Honda XR125 - Noise when Accelerating

[beatts]

Hi

I have just bought a Honda XR125 L4 (54 plate) with 1200 miles on the clock.

I have a full license and have had big bikes but wanted a cheap reliable commuter.

The problem i have is when the bike is stationary and on tickover everything sounds fine, up the engine revs (still stationary) still sounds fine, but when I am on the bike accelerating it sounds like the bike is knocking or vibrating and very hard to pinpoint where it is coming from.

I stripped the bike down when I got it, to lube everything and check bolts for tightness etc and all seemed ok, the exhaust is the standard exhaust and is also nice and tight.

If I am riding with constant revs everything sounds ok, but when I whack the revs on (as much as poss on a 125!!) the noise returns.

There is no excess smoke, I changed the oil whcih wasn't too dirty, chain tension is ok (25mm ish) so I cant think what it might be.

The bike is very low mileage so you would hope nothing serious would be wrong with it this early on (he says doubtfully!), and the performance of the bike is exactly as I would expect - no probs at all.

any ideas anybody
It may be that this is normal for 125's but

[jackw72]

I have the same bike, (for sale actually), if you could record the noise we could be a bit more helpful perhaps.


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08/11/2007 A2 Passed.
Suzuki GSXR 1000 K3
Rapid Training passed

[beatts]

unfortunately it would be very tricky due to the noise only being there only during acceleration and not with the bike on the stand.

Wind noise etc would make it pretty much undetectable if recording on the move

[jackw72]

How would you describe the noise?

Where are you based also, because someone near you might be able to help.


____________________
08/11/2007 A2 Passed.
Suzuki GSXR 1000 K3
Rapid Training passed

[beatts]

I would describe it as something vibrating on the frame. It doesnt sound engine related but more as if something is knocking against the bikes frame at a fairly high rate and only when either accelerating or maintaining a fairly high rev rate

I though it was the mudguard but this seems secure.

I'm based up in Teesside

[MarkJ]

25mm chain slack seems a little high to me, would it be possible to try closer to 40mm? Are there any wires with clips to the frame that have come loose from the frame?

[beatts]

I dont understand, you say 25mm is too high and recommend 40mm or am I getting mixed up?

Wires all look ok, I think it is something bigger than a wire, feels heavier than that.

Do you have a recording of your bike on the move to compare to mine?

[MarkJ]

I have a Hornet 600, vid here --> https://www.youtube.com/watch?v=H0KhA0kbWJ8 although my 4 cylinder 600 will sound different to your single cylinder 125.

My recommended chain tension is 30-40mm, which is why I said 25mm seems to tight, although different bikes probably have different recommended chain tensions

[eddclarke]

Hey
Im from Tees-side too, guisborough to be precise. Have you checked the Heat shield on the exhaust pipe, mine used to rattle when i had my XR125
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Honda XR125L 06 ----> Yamaha FZ6 05 + ex SAS XR250 --> VFR800 + XR250r

[beatts]

I am used to big bikes too, they sound much nicer, but I dont think this 125 sounds right.

I think I will get it look at by a pro to put my mind at ease.

The bike has a low mileage and it is in good nick but the chain was pretty rusty when I got it (it cleaned up ok tho) maybe this is the problem??


thanks

[MarkJ]

Could be, does it have any stiff links?

[eddclarke]

[beatts]

I haven't taken the chain off to check for tight links but had a good feel about in situ and as much as I could feel it felt ok. I know ideally the chain needs to be off, but as JackW72 says I doubt the chain is causing this noise.

I just noticed your thread eddclarke sorry, heat shield. eh? I thought it could have somethig to do with the exhasut tbg but everything feels tight. did yours rattle even thought it was nipped up?

[beatts]

sorry as Eddclarke suggested not likely to be chain, I should read my posts before submitting them!!

[Noxious89123]

I have a similar problem with my CBR. My chain is pretty much knackered, alot of the links have become extremely stiff and a few have seized completely.

When the chain goes over the front sprocket, it shapes itself to the front sprocket, but as it comes off, it wants to stay in a curved shape instead of straightening out. This causes the chain under the chain under the swing arm to bounce up and down.

Does your bike only do i at high RPM or high speed? Try it at a few different speeds then close the throttle and pull the clutch in and listen.

I get a kinda thumping sound, and the chain bounces back and forth against the rubber chain gaurd on the front of the swingarm.

It's not noticable when going really slow (under 10mph), and neither above about 35mph.
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[beatts]

Hi Noxious thanks for the advice,

it only makes the noise as you said at higher revs and but from 0 upto whatever the max speed is on a 125 (60 ish) so I would suggest it is more of an acceleration thing.

You could have a point about the stiff links though. I would need to take the chain off to have a proper look

[Noxious89123]

[eddclarke]

[iooi]

What are the wheel and sprocket carrier bearings like ?
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Just because my bike was A DIVVY, does not mean i am......

[Shay HTFC]

Does the noise come if you rev the machine in neutral with it on the stand?
Also, when you say it is affected by acceleration, does the noise stop when you change up gear and go back to lower revs?

It sounds like it could be your chain. If the noise gets worse simply as your speed goes up regardless of your revs as well as not occurring whilst revving in neutral then I would assume that your chain is clinking on the sprockets or whatnot and gets 'worse' as the speed increases (bad spot contacts with sprocket more often as back wheel spins faster)
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Full Motorbike License - GS500E '95

[beatts]

thanks for the advice so far to everyone.

Shay HTFC, the noise is not there at all when the bike is revving in neutral, no matter how hard I rev it.

When on the bike and taking it very slow through the gears the nise isn't too bad, if I start changing up at the higher end of the revs and accelerating as hard as one would normally on a bike (without taking the mick obviously) then the sound is at its worse.

So it seems the more load the bike is under the worse the noise.

[beatts]

thanks for the advice so far to everyone.

Shay HTFC, the noise is not there at all when the bike is revving in neutral, no matter how hard I rev it.

When on the bike and taking it very slow through the gears the noise isn't too bad, if I start changing up at the higher end of the revs and accelerating as hard as one would normally on a bike (without taking the mick obviously) then the sound is at its worse.

So it seems the more load the bike is under the worse the noise.

[MarkJ]

As iooi said, have a look at the rear wheel and sprocket carrier bearings.

Does the bike feel different when this sound is happening? Unstable?

[beatts]

no bike handles fine, how would I check these bearings?


the rear sprocket looks ok, i.e. the teeth are shaped as they should be with a flat at the top of each tooth and not ground to a point.

The bike has only done 1200 miles, could the chain / sprockets be knackered after such a short time? I know it depends on how its looked after and to be honest the chain was rusty but like I said the sprocket looks alright in my opinion.

I turned the wheel by hand and couldnt hear any grinding from the wheel bearings, the wheel turned freely.

Like I said it is more like a vibration than anything else, or something knocking at speed so it feels like a vibration.

[iooi]

If you can rock the wheel when its off the ground from side to side then you have bearing issues. Sprocket carrier you need to take wheel off and give it a good pull with your fingers. But to be honest if its only done the milage you say, they should be OK.
I would say that the chain need a real good lube up.
Maybe take it right off, clean it up and then give it a good soak with oil and hang for a while to let excess drip off.
Even better, but not sure if you can still get. Is the tins of chain greese that you put on a stove (camping one outside is best..) to melt. Once melted put chain in leave for a while then lift out. The grease gets inside all the joints, but because it then sets when cold does not get flung off everywhere.
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Just because my bike was A DIVVY, does not mean i am......