Harley Davidson Drive Belts?

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planespotterhvn, Mar 11, 12:34am
How often do they tear and break! How well do the handle stone ingestion! How much to fit a new one!
carstauranga001, Mar 11, 12:42am
A mate had one break due to a stone. Not good as was in the outback at the time. I'll stick with my shaft drive thanks.
tonyrockyhorror, Mar 11, 1:47am
I sometimes ride with guys on Buells and they're always complaining about the rubber band breaking due to stones etc.

Exposed toothed belt final drive and our roads simply don't mix.
brokebloke1, Mar 11, 2:24am
x1
HD recommned that you change the belt about every 30-40000kms
By the way they are easy to change I did one last xmas on my Harley never done one but it took me 30mins
m16d, Mar 11, 3:12am
Real motorbikes have chains.
tonyrockyhorror, Mar 11, 3:34am
Yep. I can understand the elderly wanting shaft drive though, because they're past chain maintenance.
i-n-horz, Mar 11, 5:39am
Had a stone imbedded in me Softails belt for 8yrs.wasn't a biggy but it did protrude through to the other side.thought that poking around removing it wouldn't be of a benefit.years later ended up converting to chain during transformation into the ol'skool Bobber styling.
Bro inlaw broke 2 in one weekend on a gravel road Westcoast, mate done a quick run with a replacement which was installed in a sodden relic of a dirt floor shed in 45mins to an hour then busted that on arrival home.some have all the luck ;)
carstauranga001, Mar 11, 5:56am
I'm not elderly! My St1300 tyres arn't just worn in the centre you know!

What's the average age of a Harley owner BTW!
offrd1, Mar 11, 6:36am
Ido prefer chains,but don't mind belts to much.the secret seems to be [ I've done this for years as do my mates ] run your belt a lot slacker than recommended,the stones [ most of the time.lol.] will pop through with out splitting the belt and the wear seems to be ok,ive done 30miles on mine so far [ 50k's ] all ok and i do a fair amount of gravel riding
mopar63, Mar 11, 6:54am
my old xj750 was a shaft drive , by no means a fast bike but did like forgettingabout the chain,which I was forever adjustiing and oiling on my Kwacka Triples
planespotterhvn, Mar 11, 8:23am
How have HD arranged the countershaft / swingarm pivot geometry so that the drive belt tension does not alter throughout the suspension travel! Chains are hard enough to tension right, most people have them much too tight and they become mega tight on suspension compression, wearing out your chain, sprockets, rear whell bearings and countershaft bearoings and shaft seal. I imagine Harley Davidson Drive belts will be not much difference in that they will both get tighter under suspension compression.
gunhand, Mar 11, 8:30am
Your right, its surprising how many riders do not sit on ther bikes after tightining the chain. When ya show them just how tight it gets you see a little bit of concern in there eyes lol.
offrd1, Mar 11, 9:04am
LOL.good question,never really thought about it.have no idea
i-n-horz, Mar 11, 9:21am
From a Harley Tech forum:

There are lots of opinions on belt tension, but some of those who say they actually talked to engineers at Harley claim those engineers recommend running the belt tight.I don't buy into the theory that running it tight will cause it to snap or ruin bearings.Consider how much stress is on that belt and the bearings when that bike is actually under power and load, especially when loaded 2-up and someone is lugging it up a mountain.The stress you put on the belt with a tight adjustment pails in comparison to the stress under dynamic loading.I can see running it slack causing more damage due to shock loads.In hot weather my belt gets so tight it is downright scary.Of course I have had a belt snap too, so go figure.
trogedon, Mar 11, 9:43am
National's Belt tighening policy.
planespotterhvn, Mar 11, 10:20am
Hmm pretty well disagree as the belt or chain if over tensioned is pulled tighter by the leverage action of the suspension and the entire weight of the bike and riders and luggage and fuel is amplified by this leverage and bump shock load will further pull on this overtensioned chain/belt. Someone needs to put a Harley on a bike lifter, take the rear shocks off and check which position of the swingarm will be the tightest for the belt. Set the correct tension at this position, put the shocks back on an put the bike back on the ground on the side stand and recheck the belt tension. I reckon it will be looser than the max tension you previously set. Now measure the free play of the belt and that floppy loose belt it the max tightness it should ever be. Argue, agree or disagree!
nzeva, Mar 11, 10:20am
Toothed belts aren't like chains which can run loose. They have to be run tight, otherwise the pulleys strip off the belt teeth, which is what happens to loose engine cambelts, resulting in bent valves.
Because they have to be kept tight (which increases friction and consumes energy) toothed and V belts are an inefficient way of transmitting power.
Still the most efficient way after 100 years or so is the chain, that's why bicycles still use them.lol
thunderbolt, Mar 11, 10:28am
Synchronous belts (toothed) use positive engagement provide drive, no friction is involved. Due to the lower weight and higher flexibility they provide the most efficient way transmit power.
V belts use wedging and friction to transmit power and are at least 5% less efficient in comparison.
nzeva, Mar 11, 10:36am
I think you'll find friction is involved, if toothed belts get oil on them they'll immediately slip and strip! Happened to me when my Mk3 Cortina stripped a cambelt from a leaking oil seal. Luckily they don't have an'interference' motor, so no bent valves!
planespotterhvn, Mar 11, 10:36am
So.have HD arranged the geometry of the rear axle / swingarm pivot / countershaft "pulley" so that an even tension is maintained throughout the entire upward and downward movement of the rear swing arm. If not then a fair amount of flappy looseness is mandatory at some positions of the swingarm.
offrd1, Mar 11, 10:39am
Never ever had that problem and have always run loose,i have never replaced a pulley.only went the loose way as was stuffing a lot of belts with rocks,now not having that problem,been doing this since the 90's.maybe i'm lucky.[ so far ]
nzeva, Mar 11, 10:44am
While I don't have a Harley to check, a well designed motorcycle will have the front sprocket/pulley on the same 'plane' (that is, beside) the swing arm pivot, so that under suspension movement the chain adjustment/belt tension remains the same, eliminating any chance of problems.
thunderbolt, Mar 11, 10:54am
Still wrong. The oil will break down the neoprene that your particular belt was made of, and the belt will fail most likely from the teeth stripping off.
Most high quality belts have a nylon tooth facing to ensure there is no friction when the teeth engage with the sprocket.
thunderbolt, Mar 11, 10:58am
Still the most efficient way after 100 years or so is the chain, that's why bicycles still use them.lol[/quote]
OEMs use timing belts over chains because they are more accurate and more energy efficient.
You may also want to google Gates carbon drive if you think all bicycles use chains.
tonyrockyhorror, Mar 11, 11:22am
Concentric to the final drive output, not planar.

But it's not simple to achieve without a lot of extra manufacturing work and added maintenance issues so it's not really suitable for mass-produced bikes. IIRC Bimota did it on a model. But at the end of the day it's simply not worth the expense - the benefit is so small. Chain adjustment just doesn't need to be that accurate - you much get more variation from eccentricity of sprockets once they start to wear.