help - Yamaha FZS 600 Fazer 1999 engine vibrates/wobbles...

[Martin7R]

Hello everyone around here,
Firstly I want to warmly greet everyone in this forum, I just have registered here.

What brought me here is an issue with my bike.(fzs 600)
Overnight, in the morning on my way to work as usual, I felt the engine started vibrating and produced an unstable wobbling sound and now on the second day, the vibration has been increased significantly and I can also smell of unburnt fuel coming out from exhaust.The wobble is very annoying,feels just like some pistons does not burn fuel(i am not sure, thats why I need help), almost impossible to ride, but I had to get from A to B and I am really worried about the bike.
Just got my licence(18yrs) and restrictors cerificated ( 33 bhp ).

PS.It vibrates when I accelerate or hold the throttle.No vibration when loosen the throttle.

+Chain and sprockets are in a very good condition
...

Any possible ideas, what causes the bike to vibrate?Any help would be highly appreciated.

Martin7R.

[Fizzer Thou]

I would start by checking that all of the engine mount bolts are secured and in place.If anything work your way around them with a spanner/socket/torque wrench,especially the lower ones.

If you have not had the bike for very long and you bought it from a bike shop,tell them your predicament and ask them what they will do to help you get it sorted.
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Just talk bikes.What else is there?

Always have a 'Plan B'

[Martin7R]

[janner_10]

you should try asking over at the Fazers owners club forums, just google it. Have helped me in a pickle before.
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Yamaha FZS600 (Now gone to heaven) > CBR600F4i (SOLD) > '99 YZF-R1

[Fizzer Thou]

I will not start by suggesting that it sounds like the crankshaft bearings are gone until you have done a compression check.If they are low then it could point to the head gasket has gone causing the engine to run so badly that fuel is not being burnt correctly.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[Vincent]

Is it firing on all cylinders? If unsure, check to see that all the exhaust downpipes are hot, preferably without burning yourself.
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Space Is Deep

[herulach]

[moonzoomer]

as above, it sounds like the bike is off 1 or 2 cylinders either down to fuelling or lack of sparks. also check that you front sprocket retaining nut and washer has been upgraded as this was a big problem with the Thundercat engined models . The Yamaha part number for the deeper upgraded nut and washer is 90891-10124, it is important to have this checked as the original shallow nut can work loose destroying the output shaft which means a complete engine strip to repair.

[Martin7R]

I just have checked the downpipe mufflers, all of them was warm.
While riding, It vibrates only when I am twisting only a little bit throttle arounf 2000-3100 rpm, when I twist it more then it starts to work properly and vibrate is gone, so I am sure there is getting too much fuel mixture into engine , that when I am starting it, I smell of unburnt fuel even when I am sitting on my bike( all fuel pipes are OK).
And even more, with cold start, it starts easily, because it wants more rich fuel mixture when cold.But when I try to start the engine after riding, it doesnt want to start at all, only starts in 3-4 seconds when I fully twist the throttle.