Thumper talk install#

My stock pump timing was around 4.5 secs and now it is around. I also used a spring out of a pen that you write with. You dont have to use a 4mm bolt I used a 6-32 1' long flat head screwdriver bolt.

This may sound comlicated but is the only way to get rid of the pesky bog off the bottom. 3 seconds with the adjustment screw you just installed. The timing is close when the spray just misses the slide. It may seem weird but it works! Also you need to adjust the pump timing screw so that it does not hit the slide when it is raising. I usually click the stopwatch at exactly the same time I turn the throttle and click it again when I see it stop. Remove the subframe so you can look down the throat of the carb and with a stopwatch time the length of the pump spray when you stab the throttle.

Thumper talk install#

Brian Kinney is Tim Ferry's Factory mechanic (and the originator of the BK mod) and these were his instructions.To limit the accel pump spray length you must drill and tap the pump cam stop and install a 4mm screw/spring combo.

Your jetting will most likely need to be richened up since this mod shortens the duration of gas sprayed (from 1.7 secs stock to. It also will give quicker throttle response and eliminate the bog off the bottom. When this mod is done correctly is will make your bike run and start better.