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pumper carb

Posted: May 24th, 2008, 4:11 pm
by tweav
I am wondering if a carb with a accel pump would work better or worst then the non pump carbs on a 500 . then the other thing is the tps sensor could a ignition be found that would work with a two stroke with a tps sensor ? if so off of what?

Posted: May 24th, 2008, 4:49 pm
by britincali
Accel pumps are only needed to eliminate the bog/flatspot on fourstrokes.

Posted: May 25th, 2008, 3:42 pm
by tweav
Are you sure a two stroke would not run better with one too ? It stands to reason that the carb acts the same way on ether engine . I would think you could dial in your air-fuel ratio better with a pump . I've noticed that any engine I've had on a dyno spiked toward lean when you crack on it. I realize these carbs were made to patch up 4-stroker crappy performance .

Posted: May 28th, 2008, 7:13 am
by dahondaboy
I would think that it would have a detrimental affect on a two stroke by adding fuel where it isnt needed, causing a rich spot and maybye a bog.

Posted: May 31st, 2008, 2:28 am
by tweav
I would think If you would run a two stroke on a dyno with a wide band o2 sensor , you would find it goes lean when you first crack on it just like a 4 smoked. It's just the way a normal carb has to work it does not suck extra fuel out of the bowl until the first few cfm's of air has rush passed the jets. Also you guy's do know you can adjust the accel pumps timing a discharge amounts . So it could be tuned in

Posted: May 31st, 2008, 6:00 am
by nmdesertrider

Posted: May 31st, 2008, 9:55 am
by 90cr500guy
My thoughts on a pumper carb
My '78 400twin honda did not have a pump
my '81 400 twin did
Manual stated that they went to the pump to eliminate the flat spot when they leaned out the carbs for emissions reasons

The carbs on both bike are the same type, just the later one have the pump in the bowl