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Post by bigpup on Oct 8, 2009 7:13:35 GMT -5
That is one big rear sprocket, you might not be able to go very fast!
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Post by terribletabo1 on Oct 8, 2009 22:28:25 GMT -5
Really? I didn't even think of that. I got to ask my builder about that. I do have a 750 big bore kit planned + 5th Overdrive Gear & I sent my billet camshaft to Heiden Tuning for a 270 rephase. I was hoping that would add some speed & power to the bike and I didn't even consider the rear sprocket. Is there any advantage to having a big rear sprocket before I bug the hell out of my builder? I don't intend to race it but I would like to have enough power for passing on highway etc...
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Post by bigpup on Oct 9, 2009 7:13:11 GMT -5
Well ask him how many teeth are on it? standard on North American xs models is 17T front sprocket and 34T rear sprocket. that looks like a big twin rear sprocket and the smallest I have seen is 47T on those. Even with a big bore kit I don't know if that will work. But ask your builder and see what he thinks. Or when the bike is done just see how fast it goes, you can always have a machine shop make an adapter to fit the harley wheel, then fit a 34T sprocket on the adapter.
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Post by drooling-bloodhound on Oct 9, 2009 11:43:21 GMT -5
Yeah, I wouldn't use anything larger that a 34 tooth on the rear. With the 750 a better set-up would be an 18 front 30 rear.
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Post by terribletabo1 on Oct 9, 2009 14:30:38 GMT -5
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Post by drooling-bloodhound on Oct 9, 2009 15:47:54 GMT -5
that should be fine. With the xs using a 17t and 34 back, it starts to vibrate at 60 and by 65 it can be annoying. Using a 18t and 32 or 30 It lets you hit the higher speeds without so much vibration. How this helps.
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Post by terribletabo1 on Oct 12, 2009 10:39:54 GMT -5
My builder just contacted me & advised the rear sprocket contains the rear brake rotor for the disc brake, if we change the sprocket the whole rear brake assemby is useless and will not work. He thinks the bike is going to be fast enough for the suspension and chassis design that we selected for the project. If we find that it runs out of power at highway speeds (65-70mph) he would change the front sprocket at that point and not mess with the rear brake assembly.
He estimates the bike will weigh around 350 lbs when it is done. Would it be possible to reach speeds of 80 - 90 mph after we change the front sprocket only & have the big bore kit installed? Any suggestions on what size for front sprocket?
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Post by Harry on Oct 12, 2009 14:01:38 GMT -5
My builder just contacted me & advised the rear sprocket contains the rear brake rotor for the disc brake, if we change the sprocket the whole rear brake assemby is useless and will not work. He thinks the bike is going to be fast enough for the suspension and chassis design that we selected for the project. If we find that it runs out of power at highway speeds (65-70mph) he would change the front sprocket at that point and not mess with the rear brake assembly. He estimates the bike will weigh around 350 lbs when it is done. Would it be possible to reach speeds of 80 - 90 mph after we change the front sprocket only & have the big bore kit installed? Any suggestions on what size for front sprocket? Terribletabo1, This is a very interesting project and I am looking forward to seeing pictures of your completed XS. There is a definite limit to how large a countershaft sprocket can be mounted. First of all, it's a splined shaft, so it will be difficult to find a much larger sprocket, and the size is limited by the proximity of the clutch pushrod. Regards, Harry |
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Post by terribletabo1 on Oct 12, 2009 15:55:07 GMT -5
Just talked to my builder & my rear is 49 teeth & cannot be swapped out. He suggested a 18 tooth to keep the ratio closer to the old Harley style this bike is based on. www.mikesxs.net/products-11.html#productsSteel Countershaft Sprocket - 530 Type 18T Steel Countershaft Sprocket Part #22-2618 |
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Post by crazypj22 on Oct 12, 2009 16:20:35 GMT -5
Dont see why it cant be swapped?
the mounting holes look pretty close in to center of hub.
Just took a better look at pic, needs to be wide enough for brake pads so I guess your stuck with it unless you change wheel
PJ
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Post by pamcopete on Oct 12, 2009 16:32:19 GMT -5
terribletabo1,
All examples are in 5th gear with a 18" rear wheel:
With a 49 tooth rear and a 17 tooth front sprocket, you will have 5,933 RPM @ 60 MPH.
With a 49 tooth rear and a 18 tooth front sprocket, you will have 5,603 RPM @ 60 MPH.
A standard 17/34 tooth ratio does 4,117 RPM @ 60 MPH with a 18" rear wheel.
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Post by baclay9 on Oct 12, 2009 19:54:12 GMT -5
Man, That thing is going to be screaming on the highway. 1st gear will only last about 5'.
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Post by terribletabo1 on Oct 12, 2009 20:09:03 GMT -5
terribletabo1, All examples are in 5th gear with a 18" rear wheel: With a 49 tooth rear and a 17 tooth front sprocket, you will have 5,933 RPM @ 60 MPH. With a 49 tooth rear and a 18 tooth front sprocket, you will have 5,603 RPM @ 60 MPH. A standard 17/34 tooth ratio does 4,117 RPM @ 60 MPH with a 18" rear wheel. Wow, that seems unrideable! What are my options here to make this more rideable? Is there a table or formula I can use to figure out the ratios? Thanks! |
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Post by pamcopete on Oct 12, 2009 20:20:54 GMT -5
terribletabo1,
Well, you could have an intermediate shaft with reducer sprockets 17:24. Using the stock 17 sprocket would give you 4202 RPM @ 60 MPH. A 18 tooth rear sprocket with a 17:24 intermediate shaft would produce 3968 RPM @ 60 MPH.
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Post by terribletabo1 on Oct 14, 2009 9:37:44 GMT -5
terribletabo1, Well, you could have an intermediate shaft with reducer sprockets 17:24. Using the stock 17 sprocket would give you 4202 RPM @ 60 MPH. A 18 tooth rear sprocket with a 17:24 intermediate shaft would produce 3968 RPM @ 60 MPH. I never heard of an intermediate shaft or a reducer sprocket. I checked MikeXS, 650 Central, and Heiden Tuning websites but I can't find these items. Can anyone tell me where I might get this intermediate shaft with reducer sprockets 17:24? Thanks |
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Aug 23, 2016 7:57:01 GMT -5
Aug 23, 2016 7:57:01 GMT -5