125 SM Chain too short?

[madmonkey]

Just bought a replacement sprocket set and chain off Biketorqueracing on Ebay.

Front and rear sprocket fit as though the gods at MZ made them themselves but the chain just won't fit. It's 126 links in length and seems to be about 4 links short?

Unfortunately my original chain snapped and was thrown away at the roadside 'cause I had to push it home.

Am I doing something wrong? Or are they sending out the wrong length chains? Should they be 130 links long? Sprockets are standard afaik.

Thanking you in advance.

Des

[OSPRNG]

just referred to my user manual and it lists the standard chain as 126 links.

the rear axle is adjustable in how towards or away from the engine it sits.
this might be a dumb question, but are you sure you didn't set it too far back in the swing arm?

[madmonkey]

Yeah, pushed the rear wheel as far forward as I could.

A photo tells a thousand words. So lets have two of them.





Nuts and plates taken out. She isn't moving any more forward unless I'm missing something?

Cheers for the help OSPRNG.

Edit:

Repair Manual says 132 link chain?



I'm getting proper confused now.

[DAVID THOMPSON]

my rt125 has a sx 52 tooth rear sprocket (16 front)
i just counted there are 128 rollers
and mine has 2 master links so that means the chain was short by 2 rollers at start
next time i do chain i will get the 132 or 134 rollers as 2 master links is asking for trouble
dave
the way i count them is rollers and 1 link has 2 rollers

[OSPRNG]

Repair Manual says 132 link chain?



I'm getting proper confused now.

thats weird. is that from the Service manual?
this is from the Owners Manual (the one that comes with the bikes purchase)

unfortunately there are pretty rampant mistakes and typos in both manulas.
i remember something about the tyre pressure values being way off in the service one as well.

[madmonkey]

It's from a PDF copy of the 125 SX/SM workshop repair manual. (I forget where I found it)

That's a 126 link chain on it in the photo. So I guess that a 130 would bw needed as a minimum, but a 132 would make more sense?

I'm guessing that biketorqueracing are speccing the kits off the owners manual, which may have a typo in it?

Somebody has to be wrong here.

Been lovely weather all weekend too.

[pinhead1990]

i had the same problem ( chain too small ), the rear sprocket they sent out was slightly larger than the original, luckily the next day they sent me a larger chain accidently which fit my bike.

[madmonkey]

Yeah, they seem to be helpfull chaps there.

Apparently according to the fella I talked to said that the Gangsta (The chain is listed under MZ SM 125 Gangsta, so a little confusing) is only a 126 link chain.

Although the Gangsta looks virtually identical.

Getting it replaced anyway so not bad. Just wanted it sorted for weekend though.

[OSPRNG]

glad to see you figured it out.

curious, what is the top speed youve been getting with the larger sprocket?

[DAVID THOMPSON]

my rt 125 is 16x52 and tops at 69mph WFO down hill but 60 to 65 (100kph)is what it does in the real world
measured with my gps and at 20,000 miles
it was 16x49 new
dave

[madmonkey]

Think I've hit 70mph, "doing a 16 year old" and crouching down on a nice long run with the wind behind me.

But I'm a bit of a fatty at 36.

[madmonkey]

And as an addendum. They're really helpfull. Top notch people. Just ask for a 132 link chain.

Sprockets are 100%. And the chain is great too (when it's long enough)

[DAVID THOMPSON]

But I'm a bit of a fatty at 36.

you don't say
try 237 lb and 66 yo in sept any one need an extra 37 lb
thats what i have gained in the last 9 years
dave