FZS600 - No power, won't go faster than 50, engine not smooth

[Markvanloock]

Have you checked that the exup valve moves freely? The 600s do have exup valves, dont they? I only picked up my gen1 1000 yesterday, so I'm very new to these, but my yzf750 had a stuck exup valve, and the symptoms were the same as you describe.

[red98]

no exup on the 600....another one to cross off the list 

[Torque]

I've left my bike for about 1 month, because was quite busy last time.

I've tried to run it today, so I've opened the fuel and switched ignition twice so pump could build up pressure.
I think that my mistake was that month ago bike ran about 1 minute without tank, so there was not so much fuel left in carbs.

Now before pump could build a pressure there was leak from 2 hoses coming out from carbs, so I think that float valve was opened all the time.
Since leak was not the only issue, because bike was not running good before I've took of carbs and going to do proper job again.

Last time I've used Wynns carb cleaner, but as you see that was not enough.

I think about buying ultrasonic cleaner, but my question is if I clean it with ultrasonic cleaner, rinse it, do I need to have a compressor to remove the water or I can just leave them opened for few hours/days and they will be fine? I can not afford right now to buy ultrasonic cleaner and compressor at once.

What ultrasonic cleaner do you recommend to buy?

[His Dudeness]

Is it really worth spending the money on an ultrasonic cleaner and a compressor just to clean one set of carbs?  Why not give the carbs to a proper bike mechanic let him clean and inspect them. I'd say it wouldn't cost more than an hours labour

[Torque]

Yes and no. 1 hour of labour gives about 60 quids. This is the start price for Ultrasonic Cleaner right?

I know, but intstead of spending lots of money on paying for services I prefer to get more more workshop stuff.
That's possibly not my last bike, also I've got 2 cars... there is always anything to do with that.


... also I am not sure how long I will ride a bike during a winter... so I assume when there will be summer I will have to clean carbs again... so it means paying again for service.

[midden]

It so screams ignition breakdown. 

[Torque]

Yesterday all the evening I've disassembled carbs, splitted, boiled, joined together and soaked with spray carb cleaner.
Today I've spent morning assembling carbs back and afternoon fitting them back.

Bike started, however 3,4 cylinders are not firing. It seems to be fuel problem.
The good point is that even having 2 cylinders engine don't get choked and throttle is responsive.

I've drained 3,4 carbs and tried to apply some Wynns carb through the drain valve, however it did not help.

I've checked spark plugs and were dry, seems to be fuel problem.

Crap crap crap... I am pretty sure that's the problem when you don't have the compressor.

I am angry on myself, because maybe I should from very very start buying compressor + ultrasonic cleaner or just pay someone to do it.

[Torque]

I've got a compressor and few litres of vinegar. Update soon, fingers crossed it must work !

[Torque]

Right. Carbs cleaned very carefully. Dried with compressed air.
After carb sync, bike started run on all 4 gears. Idle is still rough as it was, but it's not worse.

You won't believe there is still the same issue, but now it looks different.
It stutters mostly on revs lower than 6k, but this is no clue it can stutters than runs fine, after few yards it can stutter again.

If you have high rev and add lots of gas it will stutter for few sec than go like rocket.
If you have medium&low rev it can stutter for few sec and start to accelerate normally but can die as well.

Basically now I don't think is the carbs issue. I am going to check ignition coils and ECU again (I've got replacement). If not then I will buy ignition coils. If it don't work then all I can do it's sell my bike ... but already invested too much effort. I want to really fix it.

[humbucker88]

Check your carb to head rubbers for a vacuum leak, easy to check, not so cheap to fix though.

[apage16]

The silliest questions are the ones we don't ask, except maybe this one....


Are all four of the little black rubber vacuum nipple boots (tee hee, "nipple Boots") in place.


The ones you take off to balance the carbs.


I say this because i left one off last time I balanced the carbs and the bike was a pain to start, ran rough an died when I gave it gas.


If they are all in place, are they sound? i.e no cracks or splits?


