Chain drive?

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Chain drive?

Postby sacharlie » 26 Aug 2018, 17:55

BM how high of RPMs are the drive sprockets turning on MC or sport ATV engines? I would think there is some internal reduction but not sure.
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Re: Chain drive?

Postby Burgerman » 26 Aug 2018, 21:12

With a typical 17 tooth front, and 46 tooth rear sprocket as used on many superbikes, At 200 mph the rear wheel and 180/55 - 17 tyre is doing 2800 rpm.

So the rear end of the chain is doing 2800rpm but the front end is going 2.70x faster at 7560rpm. Which end are you interested in. The real answer is that the question isnt making sense. A chain isnt doing any rpm. Its traveling along.

Also on a motor like a 600cc to 750cc bike, the camshaft chain, is uses on a crankshaft that has a typically 13,000 to 16,000 rpm limit on the rev limiter.

As far as a chain is concerned there is no rpm. Feet per second, yes. But tensile strength far exceeds its centrifugal acceleration needs as it runs around a sprocket. What wears chains is dirt. And lack of lubrication. A typical big motorcycle drive chain never shows any sign of wear or lengthening between tyre changes as it has its grease sealed into every link with O rings. Which keeps dirt out of its internal bearing surfaces. If it ever needs adjustment then its due for the bin and basically toast. And a cam chain has a hard life at 14k rpm driving lumpy cams so uneven loads and typically never need replacement as they run in clean oil.
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Re: Chain drive?

Postby expresso » 26 Aug 2018, 22:02

talking about Chains - what do you suggest i use to clean and keep oiled etc, for my Chain Driven Chair i will get very soon ?

something simple that i can spray on to clean and spray on to oil etc, ?
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Re: Chain drive?

Postby Burgerman » 26 Aug 2018, 22:12

Dont use oil...
On big bikes I used a paintbrush and parafin which you call kerosene. When dry, several hours later I used motorcycle chain lube. Goes on like water. Dries out and sticks like s**t later on, so none flings off even at 180mph which you will not be doing!

Any spray chain lube that is non fling, on a cleaned dried chain will be fine. None of them work on a dirty chain. Kerosene and a brush. Or a well soaked cloth and a good scrub! Or use Turpentine, lamp oil, etc. They do make special brushes... But too stiff and too big... but keeps hands clean. Best to do this cleaning outside. https://www.amazon.co.uk/RBM-As-Mention ... B00LJYAESY Paint brush works better. Then LEAVE it till dry. You want it fully degreased in an ideal world. Just clean metal.

Once dry soak it in this:

Best on the market. https://www.amazon.com/dp/B00230KKJQ/re ... 19042&sr=1 Going at wheelchair speeds this should last many months with 1 application after degreasing with parafin. NON throws off, even after a 1000 mile motorway blast @ silly speeds you wouldnt believe from UK to southern spain. Chain still sticky with PJ1... Its pale blue.
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Re: Chain drive?

Postby expresso » 26 Aug 2018, 23:43

https://smile.amazon.com/dp/B00FFZU25S/ ... _lig_dp_it


would this be Ok - thanks for the info. i saved the items you linked - not sure how often i can do this - but will try my best

i will most likely purchase spare set for myself to have on hand anyway -
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Re: Chain drive?

Postby Burgerman » 26 Aug 2018, 23:50

Yes. As long as you dont use the yellow one. Its just a rebranded WD40 type thing. A substance that I never found a good use for. Its what people spray on all sorts of things. But its not much good for any of them...
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Re: Chain drive?

Postby expresso » 27 Aug 2018, 00:42

ok so i skip the yellow can - just use the first one and the 3rd one - and thats it ? once a week if i use the chair or how often if i dont or use it daily in the summer
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Re: Chain drive?

Postby Burgerman » 27 Aug 2018, 00:58

The one that cleans? How well? Not a clue. Paint brush and parrafin or kero works well.

The lube one will be fine. The secret to making chains last is cleanliness. Then, if cleared of all dirt and dust INSIDE the chain as long as some lube is there inside the chains pins and bearings they last forever. If dirty, then adding lube just makes nice grinding paste...
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Re: Chain drive?

Postby shirley_hkg » 27 Aug 2018, 02:23

Petrol or diesel cleans grease better ?
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Re: Chain drive?

Postby shirley_hkg » 27 Aug 2018, 02:52

Every motor shop here has a trough of diesel for soaking engine parts . czy
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Re: Chain drive?

