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To big bore or not ?


Badger78

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First of all hi to everyone (y) I just signed up so a newby on to the forum and to a oil boiler bike ! 

Hope someone can point me in the right direction , I'm going to drag race a 1127 next year and pulling the engine over winter to carry out a few mods (gas flowed head and probably some cams )  while it is out I'm not sure whether to go a 1216 big bore or not ? I heard it's only about 10 bhp extra and just wondered whether it's worth even bothering ? I know it's torque that's more important but can't find a lot of figures on the extra torque it would produce . Bike currently has sidewinder exhaust, 38mm carbs , 5 degree ignition advancer and shortly the flowed head .  Didn't want to go bigger than 1216 due to the extra work of new liners etc and want to keep it normally aspirated preferably (less hassle lol ) cheers any advice appreciated 

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leave it as it is and perfect your technique first. reality is that a lot of folks post better times than others who have more bhp just  because they are better at getting down the power they have.
unless that is, youre already scorchingly quick and are being held back by a shortage of power... in which case might i suggest,,,,, turbos.....

 

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The 1216cc big bore is ace. Certainly more than a 10bhp gain, and yes, it gives more midrange. Over the quarter mile you should see an improvemnet in both ET and terminal speed, although what the difference is will depend on gearing and, of course, rider technique. Personally, I'd undo the bolt holding the ignition advancer, place the advancer in the paml of your hand, and then hurl it as far away as you can... I'd also think about the sidewinder, it'll limit the venues at which you'll be able to race, and would only really be of benefit if you were going to run nitrous.

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On 6 november 2016 at 9:09 PM, johnr said:

leave it as it is and perfect your technique first. reality is that a lot of folks post better times than others who have more bhp just  because they are better at getting down the power they have.
unless that is, youre already scorchingly quick and are being held back by a shortage of power... in which case might i suggest,,,,, turbos.....

 

My idea.. (y) Also started last year with a stock 1127 engine, first learn to ride. And this year after some extra power ;) 

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