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Any of you Hexheads tried "tensioning" your Alt belt yet?


KMG_365

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We had an interesting revelation at "1bmwfan's" NorCal Tech Daze last week: there is no longer any tension adjustment and BMW requires a "special BMW Tool #blah-blah-blah" (probably 70-200 bucks! tongue.gif ) to slip it on over the two pulleys which are now fixed in their orientation.

 

When "bakerzdosen" checked his out he noticed a nice small hole in the middle of the belt with cracks that were starting to run lengthwise. To be sure that he changed it and didn't continue to ride on in such an unsafe condition, someone else (who shall reamin nameless) cut the old belt off with a pair of cutters. It was around that time we learned about the info in my first paragraph! blush.gif

 

"Stubble" took some interesting video of me trying (unsuccessfully) to do it the old "oilhead on the side of the road and do I really have to pull all this Tupperware?" method followed by a reenactment of how Eric Sokoloff and a few friends--in less time than it took Matt and me to walk a block, buy a large crescent wrench and return--slipped on the new belt with a piece of heavy nylon string! eek.gifthumbsup.gif

 

Check out his post here (linky).

 

It was also pointed out that the ST has a cable under the seat (used for a helmet lock, I suppose) that would make an excellent alternator belt installation tool! How thoughtful of BMW to provide you with that--I mean who needs the rest of the tools?? grin.gif

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OK, I don't get it. Explain the "string thing" please!
OK, string thing:

 

You can always buy the BMW tool if you'd like. However, if you want to slip a belt over a pulley without being able to loosen the tension, you need to somehow be able to pull on the belt and get it over the pulley. However, the problem is that we couldn't find any volunteers to stick their fingers between the belt and the pulley while someone cracked the engine (for some odd reason). So, if you use a piece of string or thin twine or even the helmet lock cable, you can wrap it around the belt, pull on it while cranking the motor (either using the starter, or if you pull the plugs to relieve compression, you can turn the rear wheel while in gear) and it is relatively easy to get it on.

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OK, I don't get it. Explain the "string thing" please!

 

In the video note that Jamie is trying to push the belt on.

What I did was to pull the belt on using a piece of string.

Also I elected to pull the plugs(one per head) & turn the motor via the back wheel

I used my bare hands but you could improvise handles using screw drivers or other implements.

As stated the cable helmet lock looks like a built in means to pull the belt on. Just loop the cable around the belt bring the two ends together & insert a screw driver through the ends & pull.

Also note that I did not put the belt all the way on the alternator sheave(pulley).

By only putting 1/2 way(or so) on I felt it would be easier to get the belt on the lower sheave.

After the belt was on the lower sheave I was able to coach the belt fully on the alternator sheave.

 

NOTE that this task can be dangerous & if done incorrectly you could loose a finger or two(or more).

 

KNOW this before attempting this task.

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We have belts? eek.gifwink.gif
grin.gif

 

Yeah, and the weird thing was Matt's hole was poked through from the inside and it was right in the middle. In fact it looked almost like it might've been MADE by the special BMW Tool (part # blah-blah-blah) when it was installed the first time. It only had 12,000 miles on it and if I recall the hexheads alt belt compartment was more sealed up than the oilhead's one. The back of the oilhead's alt belt compartment is half open and you can see on our bikes the accumulated sand and rocks that bounce around behind there and end up drifting into a pile on the front of the engine behind the cover. I surmised that our early belt failure might be due in part to sand or even "very small rocks" (bonus points for the geek reference! grin.gif ) getting (hint: floating! dopeslap.gif ) in between the sheave and the belt and breaking the fibers as they were pushed into the rubber. Either that or a gradual "sanding" down of the ridges on the sheaves themselves so that the ribs of the belt "bottom out" and the sharp points of the sheave slice the belt along the valleys. I've found many grains of sand embedded in the inside ribs of belts removed before complete failure. It might be all that riding through the sand-filled desert winds at 90+ mph that contributes to shortened life. Hmmmmmm . . . . confused.gif

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[quote90+ mph that contributes to shortened life. Hmmmmmm . . . . confused.gif

 

Confused is right! Have you seen Matt ride. 90 +?????? confused.gifconfused.gifconfused.gifconfused.gif

 

Does he know how to even do that???? dopeslap.gifdopeslap.gif

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Yeah, and the weird thing was Matt's hole was poked through from the inside and it was right in the middle.
Um, that just sounds either really wrong or really painful... eek.gif

 

Does he know how to even do that????
According to that nice Nevada LEO I do...

