Possible over heating symptom?

[itstartswithken]

Hi everyone, I feel the need to pick your brains on this one.

Just a somewhat brief background, I got my 07 with 14k. Supposedly previous owner checked valve clearances. *shrugs*. Around 16-17k bike started having rough idle issues. I'd stop at a light and the idle would stay at 4500 with clutch engaged. I could get it down to 1400 when I'd let the clutch engage a little through the friction zone. But anytime I gave it throttle, it'd get stuck there. So needless to say, whenever I started the bike up I never was in Neutral, because it was near damn impossible to kick it to first gear at 4-5k.

I also had difficulty starting when the engine is cold.

Well, I did my first valve clearance around 18k and found the L/R exhaust to be out of spec. Too tight. Buckets were still barely moveable. I got them up to spec. That fixed the rough idling and the starting.

Fast forward to two days ago, I had a trip to Las Vegas (I'm from Los Angeles). It was hot! The hottest part on my trip was about 105-110 getting caught in that 15S gridlock on Memorial Day.

I feel like it may have started to overheat. My rough idling issue came back when I got off the freeway to get a cold drink. And then after the engine was off, when I tried to start the engine it wouldn't. I had to put it petcock to Reserve even though I still had 3+ gallons. Filled it up, switched back to On and arrived in LA where it was way cooler. Later in the evening (after some cooling off) I started it and the rough idle went away.

Long story short, would the over heating cause valve clearances to get tighter? I've read in other threads where when you start cold and you have tight clearances as it warms up the clearances loosen up. That doesn't make sense to me. Still trying to make sense why as it gets hotter it gets looser instead of the opposite (doesn't heat cause metal to expand?).

[Gorilla]

As far as you being sure it was 3+ gallons.

Look in the tank. If it looks halfway full your down to 1-1.5 gallons. Which at that time is reserve fuel. Keep her topped off to a very high degree and issue might go away.

As far as doing valves. After about 600 miles i re checked my valves after i had done an adjustment and i again needed adjusting. But only slightly. Maybe same thing for you?

[gsJack]

...............................Long story short, would the over heating cause valve clearances to get tighter? I've read in other threads where when you start cold and you have tight clearances as it warms up the clearances loosen up. That doesn't make sense to me. Still trying to make sense why as it gets hotter it gets looser instead of the opposite (doesn't heat cause metal to expand?).

Valve clearances do get looser as the engine heats up. The aluminum head and the steel valves both expand as they heat but the aluminum expands more than steel does lifting the camshaft away from the valves/tappets, aluminum has a greater coefficient of linear expansion.  Tight valves will get clearance and tight buckets will loosen up quickly as they heat, usually within a minute or so unless they are very tight.

I set exhaust valve clearances at .003-.005" (.08-.13mm).  Suzuki's tight tolerances do not provide enough cooling seat time for exhaust valves requiring more frequent shim changes with shorter valve life.

[itstartswithken]

As far as you being sure it was 3+ gallons.

Look in the tank. If it looks halfway full your down to 1-1.5 gallons. Which at that time is reserve fuel. Keep her topped off to a very high degree and issue might go away.

As far as doing valves. After about 600 miles i re checked my valves after i had done an adjustment and i again needed adjusting. But only slightly. Maybe same thing for you?

I was 100% sure. I log every fill up and that time it took 1.08 gallons to fill up completely.

I'm going to re-check the adjustments then this weekend. But it's strange, once the engine was cooled off, my idling issues went away.

I set exhaust valve clearances at .003-.005" (.08-.13mm).  Suzuki's tight tolerances do not provide enough cooling seat time for exhaust valves requiring more frequent shim changes with shorter valve life.

I have mine set to .11 for the left and .05 for the right (FYI: the intake L/R are set to .08 and .09). That rough idling may not be related to the shim clearances but I'm just associating this past Monday's issue with it because that's what I experienced in the past.

[JAS6377]

Did you sync the carbs after the  adjustment? They may be out of sync, which could very easily cause weird issues. Also, if they haven't been cleaned recently, that might not be a bad idea either. These bikes run lean from the factory anyway, and anything that causes them to run any leaner could cause overheating.