Front sprocket knocking/scraping sound

[Pete]

Hi all. My Blackbird has developed a worrying knocking/scraping noise coming from the front sprocket area. Doesn't go away when I pull the clutch in so don't think it's basket rattle. Took a video of it which is currently busy uploading to YouTube. The chain is a good tension, if anything slightly loose. Happens most noticeably when pulling away and at slow speeds. Sounds almost like the chain is flopping around, like when you run the bike in 1st gear on the centre stand.

I'm going to try and get the sprocket cover off to investigate and tighten the sprocket down if needs be. Only problem is I may need to remove the lower fairing, and I've got a stuck fairing bolt and have just moved house so most of my tools are at my parents over 100 miles away! C'est la vie, as the Germans say. Anyway, any other thoughts on what it could be if the sprocket being loose isn't the case?

Cheers

[Tango]

Worn chain rubbing strips on the swingarm?.....

[littlecat]

had similar on the cbr when i bought it...not sure what the actual cause was, but was changing the chain and sprockets anyway ( as one does on a new to you 2nd hand bike ) and not had a problem since

[Pete]

It's a thought about the swingarm, but it seems to be coming from the front sprocket rather than further back. I managed to get the sprocket cover off, and it's definitely tight enough! Absolutely no movement from it at all, and the teeth aren't pointed or hooked.

Could an out of alignment rear wheel cause it to knock? While I was checking the sprocket tightness I gave it another few slow spin and noticed that each time there's a "knock" the chain jumps ever such a little bit. Almost like there's tension building up and then it clicks back again. If it is alignment it's strange that it's happened recently.

Bit more info on the chain by the way, I bought the bike about 25,000 miles ago and it's on the same chain and sprockets. They were brand new when I bought the bike (or that's what the fella said, and they looked it) so that's 25,000 miles on the current set. I've kept it clean enough and lubed nice with a Kettenmax. Any thoughts on when I should change the set? Seems to be a bit of stretch left in it, and I don't want to go spending £100-130 quid on a new chain and sprocket set if I don't have to obviously.

Failing all other ideas I know the rear tyre probably only has another 1000 miles left on it, I could just ask whoever changes it next to take a look at the knock and check wheel alignment etc, but I'd rather sort it myself.

Just spotted the new post about the CBR having a similar issue - cheers, looks like I'm heading for a new chain and sprocket set anyway.

[littlecat]

sounds like a tight spot... possibly... get it up on a stand , and check the tension at lots of different points around the chain while turning the wheel...if that makes any sense

[Pete]

Sadly I don't think it's a tight spot it happens all the way round consistently when turning the wheel and the chain itself is actually quite loose

[megawatt]

Sounds like the front sprocket could be "hooked" , so worn that it looks like a buzz saw blade. Replace both sprockets and chain. I recommend DID X ring Gold chain, renthal front and an aluminium rear. Think about a chain of sprocket sizes as well.

[cockercas]

Have you washed/cleaned the chain/spocket? I did with mine about a hour ago. Checked everything. Couldnt figure it out so i took it for a hard ride. Got home and it had gone.

[Pete]

Nearly got it today! But not quite

Thought I'd have a go at giving it a proper deep clean and copious amounts of lube. In the past (last 3 years or so) I've used a Kettenmax chain cleaner, paraffin as cleaner and Elf chain lube that I got in France a couple of years ago. So today I bought some Muc-off chain cleaner, must have sprayed half the can out! Rinsed it, dried it, then put some Muc-off dry PTFE chain lube on. Took it for a mixed ride, some town riding to check pulling away, and a motorway blast for 5 miles to get some heat into it. All was going very well, thought I'd cracked it (and felt silly that it was just the chain lube)...

Got back to the house, knocking/scraping had returned, but a lot quieter than before. Got it up on the center stand and gave the wheel a twirl, same knock. Applied some more lube while the chain was hot anyway.

I checked every single link for stiff links and they all feel the same to me. Movement in all of them, not easy to move but not stuck. Checked tension again whilst sat on the bike and off centre stand and there's plenty of slack. I'm baffled.

Only things I can think is either some links are stiff and I just didn't spot them (meant to feel really bendy with ease or some resistance? I dunno!), or something to do with the sprocket carrier that goes into the engine. But the sound stays even when I pull the clutch in so surely it must be chain/sprocket related? I dunno. Seems to get worse the more the bike is ridden. Heat maybe?

Thanks for your thoughts folks, much appreciated.

[megawatt]

Have you looked at the front sprocket yet?

[Mr Fro]

Don't know if this is any good but I had a mystery lightish clonking/rattling noise when I spun the back wheel round when on the stand - sounded like it was coming from the front sprocket.

I checked the tension and all was good. The chain was a bit stretched and the rear sprocket was a bit worn so I replaced the lot.

