clutch issues at high elevations

[meach]

So recently returned from a trip out west. Did around 7,800 mi in about 24 days. Visited some family along the way. Bike ran great the entire trip, even at the highest elevations with the exception of following clutch problem.

 

No issues with clutch until I came down from Stanley, ID passing thru Sun Valley. Not long after you climb to around 8,000 ft. I had pulled over to an over look and when I went to change gears I had virtually no clutch. Yikes. I got going again by rolling down hill from the pulloff and putting it into gear and was able to change gears without the clutch. As I went down the other side the clutch pressure returned either as a result of lower elevation or fluid cooling off. Turns out fluid was low so eventually found some DOT4 and added fluid which seemed to help. Still didn't shift as well at higher elevations (or maybe due to being hot due to climbing or old fluid). After leaving the mountains back across KS the clutch seemed fine even after riding all day in 90 degree heat.

 

comments/suggestions?

[MiCarl]

I suspect it had nothing to do with the elevation but with the going up and down. Fluid was low and going up the hill you managed to suck some air into the line. Angled back down more fluid got into the MC and you started to have some clutch. You topped up the fluid and all the air eventually worked its way back out so now your clutch works fine.

[Pic]

When was the last time you changed clutch and brake fluid. Probably need to change both to all fresh.

[meach]

I suspect it had nothing to do with the elevation but with the going up and down. Fluid was low and going up the hill you managed to suck some air into the line. Angled back down more fluid got into the MC and you started to have some clutch. You topped up the fluid and all the air eventually worked its way back out so now your clutch works fine.

 

Yea I had thought of that as well, had been going up and down a lot of hills just none above 7,000. Although I could could shift at higher elevations later the clutch felt softer the higher I went. Possible I guess that the elevation affected what air I had in the line when I was up at 10,000+

 

When was the last time you changed clutch and brake fluid. Probably need to change both to all fresh.

 

Yea the fluid needs to be changed. It was an over site on my part not to change it out prior to my trip. Because the sight glass is somewhat hidden behind audio control (being tall I have to stoop over to see the sight glass) I overlooked it, also all my older bikes were cabled clutches.

 

This will give me an excuse to go back out to the Rockies to make sure my clutch is working fine.

 

This last trip I rode thru Glacier (Sun Road), Yellowston, RMNP, Beartooth, Chief Joseph, and more.

[bongobobny]

Do NOT go by the color of the fluid inside the MC, what matters is on the other side of the MC!! It's not like a pump system where the fluid gets flushed back to the reservoir. All the fluid does is move from the plunger of the MC to the clutch slave and back again. When the MC gets black looking that's when there's REALLY problems from neglect! You should flush all your hydraulic systems every 2 - 4 years...