Belt....miles or age?

Just picked up a 2008 RT. I've completed oil/filter, air filter, brake/transmission/final drive fluids changed, but yet to do alternator belt. I know it's 9.5 years old, but it has less than 8,000 miles...think belt is an automatic must do because of age or can I wait?

08 with 8K......
OM

It’s cheap enough to replace, specially with that age. Belts do crack after a while....

RIDERR1150GSADV said:

It’s cheap enough to replace, specially with that age. Belts do crack after a while....

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I agree but will also offer: Two things cause the belt to deteriorate more so than age. Ultra violet (UV) radiation from the Sun and heat cycles from the engine. The belt is not exposed to sunlight and the low miles is few heat cycles. I would inspect the belt for any sign of cracking. Absent the same, ride on.

BMW puts an age limit on the belts. I think it’s five years but I’m not at the shop. You can either analyze it and make up your own mind or just change it and forget about it. In the shop, I just change them so that no one needs to think about it again. None of my customers’ bikes have ever had a belt failure that I’m aware of.

As far as I’m concerned, BMW did the homework here. I don’t need to redo it.

Miles will kill a belt on the boxers. There was a picture here a couple years ago of an R1200xx with a total shredded belt at 45K miles that had never been changed. Even with the spring coupler on the alternator, the slowing down of the crankshaft as it goes up on compression, and the the jump on ignition, just beats these belts to death. As opposed to a car, where they can run 100K miles and look new.

No idea how long they last due to age, but modern belts on cars last easily 10 years, but they have a much easier life.

tinytrains said:

No idea how long they last due to age, but modern belts on cars last easily 10 years, but they have a much easier life.

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Because of what reason? The tension idler pulley? On a related note, why does BMW say to replace the spark plugs every 12k, but spark plugs last 100k in my car?

I think there is a valid reason for their recommendations, I just don't know what it is.

Cars' belts are made of some very tough stuff - our belts (on the bike, that is...) are pretty soft.
In many cases, cars' belts are running at a lower RPM than ours, and their pulleys have a larger radius for the belt to turn through (the same reason that larger sprockets will help a drive chain live longer).
Also, since they are typically so much longer, they have more exposed surface area to dissipate heat buildup.

Many cars' spark plugs these days are Iridium-tipped - they last a long long time (but are quite a bit more expensive than "standard" plugs). My local Toyota parts guy told me to not even think about the plugs until it hits 100K miles; this was verified by two independent mechanic neighbors - if it starts easily and idles well, the plugs are most probably OK... Personally, I may not wait that long, they're easy to get to and I can afford it...

The constant pounding of a big twin is bound to jerk the belt to death.

Interestingly, when I changed my belt on my 2009 R1200R, I swear the alternator pulley had a spring coupling to help dampen out the power pulses and ease the life of the belt and alternator. But looking at pictures online, all I see a solid alternator pulleys. I wish i had a photo, but there were two springs between the outside of the pulley and the center piece to allow some dampening. Has anyone else seen this?

Or I am just losing my mind.

Had a call from a fella yesterday afternoon on a Camhead RT. Alt light on and burning smell as he was coming into town headed to Houston. Found me and rode out.

He had routine maintenance over 78K and a few trips to AK. He was going to go back through records and see if/when the belt was changed.


Anyways... had one and sent him on his way

henzilla said:

Had a call from a fella yesterday afternoon on a Camhead RT. Alt light on and burning smell as he was coming into town headed to Houston. Found me and rode out.

He had routine maintenance over 78K and a few trips to AK. He was going to go back through records and see if/when the belt was changed.


Anyways... had one and sent him on his way

View attachment 66773

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Geez Steve, do not leave us hanging..... did he need to replace the belt or not?

akbeemer said:

Geez Steve, do not leave us hanging..... did he need to replace the belt or not?

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Yeah, told him as it was falling out as I removed tne cover it may be time to replace

I think I still see a continuous loop in there... not sure what the problem is?

Peace of Mind. If you're thinking about it, change it.