running problems

[goose710]

hi all was after picking a few brains.i own a 98 fazer 600,the problem is sometimes it will run ok,then it seems to lose power like its running on 3 cylinders.had the carbs balanced and the diaphrams where checked and ok,was told by the garage that it cld be the fuel pump relay or the fuel pump itself playing up.Any ideas wld be grt as it is getting annoying.

[CharlieDee]

when was the last time you changed the spark plugs? 

[Fazer Jake]

my first port of call would be checking/replacing the spark plugs then go from there.

[CharlieDee]

my first port of call would be checking/replacing the spark plugs then go from there.

2nd that!!

[goose710]

plugs leads oil and filter done before xmas

[Diablo]

just as a thought, did u make sure the clearance gaps were double checked on plugs.
If others think plugs could be a gap to cosed/open.

[richfzs]

Plug caps is my bet.
Or carb icing, does it improve if you pull over for a while?

[goose710]

will check the plug gaps they wre new irridum plugs unless one is no duff,its like no fuel getting throu,you give it a handfull and it dies,then il pull over and start it up and itl be fine again?

[ratfazer]

Petrol tank overflow/breather blocked or kinked?  could be water in there.
 

[Fazerider]

If the fuel pump ticks for a few seconds and then stops when you switch the ignition on you can probably eliminate that as the cause of the problem, it means it's pumping fuel OK and the back pressure halts the pump once the carb float valves are closed.
If it runs fine to start with and then gets breathless and dies within a few miles, chances are the carbs are icing. Check the water path through the carbs. With the tank off you should be able to unplug the two thin hoses. If you attach a bit of spare hose you should be able to blow through the whole set... if you can't you'll probably have to take them off the bike to determine where the blockage is and clear it.

[Gnasher]

 
 
Yep sounds like a very typical case, assuming this only started a week or so ago just when the weather started to turn colder.

[goose710]

thanks everyone il check the water in carbs it has been doing this since before xmas?

[Gnasher]

thanks everyone il check the water in carbs it has been doing this since before xmas?

 Mate it's got NOTHING to do with water in the carbs that will give you other problems.  Icing is the freezing of water particles suspended in the air as they are draw through the emulsion tubes which then blocks them causing cutting out, once defrosted all's well and the bike runs fine.   Yamaha use a water heater system, these are the small black tubes you see around the float bowls going into small elbows.  These elbows block up and stop the heated water from reaching the carb bodies and allow the ice to form on the emulsion tubes, they can be carefully pulled out and unblocked/cleaned 9 time out of 10 it's the elbows.   It's possible it could be the tubes and/or the water galleries within the carb bodies, all of which can be cleaned but will if bad require the carbs to be removed.  The main causes of this are insufficient anti-freeze mixture, poor quality anti-freeze and/or hard tap water being used instead of de-ionised water.   

[Bracechenko]

Sounds like carb icing to me. I had the same prob on mine so got the carbs out and thankfully saw that it was simply one of the coolant tubes that had been crushed whilst some previous owner had been doing work.

Obviously no elbow cleaning for me