TOPIC:

Yes. No advancer. Maybe the air gap on the pickup coils?
About the sidestand switch i can say im sure it work because there is a light for it on the gauge and to switch off the engine i have to completely release the stand..

Irish Yobbo wrote:

no problem except when i am in 5 or 6 gear.
The bike hit only 7000 rpm and then wont go over this point.

In 6th gear at 7000rpm you'd be at about 170kph - I would expect your acceleration at that speed to be pretty poor on a 34 year old bike.

Why? This bike can easily pass 220 kph when in order..

Vibrations at speed can do a lot of strange things. In a troubleshooting situation like this, you want to remove as many variables as you can. I am saying run a temporary to power wire from the battery to the ignition (and coils) to bypass the ignition switch, kill switch etc., and a temporary interlock ground wire which is what the side stand eventually connects to (through logic diodes etc.). If the ignition is like the Zx550 and 750's, there should be one wire on the igniter that just gets jumpered to the ground wire. That bypasses all of the interlocks for the ignition.

Once that's done you can rule out the ignition as the cause and move on to other possibilities.

When you say you have new coils, do you mean new factory coils specifically for your bike? Or did you get some aftermarket coils? If the coils have resistance that's too high, that usually indicates the coils are too slow for your application. That can cause spark to cease under heavy load... high RPM and large throttle opening. You would notice this at lower gears as well, though, unless it takes a sustained throttle for the coils to heat up or something.

I will try and i let you know. I purchased aftermarket coil, not stock or dyna..

Coil tested again 2.6 ohm cold or hot and 13kohm output resistance cold or hot.
I had the wires tested and no resistence under a load with a 2amp lamp light.
Resistance at the multimeter with no load is 0.00
The bike start instantly and is very very responsive at the throttle. Alot of stuff is brand new but the problem is not fuel related since when i try to open tge choke lever under load nothing change....

shamal wrote: Alot of stuff is brand new but the problem is not fuel related since when i try to open tge choke lever under load nothing change....

That does not rule out a rich situation. If the engine is too rich and sputters out, then applying the choke won't make much difference since it's already too rich.

But the description of how it behaves needs to be more precise. Does the engine run smooth at 7000 RPM in 5th but just won't go any faster? Or is it sputtering and surging and backfiring?

Also, I'm not trying to be funny, but are you sure it's running on all four cylinders. I only ask because there have been many times where someone asks me to tune their inline-four bike or balance the carbs and it turns out they've been riding around on 2 cylinders the whole time.

Nono.. The bike is running on fourcylinders. Very angry and responsive. I have a thermal termometer and all the exhaust manifold are the same temp. For precision i have after a couple of minutes from cold 1234 90° 92°88°94°
Fuel level is set.. And in fact the engine is running smooooth until hit 7000rpm range. Then it show some symptoms like when you are out of gas. It try to pass the 7000rpm range and then come back to 6800rpm tgen again.. Sometimes i can reach some higher rpmthan 7000 but veeery slowly and with this on off effect
Sprry for english

Do you have any inline fuel filters? Those can flow ok for around town, but just slow enough to run out of fuel on a long hard acceleration on the highway. I've had that exact problem on the 550. It took a while to figure out. The paper element would flow sometimes and other times would slow down. It needs a fuel pump to have enough pressure. The symptom was just like someone turned the ignition off. All four carbs would run out of gas at the same time.

After a while, the filter would not flow at all sometimes, which is how I found it.

Here's a video where it was not flowing until I pressurized the gas tank. Then it flowed fine.

I have a infline fuel filter, but since i had an experience like you in the past, i use no more paper filters. What i use is a plastic filter that work with a plastic net. Like this www.bits4motorbikes.co.uk/images/PartAcc...lass-fuel-filter.jpg

What about the gas cap vent? Have you tried a high rpm pull with the gas cap popped open? (apologies if this has been mentioned but I didn't see this question when I scanned the string)

Gas cap vent e tank breather its ok. After alot of searching and testing i can say the problem is not fuel or engine related. Its something electric.
This morning i tried some pull in the highway. In 3rd gear she was able to pass easily 8000 rpm and then was like to be bolted on the endeavour shuttle. Waa!! Then i tried again and after 7000 rpm stumble again. Then another time and again she was pulling...
The only gear i cant reach rpm above 8000 is the 6th gear.
I replaced the alternator assembly some days ago and now its charging correctly. I replaced the plug caps too..
Can be a ignition coils problem? The coils are a pair of brand new generic coils from ebay, even if specific for this model of bike i think they can be crappy?

Ok. After alternator replacement ican say the problem is 90%gone. Now is much more sharp at high rpm, and eventually in 4 or 5 gear the engine is able, not always, to reach the redline in a sudden explosion of wild power. Sorry for my english.
I think, since the only thing i changed was the alternator, the problem is something electric.
My question is, can generic spare coils from ebay cause this kind of problem? Insufficient spark? Something similar?