 

And actually, he HAS seen me ride that fast. Come to think of it... haven't you? wave.gif

 

Burn the witch! Burn the witch! Burn her! Burn her! (As I said... King of obscure trivia...)

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[quote90+ mph that contributes to shortened life. Hmmmmmm . . . . confused.gif

 

Confused is right! Have you seen Matt ride. 90 +?????? confused.gifconfused.gifconfused.gifconfused.gif

 

Does he know how to even do that???? dopeslap.gifdopeslap.gif

 

 

 

Phil, I said:

I recall the hexheads alt belt compartment was more sealed up than the oilhead's one.
I was talking about MY belts failing early due to MY incredible riding prowess. ( . . . and the fact that our belts are less protected from road debris smirk.gif ) Matt's looked like it was damaged by a tech in the factory. eek.gif

 

In any event the takeaway from this story is it was good that Sagerider talked him into checking it out--even though he only had 12,000 miles on it (and there is no tensioning procedure)--as it's hard to say if it would've made it to 36,000 miles. blush.gif

 

 

Oh, and nice job picking up Tasker's old title! lmao.gif

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Oh, and nice job picking up Tasker's old title! lmao.gif

 

I

sure

wish

that

old

title

would

go

away

as

it

wasn't

ever

really

deserved! eek.gif

 

eek.gifeek.gif

 

What he[quote

 

 

 

 

 

 

 

 

 

saidquote[]!!!!!!!!

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Some belts actually come with a little curved metal tool to assist in putting them on, and taking them off.

 

It really isn't that hard, and you could make one from some thin aluminum or steele.

 

Jim cool.gif

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If you are alone it is hard to hold the belt in place and turn the rear wheel at the same time smirk.gif . My trick is to remove the motronic fuse, no. 5 on my bike, so the engine can crank but not start. I can hold the belt on with one hand and give a quick push on the starter button. I still have all my fingers... grin.gif

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Good idea Paul but there are no fuses to pull on the Hexheads. I would likely use the crank pully bolt to rotate the engine clockwise. thumbsup.gif
To do that on the side of the road you'll need to have a very large wrench with you. We didn't measure it, but it looked to be about 30mm. Phil didn't have a socket or crescent wrench big enough which is why Matt and I missed Eric's string theory! grin.gif

 

I suppose a very large crescent wrench in the bottom of your sidebag could do double duty as a means of self defense as well . . . should the need arise. eek.gif

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Well I used the resources I had at hand, manly a lot of man power.

I'm sure a method could be figured out how to perform this task without so many hands.

Perhaps this next Tech Daze we could nock, errr put our heads together & come up with a solo solution.

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Your are correct about the roadside scenario. I don't carry large sockets on the road or a spare belt for that matter. I like to keep things as light as practical, so special tools or many spare parts are not carried. Everybody has a different comfort zone.

 

If I had an on road belt failure it would show up pretty fast as a general warning light and a flat panel battery icon. I would then power down the GPS and XM. I would also power down the headlights and have an easy 2-3 hours to find a place where I could get a belt replacement (BMW or NAPA) and a tool if I didn't have another person to help with the rear wheel spin. I inspect the belt every 6000 miles when I use the crank pully bolt to set TDC. This way the belt wear is seen on a regular basis. Fortunately, the hex head front cover is much easier to remove. thumbsup.gif

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:

 

I suppose a very large crescent wrench in the bottom of your sidebag could do double duty as a means of self defense as well . . . should the need arise. eek.gif

 

I usually have something much more effective, but it sucks as a wrench lmao.gif

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