bigbore420 Posted July 14, 2011 Report Share Posted July 14, 2011 I have a 91 Yamaha Banshee with a 420 stroker motor can i run it with stock carbs until i get different ones and what would the fuel to mix ratio be Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted July 14, 2011 Report Share Posted July 14, 2011 I have a 91 Yamaha Banshee with a 420 stroker motor can i run it with stock carbs until i get different ones and what would the fuel to mix ratio be 421....not a 420 lol. And your are REALLY pushing the extreme limits of your stock carbs....and pushing hard. you really need to switch the carbs out for larger carbs. and the correct fuel/oil mix question is going to give you alot of different answers. most will run between 32-40 -to- 1 however we have seen people run anywhere from 20:1 all the way to 50:1. but 50:1 is just a tad too scary for me to run....i keep my shit running with 32:1 Quote Link to comment Share on other sites More sharing options...
bansheesandrider Posted July 14, 2011 Report Share Posted July 14, 2011 Use a GOOD oil at 40:1, Iuse Klotz R50, but Maxima, Amsoil and some others are Ok also. Quote Link to comment Share on other sites More sharing options...
No Limit Powersports Posted July 14, 2011 Report Share Posted July 14, 2011 421....not a 420 lol. And your are REALLY pushing the extreme limits of your stock carbs....and pushing hard. you really need to switch the carbs out for larger carbs. and the correct fuel/oil mix question is going to give you alot of different answers. most will run between 32-40 -to- 1 however we have seen people run anywhere from 20:1 all the way to 50:1. but 50:1 is just a tad too scary for me to run....i keep my shit running with 32:1 Did i miss where he said what exactly the motor was. There are a lot of stock cylinder 7mm's floating around that are 420's. A 4mm cub in a 68 bore is a 421 and is probably the most popular setup to date but that doesn't mean he don't have a 420. Either way depending on your porting whether it be a stock cylinder or a cub the stock carbs are definitely going to hold you back but they are tuneable. Quote Link to comment Share on other sites More sharing options...
bigbore420 Posted July 14, 2011 Author Report Share Posted July 14, 2011 i got the banshee as a basket case the guy had a blueprint of the motor at 420 big bore with .120 over bore wesico pistons welded stroker crank v force delta carbon fiber reed valves from a cr 125 36mm mikuni carbs reamed to 37mm wich are mitch matched which is why i was gonna run it with stock carbs for now. so i was wondering what i really have the jugs have pp etched into both jugs. Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted July 15, 2011 Report Share Posted July 15, 2011 Did i miss where he said what exactly the motor was. There are a lot of stock cylinder 7mm's floating around that are 420's. A 4mm cub in a 68 bore is a 421 and is probably the most popular setup to date but that doesn't mean he don't have a 420. Either way depending on your porting whether it be a stock cylinder or a cub the stock carbs are definitely going to hold you back but they are tuneable. i thought that even the stock cylinder 7mm's were equalled out to be 421's.......hmm....shit my bad.... thanks for straightening me out! M&M for the win! Quote Link to comment Share on other sites More sharing options...
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