ZX9R wont get to 100mph or pull above 7,500rpm HELP PLEASE

[duncanpage]

Hi all

I have just got myself a 1999 ZX9r and on the way home from collecting it, the bike felt quite rough when I fully opened the throttle in top gear below 3,000 rpm.

Having ridden it today I've noticed it won't go over 7,500rpm and wont go above 100mph.

The bike came with receipts for a Dyno-Jet kit and has a dyno readout.
It also came with a spare set of carbs.
The previous owner never mentioned it being restricted but he only had it 4 months. He MOT'd it and then sold it on.

I've cleaned out the K&N air-filter and noticed that the two rubber plugs were missing from the air-box. I've replaced these but it doesn't seem to have made much of a difference if anything at all.

If the bike is restricted what should I be looking for and where?

I've got my full license and am 28 years old so I don't want to be riding a restricted zx9r

Please help me!

[cb1rocket]

probably some washers between the carbs and intake manifold.

If not getting to 100mph then it def sounds restricted

[CaNsA]

AFAIK the restriction will be under the carbs, the carbs will need pulling off.

Sorry that i cant be more help.

[cb1rocket]

will it go over 7.5k in the lower gears?

[duncanpage]

[P.]

33hp ZX9R... rip the carbs off, there should be washers either between the carb and engine or you'll have a restriction in the slides area.

It will shoot past that speed no worries after

[duncanpage]

Thanks everyone.

I'll rip the carbs off first thing tomorrow and have a look.

Does a dyno-jet kit have any significant markings?
If the other set of carbs that the previous owner gave me with the bike has a dyno-jet kit fitted will I be able to tell from looking at them or will it have to be stripped apart?

[cb1rocket]

parts are inside, will involve stripping the carbs

I'm surprised the bike doesn't rev past 7.5k in the lower gears......not even in 3rd?

[P.]

[duncanpage]

[cb1rocket]

hmmmm

on the other hand while being polite ( ) don't rev it up to red in neutral - best way to wreck an engine!

[Pete.]

You dad is quite right, with no load on it there's no need for a lot of fuel/air to spin it up. Revving out an engine with no load on it is a good way of throwing a rod so best cut that out if you want it to last.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[G]

There's a RAM air tube that goes from the two main air ducts at the front to carbs I think (though may be airbox). When I had it disconnected because I didn't have the main tubes (no fairings) and it generally ran pretty badly.
Reconnecting the main ducts and ram air tube sorted it.

[moppy]

[Scythe]

[MattJ]

My FZR600R is 33bhp and it definitely does use the full rev range. You can just tell that after about 7k that there isn't anymore power to be had but the revs do still rise very slowly in 6th gear.

As moppy said 50mph can be had in first gear still.

[duncanpage]

Hi everyone.

Thanks all for your help.

The bike is now cured but it wasn't carb diaphrams.

I stripped the carbs off the bike but couldn't find anything that resembled a restrictor kit until I compared the jets to the spare set of carbs I was given when I bought the bike.
It seems like each carb has 2 jets? I'm just guessing by the way! But on the spare set of carbs the holes were the same sizes, on the set that was fitted to the bike the inner jets were smaller.
Having swapped the carbs over, the bike revs all the way through the range and pulls like a train!
I haven't taken it onto a road suitable to test it properly yet (only a quick blast down the Alfreston Road) but it definitely gets above 100mph now!

The bike is a little lumpy on tickover but I'm hoping to balance the carbs before the end of the week.
At least I won't have to pray hard before trying to over take anything now!

Thanks again for all your suggestions