Johnny Appleseed

Thanks for the reply - I did think there was a reason why I could find smaller front sprockets, but not larger ones. There certainly looked room to increase sprocket size. Johnny

On the Newbies' forum, I have been told that if I increase the size of the front sprocket on a 125i YBR it is unlikely to have any effect as the bike probably won't reach a high enough rpm - many thanks for that information. Currently, the bike reaches about 8000rpm, which (according to "Gearing Commander") means a top speed of about 60mph. In reality although I have made it to the mid to high sixties (GPS), in general the bike runs at about 55 to 60mph. My problem is that at those speeds you become prey for vans or small lorries. I find that on dual carriageways, I find myself catching up with them, but as I attempt to overtake I am struggling to do so. I know there will be some back draft cause by them, but I am positive there are also some idiots who speed up on purpose. So my question: If I drop the front cog (and it may be significant that the only two sprockets available are a 14 and 13 teeth) to a 13T, could the bike reach a higher rpm, and thus a higher top speed even taking into account a change of the gear ratio? many thanks Johnny

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

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

Thanks I gave them a call and am waiting for a quote. Johnny

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

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.

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