carb balancing

[Guest]

Hi I have been told that the vibration in my GSXf is being cased by the carbs being out of balance , The vibration starts at 80 mph (the fastest I have been as when it starts I shut off the accelerator) and has nothing to do with the revs being at any certain amount. I have also been told this will cost £150 to get sorted. Could the vibratiion be caused by anything else? as I ain't got the cash at the moment.

[Stu]

£150 for a carb balance

£30 from all the local dealers round here

i do mine myself they are easy

how bad is this vibration ?

does it only do it at 80mph or at a certain amount of revs ? try 80mph in different gears

[Guest]

I thought it was a lot but the £150 comes from having to take the fairing off (yeah really) he then went on to say it would include a full service would normally cost £120 so I suppose the carb balance would cost £30 if I had the service. But it will still cost £150 for the carbs on there own

The vibration seems bad to me and is enough for me to slow the bike down. it actually feels like it could be the fairing but that could be me and wishful thinking as I have spotted a bolt missing off the front of the fairing. I have had the bike redlining, so I don't think it can be the revs. I will take the bike for a blast tomorrow and see if I can get it over 80mph in different gears. I think I should be able to do this as it's a 600 gsxf (1991). So I'll post again tomorrow

[Stu]

if its at certain revs it could be carbs out of balance but the vibrations wont be that bad

but carbs out of balance effect the slow running of the bike more then anything else

i dont think it will be the fairing

but could be a wheel bearing thats on its way out or even valve clearances

i wouldnt go to the machanic who gave you a quote of £150 for a carb balance sounds like he is trying to screw you out of money

ps pop in newbies and intruduce yourself too

[flipper]

where do you feel the vibration?

through the bars would suggest front wheel balance or bearings. through the footpegs might suggest an engine problem such as main or big end bearings, but as it's speed related it's more likely to be front wheel, as stu said.

find another mechanic is sound advice.

[rollazuki]

What revs is the motor at, when youre doing 80 mph?

Sit on the stand and open her up to the same revs, the vibration wont be there!!!

Itll be a rotating part, ie tyre, wheel out of balance etc, maybe even a chain/sprocket issue. It wont be carb balance, at those revs/speed, the carbs are about 3/4 throttle, youll never notice carb imbalance at that point, as the carbs are well on their way on the vac circuit.

As for 150 quid for a carb balance, its acceptable at a main dealers, after removing bodywork, tank etc, and using 'specialist tools', its not out of this world, but Id bet its nowt to do with the vibration issue.

Spin the tyres on the stand, is there any mishapeness?

Get the wheels balanced, Id expect that to be the issue.

If its some kinda carb based misfire at speed, (which it could be) a carb balance wouldnt cure it anyway.

My thoughts

Rolla.

[Guest nigelf]

the fact it happens at a certain "speed" rather than "RPM" says it all to me.

probably front or rear wheel ballance.

Nigel

[Guest]

Great advice ,I'll go through as many of tese as I can todayand let you know what I've cut out of the mix. Thanks all

[flipper]

maybe the wheel is out of true? flat spotted?

[Guest]

Took the bike out to see when it started to vibrate and from where. Got up to 80 in 4th no vibration, 90 in fifth ..no vibration stayed at 90 in sixth...still no vibration. Inow can't get the bike to vibrate. My propblem now is that the revs seem to have picked up....oh well I bet it'll start vibrating again soon. Thanks all