Hi all,

I recently passed my test and bought a CBR600f (1998). Its done 6000m in total since new, so it's not too run down...

Since yesterday, I have noticed a nasty vibration on the bike. First noticed it on the motorway at 60-70 where the vibrations coming up through the handlebars was making my hands hurt. . . Its certainly a new phenomenon, it wasnt happening last week.

I am a total moron when it comes to all things engine related, but Im pretty sure it's not something on the faring. It seems the engine is running noisy and that in turn is causing the vibration.

Any advice on what to look at would be much appreciated.

ta

I may be way off the mark here, but something similar happened to me when i was going up to Squires to meet the nice peeps from here. Turned out it was my cam chain, it needed adjusting. Made a horrible crunching noise then reverberated for the next 200 miles. Just a thought that it may be the same.


Then again..... I am a engineering numpty............ Davo sorted it for me at Squires the man's a god

Oh and welcome btw

Check the simple aka cheap things first. Chain tension and wheel alignment. check the wheels that you havent put them out of balance by possible kerbing it?
Check tyre pressures, and that the handlebar end weights are tight.
See how you get on after this.
Also did you buy the bike from a garage. If so, call them adn ask tehm to look at it. You should have some form of warranty if you have recently purchased it.

Good luck.

also if you can check the front wheel bearings or headstock bearings either of those could cause bad vibes

There are also some very odd things that can cause frightening vibes - I had one getting worse and worse, kept checking things out, everyone kept coming up with theories - turned out to be a split in my exhaust gradually getting worse!

Bit difficult to diagnose a 'noisy engine' but if there's vibration I'd start off by checking the chain and sprockets, wheel bearings and head bearings. Also run a spanner round the engine mounting bolts to make sure they're all there and tight.

Just a thought, as the vibration is coming up through the bars and it only occurs at a certain speed, have you checked to see if it's simply a wheel balance weight come off the front wheel?

The engine noise maybe unrelated and it's just a coincidence that you've noticed it at the same time. That's not to say, of course, that the engine noise doesn't need further investigation.

My thoughts exactly Ex.
I had new tyres fitted to a car and when I went on the motorway the steering wheel was shaking like mad when I got to 70. I took it back to the garage and their apprentice had fitted the weights in the wrong place.

Take it to a tyre fitting place and get them to check it for you or do it yourself.
The way I check it myself is to put a chalk mark on the wheel at about the 6 o'clock position and you spin the wheel by hand.Wait for the wheel to stop spinning and see if the mark is in the same position. If your wheel is balanced it should stop in random positions, if it's not, the chalk mark will end up back at 6 0'clock.

must admit i'd go with wheel balance first.
my cb vibrates like hell but that's because the carbs need balancing.
pop the spark plugs out as well and have a look see if any of them are black n sooty.
If i plug fails the bike will only run on 3 cylinders it'll feel rough and lumpy but will also vibe like hell at speed.

Thanks for the suggestions everyone,

I am pretty sure the vibrations are coming directly from the engine. If I'm at a standstill and rev up to 4-5000 i get the problem then.

The suggestion to look at the plugs is a good one, Ill try that first I think. Any other suggestions are welcome

Bad engine vibes could also be caused by your carbs being out of balance, it is often good practice to re balance them every few thousand miles, unless you have a CB900 then you best look at them after every trip

oh yeah, but hell, where can you get a big bad vibrating thing between your legs everday? and for free!!!