XY400Y-2 Available! - Page 2

vtr99 · 04-20-2010, 03:56 PM

I've been working on bikes, and building race cars most of my life, and you definitely can have too much carburetion. The bigger the carb, the more high end HP you make, and the less torque on the bottom end. The same goes for camshafts. The equation changes a bit when you supercharge, but this is another story. For my money I will take torque and midrange power over an engine that has to be spinning high rpms all the time. Not to say drag racing, road course, MX, and any other sort of racing aren't a blast, but for an everyday machine I don't want to be fiddling with it every minute. Usually high end power comes with the expense of a lot of extra maintenance.

Wild_Alaskan · 04-20-2010, 10:34 PM

yep smaller carbs do usually result in more low end and better throttle response, however larger carbs with accelerator jets are like the best of both worlds. of course you can still go to big. for the xr400 the current consensus it that the mikuni BTS 40 pulls hardest at all rpms. I currently have a 38 or 39 mm kehin with an accelerator jet on mine and it has tons of low end power. just twist about half way and it wants to wheelie and throw you on your ass

vtr99 · 04-20-2010, 11:25 PM

Again, I have nothing against performance machines. I spent about 10 years on the local MX circuit, and then another 10 campaigning a 440 Cuda'. On a dual sport that will do some touring duty I will gladly give up a couple top end ponies for 30% more gas mileage.

04-20-2010, 10:34 PM	#17
Wild_Alaskan Join Date: Dec 2009 Location: Alaska Posts: 914	yep smaller carbs do usually result in more low end and better throttle response, however larger carbs with accelerator jets are like the best of both worlds. of course you can still go to big. for the xr400 the current consensus it that the mikuni BTS 40 pulls hardest at all rpms. I currently have a 38 or 39 mm kehin with an accelerator jet on mine and it has tons of low end power. just twist about half way and it wants to wheelie and throw you on your ass __________________ Dune buggy build http://chinariders.net/modules.php?n...wtopic&t=14470 400cc lifan build vid: http://youtu.be/20HoU8OK_Y0 other fun: http://tinyurl.com/wildalaskan
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04-20-2010, 03:56 PM	#16
vtr99 Join Date: Apr 2010 Location: St. Louis, MO Posts: 92	I've been working on bikes, and building race cars most of my life, and you definitely can have too much carburetion. The bigger the carb, the more high end HP you make, and the less torque on the bottom end. The same goes for camshafts. The equation changes a bit when you supercharge, but this is another story. For my money I will take torque and midrange power over an engine that has to be spinning high rpms all the time. Not to say drag racing, road course, MX, and any other sort of racing aren't a blast, but for an everyday machine I don't want to be fiddling with it every minute. Usually high end power comes with the expense of a lot of extra maintenance.
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04-20-2010, 11:25 PM	#18
vtr99 Join Date: Apr 2010 Location: St. Louis, MO Posts: 92	Again, I have nothing against performance machines. I spent about 10 years on the local MX circuit, and then another 10 campaigning a 440 Cuda'. On a dual sport that will do some touring duty I will gladly give up a couple top end ponies for 30% more gas mileage.
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