HarleyTechTalk

Technical Forums => Shovel Head => Topic started by: Molly on July 13, 2022, 02:19:28 AM

Title: Missing primary belt idler/adjuster
Post by: Molly on July 13, 2022, 02:19:28 AM
Bought a 78 Shovel. Noticed it's a bit snatchy when cruising but ok under load. Figured I'd tighten the primary belt but discovered the idler is missing.

Any legitimate reason for this? Would guys deliberately run the primary belt a bit loose?

Noticed BDL sell an idler so should be easy to source.
Title: Re: Missing primary belt idler/adjuster
Post by: xlfan on July 13, 2022, 02:43:06 AM
Most belt drives do not use an idler. IIRC Karata 13.8 mm used an idler.
Title: Re: Missing primary belt idler/adjuster
Post by: Breeze on July 13, 2022, 03:46:15 AM
The "snatchiness" cruising is a lack of a compensator. You're feeling the power pulses of the engine.
Title: Re: Missing primary belt idler/adjuster
Post by: Molly on July 13, 2022, 06:39:36 AM
Thanks guys. I confess I've limited Shovel experience but 20 years on Evo-up. The 'snatchiness'is pretty intrusive. Hard to imagine it just a characteristic. I'll recheck the final drive chain and see if I can dial-out some there.

Appreciate your input guys. Always more to learn. Thanks.
Title: Re: Missing primary belt idler/adjuster
Post by: david lee on July 13, 2022, 02:01:26 PM
i run the inch-half primo belt it came with the roller adjuster. without it the belt would be too loose
Title: Re: Missing primary belt idler/adjuster
Post by: JW113 on July 13, 2022, 02:08:21 PM
What belt drive is this? Many/most, including the one I had in my '77, uses no idler. Neither did the stock Harley FXB.

How loose is the belt currently?

And what does "snatchy" mean? Never heard that before.

-JW
Title: Re: Missing primary belt idler/adjuster
Post by: Molly on July 13, 2022, 10:36:54 PM
Quote from: JW113 on July 13, 2022, 02:08:21 PMWhat belt drive is this? Many/most, including the one I had in my '77, uses no idler. Neither did the stock Harley FXB.

How loose is the belt currently?

And what does "snatchy" mean? Never heard that before.

-JW

I'd say there's over an inch of play. I guess by snatchy I mean not smooth to the extent that it's intrusive / concerning. The motor itself runs beautifully.

Thanks again for the replies. Appreciated.
Title: Re: Missing primary belt idler/adjuster
Post by: motorplex88 on July 13, 2022, 11:11:08 PM
The 1.5in x 11mm belt will use an idler.Screenshot_20220714-010423~2.png
Title: Re: Missing primary belt idler/adjuster
Post by: david lee on July 14, 2022, 02:14:57 AM
Quote from: motorplex88 on July 13, 2022, 11:11:08 PMThe 1.5in x 11mm belt will use an idler.Screenshot_20220714-010423~2.png
yes thats what ive got
Title: Re: Missing primary belt idler/adjuster
Post by: JW113 on July 14, 2022, 08:43:58 AM
Here's what used to be in mine:

FLH_belt_drive.jpg

It used a Gates 1-1/2" x 132 x 8mm belt. It has some vertical play, but was not flopping around in there. This was a BDL setup.

-JW
Title: Re: Missing primary belt idler/adjuster
Post by: Molly on July 14, 2022, 02:33:50 PM
Made a short video. Wait to the end to see how the belt has worn a groove in the inner primary.


https://youtube.com/shorts/mrdilxLaZkg?feature=share
Title: Re: Missing primary belt idler/adjuster
Post by: Molly on July 14, 2022, 11:29:17 PM
Attempted to source a BDL idler from hogparts.co.uk. Even though the part is on their website they abruptly replied to say there's no such thing... I'm not sure what you do with that level of stupid (besides making a point to never use or recommend them again).
Title: Re: Missing primary belt idler/adjuster
Post by: motorplex88 on July 15, 2022, 02:01:55 AM
(BDL) Belt Drives Ltd IBK-1 Primary belt idler kit. California Phil or other vendors on here can help you. Google is your friend.
Title: Re: Missing primary belt idler/adjuster
Post by: MikeL on July 15, 2022, 09:44:21 AM
I'd say the old belt wore the groove in the primary. The belt looks new/ newer. I don't think you could get an adjuster to work.
Title: Re: Missing primary belt idler/adjuster
Post by: Molly on July 15, 2022, 12:05:01 PM
Quote from: MikeL on July 15, 2022, 09:44:21 AMI'd say the old belt wore the groove in the primary. The belt looks new/ newer. I don't think you could get an adjuster to work.

It is new. Well spotted. Maybe 500 miles on it.

Once again, thank you guys for taking the time to reply and share your knowledge.
Title: Re: Missing primary belt idler/adjuster
Post by: brent on July 17, 2022, 07:05:48 AM
ive had a primo 11mm and 14 mm both had idlers
Title: Re: Missing primary belt idler/adjuster
Post by: david lee on July 18, 2022, 03:33:05 PM
Quote from: brent on July 17, 2022, 07:05:48 AMive had a primo 11mm and 14 mm both had idlers
had my primo belt for 35 odd yrs with idler and the belt still looks new