A little sprocket advise needed

[askew]

If I buy a sprocket for my bike that has the same pitch (428) and the new number of teeth fit the range allowed, would it matter that the sprocket was not specific to my bike?

Cheers!
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[Guest]

As long as it fits to the wheel ok, is the right pitch and roughly the standard number of teeth, then no problems.

You'll find that a lot of Suzuki sprockets are inter-changable between models, same with most makes as they tend to use the same basic wheel castings. I don't know about swapping between brands though, you'd have to make sure it fits over the cast boss correctly and the bolt centres are the same.

[askew]

They're both Yamaha sprockets, and they're both from the same sized engine bikes. Do you think that the fixings will be in the same place?

I'm looking at getting less teeth than I have now (vain and silly attempt to improve speed. )

Cheers by the way!
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[Ninja]

(not vain or silly at all! It's the number one 'tuning' step - you can markedly affect your bike's performance by simply altering its gearing)

'course, to go faster you'd need to be able to 'pull' the extra gearing ...
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James
4 wheels transport the Body ... 2 wheels transport the SOUL

[TiN]

Probably the best thing to do is to look at the part numbers for each bike...if they're the same, then they are clearly compatible, but just because they are from the same manufacturer and have the same size engine doesn't mean that they'll be the same.
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TiN
dotgems.net

[askew]

Thanks guys you're all quite helpful. Just checked and the part number for my current sprocket is 13208+ and the new one is 13210+. I'm guessing they're not compatable. I was only planning on losing 3 teeth too.

Hmm... Continue the research Smithers.
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[Kickstart]

Hi

Which bikes do you want the sprocket from / to.

The old M&P catalogues listed the part numbers of sprockets as 6 digit numbers, the last 2 digits of which were the number of teeth. Think the first 4 digits referred to the fitting, so from that you can work out which other sprockets can be used.

All the best

Keith
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[Frost]

Typically as keith said they have 2 indintifiers, fitting type and tooth count.

i put a sprocket off a different bike onto the old CB, fitted perfectly.

Be careful dropping teeth though, sometimes the chain may drag alot on the swingarm, or the chain will have worn to the old sprocket and will not work well with the new one

[askew]

[Kickstart]

Hi

The pitch is the "428" or "520" bit.

There are other important considerations. For example the sprocket might not be flat so you have to consider the offset. There is also the number and pcd of the mounting bolts / stubs.

Often a maker will keep to a standard fitting for quite a while (Yamaha seem to be particularly good at having interchangeable parts).

Front sprockets are often cheaper. The other advantage is that if you add a couple of teeth at the back then the existing chain might not be long enough, but it you go down one at the front then you do not have this problem (although you might have to shorten the chain).

As mentioned above there is the possible problem that smaller sprockets will reduce the clearance from the chain to the swinging arm, etc, quite possibly resulting in it cutting into the swinging arm. Larger ones might not fit under the chain guard.

I would also say that you are best off replacing the chain and sprockets at the same time.

All the best

Keith
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[askew]

Cheers Keith, that was a great help. I've been into contact with a few people and have had confirmed each time that the rear sprocket from an XT125/350 is exactly the same as what I'm looking for. I don't want to make too much of a difference to the top speed as I'd rather not reduce acceleration so much. So I think I'll knock 2 teeth from the back (50t - 48t) rather than adding one to the front and making a load of difference. Do you think a reduction of just 2 teeth to the rear will make a noticable difference?

Thanks again everyone!
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[Kickstart]

Hi

1 up at the front would be about the same as 3 down on the back, and for chain life a larger front sprocket is better.

At a guess you will probably gain around 2~3% top speed, if it will put that gearing (probably will).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[askew]

Ok, good stuff! Well, I'll get that ordered and I'll let you guys know how it all turns out.

All the Best

Keith... whoops sorry, those words are too often read and imprinted in my mind hehe.
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