HarleyTechTalk

Considering converting my primary chain to a belt drive. Currently running a Barnett Scorpion Clutch which is designed to run dry. Since I have a chain, I keep a bit of Trans fluid in the sealed primary. In order to go open belt drive, what would I need to change?

Surf Karata and Primo's web pages, it's pretty straight forward. Engine sprocket, clutch basket, belt. I actually went the other way, converted back to chain. A little head's up: if you do this, start thinking how you're going to slot the inner primary engine bolt holes so you can adjust the belt. Like the stock HD inners are that came with belt primary.

-JW

Good point on the adjustment. Didn't think about that.

Also, primary belts break. Chains, rarely so.

Yup. I know.


-JW

if i had the chance id go back to chain.your stuffed if you break a belt anyway my primo belt came with a metal roller adjuster

This is why I love this forum. You guys always prevent me from doing dumb "Potty mouth". Lol. Thanks for the info fellas.

Quote from: JW113 on June 11, 2019, 11:09:19 AM
A little head's up: if you do this, start thinking how you're going to slot the inner primary engine bolt holes so you can adjust the belt. Like the stock HD inners are that came with belt primary.

-JW

Ive never seen a stock inner case , not doubting , Ive read about them before but there are no pics.

any pics out there?

I got a BDL 11 mm with and idler bearing makes it easy to adjust belt.It was on when I bought it , at first I didnt care for it but it seems OK so far.

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Slotting those holes does little unless you break off the O ring lip on the motor case.

Quote from: capn on June 13, 2019, 02:45:58 PM
I got a BDL 11 mm with and idler bearing makes it easy to adjust belt.It was on when I bought it , at first I didnt care for it but it seems OK so far.

im still running the same belt 35 yrs on

those aren't the holes I was thinking. I thought it would be the trans holes, because of the O ring

but that's the first pic Ive seen , thanks

With a belt primary you don't use the pri case to motor O ring, and there is supposedly enough slop in the O ring groove without the O ring to make some belt adjustment. Anyway, that's what the factory thought.

-JW

Like JW, I converted to belt but very soon went back to chain.  I liked traveling and with a chain you can get parts at a farm supply if something happens.  Never any significant down time.

True, but in fact a chain primary drive is something that just doen't break. Belts? There are two kind. Those that broke, and those that are going to...

I get it, big wide open belts are way cool on custom choppers that don't get ridden except to the bar and back. For a narrow enclosed belt that's simply replacing the chain, what are you getting other than one more thing to worry about? HD tried it, HD said screw this. I tried it, and I said screw this. I really hate pushing motorcycles.

-JW

Phil Ross used to be a regular here, he built a great belt drive. I believe he passed away in 2009 or so, I am not sure if his company still exists.

http://supermax.net/

Interesting post, my 1980 has a belt conversion when i bought it a few years back. Now a question, the primary belts are prone to breaking, why doesnt the rear belt have breakage issues? Thoughts?? 

Quote from: Skooterbumm on March 22, 2023, 09:55:13 AMInteresting post, my 1980 has a belt conversion when i bought it a few years back. Now a question, the primary belts are prone to breaking, why doesnt the rear belt have breakage issues? Thoughts??

Primary belts are often subject to more heat.
They are connected directly to the motor and don't have the extra length, transmission parasitic loss and extra pulleys to absorb the shock.
Having said that, I've broken two drive belts. It wasn't the belt's fault.
A friend of mine used to blow out primary belts on his stroker shovel all the time, running a small belt (1 1/2"?). Told him to go back to chain or 3" belt. He never did, just had to baby it to keep from breaking them.

Quote from: Hossamania on March 22, 2023, 10:36:44 AM

Quote from: Skooterbumm on March 22, 2023, 09:55:13 AMInteresting post, my 1980 has a belt conversion when i bought it a few years back. Now a question, the primary belts are prone to breaking, why doesnt the rear belt have breakage issues? Thoughts??

Primary belts are often subject to more heat.
They are connected directly to the motor and don't have the extra length, transmission parasitic loss and extra pulleys to absorb the shock.
Having said that, I've broken two drive belts. It wasn't the belt's fault.
A friend of mine used to blow out primary belts on his stroker shovel all the time, running a small belt (1 1/2"?). Told him to go back to chain or 3" belt. He never did, just had to baby it to keep from breaking them.

yrs ago my mate had a 93 fxr and his rear belt broke. his fault as he was told it needed replacing

Quote from: JW113 on June 11, 2019, 11:09:19 AMSurf Karata and Primo's web pages, it's pretty straight forward. Engine sprocket, clutch basket, belt. I actually went the other way, converted back to chain. A little head's up: if you do this, start thinking how you're going to slot the inner primary engine bolt holes so you can adjust the belt. Like the stock HD inners are that came with belt primary.

-JW

my primo belt drive came with a roller adjuster, also primary should be vented

Mine hasn't done lots of miles yet but zero problems so far. Clutch works great too.

You cannot view this attachment.

Made simple adjuster set up

You cannot view this attachment.

Obviously no vent problems but I was keen to keep stones out, so I made inner and outer cover plates fit real close.

FYI. Hope this helps.

Quote from: Hossamania on March 22, 2023, 10:36:44 AM

Quote from: Skooterbumm on March 22, 2023, 09:55:13 AMInteresting post, my 1980 has a belt conversion when i bought it a few years back. Now a question, the primary belts are prone to breaking, why doesnt the rear belt have breakage issues? Thoughts??

Primary belts are often subject to more heat.
They are connected directly to the motor and don't have the extra length, transmission parasitic loss and extra pulleys to absorb the shock.
Having said that, I've broken two drive belts. It wasn't the belt's fault.
A friend of mine used to blow out primary belts on his stroker shovel all the time, running a small belt (1 1/2"?). Told him to go back to chain or 3" belt. He never did, just had to baby it to keep from breaking them.

im still running the same 11mm 35 yrs on but i will say its done not much mileage and still looks new

I still like the dry clutch rattle with the belt drive.

Quote from: Hossamania on March 23, 2023, 04:46:05 AMI still like the dry clutch rattle with the belt drive.

the rattle tells you the clutch is working