uk500
Junior Member
Posts: 47
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Post by uk500 on Apr 29, 2007 7:33:15 GMT -5
Hi all, I'd like to fit an 18 tooth front spocket, I find the sr pretty low geared and I live in a fast road area, I've heard that 17 teeth is as far as you can go without modifying the sprocket housing, I was wondering just how much you'd have to "chop" the housing to fit an 18 and how difficult it would be, has anybody tried it? When I'm in 5th gear I get to 60 MPH and feel as though I need a 6th gear, I am already running a 42 tooth rear, I reckon that it would still pull it without increasing engine power and change the gearing by about 12%, and JT spockets have them, www.jtsprockets.com any thoughts? Cheers,,,,,,,,,,,,UK |
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Post by StewRoss on Apr 30, 2007 4:20:11 GMT -5
Hi, There might be a way to go...simply fitting an 18 would probably end up with the chain eating into the clutch actuator lever housing on the cases... You could look at making a 520 chain sprocket out of a 530 one by machining down one side sufficiently to suit the narrower chain and then fitting the sprocket so that the reduced area is on the inside. Then you could either do the same with the rear or space out a 520 rear sprocket the same amount. Now I havn't done this on the SR so you'd have to do some clearance measuring to see if it'd fit...but it may work. Oh yes and don't use an O ring chain or that will negate any gains in width... I have machined 530 width sprockets down to suit a 525 chain for my black CR...that one runs 17/38 gearing as I recall... sr500forum.bravehost.com/cafeproject.htmlSR  |
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uk500
Junior Member
Posts: 47
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Post by uk500 on May 1, 2007 17:25:56 GMT -5
Thanks for taking the time for your detailed reply SR, I didn't realise that it would take that much to do the mod, the work is to advanced for me and I'd have to approach an engineering company for the machine work, so I reckon I'll get a17 sprocket and stick with that, at least for now, (you live and learn :-) I visited your site very nice mods and very well cafe'd, you've done a great job I enjoyed looking, Cheers for now,,,,,,,,,,,,UK
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Post by wotavidone on May 1, 2007 23:25:28 GMT -5
I'm running 17/42. 530 chain (plain, not o-ring - definitely would not clear)
This gives 94 km/hr at about 4000 rpm. This is measured on a straight road with a GPS unit, using a new 4.00*18 4PR K70 Dunlop rear tyre. (This is original size and is a very tall tyre.)
At that rate, if I could get the ol' girl to pull the redline in top she'd be doing 160km/hr. About 100 mph. She just will not pull to the redline with that gearing. I actually suspect I would get more speed if I went down to a 16t front.
I reckon my bike would be a dog with 18/42 gearing.
Mick
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uk500
Junior Member
Posts: 47
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Post by uk500 on May 3, 2007 16:41:39 GMT -5
Hi again,
I've just fitted a 17 front sprocket ( existing 42 rear), I'm happy and think it might be about as far as you can go without increasing horsepower, especially as I often carry a passenger too. It was difficult looking at gear ratios on paper as it doesn't give you much idea of what it would feel like in reality. Thanks to SR & Mick for their joint good advice, I'm glad I haven't fitted a "18" it would have been too high, with "two up" without extra horsepower. By the way I was surprised to discover that "JT" actually manufacture the sprockets for a "ready made" 520 Chain conversion, I reckon that might be ok for solo riding, or people with a few extra bhp? I had read previous threads regarding this subject before I started this thread but didn't find anyything regarding the fitting of an 18 tooth front sprocket and what it would take to make it fit, I didn't want to start a duplicate thread. Thanks again to SR and Mick it Helped me a lot, Cheers, ,,,,,,
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Post by 1980thumper on May 3, 2007 22:36:36 GMT -5
im totally factory standard and get 85mph at 6000rpm, im thinking of going up a tooth on the front sprocket though, this wouldnt require any mods would it?
Damo
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Post by aero on May 4, 2007 3:07:02 GMT -5
Why not just fit XT 500 sprockets? They go straight on and are right for 520 chain. Also there is a huge number of sprockets to choose from if you go for XT ones.
Both my bobber and other reuild will be running the lighter 520 chain. Its not like they total output power or the wieght of the bike require much more then 520 chain!
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uk500
Junior Member
Posts: 47
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Post by uk500 on May 4, 2007 3:43:49 GMT -5
Damo, going up one tooth (from a 16 to 17) on a SR500 won't need any mods, Just done it ,,,,,,,,,,,,,,Cheers
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Post by StewRoss on May 4, 2007 3:56:21 GMT -5
Hi, No worries at all...I'd still stay away from O ring chains though with a 17...I can show you pics of my cases on a few of my bikes with damage from the chain eating into them...it also occurs if you leave a worn chain on too long as well. SR |
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Post by 1980thumper on May 4, 2007 7:54:14 GMT -5
cheers uk500
Damo
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uk500
Junior Member
Posts: 47
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Post by uk500 on May 5, 2007 4:57:43 GMT -5
I didn't Know that a plain chain would start eating cases when it got worn, I reckon I'll have to pay a bit more attention to chain wear/tension from now on, thanks,,, SR
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Post by StewRoss on May 5, 2007 6:55:39 GMT -5
Hi, No worries...it does with the oversize sprockets...I made the mistake of leaving a knackered one in for too long...won't do it again. SR  |
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