any of the headers. Muzzy is very good and popular (even though they are no longer in business). That is what I have on my 1200. Akropovic is another good one, Yoshimura, some Kerkers out there, Holeshot Performance. Headers are going up for sale on the ZRX forum all the time in the for sale section, or you can still buy them new but fairly spendy relatively speaking. Another good one guys have discovered is Black Widow. They are from the UK however you can pick one up, brand-new stainless steel, for $450 off of eBay including shipping.

Yes, you will re-jet with a header, however for the cost of a used header and a new jet kit, you are going to uncork 20 hp and some good torque all through the rev range. Most guys that have a drop of performance blood in their veins put on a header and jet kit. As well, it drops almost 20 lbs of weight vs the stock double walled header, mid pipe and exhaust can. Can't go wrong.

Take a look at this link... http://www.sportrider.com/kawasaki-z...-project-z-rex

And this period road test of the ZRX1100... http://www.sportrider.com/kawasaki-z...meanie#page-11

And this test of the ZX11... http://www.zx11.info/zx11/cycle1990.htm

Basically for the cost of a header, jet kit and used ZX11 cams which can be had fairly inexpensively, you will open up almost 30 hp and keep a totally reliable engine. Your ZRX 1100 uses the same engine as the ZX11. The articles will tell you the differences and are fun to read.

Another thing you may want to do is check the rear shocks to see they have held their charge over the years. They can lose their nitrogen and not perform as well as you might expect. A freshening up can make a nice difference in handling. I believe the 1100 has a Schrader valve under the bottom cap, 1200's do not.

You have an outstanding bike in the ZRX1100! I like my 1200 very much however having an 1100 sitting next to it in the garage would be a great stablemate at some point down the line!

Please keep posting up as you discover your new bike!

[HalfCentury]

Thank you for the links. I will study them when I get some time.

I picked up the bike and rode it 15 minutes over some nice roads. Tomorrow the hauler will load the bike and drive it to NC.

The bike is fun to drive. The bike is stock now. The Yoshi muffler is in a box in my car.

I have started reading the ZXROA forums. Fun stuff

[Bonz]

It can and does get a whole lot more lively over there depending on the topic of discussion and the crowd that joins in.

Yeah, the ZX11 info is just to show you the performamce lineage your engine comes from and what it is capable of doing with just a few mods. It is absolutely bulletproof.

[HalfCentury]

The Black Widow ebay listing states that adding the Black Widow headers does not require re-jetting of the carbs.

Do you know if there are any dyno before/after measurements of the Black Widow headers?

Are the ZRX1100 and ZRX1200 headers identical?

I would definitely try out a header swap that did not need a carb re-jet.

The bike has a K&N filter installed.

[Bonz]

You can run any aftermarket header and not rejet...

However your performance will not be what it is capable of (but still runs well from what I know). The bike will gain a few horsepower and lose the extra weight.

Read this thread. It is everything you need to know about the BlackWidow system. First page of posts is very good, post #74 has a dyno chart of it on a 1200 with jet kit.

http://www.zrxoa.org/forums/showthre...p-in-the-world

The Black Widow situation has been discussed a bunch since earlier this year on the ZRX forum.

Black Widow says no to rejetting required, IMO, because if it was not a "no jetting required" stock replacement folks would stay a way from it because they don't want to rejet. I think in the UK there is a lot more of an issue with rust and corrosion and the stock systems rust out and there is a healthy need for replacements, thus keeping it "no jetting required" is by design.

The Black Widow has been put on a dyno and with a jet kit makes power comparable to a Muzzy, Holeshot, Kerker, Akro, Yosh, etc. It is a legit header.

Rejetting your carbs is not hard. The most difficult part with the airbox, just like the XS1100, is getting the carbs on and off because of the tight fit.

A legitimate 20 hp gain (94-97 stock, 114-117 header and jet kit) and a handful of torque on the 1100 is worth every bit.

Having gone from a slip on with the stock header and a jet kit on my 1200 all the way to the full system with cams, pistons, ZX11 ECU, double valve springs (from the ZX11 to utilize the 11,500 rpm redline of the ZX11 ECU), At no point have I wanted more low-end or mid range with any combination I have run. However, relative to the 1200, the 1100 isn't as strong down low and makes the most use of a header and jet kit.

Everything I have done has kept and preserved the low and mid range or increased it. The top end gains to put down almost 150 horses at the rear wheel on a daily driver is pretty cool even if I don't use it (much)... it is called my altitude compensation. I've had to increase the power to make up for losing 20 to 25% because I live at 7200 feet. Now I know what most guys feel like riding a bike with 120-130 hp at lower elevation.