More rough running.

[dinodelta]

Just wondered if anyone had some ideas I haven't for my 3en2 FZR400.

Just cleaned my exhaust and EXUP valve with new cables, my battery has been 'conditioning' for 2

weeks and the bike is running a cx500 regulator that is raising the battery to 13+V below 5k and 15V

above.

It starts straight away with half choke.

On my test run today, the bike wouldn't go over 5/6000rpm for most of it. My route went up a steep

hill out of town which resulted in the bikes revs slowing toward the top and as I pulled to the side

and pulled the clutch in, I couldn't keep the engine running. Just seemed like it was out of fuel.

Got the bike on a level and the bike started after 2 roughly 8 second turns. Rode off to a long

straight but it the bike still wouldn't go over 6k on the level.
BUT, the 2 times that I pulled over and let the bike tick over for about a minute, pulling away I

could rev the bike to 15k. After the next corner, back to 6k. (Sorry, no long straights) AND, every

uphill climb would have the revs dropping slowly.

I am going to give the carbs a clean when I find some cheaper service kits. I'm working along the

line of it being the float levels and maybe a lazy pump.

[buzzawak]

Just wondered if anyone had some ideas I haven't for my 3en2 FZR400.

Just cleaned my exhaust and EXUP valve with new cables, my battery has been 'conditioning' for 2

weeks and the bike is running a cx500 regulator that is raising the battery to 13+V below 5k and 15V

above.

It starts straight away with half choke.

On my test run today, the bike wouldn't go over 5/6000rpm for most of it. My route went up a steep

hill out of town which resulted in the bikes revs slowing toward the top and as I pulled to the side

and pulled the clutch in, I couldn't keep the engine running. Just seemed like it was out of fuel.

Got the bike on a level and the bike started after 2 roughly 8 second turns. Rode off to a long

straight but it the bike still wouldn't go over 6k on the level.
BUT, the 2 times that I pulled over and let the bike tick over for about a minute, pulling away I

could rev the bike to 15k. After the next corner, back to 6k. (Sorry, no long straights) AND, every

uphill climb would have the revs dropping slowly.

I am going to give the carbs a clean when I find some cheaper service kits. I'm working along the

line of it being the float levels and maybe a lazy pump.

Hi dinodelta,
After cleaning the EXUP valve, did you reset its start position?
Can you hear the fuel pump tick over a few times when you have the ignition on (before you turn her over)?

Also you could try the following. When you are in the situation where the bike cant go over 5K.
Try to reach down and turn off the fuel cock while your keep riding. If the bike suddenly pickups up after a minute
it is a carbi problem.

[dinodelta]

Yep reset the EXUP. Moly greased with new seals and new grapite pulley cables in PTFE liners.
Pump and servo prime with ignition on. New inline filter.
My test run was 7 miles. Even playing up, I was still grinning away! :)

Good idea about the fuel tap. Will fit the petcock service kit I've got first as I can check the tap filters then. And check the cap vent.

[buzzawak]

Its funny how the fzr can do that to you. I had a long break from bikes (10 year +) and got myself a FZR 9 months ago.
It at times had been a pain with getting parts and asking about stuff at the local bike shop (I am in Australia and the FZR is a grey import here, not many here). Plus the bike was in a sad condition when I got it. But I just love it when she is running well. I ride to work each day and a few times I was late to work because I rode right past, Just didnt want to get off my fizzer.

[dinodelta]

Looking more and more like a 600 engine swap. My carb rubbers have split on the outside (Not all the way through) and are reinforced by amalgamating hose tape, with only second hand ones available.
Then carb service kits are disgusting prices now. Mukini used to be dirt cheap for gaskets. With it's age I'd rather replace everything now so know the service life of everything on the bike. Cheapest diaphragms are about £26 each and float bowl gaskets £7 each plus all the jets, o-rings, etc. At least a quarter of the price of a complete Thundercat! Plus I can strip the Thundercat for eBay and sell the 400 motor.

[Evilchicken0]

Did the bike run well before doing the EXUP ???

If it is the carbs it would seem like the main jet area as it seems ok on low revs.

Fotr my money though ... I'd check the vale clearances

[dinodelta]

One of the cable ends had fallen off the universal cable I used as a replacement. The one that fell off was the one that came fitted to the cable. The other three I soldered on and they were OK.

When I checked the EXUP I noticed the fuel pump didn't tick when I turned the ignition on. Been ticking upto yesterday. Put a test meter across the pump plug socket and no voltage when I turned the ignition on. Shouldn't there be a feed to the pump for 5 seconds to prime the carbs? Oh well, checks tomorrow.

[buzzawak]

One of the cable ends had fallen off the universal cable I used as a replacement. The one that fell off was the one that came fitted to the cable. The other three I soldered on and they were OK.

When I checked the EXUP I noticed the fuel pump didn't tick when I turned the ignition on. Been ticking upto yesterday. Put a test meter across the pump plug socket and no voltage when I turned the ignition on. Shouldn't there be a feed to the pump for 5 seconds to prime the carbs? Oh well, checks tomorrow.

Yes the ignition and run switch (both on) activated the pump for 5 or so seconds before start.

[dinodelta]

Did the bike run well before doing the EXUP ???

If it is the carbs it would seem like the main jet area as it seems ok on low revs.

Fotr my money though ... I'd check the vale clearances

I wasn't using more than half throttle when it was struggling, I was roughly matching throttle position to engine revs. Therefore the main jets wouldn't have come into play. The EXUP valve was positioned mostly shut after the cable end came off.

And the valve clearances wouldn't explain why letting the bike sit at tickover for a minute allowed full revs on take off.

So now PV is restored, full revs should be back on the level roads. I expect that the uphill related power drop off is just the float levels. It is a very steep hill.
Power delivery wise (besides being mental) was very smooth, matching the throttle position, with no hesitance or surging. So I take it the various jets will survive till the winter strip down. (Famous last words) :)

[Evilchicken0]

From what you say if the fuel doesn't work then that would be the main cause

The valves stretch to the point that you use compression, as they warm up the tollerances close so compression (well some compression) returns.