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Old 02-20-2007, 11:18 PM   #7
Cheese and Rice!
potatoho's Avatar
Joined: Aug 2004
Location: Sea-level
Oddometer: 4,706
Originally Posted by rjf
See, I'm the oposite, using the clutch is no worries, but the BST is what annoys me. I just had my suspension re sprung and re valved so that should reduce the bog a bit (hopefully), and lowering the float level lower will hopefully eliminate it.
I will have my souped up BST running within a week or so. Today I just began work on making the LC4 rideable again. That ids2 is some piece of work, you know. That is the hardest thing in the universe to repack. I felt like filling it with FFF and sealing the ends just to get some satisfaction.

I scoped out a location for the O2 sensor on the right side of the midpipe. I should be installing that tomorrow.

BST40 mods:

* grose-jet instead of useless float needle valve system
* dial-a-jet installed onto airbox boot
* bore divider on intake side
* loaded's fuel mixture screw

I wanted a full set of needles to work with but the ones I ordered don't fit correctly, so I only have OEM to work with. Hopefully that will get me somewhat close to correct AFR. That's the most important part, and the reason I'm going back to the BST. I want to dial it in to a reasonable mixture with the jet4power meter. Honestly I have no idea what the stock settings will look like on the meter.

I think when I was jetting by seat-of-the-pants I was going around in circles. I couldn't have been anywhere near the ideal mix. I know on my two stroke it was all over the map until I dialed it in with the help of the meter. This should be a lot easier, without having to worry about premix fouling or low exhaust temps screwing with my readings. The downside is that I have no needles to swap on the BST so I'm scratching my head as to how tightly it can be tuned.

One thing I did before was I installed an intake bore divider on the BST. I think it ties in with something Creeper mentioned above about intake velocity. It added quite a bit of off-idle torque, in fact it was the one time I actually had it running like a champ, but then it broke and I didn't feel like fixing it so I went off to the pumper carbs. I got better at machining the divider by slotting the bore and using thicker material, so that's what I'm doing to the BST. I need to get a baseline AFR reading first though.

I actually didn't have a good experience with dial-a-jet before when I used it. I ran it for a while on a two stroke. I became convinced that a two stroke doesn't care at all about fuel atomization at the carburetor, so the dial-a-jet didn't offer anything. On the BST, my belief is that it will provide enough supplemental atomized fuel to cover the transition periods of the slide. So in effect, it should behave similarly to an accel pump.. as a quicker acting siphon than the main jet.

I think my ignition is kinda flakey too. I need to go through my electricals and make sure things are proper.

potatoho screwed with this post 02-20-2007 at 11:39 PM
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