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Tight spot - chain


MatBin

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MatBin

Why would I have a tight spot on a virtually new DID chain. Checked the slack yesterday and it varied from 35 to 25mm depending on where along the rotated chain I measured it. Reckon it's done 400 miles since fitting it, this was the first adjustment. I fitted new sprockets as well at the same time. I used a split link to join the ends, so it's not an over done rivet link.

Oh and does it matter?

I suspect it might be a non round sprocket, I haven't measured it (yet).

Edited by MatBin
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Andy m

Are the sprockets also new? 

 

Andy

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Grumpy old man

Have the new Sprockets seated properly?

 

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fj_stuart

I'm sure there can't be anything wrong with the new chain. The change is slack isn't very much. If my trigonometry is right it would only take a run-out of about 1mm in either sprocket to cause this. And a split link? really?

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jeremyr62

I have posted this before.

 

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MatBin
11 hours ago, Andy m said:

Are the sprockets also new? 

 

Andy

Yes, both front and rear.

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MatBin
3 hours ago, fj_stuart said:

I'm sure there can't be anything wrong with the new chain. The change is slack isn't very much. If my trigonometry is right it would only take a run-out of about 1mm in either sprocket to cause this. And a split link? really?

We have had split links for years on bikes with 54 bhp, plus it's DCT so no manic take-off from the lights, I don't ride like that anyway these days.  There are differing opinions on split or rivet links and I am happy to take my chances with a properly fitted spilt link as opposed to a poorly, by me, fitted rivet link. 

10 hours ago, Grumpy old man said:

Have the new Sprockets seated properly?

 

As far as I know, yes.

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Steve Case

You need to put some slack in the chain sounds a bit tight to me.

 

both chains I've had have had slack and tight spots, but it has had no affect that I can determine.

 

Mass produced chains and sprockets, it is what it is.

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Xactly

Adjust it to spec at the right tight spot. Loose is better than tight.

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Steve Case

Yup I'll go with that also.

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MatBin

I will re-adjust to spec at "tight" spot. I might also do a dial check to see if the runout lives on the sprocket.

Edited by MatBin
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Steve Case

Not sure I'd bother, truth be told. Pretty sure it will simply confirm what you've already guessed.

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Grumpy old man
12 hours ago, MatBin said:

I will re-adjust to spec at "tight" spot. I might also do a dial check to see if the runout lives on the sprocket.

I'd find that interesting please report back.

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MatBin

@Grumpy old man I put a magnetic dial gauge mounting block on the underside of the  swing arm and used the outside chain plate, not the rivetted plate, as the datum, the outer underside edge of the 8 as it were. Then rotated the rear wheel. I expected each link to measure the same. I measured at just before where the chain seperated from the spocket.

They didn't, in the worst case(es) the gauge deflected 0.7mm more than the others, there was some consistency over a number of links, then it increased for a few links, then decreased and stayed stable for a few links.

I am assuming all of the links were as near identical as makes no difference but I will remove the chain, the split link being useful for this at least :) then measure other points on the sprocket and/or hub when I get a chance.

 

Before I did this measuring I thoroughly cleaned the chain and the sprocket, so there was no grime to deflect the link.

 

I think I will repeat this and mark chain/sprocket to see if there is consistency in position against readings.

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Steve Case

Hi Matt,

I'm wondering how many DID chains sold online have ever seen a DID factory.

There will be variation, but 0.7mm seems quite large.

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MatBin
10 hours ago, Steve Case said:

Hi Matt,

I'm wondering how many DID chains sold online have ever seen a DID factory.

There will be variation, but 0.7mm seems quite large.

Bought the kit from Wemoto, they have as far as I know a decent reputation?

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Slowboy
33 minutes ago, MatBin said:

Bought the kit from Wemoto, they have as far as I know a decent reputation?


Always been very happy with them myself.👍

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Steve Case

Oh I agree, I use them as well.

 

But even they buy from distribution so its not impossible for fakes to get into the supply chain.

 

Problem would be spotting fakes could be very difficult and it could actually be that DID's QC is at fault here.

 

All I can suggest is if anything appears 'off', the supplier needs to be informed

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  • 1 month later...

Just got my DID VMX3 chain and JT sprockets from Wemoto. Just waiting for my new tyres to arrive, so I’ll fit em at the same time. Hopefully, they’ll be fine. I’ll be disappointed if I find chain tight spots almost immediately. Stand by, I’ll report back soon. 👍

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Slowboy
6 hours ago, RC166 said:

Just got my DID VMX3 chain and JT sprockets from Wemoto. Just waiting for my new tyres to arrive, so I’ll fit em at the same time. Hopefully, they’ll be fine. I’ll be disappointed if I find chain tight spots almost immediately. Stand by, I’ll report back soon. 👍


My new chain (DID) for the Super Cub was fine and buttery smooth. Not bad for £14.99 😂😂😂

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  • 2 weeks later...
SteveThackery

Surely this is a sprocket issue rather than a chain problem?  Have you marked both of them up and measured over several turns to see whether the tight spot is definitely at the same point on the chain, or the same point on the sprocket? 

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MatBin
6 hours ago, SteveThackery said:

Surely this is a sprocket issue rather than a chain problem?  Have you marked both of them up and measured over several turns to see whether the tight spot is definitely at the same point on the chain, or the same point on the sprocket? 

Not yet, no garage and it's too bloody hot on my drive :)

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  • 3 weeks later...

This got me thinking, so after reading this, I ensured I double checked measurements after fitting a new DID VMX3 chain and JT sprockets bought from Wemoto. Using rivet link correctly fitted, no stiff link.

 

Guess what? So Brand new chain and sprockets, not ridden, but about 8mm variation using 35mm as tightest spot. I am surprised, but not concerned. I’ll keep a close eye on it, and if it does wear quickly I’ll be investigating further.

 

How is your chain now Matt, and did you measure several at points when you fitted yours before any riding?

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