ZX7r mods

Hi all,
I am race prepin a ZX7r and i am after all the basic mods that will assist in giving extra HP.

This is what i am planning,
1. Light head work
2. New piston rings and a light dusting/honing of the cylinders
3. Cam chain and guides and if needed cam sprockets
4. Ignition advancer
5. Jet kit
6. that mod for equal pressure in the fuel bowls
7. scraping all the metal brackets and replacing with alloy
8. removing wheel bearing seals
9. 520 chain kit, and yes i will be changing the gearing (read in another thread it wont make a diff... Cause it will!)
10. ZX10 05 throttle tube
11. Suspension work F&R
At this stage i am leaving the stock headers on till i get more coin..
Any suggestions?? Have i missed any

All i would say is ask Wetty, i bought my 7R stock rd trim had it for a few weeks then thought stuff it i'll sell it and buy one already preped...

Well I dunno of any specific mods however I would be asking the people in this forum for the name of someone who is currently race preparing zx7r engines and has been successful with them. They should know what mods actually work and what doesn't. That way you might be saving yourself some dollars and get gains.

Personally I believe it's hard to improve on a relatively high performance engine without that specific knowledge.

Just for example , I'll give you an example of a car engine that has been much modified by plonkers over the years with stupid results. When I first started in rallying I drove a MK11 Cortina with a ford 2 litre pinto engine. This particular engine has been used and modified for years by many people for this exact purpose.
The problem is that many engine builders would prepare this engine exactly the same as all their other competition engines. Increase compression ratio, put larger inlet and exhaust valves from the 351 cleveland engine, open up the inlet ports and put a high lift long duration cam in (plus valve springs to match).

When these guys ported the heads they opened them up which would allow a huge air flow down the things. Then they put the head on their flow benchs the things would flow a huge amount of air indicating that they would potentially produce high horsepower. The problem is that they didn't. They produced more horsepower than standard, yes, but they didn't get anywhere near similiar horsepower that you would get from similiar work done to Datsun or toyota engines.

The problem with the ford 2 lt engine was in fact the fact that inlet ports were too large to start with and the wrong shape. They inlet port shape was almost a right angle bend. By opening up the ports all they did was slow the air speed down which cause fuel droplets to form in the ports. The large port size ment that that you needed really high revs to get the thing to work which ment huge dollars on pistons, cranks etc to take the revs. The cams would have to match the rev range which all resulted in a narrow pecky power band that made the car undrivable.

A few had done a large amount of research and development work on them for Ford. One was Frank Lowdnes (the father of Craig Lowdnes which is why Craig had more of an affinity with Ford then with Holden) who worked out all this and produced good horsepower and driveable engines. If you wanted to get more horsepower you in fact had to fill the lower quarter of the port and machine the upper.
The point of the story is unless you know what your doing, all your doing is embarking on expensive development program all your own.
Ofcourse you could move to invacargill, live in a shed and make your own parts an din about 20 years you'd have the worlds fastest Ninja.

Last edited by Tack on Sun May 16, 2010 11:55 am, edited 1 time in total.

All i would say is ask Wetty,

His Idea or performance is to whack on a $10,000 set of front forks & blow away a field of competitors that don't have such deep pockets

Slack your list is pretty comprehensive do all that, get the farker on the track & sort suspension etc, then worry about getting more from the old girl.

I am very concisous of spending big dollars...Point to the question was what are the BASIC mods that people know work.. Where do you stop if ya mod.. Suspension will give me 6 secs over engine work.. Been there done that...
When i say head work, pressured checked to make sure it seals 100%, make sure its not warped, freshen up the seats if need be, valve stem seals, and get rid of all the carbon and whack in a thinner gasket to bump the compression up a little.
I am chainging the cam and guides so i know its ok, and if need be the sprockets... Its the same as any other chain!!
While the heads of i may as well change the pistons rings, clean the pistons and clean/hone the cylinders... I dont plan on any bottom end work..
This is bugger all mods just a basic freshen up..

What i am aiming for is mid range punch... I wont be breaking lap records, beating wetty, or the Clarke's but i am sure as shit i will be up in the top 5... I can run with them on a 600 so i confident on a 750...
So back to my question....

steal wetty's airbox

a zxr750 crank (takes the zx7r motor to 793cc)..
39 or 41mm flatslides..

There was a full Akro for sale on here the other day..

Or toss the 750 engine and put a zx9 motor in..

Heaps of info here
http://homepage.ntlworld.com/webzxr/zxr ... tuned.html

.....Or toss the 750 engine and put a zx9 motor in..

I've got one (zxr750r M1, not a zx7r) with the zx9 engine in it already if you're interested

hmmmm,???
I'm getting a bit old for this superbike lark...
What are you looking at for that beast Dave... ?

Given the cost of the mods, the engine probably wouldn't leave much change out of $4-5k, my preference would be to buy a proven race prepared bike, with all the hard work done by somebody else, like Dave's mutant or this one

http://www.ksrc-au.com/phpBB3/viewtopic.php?f=16&t=28286&start=0

Given the cost of the mods, the engine probably wouldn't leave much change out of $4-5k, my preference would be to buy a proven race prepared bike, with all the hard work done by somebody else, like Dave's mutant or this one

http://www.ksrc-au.com/phpBB3/viewtopic.php?f=16&t=28286&start=0

Exactly my point, parts are hard to find and are expensive...

Think Muzz is keeping his now....

IIf you are taking any off the head I would consider the adj sprockets for the cams a good purchase. Otherwise setting the cams up is a bitch. You may also want to consider a manual cam chain tensioner. I have some factory superbike spec followers and spring retainers that I may be selling as they are overkill on my 950 big bore ( as it just don't rev that high ). manual chain tensioners are cheap in the states on line, however I am currently looking for a good price on some adjustable sprockets ( maybe a bulk buy would be good). I am only new to this forum so I am looking forward to hearing about all your projects on hear. so far from lookin around it seems like some good stuff goin on. One more thing on the 7, If you get the fcr flatslides you may want to check out the SP CDI Igniter as It had an output for the fuel enrichment solenoid based on Throttle position. On the zxr400 SP it actually was a full PWM 3D fuel enrichment map. This will create easier throttle roll ons. cheers

regards TK400