Return of the high revs . . .

Went about 40 miles on the freeway around 75 mph, stopped for a pee (too much coffee).
Restarted the bike and RPM's shot up to 8500.
Turned the bike off and waited 20 minutes or so, started ok, went and topped off the tank 5 miles down the road, started it up and RPM's kicked up again. Started heading home and throttle was acting 'sticky' again (same as the issue I had last year). Occasional hanging elevated RPM's.

Thought I had fixed the issue by loosening butterfly screws and then tightening the throttle shaft locknut on the side . . . Then re-tightened butterfly. Also found diaphragm on #2 must have been loose on the slide as it was turned about 30 degrees - offsetting the 2 little breather holes from the carb throat. . . After doing that the bike ran good. Now today craziness.

Funny thing after about 3 minutes down the road from the gas station the bike ran great 40 miles home.
However - shunpiked it home and didn't go over 60 mph, also the sun was going down and ambient air temperature had dropped considerably.

any ideas?

 

Cable wearing and hanging it up maybe, mine did that once soon after the cable needed replacing

 

DId you lube the throttle cable with something that could become sticky when temperature is colder?

 

Remind us; when you did the carbs did you replace the throttle shaft seals? I think you did, but can't remember for sure.

 

When you had it apart did you polish the slide bores? Did they pass the clunk test?

If the slides are tight and hanging up that doesn't help matters much.

 

Did the Deluxe Rebuild kit a year and a half ago. Included throttle shaft seals.
Replaced the throttle (clutch and enrichment) cables after my clutch cable broke about one year ago.
Slides passed the clunck test. Did the propane test.

As some may recall I had very intermittent elevated rpm issues which showed up months after the carb rebuild.
I replaced the throttle cable and first routed it wrong (doh!) then got it right, then put the old cable back on to see if elevated RPM's was associated with cable.

This is similar in the effect that the butterfly valves are open, throttle cable is slack at the rack and a push of a finger on one of the synch adjustment screws will drop the RPM's.

I foresee pulling the rack, actually breaking it apart (this time) and redoing the throttle shafts and valves. . . . As mentioned before I had originally locked down the butterfly valves prior to tightening the nut on the shaft and noticed a sporadic mechanical hanging up. I adjusted as mentioned above, but without breaking the rack (Fitz would scold me for taking a short cut).

Ironically enough (or maybe this is what cursed me). I just ordered replacement butterfly valve screws from Len the other day because last time I was on them they were getting to the sketchy point.