FZR400RR 3TJ New Purchase, just Dyno'd....won't rev above 5k

[EMC212]

Hi all,

As stated in my intro, I've just bought an FZR400RR 3TJ (89) from ebay. The seller was less than honest about a few things but essentially she is a great bike, I tried her out on a quick ride after paying cash and had no noticeable problems. My partner also took her for a 10 minute ride before we put her in the workshop and started stripping bits.

Since getting her home and ready for my next trackday I decided to dyno her and see what we were dealing with. In prep I did the following:
- Removed fairings, front and sides. The connections for the fuel reserve switch were bagged and tied away.
- Removed left hand switch gear in order to fit clip ons. LH switchgear loom bagged and stowed.
- Removed downpipes...completely rusted...which wasn't shown on the ebay pictures!! Filled holes with alu paste and painted in high temp pain until new downpipes sourced. Refitted.
- Wirelocked Exup valve open on advice of tuner as it will be raced.
- Removed and re-fitted airbox.
- Not related but removed fitted master cylinder and replaced with a Brembo. Electrical wires for the front brake not currently connect.

So....took the bike for dyno today, started and warmed up fine in neutral. Revved OK initially, as soon as the bike got hot it would not rev above 5-5.5k. We hunted around and checked
- HT lead (all on)
- Wiggled everything, no difference
- Scratched heads

As soon as the ignition was cut for a minute or so, the bike could be re-started and revved cleanly once or twice. It would then revert to the original problem. We are all thinking along the lines of coils, CDI or pick up but as we all deal with newer bikes rather than 400's I figured it would be sensible to ask around first incase it is an easy fix prior to buying lots of bits.

Thanks in advance,

Emily

[rockTJ]

From what you have said I get a funny feeling about the fuel switch and fuel level sender.

I am pretty sure I am correct in saying that when the fuel tank hits reserve it cuts the ignition - reminding you to flick the reserve switch and look for a fuel station! If you look at the wiring diagram the fuel level/switch circuit does go through the CDI unit.

Evilchicken has a lot more stored up in his grey matter he could recommend you look at.

Whereabouts are you??

Chris

[dobbslc]

Doesn't the low fuel level cut out a coil untill you switch the reserve switch?

[Evilchicken0]

That's odd huh ?

Welcome to the forum though

So, did you wire the exup closed by any chance ??? that would strangle the engine a bit, take the lockwire off for now, the valve will pop and bang a bit but for now it should be ok.
Next - the 3TJ has a Japanese speed restriction, the CDI has to recieve a signal from the speedo (remember those wires you disconected) or it will restrict to 12,500 rpm in all gears. It uses the same circuit as the side stand, red line and fuel reserve switch .... so maybe that has something to do with it.

Clean the carbs and pay attention to the main jets they come in about 6,000 rpm - they fit into the idle jet holes so it's possible to get them crossed, ask me how I know The bike will smell rich it will be fine low down then strangle higher up.

[EMC212]

Hi all,

Many thanks for the replies.....I now have a very sheepish other half....who admitted he hadn't electrically re-connected the Exup Vv. The bike is now purring like a kitten. OH is in the doghouse with his 2011 ZX10 (older bikes aren't his thing!)

Dyno is re-booked for Tuesday. Hopefully no other human induced gremlins will show up and we'll have an idea of what we've got.

[Evilchicken0]

Is this bike going to be track day, race or road and occasionally track ?

[EMC212]

It's going to be my trackday bike for this year, then it will be raced next year. I'll be putting race fairings on it as soon as everything else is in order and will daytime MOT it for the odd trip to the coast (wherever I can lean it against a wall!)

I've employed my local tuner as he has raced one years ago and also AR Racing as Andy is pretty handy!! My OH raced Endurance but on modern bikes, he's a great mechanic and I'm a grasstrack/speedway sidecar passenger but were both learning our way around this wee beastie.


1001171_10152905100875713_595110390_n by EMC212, on Flickr


942581_10152890755075713_1161360666_n by EMC212, on Flickr

[Evilchicken0]

Ahhh pictures glad you understand the etiquette

Check More power and get some frame covers the bars dent the frame when the bike is dropped.

Sidecar passenger on the rough stuff, you're a lot braver than a lot of people then. Whereabouts are you based ?

[bendy3]

It shouldn't make any difference if the ex-up is connected or not? Your best off taking the ex-up out of the exhaust if your racing or better still put a full system on it.

[EMC212]

Thanks for the replies guys. I'm looking at a BDK full system for it which will do away with the Exup, my aims are to get the engine sound (hence the initial dyno), have the oilways drilled, downpipes and exhaust and then more tuning over the next six months. I'm also doing atleast two trackdays a month with No Limits to get me up to speed. As I don't have sponsors all of this is self funded, so bear with it! Any tips are most appreciated

I'm based in Somerset, raced on the grasstrack for four years. Last race was the 500cc Sidecar British Final with Simon Beard in 2011, ranked 4th overall. I miss it, still have my National Licence and a Novice Road Race Sidecar licence too but I figured with the amount of money I was spending racing in the UK and abroad, I may as well be on the throttle.

Whereabouts are you guys?