Resonance / Vibration issue... please help!

[graingerblaze]

I have used the search function but cannot find my issue directly. I have read various reasons for resonance / vibrations to occur, from engine bars, clutch basket, throttle setup, loose bolts etc. I'm at a loss and getting frustrated with a bike which was once lovely and now numbs my feet and hands after 20 minutes  .

I first thought it was the Givi engine bars, and spent a week playing with installation procedures, bolt torques, rubber washers etc. I removed the bars, went for a ride and it made almost no difference! So I have fitted the bars back as I don’t think they are the cause, more of a symptom of something else.

I gave the bike a full service, so all fluids and filters changed, new spark plugs, new radiator and fuel lines. At idle the bike runs as smooth as silk, revs happy and is lovely up to about 60mph (4,000 rpm) as it was beforehand. So I don’t think the issue is with the throttle or engine running, it’s too smooth for that I think.

I did find one of my exhaust bolts had rattled loose, the one closest to the brake lights. So I replaced it and the second one down with new stainless bolts and nylocks, now secure.

The chain has +/- 20 mm slack as suggested in the manual, I haven’t actually adjusted it in the past 3,000 miles as it hasn’t stretched at all (but I do check it every week). It is an old chain but I doubt it’s the problem as when the bike is badly vibrating at 75mph + and I pull in the clutch, the bike rolls very smoothly. So I don’t believe the problem is the drive or tyres, but something to do with the engine mounting and resonating at 4-5k rpm.

Please if anyone has any ideas I can try out I would be most grateful. The bike was lovely when I got her back in March, I have since covered over 4,000 miles but for the past 2 weeks have been pulling my hair out (what’s left) to stop the vibes.

Thank you. 

[Fat Rat]

The 650 isn't prone to the same Clutch chudder as the 1000, if you have ruled out the Engine Bars, could it be tyre or wheel bearing related?

Edit, I see you have ruled out the drive and tyres.

[graingerblaze]

It could possibly be wheel bearings as they are almost the only thing I haven't replaced yet... but when at speed and I pull the clutch in the bike vibes stop and everything rolls smoothly. So I think the tyres, bearings and chain are all fine, I could be wrong though...

[kwackboy]

Hello , I think you have just answered your question. If you pull the clutch in,  let it roll and vibe stops then it's sounds like it's the clutch .

[graingerblaze]

Quote removed

Thank you.

You may be on to something there... although I thought it was the 1000 that has the issue with the clutch basket not the 650? Also I probably read it wrong but if the clutch was causing issues, would that not be noticeable at idle or any speed for that matter? I only get vibes at 60mph and above, up to that speed the bike is lovely and smooth but I need to be able to ride in comfort on motorways too.

[graingerblaze]

I just popped out to test the clutch. With the bike on the centre stand, there is no slippage on the clutch and all sounds good wither at idle or at speed. If it was the clutch basket, what tale-tale signs should I be looking out for please?

I'm trying to rule out as many parts as possible, getting there but your thoughts are all very helpful. 

[Fat Rat]

Have a look on Sharealike's site  www.vibefreev.com it will show how the basket starts to move around due to wear. It is the 1000 that is prone but that doesn't rule out a 650 Clutch having issues.

Contact John (Sharealike), he is a knowledgeable and helpful fella. 

[graingerblaze]

Thank you Fat Rat, very kind 

[Gassoon]

The logic of it being the clutch is undeniable, but being a skinflint and generally sceptical sod, I would check the engine and rear sprockets first, and all other bearings to boot!

How many miles has your K5 done ?

[graingerblaze]

I bought her back in April, the previous owner bought her new (2004, 54 plate). He barely used her over the past 5 years other than take her for her yearly MOT and service at his local Suzuki dealer, hence why I couldn't resist it!

So back in late April it had only done 8.5k, she has now covered 11.5k hence why I gave her a big service as I cover 2.5k a month. I have looked at videos on DL/SV clutch chuddar and mine is silent, no noise how ever high I rev the engine.

that's my problem, the engine is silky smooth and sits quietly at idle. The vibes are coming from somewhere and so must be the engine or the mounting of it...mmmmm

[kwackboy]

To rule out the clutch ride along at its worst point pull the clutch in and while rolling bring revs back to the same point (keeping the clutch in) as if you were in gear. If the vibes reappear then it's something else . 

[hotbulb]

Puzzling, eh?
If the chain has a tight spot or two, I suppose it could run rougher under load .... have you tried running it with the chain adjusted to the "slack" end of the acceptable range  (30mm)? (And is the alignment spot-on? )

[graingerblaze]

Some good ideas, thank you. I have a 60 mile ride home so will try the clutch both in/out and at different rev's on the motorway, see how that feels.

The tight spots on the chain is a possibility, it's one of the few things I have yet to replace. There is little wear on the sprockets but I suspect the chain is original, although well maintained probably needs replacing. I will have another go at adjusting it and see if it makes any changes  .

[kwackboy]

If it was the chain you'd feel the vibes when free rolling

[hotbulb]

I'd have thought any roughness would be more apparent when the chain was under tension... I.e. when being driven.

[Gassoon]

Aye, the clutch effectively links the engine to the drive which is why I suggested checking the sprocket security/fasteners etc...Just nip out now grainger and check - it's driving me mad!

[doboy]

have you had your throttle bodies balanced ?...I had a super tenere that was smooth as silk ..then it started to vibrate tried everything ..then had throttle bodies done ..vibration gone ..

[graingerblaze]

After a late night I think I might be getting somewhere. I degreased the chain and cleaned it back to like new condition, then I adjusted it to have 30mm of slack to limit the effects of any tight spots. I need to replace the chain and sprockets, they look fine but are old and the little 0'ring seals in the links don't last forever.

I then re-adjusted the clutch lever and linkage, cleaned and re-assembled. My ride in to work this morning was much better, there is still vibes between 70-80 mph but no numb hands or feet. I suspect when I next service the bike I will adjust the throttle bodies, they are the route cause I think.

If when I'm free wheeling at 60-70 mph I rev the engine, I can feel the vibes at around 5000 rpm. So I can rule out the clutch (I hope), and aim to rebalance the throttle but for now it's sooooo much better.

 

[graingerblaze]

Update...

I have replaced the chain and sprockets and now the bike is vibe free! I didn't touch the throttle or clutch, the vibes were just an old chain with tight spots that when under load ran lumpy.

Thank you eveyone for your help