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Sprocket change problems

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I have changed gearing from 12/51 to 13/53 and used a new DID VX2 chain and iron man 13/53 sprockets,I already have a tm design works rear chain guide,the problem I have is chain slack is set at 55mm which is right in the middle of specs but the chain can be pulled off the back of the sprocket,pretty much can see 3/4 of the sprocket teeth,it is very loose all round the rear sprocket.At first I thought maybe there is too many chain links but surely removing links will just tighten the chain and end up with no slack at all?

 

Photos to follow...

Edited by ozglenn

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Tighten it. I've always run mine with about 30mm or two fingers of slack. Never an issue. I can just barely move the chain away from the rear sprocket.

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At the moment I can fit two fingers snuggly between the chain and swingarm where you are normally meant to measure slack,ill tighten slack to 30mm instead of the 55mm and see what happens

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I rechecked  the slack and it was more like 2  1/2 fingers so tightened it to 40mm which for me is two fingers barely under the chain,took it for a test ride and it makes a really loud whurring noise from the front sprocket area,also when on the stand pushing the rear wheel I can feel resistance of the chain not wanting to go through the chain guide,it doesn't roll through smoothly and it kinks a little at the top of the sprocket,I thought 53 rears will fit without having these problems?

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I just put the chain back to 55mm slack and it now rolls through the guide nicely,it still makes the whirring noise,I have never run the chain tighter than 50 before so im not sure if that's just what you have to put up with when running a tight chain? it just doesn't feel right when you push it through the guide any tighter than 50mm,I am stumped as to what to try now,the rear sprocket is $150 so don't really want to have to end up changing the rear sprocket down to smaller,from the road test I did the 13/53 feels right where I want it so want to make this work first

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G'day mate. Reading this post with interest and was wondering why you changed from 12/51? My KLX is running stock 13/50 and I find this ok in the open but a little high geared for the tight single trail stuff. I was considering going to 12/51 but maybe I should consider other options?

 

I have done about 1300 km and the stock front sprocket is noticeably worn. The rear is also starting to chop out. The stock chain was a DID x-ring and it stretched a lot when new, but settled down after about 10 hours. I find it slaps unless I run it fairly tight. I expect that running it a bit tighter contributed to the premature wear. I'm hoping to fit the TM Designworks Baja kit with the new chain and sprocket combo, perhaps this might help to ease the slapping also.

 

The rear sprocket I was considering is a DRC Dura - see http://www.ebay.com.au/itm/310625630075?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648.

Wondered if anyone else has tried these? They're cheaper than Ironman but perhaps not made of chromoly. Got to be better than an alloy, from the wear perspective?

 

Any advice greatly appreciated.

 

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I love the 12/51 gearing as it's mostly suitable for the riding I do and I'm not worried about a lack of top speed as I don't like riding fast anyway,the 12/51 is light years ahead of the stock gearing but I went to 13/53 as the 12t front wears too quick for my liking,I had a primary drive steel sprocket on the rear and it was hardly worn but the chain and front 12t were toast.

 

I was under the impression that to get likewise performance of the 12t by using a 13t then I would need to go to a 54 on the rear which I believe is too big so went with 53 so it will be close but still alot better than stock gearing,I did a quick road test and 13/53 feels great.Havn't trail ridden it to see if it works or it's longeviety

Edited by ozglenn

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No worries, thanks. I might give 12/51 a go, but buy an extra spare 12 to swap out. See how it wears. Going to try a DID520VX-2 gold x-ring chain too, see how that lasts.

Considering its weight, and hauling my fat arse, it fairly flies along now with the stock gearing, so I reckon the KLX would tractor up anything at 12/51.

Mine is a 2011, I've got a Yoshimura full system, the JD jetting kit, R&D fuel screw, took the airbox snorkel off. The motor was good before, but with these mods it is really strong. Given the power of this KLX, I can't imagine how a works KX450 would perform, probably launch me into orbit!

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By the way, I saw on another post that a guy attributes this whirring sound to the TM Designworks plastic being harder than stock. He actually used the exact word you did 'whirring', so maybe there's something in that. But if you have already been running the TM guide, perhaps you would have heard it before? Otherwise it could just be the chain wearing in a new place with the slightly larger 53 on the back.

