ZX9 tuning options

[Fifer]

Here's the idea: I have a ZXR750 with a kit motor full of rare bits that has to race against 10 year old 1000's. I don't want to chew through precious hours on the kit parts for my club-hack racing efforts so the logical thought is to put a warm early 900 in. This should give the same and possibly more outright bhp, might not cost the earth and preserves the kit motor for…I dunno what, period 7 maybe.

What mild tuning options are there for the first series 900 motor? Let’s say I’m aiming for 135-140 rwhp and it would/could run the existing flatslides. Are we talking mild porting and cams or more extensive work to get those kind of figures??

And that’s assuming I can get the taller 900 motor in the braced 750 frame……

[paulsj]

Talk to Kwak Addict he has the same setup. I believe he milled the rocker cover to fit past the bracing on the frame as it will interfere on the 9 motor. But if I were you and had the trick parts I would use them even if I was the slowest bike out the just to know I'm fanging old TKA goodness!!! And the sound would be awesome! Just depends how much satisfaction you get from it sitting on the bench knowing you have it........

[Fifer]

Thanks for that, and I can confirm it does sound awesome. Raced it recently and its by no means slow, it wasn't getting dropped off too much by an early GSXR thou on the short straights at Broadford....

[paulsj]

At broadford I think it's more who has the bike setup more than outright HP to not only get on the throttle early but also wide open early. On the front straight on my 99 9R I get smashed by everyone because I'm the left gander freaks me out and I can't get the throttle open early but out of the right onto the back straight they only just pull away on the modern litre bikes as I can get the drive out of there quite well and comfortably.

What times are you doing around broadford on your ZXR? Which club you racing with?

[Fifer]

I just did the last Interclub round, hadn't raced for a year and first time to race the ZXR, managed a flat 3 but I was a little disappointed with this as I did those times on my stock engined P6 750 with old two pot sliding front calipers etc, so expected to at least get someways into the 2's - that'll come later I guess, and I was still riding a lap per the old bike if you know what I mean - that memory muscle from doing loads of laps on the old bike doesn't get overwritten straight away, braking points and so on. The bike is certainly well capable, with the right rider on it, it should get close to 1.01 or better I'd say. The setp up is quite good as is but will benefit from some fine tuning. Getting on the gas out of the last turn is always a tricky proposition, and I've got 30 more bhp now so I'm a bit cautious (ie: scared!) of getting it on too soon.