[gpzracing23]

Hello all,

Here is one photo of my kawasaki GPZ 900 from 1984, which i ride on Portuguese "oldies" championship.

Can do some modifications to enable the GPZ to give more handle as the engine is some what capable to do great things...

Cheers,

 

[1Adam12]

Whats inside the engine? or is it stock. What will they allow you to modify from stock OEM? cause I noticed that you have the stock rims on still and they are very heavy....

Daron

 

[gpzracing23]

racing GPZ 900

Whats inside the engine? or is it stock. What will they allow you to modify from stock OEM? cause I noticed that you have the stock rims on still and they are very heavy....

Daron

Hi Daron,

Sorry did not explained my self well... The engine is stock and what i can modify is inside air box, dynojet for carbs, sparks, battery charging coil(?) and battery...
Also can change wheels, chain and sprokets, full exhaust, fairings, rear suspension (unit) and springs and oil in front fork, handle bars.
Of course could be much more tips and tricks that can skip to technical verifications, which i do not know...

Still stock engine is very good (little bit peaky) and have a good top speed on Estoril track, but the handling is very bad...

Still have stock wheels and i´m searching for compatible spares that fit the GPZ, so the winter in my garage can be very well spent...

This Kawasaki was with 33.000 Km's when i bought it, in very fine condition, but could not register with Portuguese number plate, so the track is a very nice place to enjoy the GPZ 900!

If there is any help you can give me, i'll be very appreciated!!

 

[1Adam12]

Try German Ebay and pick up a pair of PVM rims in either Aluminum or Magnesium. You can buy new at $2000.00 USD or $3200.00 for magnesium rims. Cheaper to buy a second bike with the rims on them or just get the rims second hand.

If you plan to do a 17" conversion, that opens a lot of wheel options though. I have seen some very nice forged magnesium rims from marchesini out there and better yet you would be able to go to BST carbon fiber rims...

Suspension wise you can benefit from a Penske rear shock vs Ohlins as it has more adjustability and easier to work on. A budget way to go is to get a ZZr1100C rear shock and machine it to fit. You can see more info on that from Patricks Gpz page in germany.

Front suspension wise, I would suggest you contact Race Tech for custom springs at about $109.00 USD or Works Performance. Ohlins does make a spring for our bike. If it were a street application I would say look at a progressive spring like the Hagon or progressive suspensions.

Let me know if you need more information on coil wires and other specialty parts. I was in the process of building my bike up to go faster when I got in an accident - those plans are on hold for now.

 

[Freakinout]

Any lightweight 17" wheels will make that bike handle a lot better. The tire choices alone would be worth the conversion.

 

[gpzracing23]

rear wheel

If you plan to do a 17" conversion, that opens a lot of wheel options though. I have seen some very nice forged magnesium rims from marchesini out there and better yet you would be able to go to BST carbon fiber rims...

Our FNM regulations do not allow to change or modify swing arm or rear rotor disc outside diameter...
I've got 2 options:

1st: Find a large rear wheel that fits the original swing arm and a similar rear rotor disc with minor changes.

2nd: Find a complete Kawasaki swing arm with larger rim wheel and rear rotor disc with the same 280 mm, but... cut, weld, modify during the winter in my closed garage with so much "state of art" that must pass on to the technical verifications without anyone notice that the swing arm is not original... but from a 165 to a 190 tyre is impossible to hide those mods...

For now one more info if u can help me:
The steering damper, do you know which one fits in GPZ 900 and where on the bike?

These are things that i'll do during the winter, and without any strees or drama, because i do racing for fun, in low budget (preferencially).

Cheers.

 

[1Adam12]

PVM supplies 3x16 front and 4x18 rear. You will be able to get a Metzler 170/60/18 on the rear or like tire in 170. I have seen a few japanese sites that talked about a 180, but I would not go that route with the tires expanding with heat.

 

[gpzracing23]

17'' wheels

PVM supplies 3x16 front and 4x18 rear. You will be able to get a Metzler 170/60/18 on the rear or like tire in 170. I have seen a few japanese sites that talked about a 180, but I would not go that route with the tires expanding with heat.

Many thanks your support.

i'm after a ZZr 600 rear wheel, since it is easier to fit, with the 280 mm rotor disc. On the front i will search the most looklike wheel with mesauses very close, so that fitting 17'' front wheel can be also easier.
I know that a rear 180 tyre offers more power band than one 170 tyre, but if i do not be albe to do that, i'll have to manage with front 120 and rear 170, which is much better than the original dims!...

 

[Tristen2000]

The most adjustability for shocks

A bunch of my buddys including me have switched there progressive forks and also there shocks over to a company called Wilbers. The camparison is uncomparable. Its a high quality shock, but we believe its the fully adjustable High and low speed compression damping option that has made the big difference. We all take rides all over the country, and ride hard, were all sport ridersall i can say is tremendous. I dont know what kind of product line they have for all kawasakis but u can email this guy Steve at [email protected]. He'll let you know any details you need. Enjoy the ride

 

[1Adam12]

Some of the shocks available for the Ninja 900 are top of the line. You have Works Performance, Ohlins and Penske shocks. The WP being the least expensive at around 350-400. There are other conversions out there taking newer shocks off of current bikes and retrofitting the the 900 as well and then you are talking about ebay cheap.

Where is Wilbers located?

 

[Tristen2000]

Wilbers Shocks

The Wilbers distributor is located in NJ. But they are manufactured in Germany. I have a handful of people i know that had ohlins and switched to this company. The shocks are of equal or better quality, around the same price, i think a little cheaper, but they offer more adjustability, and high low speed compression damping, also they are serviced here and built to your specs. I only hear great things though. You have have to at least consider these guys when buying shocks, they are getting some attention pretty quicklyfrom the performance nuttheads. [email protected], they have lots of info to send out and pics and stuff. I think theyre website is under construction right now, so......

 

[kc908]

Do you have some examples of Using other shocks for the 84-86 900's?

 

[gpracing]

Past almost 3 years since I've bought my GPZ. Since then I also changed home address, car, and garage accomodations. But didnt married yet...

Here is the GPZ 900 with new look:

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I've bought a pair of wheels from a Suzuki GSXR 750 which will suit well with minor changes.

Still this year I think I can finish this baby and have some test on track days.