Postby Burgerman » 27 Aug 2018, 03:29

Kerosene is best. Parafin, lamp oil, whatever you call it there. Diesel takes too long to evaporate so stays wet. Then the chain lube cannot dry out and become sticky and stay on or in place as intended.. Pertoleum is OK but a fire hazard. And leaves its own lubricant behind.
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Re: Chain drive?

Postby ex-Gooserider » 28 Aug 2018, 01:25

I think what sacharlie was asking about is whether or not there is internal speed reduction between the crankshaft and the countershaft sprocket on MC and ATV engines...

I don't have the exact numbers, but there definitely is transmission gearing internally so the countershaft sprocket is turning a lot slower than the engine, how much slower will depend on what gear one is in, and the gearing choices used by the engine maker.... Note that in the case BM mentions the engine would be spinning on the order of 15,000rpm, and in top gear.... Lower gears would have even more reduction for less speed but more torque.

sacharlie wrote:BM how high of RPMs are the drive sprockets turning on MC or sport ATV engines? I would think there is some internal reduction but not sure.
Thanks
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Re: Chain drive?

Postby sacharlie » 21 Sep 2018, 17:36

I'm confused! banghead
I always use the #336 when figuring speed in mph, but where did I get that 336. It does work though. Say you have a 20" diameter wheel driven by a 3000rpm motor that you want to go 7mph. I say 7÷20×336=117.6. Then 3000÷117.6=25.51. So 25.51 is the reduction needed.
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Re: Chain drive?

Postby Burgerman » 21 Sep 2018, 20:16

I'm confused! banghead
I always use the #336 when figuring speed in mph, but where did I get that 336. It does work though. Say you have a 20" diameter wheel driven by a 3000rpm motor that you want to go 7mph. I say 7÷20×336=117.6. Then 3000÷117.6=25.51. So 25.51 is the reduction needed.


No idea where that came from.

But its easy to work out speeds/diameters/rpms/gear ratios etc.

For eg. Car engine, 6000redline. So at 6000rpm, x 1.15 in 5th gear (gearbox) means a prop shaft speed of 6900rpm. Then, div by say a 3.6 to 1 (typical diff ratio), gives you a wheel speed of 1,916 rpm's.
So a tyre with a 26 inch overall diameter x pie gives you a 81.6 inch movement for 1 revolution. = 2.26 yards per revolution. x 1916 rpm is 4330 yards per minute. x 60 is yards per mile. So 259809 yards per hour. Div by 1760 for mph (yards per mile) is 147.618mph at the redline.
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Re: Chain drive?

Postby woodygb » 21 Sep 2018, 20:42

336 Constant K.

https://books.google.co.uk/books?id=-do ... &q&f=false



12 ( inches in a foot ) x 5280 ( feet in a mile ) / 3.14 (Pi ) x 60 ( mins in hour )= 336.3
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Re: Chain drive?

Postby Burgerman » 21 Sep 2018, 20:52

A coincidental constant.

It doesent help much when you are looking at multi stage gears like say the motorcycle gearbox/chain etc. That is similar to an ATV The motor has x rpm, then the clutch and gearbox primary reduction ratio is added. Then the gearbox ratio. Then the drive chain ratio. Theres three reduction ratios.

The gearbox itself can be a reduction in the first 3 gears, and either a 1:1 4th gear or positive or negative, and 5th or 6th gear are usually positive ratios. Esp 5th in cars. Since traditionally 5th gear was added on as an after thought historically, and 4th was a direct drive with no gear used.
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Re: Chain drive?

Postby woodygb » 21 Sep 2018, 20:54

But not an irrational number.
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Re: Chain drive?

Postby sacharlie » 21 Sep 2018, 21:04

thanks woody! YOU THE MAN WITH FORMULAS
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Re: Chain drive?

Postby Burgerman » 22 Sep 2018, 08:47

An expert is a person who has made all the mistakes that can be made in a very narrow field.
Niels Bohr


A master is a person thats made the same mistakes many times!
Me.

Having just forgotten to empty a night bag last night (yet again)... After 20 years of practice. :fencing
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Re: Chain drive?

Postby sacharlie » 22 Sep 2018, 14:09

¿~it happens! cheers
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Re: Chain drive?

Postby Burgerman » 22 Sep 2018, 14:28

And I find that this happens more when you have more of this cheers
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