I'd hate it if it was something so small!! But it's probably not.  :b

[Torque]

[size=1em]
Are all four of the little black rubber vacuum nipple boots (tee hee, "nipple Boots") in place.
[/size]

[size=1em]They are in place and they have no cracks.[/size]

[size=1em]I've managed to record a video: FZS 600 - stutters[/size]

[size=1em]At the beginning bike it's just slightly warm and runs like crap, but check for example moment after 2m and 45s[/size]
[size=1em]It runs much much better, I've even lost the traction, it was slighty wet though.[/size]

[size=1em]In addition to previous posts I've also cleaned the underseat, ECU, coils, fuel pump, electrical connections.[/size]
[size=1em]I've also cleaned the carbs again with vinegar and blowed them with my newly bought 24l compressor.[/size]
[size=1em]Becaused I dismantled them I had to sync them again, also I changed the setting for IDLE (which is crap right now), but it does not really affect the issued I have with that bike.[/size]

[size=1em]Any one in Trowbridge, Bath, Bristol area is happy to have look at it / fix it  (of course for money, time is precious)?[/size]
[size=1em]I like working on my bike, but this is actually much more smarter than me... I am angry on myself and have totally no idea what's wrong with it. [/size]

[size=1em]I didn't checked the valve clearence also I did not try to replace the pickup coil (however it seems to be pointless if ohms are OK?)[/size]

[Lawrence]

This sounds pretty similar to mine, if you work it out please let us know what it was!

[darrsi]

I know you've already done it, but do another TPS check.
The fact yours was out before means it's possible that it's breaking down, especially as i notice your bike is the same mileage as mine.
Mine broke down very gradually, and i took a chance changing it, but just before i changed it the reading was correct and although the bike ran like shit it was ridable.


When i last balanced my carbs it was suggested to make sure the TPS was set before and after balancing.
So, if you had a moody TPS i'm guessing it's "possible" that the carbs maybe balanced incorrectly?


Feel free to knock that theory down if i'm talking out of turn here?
But out of sync carbs could cause the vibration and rough running i was hearing in the video couldn't it?

[His Dudeness]

Sounds a bit like it's running on three cylinders at the start. Try throwing some water on the headers and see if they dry at the same rate

[Fazerider]

The easiest way to prove a pickup coil is faulty is to swap it.
A resistance check will show some types of failure, but not all. It's possible for two adjacent turns to short together... this makes sod all difference to the overall resistance of the coil, but kills the pulse completely.

[JoeRock]

This sounds exactly as though your plug caps have broken down, it's what mine did. Get a new set of NGK ones off eBay for about 15 quid, unscrew the old ones, trim the leads down  a few mm for a good contact and fit the new ones. Sorted mine out completely and g had the same symptoms as you

[Torque]

This sounds exactly as though your plug caps have broken down, it's what mine did. Get a new set of NGK ones off eBay for about 15 quid, unscrew the old ones, trim the leads down  a few mm for a good contact and fit the new ones. Sorted mine out completely and g had the same symptoms as you

Of course that was the very first thing I did. There was no difference at all.


Currently I am waiting for the spare alternator wirings and pick-up coil. Will replace and see what happen.


I guess my problem is related with electrical system malfunction.
Anyway did not check the Rectifier yet (don't have even idea whow to check it), but it should not cause any problem right? It's just rectifier?

[BluprintZ]

Well, i might as well throw my tuppence into the ring.
My bike had a similar problem when it was at the dyno man's, turned out that the charging system was conflicting with the ignition system, replaced the reg/rec unit and all was well, although the problem did cause one of the cells on the battery to bulge slightly.

G ; )

[Fazerider]

Ah, that's interesting BluprintZ... the same cause as in Red98's stuttering thread. Though, if it upset the battery too it may have been been a simple failure of regulation allowing the volts to get too high for the ignition to cope.


Torque: a basic check of the reg/rect just needs a voltmeter to check the battery volts rise from 12.7 (ish) when the bike's stood overnight to 14.5 (ish) by 5000 rpm with the headlights on and doesn't rise beyond that at higher revs. That indicates a healthy battery, charging and regulation.
IIRC Red98's regulator seemed ok on that check and my guess is that it had gone into some weird oscillating mode, the simplest check for that is to swap it.