Z750s engine upgrade with Z1000 parts - Done

[timsav]

Yes, I now have a 05 Z750s with Z1000 displacement, torque and power!

I've known for some time that the Z750 motor is a sleeved down version of the Z1000 motor and have read many enquiries about bolting on a Z1000 engine top end but I have not yet seen the process documented.

With a little research, I found that the cylinder head, cylinders, pistons, clutch, throttle bodies and injectors were different on the Z1000, but saw that the gearbox, crankshaft, conrods and crank case were the same, so I thought I would try to bolt z1000 bits on to my bike. The promise of hp and torque gains with no weight gain was irresistible.

Everyone that I mentioned this to asked why I just did not sell my z750 and buy a Z1000 and the reason is that I have modified my bike so much and it is so perfect for me that I really don't want to sell it, without getting it back to stock, which would take a lot of time. Also, I like the half fairing on the Z750s.

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Parts Required:
from 03 -06 Z1000 (all bought off ebay)
Cylinder head
Cylinder block
Pistons
Clutch
Clutch cover (the zx9 cover does not fit!)

Here are some comparison pics of z750 vs z1000 parts:
Pistons:





Cylinder head covers (z1000 is black , but identical size):


Clutch (z1000 left is beefier and has more springs and plates)




The z1000 has 38mm throttle bodies (vs 34mm) and different injectors to the Z750. I tried to find out the Z750 injector ratings, but was not able to, so I bought some orange, reconditioned and balanced z1000 injectors (actually off of an R6) and put them into the existing fuel rail and throttle bodies:


Other bits:
New gaskets, clutch nut, piston pin clips, valve guide oil seals etc from dealer

Oil, moly grease and coolant

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Doing it:

I started with the Z1000 head preparation.
Removed all the valves, springs and buckets and stored them carefully in this handy organiser with 2 rows of 8 compartments:


Then I took the head to a specialist shop who checked it out and skimmed and ported it.



These tools worked very well to remove and replace valve stems:



I used a 19mm socket with a magnet on top to remove the valve spring retainers and the Sykes Pickavant specialist tool to reinsert them. A magnetic pick up tool is really handy when working with those tiny little collets.
The manual says to replace the valve oil seals, so I did.

I also set all the valve clearances with the head off the bike, by resting it on some soft foam and turning the cams with a large screwdriver levered off a block of soft wood.

I also lapped in the valve seats using some fine chrome polish. They did not need much work.

Here is the prepared head covered with cling film ready to go. Isn't it a thing of beauty...:


To ensure proper mating of the surfaces, I sanded the top of the cylinder block by taping a sheet of 600 grade water paper to my kitchen counter and sliding the block repeatedly over it, until it was perfectly flat and smooth.

I also cleaned, checked and prepared all the other parts and wrapped them up ready for installation.

Next it was time to tear into my Z750s engine top end. The service manual gives very detailed instructions, although you have to jump about a bit to follow them. My laptop got a bit greasy in the process!

What the manual does not tell you is that you also need to remove the front fairing subframe.

The manual says to use a special tool to remove the piston pins. This is not required, they can easily be pushed out by a finger or the plastic handle of a screw driver, once the little circlip is removed.

When I was taking off the old cylinder block, I noticed some pink/red fluid dripping, which puzzled me, until I realised that I had cut my finger on the base gasket. That thing is really sharp!

Here are the z1000 pistons fitted to the existing conrods:


Reassembly of the engine was easier than I expected. I was really worried about fitting the block onto the pistons. I made some guides to slide it on down out of 10mm threaded rod:



and screwed them into diagonally opposing corners:



With my son helping to lower the block and a bit of moly grease and jiggling about the block slid on fine over the pistons and rings.

Some wire tied to the handlebars helped to keep the cam timing chain in place:


There are 2 cylinder head bolts that cannot be inserted after the cylinder head is in place because access is blocked by the frame. I used elastic bands wrapped around then to hold them partially down their holes so they could fit underneath the frame while getting the head in place:


I very carefully torqued my used cylinder head bolts in the order set by the manual and assembled the rest of the engine top end without any problems.

