Topic: CB750 Rear Sprockets - 48 tooth (Update 10/11/09)

[mystic_1]

Man, wish I could help out with the testing but my bike is no where near running and even if it were I'm not that hardcore about riding during winter in Chicago.

Come spring though I'd love to get in on this deal as I'll be needing new sprockets anyway.

Think you might offer other sprockets with different ratios some day?

mystic_1

[HondaMan]

Man, wish I could help out with the testing but my bike is no where near running and even if it were I'm not that hardcore about riding during winter in Chicago.

Come spring though I'd love to get in on this deal as I'll be needing new sprockets anyway.

Think you might offer other sprockets with different ratios some day?

mystic_1

I will, if I can get past this testing phase of this project. I'm planning on 45T and 52T for the 750, as with the 17T and 18T counersprockets out there, this will yield a very wide gear ratio set for the bikes again. Only drag racers went lower in gearing than this range, and they can get aluminum sprockets for that task (short-lived on streets, though).

Then will come the ones for the 500/550.

[mystic_1]

with the 17T and 18T counersprockets out there,

So what's the situation with counter sprockets?  Honda still selling OEM ones?  Are the aftermarket ones well-designed in your opinion?

I'd imagine that the aforementioned tooth profile changes would be equally applicable to the counter sprocket as to the rear sprocket, yes?

mystic_1

[754]

I would run a 19T front before putting a 45 on,
 I never saw  bad like out of aluminum sprockets, thought they held up quite well.. 7075 is pretty tough..

[HondaMan]

with the 17T and 18T counersprockets out there,

So what's the situation with counter sprockets?  Honda still selling OEM ones?  Are the aftermarket ones well-designed in your opinion?

I'd imagine that the aforementioned tooth profile changes would be equally applicable to the counter sprocket as to the rear sprocket, yes?

mystic_1

At my last look, Honda still sold the 17T and 18T fronts.

[HondaMan]

I would run a 19T front before putting a 45 on,
 I never saw  bad like out of aluminum sprockets, thought they held up quite well.. 7075 is pretty tough..

The main problem I've seen (we all did, in the 1980s) with aluminum sprockets when they got popular: the aluminum grinds off and then packs itself into the clearance spaces in the chain rollers, freezing up the links and rollers after a time: you must be VERY diligent about lube and cleaning (with high-pressure carwash, frequently) to make the aluminum ones work well for you (especially on touring bikes). On O-ring chains, the powder would tear up the O-rings by chewing them away.

The steel of the chains is very hard (Diamond's rollers and side plates are Rockwell 55-65) and the steel sprockets are soft, much like 7075 aluminum, so the steel wears in much finer particles (steel motorcycle sprockets are not hardened, much like crankshaft bearings, so that grit can embed without tearing up the bearing surfaces). Also, the steel has the same electrovalence charge from sprocket to chain, so it tends to fling off, or get suspended in the oil, and not stick so well to the rest of the assembly: aluminum has a different charge and the bits are attracted back to the steel (sort of like lightly iron magnetized filings would be). All this junk happens at the microscopic level, but it's what makes things wear... 

[754]

Ahh,, I never pressure wash, and I never let the chain get dry...
 I dont think I used one for touring, but ran the bag off it a long time and expected it to wear but it didnt..
 Come to think of it I did maybe ride 1300 miles to Sturgis with that Alum 54 t on it.. I would throw a 19t on for the road and (in town) switch to a 17t, for better acceleration..

 I could see how running on the dry side could cause problems..

[lordmoonpie]

Don't want to rain on your parade Mark but I had a custom 48 tooth sprocket made, from scratch to my spec. for just £36 GBP. It had to be custom as I'm running the CR750 magnesium works hub so has a different centre and PCD for the bolts pls it's cut down to 520.

That's everything by the way, no tooling, no setup, no minimum order, just £36 including postage! They're Dural instead of steel but that's my preference, they do steel too. Postage may be more expensive for you from the UK but no tooling costs....

http://www.bandcexpress.co.uk/

[voxonda]

Don't want to rain on your parade Mark but I had a custom 48 tooth sprocket made, from scratch to my spec. for just £36 GBP. It had to be custom as I'm running the CR750 magnesium works hub so has a different centre and PCD for the bolts pls it's cut down to 520.

That's everything by the way, no tooling, no setup, no minimum order, just £36 including postage! They're Dural instead of steel but that's my preference, they do steel too. Postage may be more expensive for you from the UK but no tooling costs....

http://www.bandcexpress.co.uk/

Hey LMP,

What front sprocket do you use, if you don't mind me asking?

Thanks, Rob

[lordmoonpie]

Hi Rob, it's a 17 tooth at the moment - again custom cut down to 520 by B and C Express...what's your thinking?

[voxonda]

Hey LMP,

Want to go down from 530 to 520. Looking for front sprockets. Think I must contact B&C express.

Rob

[lordmoonpie]

Yes they're very good - let me know if there any shipping issues, I can always order for you and send on. Also, have a think about which side want to thin down the sprocket - it has to align at the back so for example you don't want the inside front thinning off with the outside rear

[HondaMan]

Don't want to rain on your parade Mark but I had a custom 48 tooth sprocket made, from scratch to my spec. for just £36 GBP. It had to be custom as I'm running the CR750 magnesium works hub so has a different centre and PCD for the bolts pls it's cut down to 520.

That's everything by the way, no tooling, no setup, no minimum order, just £36 including postage! They're Dural instead of steel but that's my preference, they do steel too. Postage may be more expensive for you from the UK but no tooling costs....

http://www.bandcexpress.co.uk/

Thaks, LMP: I sent them an inquiry.
But, this is much more complicated than simply specifying "different material" or "number of teeth". It's a complete re-engineering of the tooth profile, the base circle, the hardness, and some other sprocket features. It's not a trivial thing...

[lordmoonpie]

It sounds a bit involved for sure - worth trying another manufacturer though, it may lead to somethign viable for you commercially...

[754]

Its all a numbers thing, setting up cost changing profile costs(expensive)

If they see that it works, they would be way more interested.

  Generally when sprockets are hobbed, they are cut in a stack 18 inches high if desired that is  around 45 sprockets.. walk away till they are finished. Repeat, load another stack of blanks and go again.

 Then they sit on them, pull them as ordered, cut the middle and bolt pattern and lightening holes.. most of that can be pre programed..

 but that is a completely different thing than cutting 4 of, with a changed profile, to a specific tolerance.. much more specialized. I will not be surprised if Honda had figured out a better profile, they were pretty good at it..

[Simpson]

Perhaps I can help.