strange engine buzzing

[tatters]

having some troble with my kawaskai KR1-S, when l ride or rev the bike l,m getting a buzzing/humming sound (sounds just like the creature in "The Grudge") coming from the gearbox/clutch. but if l hold the clutch in and let the bike tick over there is no nosie. it suddenly appered today and is having no effect on performace or on the gears and is not the power valves or oil pump as they are working fine, the bike was re-built 2,000 miles ago.



any ideas are well welcome.
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[mchaggis]

It could be a bearing in the gearbox. As it only occurs when the clutch is engaged, it pretty much means it has to be the gearbox, and other than poorly meshing teeth (quite unlikely without having broken teeth or shafts out of alignment), worn bearings sound like the primary culprit to me. Of course, a damaged bearing could let the shafts get out of position and cause the gears to rattle.

Just a few ideas really, I've not had to deal with exactly that kind of problem before.
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I must not be a troll...
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Discovering the delights of Hammerite and a 3/4" brush.

[Robby]

I'd go with bearing wear too. Drain the gearbox oil, and run the old stuff through some old tights to see if theres any significant metal in it.

[tatters]

gearbox bearings would mean striping the bottom end down? (did a top end re-build back in august), the bike has only done a total of 12,000 miles, l,ll have a look at the oil in the morring.
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[Kickstart]

Hi

How much play is there in the clutch cable? There is a thrust bearing behind the clutch which if continually loaded (from an overtight clutch cable, for example) will fail.

Gearbox is still likely but just trying to think of something cheaper and less depressing for you . I had this with the Divvy. Bearing was ~£5. Gearchange became very nasty, and if you had it on the centre stand with the engine running and in gear, then pulled the clutch the back wheel stopped almost immediatly. This is what it looked like.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[K!K @]

Cluch Rods.
My mate had exactly the same thing.
Hope you get it going
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Suzuki AY50 Katana
~Elite~Knights~

[DM]

Might just be something loose that's vibrating when you're running in gear. I've sworn I've heard noises coming from my engine before that later turned out to be my gas tank touching the frame when a rubber spacer fell out. Just something to check .

[Aikman666]

Im only 15 and own an old 2 stroke Bantam, so im hoping if im wrong the other folks will correct me. But there should be a big what looks like a bolt head on the underside of your engine at the gearbox, if you remove that the oil should simply drain out of the hole. There should also be the same type of bolt at the top of the gearbox where you should re-fill it. As i said im pretty inexperienced, and either one of the veterans should correct me, or i would refer to the good ol' Haynes Manual
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Will work for petrol
My Design Blog

[stinkwheel]

I don't know about your bike, but a lot of smaller hondas get rattly clutches when a bearing between the clutch basket and gearbox shaft starts to go. This shows the same symptom of going away when the clutch is pulled in and is easily replaced.

Here's hoping yours is similar.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[tatters]

well l,ll got the oil out and drain it through some tights, but found no bits of metal. re-filled the gearbox back up with fresh oil and took it for a ride, nosie was still there but now is much quiter. so next week l,m going to strip the clutch.

l just don,t under stand how the gearbox bearings can go on a well looked after bike with only 12,000 miles on the clocks.
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[Kickstart]

Hi

Depends how it has been treated. Water in the gearbox for a while might result in some pitting of a bearing, greatly accelerating wear.

Also the bearing myself and Stinky have suggested can fail quite easily from clutch abuse or just an overtight clutch cable.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Fortuna]

My impellor went on mine which caused a noise but wasn't a buzz. The only time mine did is when I hadn't tightened a bolt up and as the revs rose it vibrated the connection making a sort of buzzing. KR-1 is a very tempremental bike so I would also say clutch or gearbox.

[kasandrich]

[tatters]

good news, took the KR1-S for a spin today noise was still there but l noticed the bike was getting much hotter than ushall (temp needle was 3/4 over). got it home took the side panel off and there was barely any coolant in the res bottle. fill it up and the noise has disapeared what l reckon has happened is that because there was so little water in the system the pumps bearing/propela were,nt getting another water so were making the noise.



cheers for the help and suggestions guys
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV