www.zxrworld.co.uk

Hi Everyone
I have been busy getting the bike ready for a trackday at Mallory, completed yesterday. This was a real rush but now I can concentrate on the details.
Has a race loom with alternator still in place charging a small 7Ah alarm battery. Rear shock is now from a ZX6 giving rebound and compression damping. Has had the effect of raising the rear so steering has quicken up with no loss of stability.
The bike has also gone through the first stages of weight saving with more to follow.
Jet kit is coming as there is a big hole in the power at about 4000rpm which I put down to the can.
Ok, so increase in bhp? I'm on a tight budget but can do any job. What has everyone done to get the best out of the motor?

Cams, full zorst and FCRs are best bang for buck

After that there are plenty power mods to start gaining an extra pony here and there.

I have still to see a race detailed engine that makes considerably more than a street bike with the above done

hi mine has a smaller sprocket to give it more setting off speed or something lol not sure what it all means but i was given the other sprocket and will get my husband to put it back on i think lol because im not going to any track days or anything , im a woman i dont understand it all lol

You don't really need the bike rejetting to get rid of the flat spot, it's caused by the OEM can for noise regulation compliance. One you fit a decent aftermarket can it will go with no other work required. However, some race cans (as opposed to road legal with baffles in) will also need carb work. The A16 can gets rid of the flat spot with no need for rejetting.

Before buying a jet kit why don't you get yourself a decent can and take it to a dyno? Some people just fit jet kits then go through the process of getting the bike set up - that's butt about face. You need a benchmark from where to start. Dyno it with the OEM carb set up and the dyno guy can then tell you what (if anything) needs to be done to improve the fuelling. You may not need the expense of a jet kit, he may be able to simply fit a different size jet to the carbs or shim the existing jet. My understanding is that the Dynojet Stage 1 kit on the ZXR400 is pretty much a waste of money, it doesn't have a fuelling problem that needs fixing once the OEM can is gone.

This flat spot is more like a black hole lol

You will never be at those revs on the track so you wont notice it.