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The noise wasn't there before and have had the tm guide for ages now,the noise is more towards the front but can be hard to tell when riding and with helmet on,will just put it down to as you say a larger sprocket and new chain,I bought the black version of the vx2 chain,had a vt2 before that but found it stretched too much too quickly,the vx2 has nearly identical specs with same width and I believe the vx2 has a slightly higher tensile strength,if this one stretches I just won't buy DID again.

 

What State are you in Nugget?

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If you can pull the chain 3/4 of the way off the sprocket, then either the chain is worn out or the sprocket has been cut wrong.   Chain tension will not affect this; always set the chain slack to that which is recommended in your manual....and use the same method as in the manual!   Never tighten a chain beyond the factory specs.

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If you can pull the chain 3/4 of the way off the sprocket, then either the chain is worn out or the sprocket has been cut wrong.   Chain tension will not affect this; always set the chain slack to that which is recommended in your manual....and use the same method as in the manual!   Never tighten a chain beyond the factory specs.

Chain and sprockets are brand new,sprockets are both iron man so quality shouldn't be an issue I would have thought?

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I don't know who actually manufacturers the sprockets for DirtTricks, maybe DirtTricks does.  I can't find any information on their machining capability.  Chances are they subcontract the manufacturing to a local, or even Chinese, source. My point is, all the machined components in our world do not have the same quality. 

  You might find someone who has a new JT or Sunstar 520 rear sprocket and wrap your chain around it.  If you can't pull the chain off the teeth on the JT/Sunstar, then you know the problem lies with the DirtTricks sprocket.  If you CAN pull the chain off the JT/Sunstar, then you know the chain is bad (either worn or bad quality).  I have great faith in DID products, but you never know.  You said the chain is "new", but what does that mean.....?  Used a little?  Never been used?   The pictures show wear on the sprocket, if the sprocket and chain were replaced at the same time, there will be some chain wear.  If you ran in sandy mud, with a too-tight chain, wear can occur quickly.  I don't know if/how the chain has been used.....just giving you some things to consider.

  One thing I do know: if you can pull the chain off the sprocket like that, then they don't match.  Either the chain is out of spec, the sprocket is out of spec, or both.  There is no other choice.

 

Good luck, and let us know what the outcome is.

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The wear in the pics is just the grease from the chain,chain is brand new out of the box as well as the sprockets,I havn't ridden the bike except for a small test ride around the block after tighteneing the chain,unfortunately the KLX isn't popular over here so I have little chance of finding someone with a 53 rear they can give me to try

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Have you checked the slack in multiple places on the chain for uneven stretch? Even though its new can still be fugged. If you want I can drop off my rear wheel to ya with a stock cog on it on Saturday 1/3/2014 as I got a wedding in noosa(you are up that way aren't you?) to go to if ya want to check.

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Have you checked the slack in multiple places on the chain for uneven stretch? Even though its new can still be fugged. If you want I can drop off my rear wheel to ya with a stock cog on it on Saturday 1/3/2014 as I got a wedding in noosa(you are up that way aren't you?) to go to if ya want to check.

How would you check for slack in different places? If im measuring at the end of the chain slipper as per manual then I always have that reference .what reference do I use to tell if the chain is out of spec elsewhere,or do you mean keep pulling the chain through and measuring different sections of it at the same point at the end of the slipper?

 

I have a 51 rear I can put on to rule out the sprocket as the cause but not willing to take it off and swap yet,getting some other work done on the bike soon so it will get looked at then,will swap back to 12/51 if we can't get this combo to work,thanks for the offer though.

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check as per the manual. rotate wheel 1/8 turn measure again and repeat till you have made it all the way round. There will always be tight spots in the chain. but it should not vary too much. When I do mine I will set to 50mm then turn the wheel and check again sometimes it'll get tighter by up to 5mm sometimes 5mm looser, depends where I start. I also have an old chain need to replace soon I thinks

Edited by pantera66

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