Hi everyone. I've just bought a new front sprocket (well 2 actually) and I am having problems fitting it. The old one has a tiny bit of play on the shaft and pulls off and goes on easy, but the new ones seem to have inner teeth that are fractionally wider than the old ones.

This measn that you need to knock it on with a mallet or something similar in order to get it on to the shaft. Is this normal for a new sprocket? I have a 14t and a 16t, both for NSR250 and from different manufacturers, and both with the same issue.

Are they both wrong or is this normal for a new sprocket? You would need a puller to get them off unless they wear down a little...

Dont sound right to me, never had that problem, but i have seen front sprockets advertised as being for NSR, and clearly not.
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Proud Father of , 05 ktm 400exc supermoto 2018 honda crf rx supermoto

Hello, definitely wrong you should take them back, the sprocket should be a nice fit where a little play isn't a problem, the only issue with a sprocket is that its held on the shaft every Honda I've had the sprocket(front only) was a fairly loose fit.

Interesting, as one came from a pretty reputable supplier. That's why I assumed they came like that, but perhaps it was out of spec.

Next question would be, is it possible to grind down the inner teeth by a tiny amount (not the leading edge that takes the pressure, I mean the other side) to enable it to fit? Has anyone done this?

Otherwise it's back to the standard front.

Just file them slightly by hand, sometimes the laser cutter leave them with sharp edges which cause them not to fit properly.

Cheers,
Mario

Mario's advice sounds a good option, not having any facilities I would have to go for the exchange option but filing a small amount if it is a small amount could do the trick, it will depend on how much you think you will have to take off, use the 15t you have as a guide, I would be loathed to take out too much, so shaft to 15t sprocket gap is what you need.

It should work but if not you cannot then take them back, you could ask whoever sold you them to do the work, give them the gap measurements of the 15t sprocket as a guide.

Cheers,

Daniel.

Hello, how did you get on with your front sprocket problem ?

Cheers D.

DUX wrote:Hello, how did you get on with your front sprocket problem ?

Cheers D.

Not very well actually. Both front's that I had would not fit as intended. The inner 'teeth' on the aftermarket ones are too wide, and not as 'tall' as the standard shape. Without modification with a specialist tool they will not fit without being pushed or hit on with a mallet or similar, which I'm not willing to do.

The specs on paper look right, but the reality is that it just doesn't fit. Good brands too. Afam and one other I forget as I sit here.

Bit of a bummer really as I now have two I can't use, and have to buy another rear sprocket as well to sort it.

My advice from here, is to try before you buy if possible.

Hello, sorry too hear they are no good, as you say Bummer.

I did a similar thing a few years ago and as it was sometime before I attempted to fit this, silencer, as it was about 2 years it was not an option to take it back, it looked OK but on offering it up the flange from silencer to pipe was different being from an earlier model, not much different but enough and because of it being chromed wasn't really abled to be altered without making a pigs ear out of it.

We live and learn or sometimes even, why don't I learn, so now I check everything as it arrives.

Cheers D.