In the end it turned out to be the rear wheel alignment, it was everso slightly out as it was running a narrower chain than OEM.

A quarter turn on one of the adjusters was all it took to sort it out.

[Pete]

Cheers Fro, could well be alignment. Looks OK by eye but I'll tweak it a quarter turn each way and see what happens.

Will update with pics once uploaded somewhere! Had a look at the front sprocket, megawatt, all looks fine to me and it's tight on!

[Grumpy Old Git]

Checked tension again whilst sat on the bike and off centre stand and there's plenty of slack.

 

Are you sure it is not too slack?

[Pete]

I don't think so. When I rotate the rear wheel it makes a "click click click" noise like when the chain is too tight, but it's not. I think I'll loosen the back wheel off and move it forward a bit and THEN check for play in the front sprocket. I guess with the chain tensioned up it won't move at all...

[fq-craigus]

When I bought my bike I had a scraping noise coming from front sprocket, took the cover off and there was so much congieled oil grease mud and crap along with a stone that got caught behind the sprocket.......... Just saying, pull the case off and sprocket clean deep and maybe you will find something or maybe you won't but worth a check

[Pete]

Hey folks! Got an update. Thought I'd fixed the problem, but haven't.

I've checked behind the front sprocket cover, really clean actually from when I cleaned it about a year ago.

I bought a chain alignment tool, which I actually HIGHLY recommend. Only £12.71 from Amazon and quickly showed me my chain was off quite a lot! [http://www.amazon.co.uk/Laser-5051-Motorcycle-Chain-Alignment/dp/B004499M20]Here's the link[/http://www.amazon.co.uk/Laser-5051-Motorcycle-Chain-Alignment/dp/B004499M20]

So I thought that'd had done it. Re-aligned chain, checked tension, all good. Again the chain is probably slightly on the loose side just to be sure it's not too tight. Took it for a 15 mile ride, down some lanes first to get some heat into the bike then some stop start traffic. All good until after about 10 miles at slow speed the noise returned. Not as loud as before, but the first time was after a 100 mile blast up the motorway!

First thing I did when I got back to my garage was put it on the stand and take these two videos:

http://youtu.be/ruHRwkXoZJk?list=UU8TWv ... dbFfV7pw5g

https://www.youtube.com/watch?v=tXtUOCf ... dbFfV7pw5g

The second one shows the chain jumping a little bit as it clicks. Any ideas? I'm stumped. Got some pics of the rear sprocket that I'll upload later for your inspection...

[fq-craigus]

Might seem random question but is it the right chain for the sprockets? Did you get it as a set or match yourself

[Tango]

I'd just replace the chain and sprocket set mate......just to be sure......

[Stu]

the chain looks to be really good Bob!!

how is the tension with the weight on the wheels?

[Pete]

So the the current chain and sprocket set have been on for around about 20,000 miles at least. They were on when I bought the bike 20,000 miles ago and looked brand new then. The bike's got a Scottoiler on, but I detached it about 15,000 miles ago as it stopped working on anything but the "prime" setting which essentially pisses lube out at a fast rate!

To my eye the chain does look good. The front sprocket looks fine too, but don't know about the back. The sound seems like it's coming from the front sprocket area, and as I say when I pull the clutch in the sound doesn't change or go away so makes me think it's chain/sprocket related.

Here's the pic of the rear sprocket as promised. The width of the toothed area hasn't changed at all, but what do you think to the teeth? This is the most suspect looking area to me, but I've never changed a set before so don't really know what's acceptable. Are chain and sprocket sets something most garages carry or will they have to order in? If I have to wait I might as well buy the breaker/riveter and do it myself...

http://i976.photobucket.com/albums/ae248/peteblakemore/chain.jpg

I'm looking at buying this chain and sprocket set if it needs doing. Any thoughts?

http://www.demon-tweeks.co.uk/motorcycl ... heavy-duty

[Tango]

That sprocket looks fooked to me....

Even if the chain looks good externally, the grease inside the O/ X- rings may have gone.....so it will be a bit graunchy.....

Stick with my earlier comment about a new chain and sprocket set......20,000 +miles on a bird ain't bad.....about time that set was put out to pasture.....

[Pete]

Cheers fella, good to have the confirmation of what I think I was thinking anyway! Any thoughts on the set I posted. Not sure what sprocket set that comes with. I'm sure I read it on there before but can't seem to find it again. I'm not looking for a smaller front/bigger back, just standard set.

[fq-craigus]

By the looks of it that rear sprocket is nakard, and if the front has been on same time it would be worse than that as the front takes all the brunt. 20k is good for a set but I say your due for a new one.

[fq-craigus]

Oops tango beat me to it lol

[Tango]

Yeah.....that DID set looks ok.....not a bad price either..... Sprockets will be standard unless they specifically state a difference.....but you can check with them first, before you order.....