I justpicked upa 94F2 and have been working over the past week to get the bike into shape. When I first rode the bike it was a little choppyand had trouble pushing past 7k rpms.I had the carbs syncd, new plugs and had the idle mixer set to 2 turns, bike runs very nice, except today.
It was warmer out and the bike was stuck in traffic and got up to3/4 on the temp gauge and it started running like junk! Off idle it was still great and pulled nicely until 7K rpms and could not get past 7K, so I just shifted at 6k and limped it home. I am thinking needles, the are set at #2 with a washer under and over the clip. Should I move the needle clip or do You guys think it might be something else, thanks

 

In addition to checking what the stock settings are for the jets, slide needle, etc....I would also check the compression and cam timing of your bike.

A lot depends on how many miles the bike has on it...condition it is in...etc.

 

Thanks BMG,I am not sure how I would check the cam timing but I will say the bike runs flawless when the temp is under 1/2 on the gauge. It always fires up on the first try and purrs, no funny noises and great throttle response.

Even when hot it runs great until 7k, thenits like someone just pulled two plug wires. You shift, and it runs great. Like a 7k rev limiter. When the temp comes down to 1/2 You can then go past 7k rpms but it stumbles until 8.5k and then starts to clear itsthroat and pull hard.The bike does have a Yoshi exhaust and a dyno jet kit stage 1 with 12k on the speedo. I was also thinking maybesomethingwith the ignition??? I dont know.[]

 

You are going to have to do a little research....

1. Check your air/fuel mixture. Check for too lean a mixture or if the engine is starved for fuel.

Do this first by making sure there are no kinks in any of the fuel lines going from the gas tank to the carbs.

Also pull the plugs and check for too lean a mixture. Plugs will be dry...not wet...and white-ish in color.

If your air/fuel mixture is ok...


2. Check your battery and ignition system. If you don't know how to use a voltmeter...let a good mechanic do it.

3. Valve timing...seized or partially seized valve...check valve clearance...

4. Check compression...this is pretty easy...if you have the proper gauge.

One easy, shade tree test is to put the bike in 1st or second gear, let the clutch out, engine OFF,
and see if you can push the bike forward. If you are in 1st gear, and can push the bike...if the wheel rolls foward...you are in trouble.

5. Last thing I can think of is some kind of thermostat problem with your cooling system.

Hmmmm....

 

[ul][*] Check for known good battery. Note: Many bikes (especially 79-83 Honda DOHC 750/900/1000/1100/CBX) absolutely require a hot battery to rev.[*] Charging system should be putting out 13.5 Volts DC at the battery at midrange. The charging system should actually put out around 14.7 VDC before the voltage rectifier shunts to ground as too much voltage would cook the battery. If the battery is not seeing (or able to hold) this voltage it may not have enough volts to send to the ignition system to keep up with the RPM demand, and requirements of an electronic spark advance unit.[*] Carburetor dirty[*] Carburetor not jetted for some changes in: [ul][*] Altitude. Decrease main jet size one size per 2000' above sea level.[*] Exhaust[*] Intake.[/ul][*] Fuel flow requirements not being met. [ul][*] Too small a float seat[*] Partially clogged or undersized fuel filter[*] Trash in fuel delivery system. (Petcock, Tank fitting, Hoses, Fuel Tees, Filter)[*] Float/Fuel level too low.[/ul]
[/ul]

 

OK, this is what I have done so far and problem still not solved.

1.Cleaned fuel tank and petcock valve.
2.cleaned carbs, synched.
3. New stock air filter, oil change, new spark plugs.
4.used three different main jets, and threedifferent needle settings..
5. flushed coolent system, and verified that the fan works, NO overheating.
6. Replaced fuel lines fromtank to carbs....

Basically I can go out and start the bike on the first try, idles like new and runs like a dream. Then when the bike gets fully warmed up You can't go past 7k in gear. It will still idle great and pullnicely up to 5k and then it start to sputter, by 7K it is sputtering so bad that it wont go any higher. I thought my next step would be new plug wires. But if there is anyone that has had this problem please let me know.

 

maybe coils?

 

Well....your fuel problem is solved...if you had one.

I am thinking now that it is either your

Battery

Coil

Plugs

Or maybe something in those black boxes...ECU's.

It's something electrical...

 

I just picked up two coils with wiresfrom a 97 F3. I installed them and the same thing. [:@][:@][:@][:@]

When the bike iswarmed up You can put it in neutral and WOT and the bike wont go past 7.5K. Just sounds like a some crazy 2 cycle.lol

 

I would look at electrical...either the ignition or R/R. The R/R's on our bikes are crap anyway, and they can do anything from make your bike die, drain the battery, or even blow up a battery when they go bad. An aftermarket R/R, or a modded GSX-R R/R is a good upgrade regardless...and relatively cheap and easy...less than $90 on EBay and two bolts...something to try anyway.