Open Primary - Pro's and Con's
#12
I haven't looked at belt drives in years. But...
There are the wide belts, 3-4" out now. There at least used to be narrower belts, even ones that would fit into a stock primary case, probably a Shovel. The narrower ones your boards should be fine with.
Truly open primary can be dangerous. I ran an open with chain on a '57 Triumph years ago. Pants and other things could get caught in it, trust me on the pants, wasn't fun. Or if you tipped over on that side and didn't get you foot out of the way. There are covered open primaries. From a simple chromed sheet metal top cover with a screen down the side to the one in the picture.
Lube... Years ago I was told that HD clutch friction plates can be run dry or wet, don't know for sure. I was also told there are aftermarket plates designed to be run dry.
Belt tension.... Again, don't know what is used now to adjust the belt tension when the engine and trans are bolted together like my Dyna. When I had my open, it had a separate trans and it was used to adjust the tension.
If you really want to run one, personally, I like the look of the screen sided ones over the stock looking cover with holes in it.
Hope this helps a bit,
Tom
There are the wide belts, 3-4" out now. There at least used to be narrower belts, even ones that would fit into a stock primary case, probably a Shovel. The narrower ones your boards should be fine with.
Truly open primary can be dangerous. I ran an open with chain on a '57 Triumph years ago. Pants and other things could get caught in it, trust me on the pants, wasn't fun. Or if you tipped over on that side and didn't get you foot out of the way. There are covered open primaries. From a simple chromed sheet metal top cover with a screen down the side to the one in the picture.
Lube... Years ago I was told that HD clutch friction plates can be run dry or wet, don't know for sure. I was also told there are aftermarket plates designed to be run dry.
Belt tension.... Again, don't know what is used now to adjust the belt tension when the engine and trans are bolted together like my Dyna. When I had my open, it had a separate trans and it was used to adjust the tension.
If you really want to run one, personally, I like the look of the screen sided ones over the stock looking cover with holes in it.
Hope this helps a bit,
Tom
Last edited by Tom H; 10-25-2024 at 06:56 PM.
#13
I run opens on almost every shovel I build - mostly because I like hand-shift kick bikes and like the ease of maintenence with the divorced motor/tranny setup - plus no oil - quick clutch access - sh%t like that - plus - it does bring a good look to the bike if done right and fits the build style - I never had issue with the belt rippin up my pants - even ran a floorboard setup with an open - a 3" does stick out a bit but has a nice look on a fat build - skinny bikes like the 1.5" look - not sure if an e-start and open go well together in terms of functionality and that drag bike style look but your bike would look slick with a 3" belt - no covers - and a tattoo on the built itself - here are a couple pics of bikes of mine that I built to run 3" belts - the big black bike was a belt-belt and was really nice rider both in town and the highway
#14
I love a bdl open primary. This is my bike and I've had that specific primary on two bikes that I've built. They didn't have a 1.5 inch one when I got the three inch. Makes any primary work waaaaaaay easier than the stock chain primary. Minor maintenance. Don't buy an off brand one and it will be great. People complain about open primaries and they are often people who have never ridden with one. Just like rigids
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Architect (Yesterday)
#15
what's the purpose of them?
meaning, what makes them a better mousetrap/why were they developed?
for the record, I don't have an opinion one way or another on them.
My only "thought" comes from being a ten thumbs kind of guy and learning to be cautious of not becoming a "nine" thumbs guy
..L.T.A.
meaning, what makes them a better mousetrap/why were they developed?
for the record, I don't have an opinion one way or another on them.
My only "thought" comes from being a ten thumbs kind of guy and learning to be cautious of not becoming a "nine" thumbs guy
..L.T.A.
Last edited by Cap77; Yesterday at 06:58 AM.
#16
Open primary is one less fluid to maintain. One less place for oil leaks. Weighs less than stock primary setup. Zero maintenance, the belt tension is not adjustable. I love the look and the sound of the rattley dry clutch, especially at a red light. Running mine for over ten years, my jeans are not near the belt nor have I ever gotten anything caught in it. Only maintenance was changing the hub bearing last winter. This is the 2" Ultima setup, I bought from Jireh.
And it looks COOL!!!
And it looks COOL!!!
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Cap77 (Yesterday)
#17
#18
If I remember correctly, drag racers used to exceed the power limit on the primary chains, so they went to an open, 3" (??) primary belt. I'm talking about top fuel drag racing classes. I believe they were changed almost every pass.....
Of course, people saw them, thought they looked cool, then they started popping up on street applications..
As far as I know, they are not a "better mousetrap" for a street application...
I have to admit, I think they look cool on a suicide shift, shovel head...
Last edited by hattitude; Yesterday at 08:07 AM.
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Cap77 (Yesterday)
#20
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