Pumper Carb Fix for TE250

[MotocycleWriter]

A friend was telling me about a relatively simple fix for the accelerator pump on the carb for my '07 TE250. Something about using an o-ring to couple the bell-crank or something like that. He said it was on Cafe Husky, so I'm here. I already have the JD jetting kit and it has the o-ring and bypass jet to do the job. Just need directions. Does anyone know where I can find them?

John

 

[Max Payne]

http://www.cafehusky.com/threads/in-search-of-snap…-is-this-stuff-useful.6411/

 

[Boogie]

Did you get instructions with the JD kit?

Here is what I got with my 510 kit. The AP mod with the oring should be the same.

 

[Boogie]

Yep what Max Payne said

 

[Coffee]

...I already have the JD jetting kit and it has the o-ring and bypass jet to do the job. Just need directions. Does anyone know where I can find them?

John

Not sure if you are asking for what jets to put in & what the o-ring does, or how to change the jets. Here is how to change the jets:
http://www.cafehusky.com/threads/how-to-re-jet-a-carb-video.1160/

For the most part, having a larger amount of Accelerator Pump (AP) squirt works fine on smooth surfaces like a paved road, but having large squirt in the bumpy off road stuff, especially uphill in hot weather, will tend to flood the carb and stall the bike - and the hot start might need to be used.

 

[MotocycleWriter]

So help me understand this:
1) the cap on the AP screw disables the accelerator pump entirely?
2) removing the cap engages the AP at the rate determined by the spring in the AP diaphragm?
3) installing the O-ring physically "links" the AP to the throttle increasing the rate of AP fuel delivery?

I'm setting my bike up for enduro-style off road. Single track, varied terrain, basically zero street. I've stripped every bit of street off the bike until my dual sport trip to Colorado this summer when I'll have to re-tune the bike. So for my kind of riding which of these options is best? Is there a thread somewhere on jetting? I think my bike might be running a bit lean. A little harder to start than I think it should be, and stalls a little easier than I think it should. On past bikes these symptoms have been linked to running lean. Other than that, she runs pretty darn good, especially after I took off all the stickers!

 

[Coffee]

NOTE: this information only applies to a 2006 or 2007 TE250

So help me understand this:
1) the cap on the AP screw disables the accelerator pump entirely? - yes
2) removing the cap enables the AP at the rate determined by the spring in the AP diaphragm, and the leak jet
3) installing the O-ring physically "links" the AP to the throttle increasing the rate of AP fuel delivery? - it connects them, but how well depends on how strong the oring is

Answers in red above, hopefully that is an easy color for you to read.

I'm setting my bike up for enduro-style off road. Single track, varied terrain, basically zero street. I've stripped every bit of street off the bike until my dual sport trip to Colorado this summer when I'll have to re-tune the bike. So for my kind of riding which of these options is best? Is there a thread somewhere on jetting? I think my bike might be running a bit lean. A little harder to start than I think it should be, and stalls a little easier than I think it should. On past bikes these symptoms have been linked to running lean. Other than that, she runs pretty darn good, especially after I took off all the stickers!

My personal opinion is that every bike is different, and it seems to depend on float height. For that reason I have not focused on a jetting thread, but by all means start one.

The quickest way to determine rich/lean is to play with the choke & hot start. Pull each one out a bit to see if you need to go lean or rich. That would include evaluating the AP circuit (o-ring (if any), leak jet, AP screw placement).
I've done several videos which you should be able to find via the links already provided so you can get a sense of how the AP circuit settings affect each other.

But something like this for the AP: 2.75mm for the screw, and maybe a 55 or 65 leak jet should put you close. The o-ring is easy enough to experiment with, carry some needle nose pliers and some o-rings around while leaving the plastic cover off the carb, and experiment while riding.

And something like this for the rest of the jets: JD blue cir clip in #2 or #3 from the top of the needle, JD red cir clip in #4 or #5 from the top of the needle (sorry, I do not know about the other needles)
And maybe a 175-185 main (I rarely go WFO which is about the only time that matters), and possibly a 38 to a 45 pilot jet, then of course set your fuel screw to max rpms at idle with that screw, which should be about 1.5 to 2.5 turns out. If you need the screw farther out for max rpms then you need a larger pilot jet.