Johnny Appleseed Posted October 13, 2011 Share Posted October 13, 2011 Hi My name is Johnny and I own a YBR 125. (2009 on a '59 plate). Strawberry (the motorcycle) is named after the hansom cab horse in "The Magician's Nephew" who is give power of speech by Aslan the Lion and later the ability to fly. I bet you can't guess the colour of strawberry. After failing my DAS in 2007 by leaving the indicators on I decided to get a small bike to practise on. In February 2011 I passed my A2 bike test. I live in Bath but am originally from Cambridge here I spent my first 40 odd years regards Johnny and I have a question on where to get sprockets. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 13, 2011 Moderator Share Posted October 13, 2011 wemoto.com Link to comment Share on other sites More sharing options...
Johnny Appleseed Posted October 13, 2011 Author Share Posted October 13, 2011 Hi Thanks for the suggestion, I've looked at their website. I want to change the gear ratio by increasing the front sprocket size and decreasing the rear sprocket. I'd heard stories of sprockets with 15 and 16 teeth that would fit a 2009 YBR, however I couldn't find any. It would appear that they don't exist. My next option is to decrease the rear sprocket. Allegedly I can get anything down to a 39 teeth sprocket - although I think that might be too extreme. As Strawberry is hardly the fastest accelerating bike I don't mind sacrificing acceleration for more top end (and better economy). Any suggestions? regards Johnny Link to comment Share on other sites More sharing options...
Screw Guernsey Posted October 13, 2011 Share Posted October 13, 2011 Try here: http://www.bikebitsni.com/ If you contact them, they may be able to help, even though they don't necessarily list your bike. They got me an interesting combination of sprockets for my FZR! Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 13, 2011 Moderator Share Posted October 13, 2011 Looks like the '05 to '10 use the same front sprocket. Take the details from here and search the brand and number in the UK LINKY Link to comment Share on other sites More sharing options...
Johnny Appleseed Posted October 15, 2011 Author Share Posted October 15, 2011 Thanks I gave them a call and am waiting for a quote. Johnny Link to comment Share on other sites More sharing options...
Johnny Appleseed Posted October 20, 2011 Author Share Posted October 20, 2011 Thanks for the help (and I'm not being sarcastic). I am now under the impression I cannot get a 15 or 16 tooth front sprocket unless I manufacture one myself. My reasons for changing the gearing is when I use the bike on a dual carriageway, I feel that having a top speed of about 60-65mph is a bit dangerous as I struggle to get away from vans and small lorries. When looking at "Gearing Commander", if I keep the front sprocket standard and reduce the teeth on the rear sprocket to as little as 39 (from 45) I should achieve a top speed of about 70mph. My question is, will he bike actually get to that speed, and how much is the pay off in acceleration? Could anyone please advise on the best rear sprocket size? And I know Yamaha spent thousands creating the perfect sprocket ratio, but the bike is a worldwide seller and is sold in countries where 60mph is more than adequate (and has huge markets). Many thanks Johnny Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 20, 2011 Moderator Share Posted October 20, 2011 I thought I posted a link to a 15 tooth sprocket. if you are going the rear sprocket route I would not alter it by more than 3 teeth. the engine will run out of legs with anything lower unless you are riding downhill and you will be constantly changing down, reving to hell out of the bike and then 6th will just be an overdrive gear and you will struggle to accelerate in that gear. Link to comment Share on other sites More sharing options...
Johnny Appleseed Posted October 20, 2011 Author Share Posted October 20, 2011 Thanks DirtyDT. I've just phone bikebitsyNI, who have confirmed only a 14 and 13 tooth sprocket is available. Thanks also for the advice on not going too far with the sprocket. The YBR has only 5 speeds so I assume what you said for a 6th gear would happen in 5th (i.e. an overdrive gear) Johnny Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 20, 2011 Moderator Share Posted October 20, 2011 ok. the assumption is right. basically you would struggle to acceleratorate in top gear and the bikes revs would just drop. any hill would just see the bike slowing until you had to change down. Link to comment Share on other sites More sharing options...
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