Pumper carb - Waht is it?
#11
02-03-2007 | 06:06 AM
Admin
1st Gear Member
Joined: Jan 2006
Posts: 7,269
RE: Pumper carb - Waht is it?
Here's a little video I made when bench testing the AP squirt - the fuel squirt is coming from the little brass nub in the intake passage. I made the video because I was trying to time the squirt. Some folks over on Thumpertalk were saying the AP squirt should be only 1 second at max throttle and there's a "Taffy" mod one can do to address this. I did the Taffy mod but I didn't notice any difference whatsoever in the bike afterwards, so I undid it. The clip is before I did the Taffy mod. But the clip is also good for seeing its general operation. Also notice that when I turn the throttle pull, the slide is directly connected. This is another benefit over the CV carb - on the CV carb the throttle pull opens a butterfly valve and as the engine picks up RPMs, the engine vacuum is what actually lifts the CV carb's slide. This is why the throttle response on the FCR is so much better than that on the CV. The accelerator pump is there to feed the lean condition that occurs then the slide is first opened.
http://video.google.com/videoplay?do...98081774527257
http://video.google.com/videoplay?do...98081774527257
#12
02-03-2007 | 03:44 PM
Senior Member
1st Gear Member
Joined: Apr 2006
Posts: 1,349
From:
RE: Pumper carb - Waht is it?
ORIGINAL: Nobrakes
Here's a little video I made when bench testing the AP squirt - the fuel squirt is coming from the little brass nub in the intake passage. I made the video because I was trying to time the squirt. Some folks over on Thumpertalk were saying the AP squirt should be only 1 second at max throttle and there's a "Taffy" mod one can do to address this. I did the Taffy mod but I didn't notice any difference whatsoever in the bike afterwards, so I undid it. The clip is before I did the Taffy mod. But the clip is also good for seeing its general operation. Also notice that when I turn the throttle pull, the slide is directly connected. This is another benefit over the CV carb - on the CV carb the throttle pull opens a butterfly valve and as the engine picks up RPMs, the engine vacuum is what actually lifts the CV carb's slide. This is why the throttle response on the FCR is so much better than that on the CV. The accelerator pump is there to feed the lean condition that occurs then the slide is first opened.
http://video.google.com/videoplay?do...98081774527257
Here's a little video I made when bench testing the AP squirt - the fuel squirt is coming from the little brass nub in the intake passage. I made the video because I was trying to time the squirt. Some folks over on Thumpertalk were saying the AP squirt should be only 1 second at max throttle and there's a "Taffy" mod one can do to address this. I did the Taffy mod but I didn't notice any difference whatsoever in the bike afterwards, so I undid it. The clip is before I did the Taffy mod. But the clip is also good for seeing its general operation. Also notice that when I turn the throttle pull, the slide is directly connected. This is another benefit over the CV carb - on the CV carb the throttle pull opens a butterfly valve and as the engine picks up RPMs, the engine vacuum is what actually lifts the CV carb's slide. This is why the throttle response on the FCR is so much better than that on the CV. The accelerator pump is there to feed the lean condition that occurs then the slide is first opened.
http://video.google.com/videoplay?do...98081774527257
It really doesn't take much to entertain us does it? [sm=type.gif]
#14
02-04-2007 | 01:46 AM
Senior Member
1st Gear Member
Joined: Sep 2006
Posts: 1,399
From: Bangor, PA
RE: Pumper carb - Waht is it?
Was wondering if the tm33 is big enough for a 331 big bore. I thought I had read on a site somewhere else that the 33mm carb is good for the 250 but a 36mm Tm should be used on the 300. Anyone have an opinion on this.
#15
02-04-2007 | 04:25 AM
Senior Member
Joined: Oct 2006
Posts: 3,106
From: Misawa Japan
1st Gear Member
RE: Pumper carb - Waht is it?
ORIGINAL: 2k1w=no$
Was wondering if the tm33 is big enough for a 331 big bore. I thought I had read on a site somewhere else that the 33mm carb is good for the 250 but a 36mm Tm should be used on the 300. Anyone have an opinion on this.
Was wondering if the tm33 is big enough for a 331 big bore. I thought I had read on a site somewhere else that the 33mm carb is good for the 250 but a 36mm Tm should be used on the 300. Anyone have an opinion on this.
#16
02-05-2007 | 11:12 PM
Senior Member
1st Gear Member
Joined: Dec 2006
Posts: 108
RE: Pumper carb - Waht is it?
"I thought I had read on a site somewhere else that the 33mm carb is good for the 250 but a 36mm Tm should be used on the 300. "
That info is from Planet KLX.
I am mulling over the same decision...what carb bore? Sadly I have come across very little discussion of it. I rode a couple KLX 250's w/ 300 barrels and FCR 33mm and noticed a fantastic low end to midrange pullthen they signed off a bit on top. However this was in Thailand where getting jets is somewhat awkward. So it may simply be a lean condition. Language barriers caused difficulty so could not get a clear answer on jetting.
That info is from Planet KLX.
I am mulling over the same decision...what carb bore? Sadly I have come across very little discussion of it. I rode a couple KLX 250's w/ 300 barrels and FCR 33mm and noticed a fantastic low end to midrange pullthen they signed off a bit on top. However this was in Thailand where getting jets is somewhat awkward. So it may simply be a lean condition. Language barriers caused difficulty so could not get a clear answer on jetting.
#18
02-07-2007 | 05:27 AM
Senior Member
Joined: Oct 2006
Posts: 3,106
From: Misawa Japan
1st Gear Member
RE: Pumper carb - Waht is it?
ORIGINAL: 2k1w=no$
anyone else wonder if the tm 36mm pumper carb would be over carburation for 331cc displacement.
anyone else wonder if the tm 36mm pumper carb would be over carburation for 331cc displacement.
Thread
Thread Starter
Forum
Replies
Last Post
