Break in

tz375 · Post by **tz375** » Sun Apr 12, 2009 10:00 pm

John,

Did you raise the needles this time, or are the clips in the stock position?

It should hold a steady rpms but with CV carbs anything is possible. My guess is that 6,000 with very little throttle probably has the CV carbs trying to work out what to do about it.

bighole · Post by **bighole** » Mon Apr 13, 2009 6:38 am

Richard,
I will have to go back and check my notes as I went through several jet sizes and clip positions until I found the best combo because of the porting changes. I didn't adjust any settings sinve the overbore yet. Would boring 1st over require needle or jet changes?
-John

tz375 · Post by **tz375** » Mon Apr 13, 2009 8:43 am

Unlikely that a rebore would need a jet change. Did you ever work out what caused the meltdown last time?

The most common cause of melted pistons in my experience is lean on the needle and they melt down cruising along on about 1/2 throttle. Yours was a more sever as I recall and involved a broken rod.

bighole · Post by **bighole** » Tue Apr 14, 2009 8:26 am

The last meltdown on this bike was back in the fall when I chopped a piston ring (due to a crack in an expansion chamber). The broken rod was on the 73, still havent figured out why...
-John