Kawasaki ZGRX 1200 Concours

bergmen

Well-known member
Some of you may know about this project I started in April of 2007 and began first test rides in November of that year.

Briefly, I took the engine from a 2003 Kawasaki ZRX1200R, converted it to shaft drive, designed my own front engine mount and ended up with a 1200cc Concours (more than 25% more horsepower and torque).

There is a LOT more to this story that I can expand on if anyone is interested. BTW, once I had all the bugs worked out I rode this for seven years with zero issues until I got my 2014 Yamaha FJR1300A.

Dan
 

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Frame Maker

Well-known member
...Briefly, I took the engine from a 2003 Kawasaki ZRX1200R, converted it to shaft drive, designed my own front engine mount and ended up with a 1200cc Concours (more than 25% more horsepower and torque).

There is a LOT more to this story that I can expand on if anyone is interested...

You're now in the right place, so go ahead and post up your story. And be sure to include lots of pictures, we like pictures :thumbup
 

budman

General Menace
Staff member
The conversion to a shaft drive alone is worth hearing more.... :popcorn
 

bergmen

Well-known member
The conversion to a shaft drive alone is worth hearing more.... :popcorn

Well,the original ZG1000 engine block is identical to the ZRX1200 block from the input shaft rearward. Same bearings in the transmission, same center-to-center spacing, same oil system, everything. Same rear engine mounts.

I needed to install a six-speed Concours transmission in order to have the bevel gear coupling on the end of the output shaft. The bolt pattern for the bevel gear was there in the crankcase output side with one exception. I needed to drill and tap one extra hole (the boss was there). The ZRX clutch basket (necessary for the ZRX primary drive) bolted right up to the Concours input shaft.

Here are pictures:
 

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bergmen

Well-known member
Before I worked on the transmission change over I needed to design a new front engine mount. The ZG1000 engine was a stressed member of the frame and the cylinder head was mounted to the frame as a result (same as the Ninja 900 which this motorcycle was derived). The ZRX engine was not mounted this way. I designed a new engine mount using my 3d CAD system.
 

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bergmen

Well-known member
I was able to acquire a spare Concours frame to use for developmental purposes so I could leave my Concours unmolested during the engineering of this conversion.
 

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budman

General Menace
Staff member
Sweet.

Drilling the hole had to be the deal. Screw that up and start over.... with new cases. I am impressed.
 

bergmen

Well-known member
The Concours shift drum, shift shafts and gear indexer arms mounted in the crankcase without modification. Here I am doing a complete function test of all of the transmission components in the ZRX case.
 

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bergmen

Well-known member
Sweet.

Drilling the hole had to be the deal. Screw that up and start over.... with new cases. I am impressed.

I mounted the bevel gear case to determine exact location of the hole to be drilled. I marked it with a drill of the same diameter as the clearance hole in the case. I then measured the depth of the other holes in the case and used an extension drill concentrically located in the case clearance hole to drill the pilot hole.
 

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Pushrod

Well-known member
Drilled into a case, got it square and straight, with a hand-held drill?

That qualifies for admiration.
 

kpke

Veteran
EGADS. Subscribed. That is a really cool transformation.

I love the photo with the frame/engine supported by the galvanized pipe.

And all the other photos :thumbup


I was able to acquire a spare Concours frame to use for developmental purposes so I could leave my Concours unmolested during the engineering of this conversion.
 

bergmen

Well-known member
Drilled into a case, got it square and straight, with a hand-held drill?

That qualifies for admiration.

It was fairly straightforward to maintain concentricity by using the clearance hole in the bevel gear case as a guide. I took my time and was very careful. I then tapped the hole (M6) with a taper tap followed by a bottoming tap I had to make myself (ground the end of a spare taper tap). Hard to find M6 bottoming taps in this town.

Dan
 

bergmen

Well-known member
The oil systems between the Concours and ZRX1200 were identical with one exception. Since the ZRX did not have a bevel gear case to lubricate, the oil from that passage was diverted to an oil "spray bar" running spanwise in the transmission. I needed to plug that to divert the oil to the predrilled passages for the bevel gear case.

There were a couple of options to consider. One was to tap the hole on the inside of the case and install a very short hex set screw to plug the hole. This would have been ideal but I did not want to risk getting chips down into the oil passage that would be very difficult to remove. So I opted to plug the end of the "spray bar" and re-install it into the transmission.

Dan
 

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bergmen

Well-known member
I need to go back to the beginning for a minute. Before I could start this project, I needed donor parts from a healthy ZRX. I found that there were engines available (hooligans at the time were totalling these here and there making parts available). But I did not want to have to trust an engine from a crashed bike not knowing if it had laid on it's side with the throttle wide open before getting shut off.

So I did the next best thing and found a nice clean 2003 ZRX an hour south of me and bought it for $4000 (I ended up selling all of the unused ZRX and Concours parts for about the same so it was a wash).

I built two plywood roll-around platforms to do the surgery. One of them was used for the ZRX and the other ended up on saw horses for the engine/frame/ engine mount work.
 

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bergmen

Well-known member
In addition to all of this, there was an excellent source of brand new Concours parts I could draw on. An outfit in Texas got a contract to build 100 police outfitted Concours for the Egyptian armed forces. Part of that contract was to also supply 30 complete new engine assemblies as spares. Kawasaki had no means of supplying these so they bought 30 extra Concours motorcycles and harvested the engines out of them. They sold the rest of the parts for pennies on the dollar. I bought a bunch of parts (you'll see later in this saga) along with two brand new frames (frame numbers ground off and officially removed from registration and were to be scrapped). I got these free for the cost of shipping from Texas.
 

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bergmen

Well-known member
I needed a transmission and bevel gear case from a donor Concours so I would not have to tear mine apart for this (I wanted to continue to be able to ride during this project not knowing how long it would take).

One of the issues plaguing the Concours was a tendency to hydrolock due to a lousy petcock design. Often, owners would just remove the pranged engine and go find another to replace it. So, it was pretty easy to find one (a 1994 IIRC) and I offered to buy basically everything aft of the crankshaft (transmission, all shift parts, bevel gear case, clutch hub, etc.). The owner gladly obliged and sent me a box of parts.

Here I have just unpacked the donor parts.
 

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auntiebling

megalomaniacal troglodyte
Staff member
did the ZRX transmission not need the lubrication from the spray bar? maybe i'm misreading but if they're otherwise identical transmissions why does the ZRX need more oil on that area?
 
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