Quick shot accelerator pump
- Thread starter atcomx98
- Start date
Does you ap circuit need more gas?
A lot of research has gone onto this!
The flood of not very atomized fuel can't be good, it is supposed to help the engine off idle, then the rest of the circuits take over. Better, constant flow and no more. A richer bike comes off idle slower, sometimes bogging but has good strong top and higher rev. Corrected it hits sooner, cleaner and pu;;s clean to the top. Stock the crf 05 and 06 are real fat, aren't all the 4t carbs about the same? The more volume sales pitch I find offensive, the o-ring on the adjuster arm good, the shorter diaphragm: if its purpose is to chug more fuel not good,stronger spray might be interesting. The needles being multi-tapered sounds good, and if anyone can tell me what a #30 leak jet could charge, maybe a car?
BadgerMan
Mi. Trail Riders
- Jan 1, 2001
- 2,479
- 10
Ol'89r said:
Yes :cool:
If it is rich off idle, try a larger leak jet. However, if it is hesitating off idle my bet is that the circuit is lean in which case a smaller leak jet is in order and a larger jet will make it worse.
The very first YZ250F's had a terrible bog off idle. A much smaller (or even plugged) leak jet completely fixed the problem.
On older 4 strokes the cover made a good improvement on throttle response and on some bikes minimized bogging/hesitation when landing off big jumps.
On newer 4 strokes there has been significant improvements in the carb, mainly the AP circuit so the cover may not show such an improvement as the older 4 strokes (Y05 and older).
I installed in on my Y05 CRF450R and noticed immediately improved throttle response!
But that was on an older bike than todays bikes that have newer carb modifications to the AP circuit.
If money is tight, you may want to try the AP Circuit mode first which is suppose to work real good - or good enough that you do not need to spend $90 on the cover.
there are instructions on how to do this mod and its quite easy. Two versions exist of it- 1- is just a simple wiring 2-is the wiring and grinding down of the AP needle.
Leak Jet? the cost about $8 and you can the local honda dealer to order. Typically I have seen this changed needed on YZ250F's for some reason. Smaller leak jets force more gas back into the circuit! Which is what most folks want.
Spokes574
California
On newer 4 strokes there has been significant improvements in the carb, mainly the AP circuit so the cover may not show such an improvement as the older 4 strokes (Y05 and older).
I installed in on my Y05 CRF450R and noticed immediately improved throttle response!
But that was on an older bike than todays bikes that have newer carb modifications to the AP circuit.
If money is tight, you may want to try the AP Circuit mode first which is suppose to work real good - or good enough that you do not need to spend $90 on the cover.
there are instructions on how to do this mod and its quite easy. Two versions exist of it- 1- is just a simple wiring 2-is the wiring and grinding down of the AP needle.
Leak Jet? the cost about $8 and you can the local honda dealer to order. Typically I have seen this changed needed on YZ250F's for some reason. Smaller leak jets force more gas back into the circuit! Which is what most folks want.
Spokes574
California
THis comes down to basically Ignorance with money and to many magazines around the house vs. knowing what you are doing.
Yes the cover would be a good cure for the older FCR1 carbs that done have in internal AP rod nor a leak jet. But anything Honda, Kawi and suzuki have the FCR2 carb with a leak jet. The 250F yamahas and all 450s have the leak jets also.
Spending some time checking the timing of the squirt vs the slide and then the movement of the AP rod off the cam will pay big dividends on responsiveness and eliminating the bog off idle. You can further adjust the AP circuit with the leak jet and diagaphrams that are optional in sizes. Typically most of the modern bikes like the leak jets in the 40-60 size range here around the west coast sea-level. This includes all brands, 250s and 450s that I have jetted. Yes leak jets are hard to change especially in the honda and copied honda frames, but worth the time and effort.
Also installing a longer fuel screw so you can adjust it easily should be the first thing you buy for any new 4 stroke MXer.
Yes the cover would be a good cure for the older FCR1 carbs that done have in internal AP rod nor a leak jet. But anything Honda, Kawi and suzuki have the FCR2 carb with a leak jet. The 250F yamahas and all 450s have the leak jets also.
Spending some time checking the timing of the squirt vs the slide and then the movement of the AP rod off the cam will pay big dividends on responsiveness and eliminating the bog off idle. You can further adjust the AP circuit with the leak jet and diagaphrams that are optional in sizes. Typically most of the modern bikes like the leak jets in the 40-60 size range here around the west coast sea-level. This includes all brands, 250s and 450s that I have jetted. Yes leak jets are hard to change especially in the honda and copied honda frames, but worth the time and effort.
Also installing a longer fuel screw so you can adjust it easily should be the first thing you buy for any new 4 stroke MXer.
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