Any advantages or disadvantages to open primaries? Harley Transmission, Harley Clutch & Harley Primary Discuss Any advantages or disadvantages to open primaries? in the Harley Tech & Harley How-to forums; Been thinking about swapping to an open primary on the Night Train and before I make any kind of investment I was just wondering what the advantages and disadvantages in ...

[unfknblvbl]

Been thinking about swapping to an open primary on the Night Train and before I make any kind of investment I was just wondering what the advantages and disadvantages in doing this were. My main reason for doing this is just to make the bike a little more mine, plus I think they look bad@$$. I may wait until I get her stroked :goodkitty:

[milindh]

Hey Gunny

There's two types of open primaries. One is semi enclosed but runs a fairly narrow (usually 1 3/4"w) belt and the other is the totally open type you see on some customs (usually 3" w). I have a 3" BDL open primary on my FXR4. The wide units were developed for big inch drag bikes.

The good:

1) maintenance free

2) stays cool and strong grabbing and lasting clutch

3) looks bad (meaning good)


The bad:

1) It makes a loud ding-a-linging noise which comes from the dry clutch
plates clanging against each other. Very obnoxious and it makes your bike
sound like there's something wrong with it, especially when you pull in
clutch. This is considered "normal" according to BDL. They claim to have
a quieter clutch available now but I can't verify that.

2) Reduced cornering clearance with the 3" or wider units like mine.

3) If you go down on the left side it's gonna cost you big bucks to fix it.

4) You can't run mid controls on the shift side. You have to have front
controls.

[Hammerhead Pat]

On certain bikes I think open primarys look OK, but I would think the belts would be better protected from debri ( that word doesn't look right) getting into all those spinning parts. I've also noticed that the bikes with open primarys have a sort of rattle type sound from that area.

[unfknblvbl]

milin- Thanks for the info. I didn't even think about the corner aspect of it. I am looking at a 14mm (which I believe is 2.5") open belt drive. I have forward controls as it is, and I can see it costing big bucks if I were to go down on the left. They're not cheap to start with.

Hammerhead- it's debris You were close enough for me and understand what you are saying. That was the first thought that popped into my head. I could see a rock/pebble getting in between the belt and pulley and doing some damage.

I've read a lot on the rattling and many companies out there who produce open belt primaries are saying they have newer clutches out there where this has been drastically reduced or even gone. As Milin said can't verify it unless we try it. Like I said it is something I would like to do and will probably wait until after I get it stroked. Hopefully that comes sooner than later.

Thanks for the input! Frisco? HC?

[Tbone]

Uh. There's 25.4 mm to 1 inch. 14 mm would be a little over 1/2 inch.
2.5 inches would be 63.5 mm.
They must be measuring something else besides belt width.

[unfknblvbl]

Tbone- Thanks...I'll go back and look at someone of the ones I was looking at...hhhhmmmm. I probably jacked that one up.

[Tbone]

It could have been a 64 mm which would be about 2.5 inches.

[unclepsycho]

hay UNF
As far as going down on that side of the bike being expensive.... uh, when I got back on a bike after having back surgury, people would ask me what I am gonna do if I crash.... my response has been and will always be... " I bought the bike to ride, not crash" so there ya have it.... build it the way ya want to "ride" it. insurance is there for a reason.
PS I think the 3" wide open primary is about as bad-azz as you can get on a bike. the ding-a-ling sound from the clutch is something you get used to, and after a while you dont even hear it.

oh yeah, be ready to have your pant leg eaten by the belt at least once.

[frisco-rigid]

Hey Un

We always used to call the left side the "cheap side" cuz it's the side you wanted to drop if you had a choice..
Dropping on the Outer Primary only scratched it up and in most cases you can still drive it home cuz no machinery got hurt,, and heck, ya don't have to replace it, it's just an outer cover..
The chopped down rear outer piece on the shovel is partially destroyed from several road drops, heck, I don't care about looks..

Anyway, I know that very few new riders think like that anymore..

If you were my best friend I would try to coax you NOT to run a total open primary cuz of the reasons already mentioned..

I run what used to be called an "open" primary--- a full inner and a chopped down 2 piece outer (still very strong, no flimsy cage or expensive crap).. It is waay enough protection for that expensive machinery but well open for efficient cooling..

As far as debris, rain, gravel, dirt,, I have Never had a prob.. I started running my open primarys in 1978..

I'll send you a couple photos Un if you'd like..

BTW--- 14mm is the width of each belt tooth..
The more teeth the greater the tooth to pulley contact and less likely to pull teeth off in a show of force..
Think about it..
An 1.5" 8mm belt has 19 teeth sharing the force/load around the motor pulley at all times, 23 if you use a belt tensioner like me ( I went and counted)..
Using an 11mm or the newer 14mm you have fewer belt teeth meshed with fewer pulley teeth in the same front half of that pulley AND they're longer too providing more leverage to pull it off.. I have seen them with many teeth pulled right off..
And here's the goof of it all---- the actual "belt" part of the belt is the exact same thickness regardless of the tooth size, soo ah, why the bigger teeth..
That's like a 95lb. weakling with 18" biceps.. Yawn..

I've stated here in the past that I have only broken three 1.5" 8MM belts doing Beau-Coup hole-shots and general mistreatment,, 2 on the 120" and one on the shovel.. When I break em, they pull dead in half.. Yeah baby..!

[Tbone]

Originally Posted by frisco-rigid

Hey Un

BTW--- 14mm is the width of each belt tooth..
The more teeth the greater the tooth to pulley contact and less likely to pull teeth off in a show of force..
Think about it..
An 1.5" 8mm belt has 19 teeth sharing the force/load around the motor pulley at all times, 23 if you use a belt tensioner like me ( I went and counted)..
Using an 11mm or the newer 14mm you have fewer belt teeth meshed with fewer pulley teeth in the same front half of that pulley AND they're longer too providing more leverage to pull it off.. I have seen them with many teeth pulled right off..
And here's the goof of it all---- the actual "belt" part of the belt is the exact same thickness regardless of the tooth size, soo ah, why the bigger teeth..
That's like a 95lb. weakling with 18" biceps.. Yawn..

I've stated here in the past that I have only broken three 1.5" 8MM belts doing Beau-Coup hole-shots and general mistreatment,, 2 on the 120" and one on the shovel.. When I break em, they pull dead in half.. Yeah baby..!

Thanks for clearing that up Frisco. I learned a little more here. I also should have known that the Gunny didn't make a mistake.
I'm pleasantly surprised that you know a traditional Cajun term of "beau-coup" to mean "many". I don't hear that much outside of Cajun Louisiana. You must be a man of many talents and well-traveled.