Replacing the clutch was the most difficult part of this job. There is a 30mm brass nut that I just could not undo with my underpowered air impact wrench or any combination of heat, oil and levers and I ended up bending the cheap tool that I bought for the purpose and breaking the old clutch. @#$%^&*





I had to buy a stronger clutch holding tool and hire a very powerful 3/4" electric impact socket to get it off. The hire charge was for 1 day, but I only needed it for about 3 seconds!

Here is the holding tool, with 2 old clutch plates with holes drilled in them that did hold it while the impact wrench did it's stuff:





I had to make a new bracket for my Hebo hydraulic clutch slave cylinder, but the hose reached fine:


The z1000 has an oil cooler, but I have not yet fitted one to my bike. Instead I bought his little gauge and I will keep an eye on it to see if the oil does get very hot:




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So how does she go now?
Bl**dy amazing!! So much power and torque!

Here are the dyno charts comparing the Z750 performance with this upgrade. They were done on different dynos, so I know it's not right to compare directly, but fun to see anyway:




So, roughly 18% power increase and 32% torque increase, for the weight increase of a slightly bigger clutch (500 grams??) I'm happy

[sean c.]

Damn!! Are you a mechanic or just particularly handy and adept? That's a fine job, and please let us know how it all turns out. I have my eye on an '06 750S. I love the looks and the performance, not to mention the cheap insurance.

[whitebread]

Outstanding job!! Good on ya for tackling a task like that!

[timsav]

Originally Posted by sean c.

Damn!! Are you a mechanic or just particularly handy and adept? That's a fine job, and please let us know how it all turns out. I have my eye on an '06 750S. I love the looks and the performance, not to mention the cheap insurance.

Thanks for the kind words. I am only a hobby mechanic, but I have tinkered with cars and bicycles for many years. My only previous experience of motorcycle engines was setting the valve clearances.

This would not have been possible without the internet. There is just so much info out there from being able to download service manuals, check and compare part numbers and even watch youtube videos of work being done on other bikes. This forum has been an inspiration for all my mods.

I was worried about insurance, but I have found this company in the UK called eBike (http://www.ebikeinsurance.co.uk/) who offer cheap insurance on modified bikes. After this mod they increased my premium by about 30 pounds for the year.

[BB-z1000]

yea man, damn good job, 20 extra horses is an awesome outcome

[greencheezeeta]

Sweet job man!

[03kraz1000]

<---- Yea that's me b/c I don't have your bike . . . your write up was just as good as your mod. How much of a weight difference is the z750 from the z1000? How's the sound? Once again great job!

[Rhinotheking]

Yup, you've got skills. Nice job.

[BB-z1000]

how bout a pic of the whole bike?

or better yet video clip!?

[timsav]

Originally Posted by BB-z1000

how bout a pic of the whole bike?

or better yet video clip!?

Here's a pic of me going for the initial test ride:



I'll post a better picture when I fit the final part - it's being shipped now. Will also try to post a video clip, if I can get around the technology...

[timsav]

Originally Posted by 03kraz1000

How much of a weight difference is the z750 from the z1000? How's the sound?

The specs say that the dry weight of the Z750s is 199kg and the Z1000 is 198kg, so they are pretty similar in weight. My bike is a little lighter than standard after I upgraded the swingarm and fitted the Akra full exhaust. I do have a heavy Corbin seat, though. The point is that I gained all the power and very little weight, so power to weight ratio moves in the right direction.

It sounds really loud, beautiful deep throb, but I am thinking of putting the baffle in to stop annoying my household and the whole neighbourhood every morning when I start her up and blast off to work! Children cry and hold their ears when I go by

[03kraz1000]

Originally Posted by timsav

Children cry and hold their ears when I go by

They will appreciate it when they get older . . . it's amazing how much power you gained. Do you have any pics of the bike or even better videos with the power/sound?

[Zammy]

That is a truly awesome combination.

[KXonZ]

HOLY WRITEUP!!!!! you sir are truly a pimp. i would now like to enlist you in finding out how to add 200cc to my z1000!! well done. enjoy

[timsav]

The final part for this mod arrived yesterday - this nice billet cover plate:






Here are pics of the complete bike:





and a short vid:
http://www.4shared.com/file/12840431.../MVI_0940.html