First I apologize for being a shameless name dropper, but I am so stoked by what transpired yesterday I have to share it.
After wading through so much discussion about tuning the BST40 here and on other websites, I finally decided it wouldn't hurt to take the bold step of shimming the needle and getting the extended fuel mixture screw. I found that Kientech Engineering has them for just $15. Jesse's name and phone number appear prominently on the banner at the top of the page, and just below that I could hardly believe the address I saw in fine print; a place nearby!
The time is a little after 8 am Monday morning and according to their website they are open for business, so I call the number and a woman answers confirming I have reached Kientech Engineering. When I ask her if Jesse is available to speak with me about a DR650, she answers in the affirmative and puts him on. Our conversation went on for about 20 minutes with him generously answering my questions and giving me a general idea of the extent of his work. Of course he's got the extended fuel screws, and he explains he has them made right in Grants Pass by a firm having some kind of impressive CNC lathe, and he's got the SS carb screws, and my DR carb is lying on the workbench in the garage just waiting, so I get things together and drive over to Kientech Engineering.
There is no sign announcing the business, just the last name and address confirming this is the place. Passing a large shop building next to the driveway, I pull up and stop by the house. The door to the shop building slides open behind me, and when I identify myself as having called that morning to the man in the doorway, Jesse invites me inside. The first thing I see, besides all the machinery for welding, bending, grinding, you name it, is a DR650 frame elevated with an engine having various sections cut away. This is his mock-up for fitting his aftermarket parts. He showed me his oversized header and mid-pipe for the DR which he makes to fit the lighter and less restricted cans such as the GSXR. I mentioned that I like the quiet stock exhaust and he showed me one, don't recall the model, which he said was only slightly louder than the stock exhaust and of course weighs much less. Jesse also says his oversized header and mid-pipe run much cooler than stock, saying a heat sensor will show the stock setup can get as hot as 600 degrees F, but his are so effective at pulling heat away that they only get to half that temperature; cooler running temperatures contribute to engine longevity.
Though I am only after a few screws on this day, I certainly enjoyed the short time I had with Jesse at his workshop where he produces all his acclaimed pieces for the DR and other bikes. There is no question where I will be going for my future DR upgrades.
Getting back home, the needle shimming went smoothly, but I found the washers I selected for shims were 1 mm thick! I put one in. Jessie recommended I start with the new fuel mixture screw at 3/4 turn out from bottom. The old screw was out 2 1/4 turns! The bike started but wasn't quite right, more popping than before. After warming up things seemed best with the mixture screw out about 1 to 1 1/4 turns, both idling and revving in neutral. Hopped on, took it down the road a mile and rolled the throttle on and off coming back. It runs excellent and no decel popping at all.