Sunday, January 3, 2010

RD400 carb work

Well it's time to start screwing with the old two stroke again. I took a extended brake after this spring when I had hand problems. I started to replace some of the engine mount bolts. The longer engine bolts will be a big issue for finding replacements.

Two of the short engine bolts in and two nuts on the really long mounting bolts. The ACE hardware by my house closed and they were my source for metric flange head bolts. Now I have to another ACE about nine miles through road construction. Kind of a PITA but at least I don't have to mail order them.
Next up is replacing the needle and seats in the carbs. They are original and were seeping when the bike was off and dripping on my floor. You don't want that with a heated garage and forget to turn off the petcock. Besides that, just getting a good tune out of the engine could be hard.
bowls off and seat needing to be removed..
The original needle was just brass on brass. The trick is to replace with a rubber tipped needle style.
Top one is the good style.

If you click on the picture you can see the wear groove on the needle.

The spec out of the RD forums is to set the float height at 23mm +/- 1 mm. You can see mine are set at about 20mm and that would put more fuel in the bowl.

After many small adjustments it's set on the money. I'm expecting a little better control of fine adjustments at idle and a little smoother off idle drive-ability. For now I have to wait another weekend to pick up yet some more bolts behind and under the carbs to see if this will make a difference.

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