DOC HARLEY: PRIMARY CHAIN ADJUSTER UPDATES 

Excellent tip about the flashlight and screwdriver because everyone gets a little throttle happy once in a while.

Thanks for the info on this auto primary chain adjuster. I've used the screwdriver trick many times. Although I agree snapping the throttle will tighten the primary chain with this adjuster, I also found out that pulling a long mountain grade will also cause a tight chain. One of the best things I ever did to my 2007 FLHTCU was to install a Braker Drivetrain compensator and the manual Attitude primary chain adjuster. It eliminates the false over-tightening once and for all, along with smoothing out the dreaded primary chain snatch at startup.

Thanks doc ... history, mechanics, part numbers, you hit on all of it. Much appreciated

Thanks for the video! Your time and effort is appreciated. Owned Evo, Twin Cam, both old and new. Tried different chain adjusters. Despite the downside of the Harley one, it's as good as anything. Just maintain it if you ride it. Buy a factory manual and get the right tools...and watch Doc and others with the help here.

I threw my stock 2010 Street Glide auto tensioner in the garbage where it belongs. My chain was way too tight and the primary was wining big time (bike only has 3,700 miles. I installed a hydraulic SO Hot Bikes HB125-07 Primary Chain Tensioner for Big Twins and wow what a difference. No more wining and the bike shifts and drives amazing now.

Thanks Doc... you always break it down... so even us carpenters can understand.

Didnt really cross my mind but i love learning all i can from one of the best HD techs out there.

This is the only part on my 06 Dyna that I consistently worry about. Going to the Southern Oregon Hot Bikes unit next time I crack open the primary. They are local to me and I've heard great things.

Thanks Doc! I had a 2004 Fatboy as my first Harley and I learnt a lot on that bike as far as maintaining a Harley and I would regularly check my primary chain tension, when doing oil changes ect. But I sold that bike a few months back and I bought myself a much lower kms Fatboy this time a 2009 model. When I did my first oil change and service on the new bike I noticed there was no inspection plate on the primary side like my 04. Now I know why! Thanks again Doc, and keep the videos coming. I have learnt so much and gained so much more confidence from watching your videos. Jason. Queensland Australia 🇦🇺

I love hearing that a young man bought that Road King. 👍

This is the best explanation I have seen !!! 10 PLUS !!!!

On my 2008 FXDC the automatic adjuster was over tightening my primary chain so much that the splines on my clutch hub broke off. I switch it out to a manual adjuster and have not had that problem since.

Been thinking I should check my primary chain on my '04 Fat Boy and this shows up. Talk about timing !

Excellent video and thorough explanation on everything, including why the automatic tensioners can get too tight. Thank you!

Thanks for the video. I appreciate you for taking the time to make these videos for us. I'm working on my 2012 Heritage and this is definitely helpful.

Thanks, this is great information for the few of us with stock bikes. So much chatter about how the automatic adjuster causes problems and this video adds much needed context to the conversation.

One of the best Harley service channels out there.

Great video. The internet seems to magnify problems. From some channels you’d think the stock auto tensioner trashes everyone’s transmission bearings in 20,000 miles.

Great information! I used aftermarket hydraulic chain tensioners on both of my Evo primary chains and was totally happy with the results. Did my research, then purchased them from Southern Oregon Hot Bikes part #HB-125.

Thank you so much for this video. This helped me understand my primary so much better. And put my mind at ease about worrying if it needed adjustment or not.

I see @4:18 you got Mechanics finger complete with oily bandage LOVE IT !

Have an 06 softail has the manual chain tension easy to check 🤙🇺🇸

Glad to see harley has an automatic adjuster for pre 2006 bikes.

Like Chad, below, I love learning and seeing these parts. Now I can have an intelligent conversation with a tech if I need to. Thank you!

Love all these videos, so many useful things to see.

Gold, now I can at least check my primary slack or lack of...thanks.

The Doc is always on call and on point. Ha!

So Doc mentions the Achilles heel being the fact that the design doesn't do well when "your motor makes more horsepower than the factory design". YET, this same design has been used in several interations of motors each with different horsepower. So either it can or it can't handle the horsepower whether it's a Stage 2 103 or a 107, or a 114.

Great video Doc, I have that same screwdriver, hundred different uses

Great video-not sure why my 06 FLHRCI has the earlier manual adjuster fitted, a friday afternoon bike perhaps. Judging by some other problems I've had,probably!

Thanks, I love your videos.

Like the screwdriver trick👍🏻 Although I run a Baker.

My stock 96 broke the tranny main shaft with this auto chain tightener in my first 20K. When I had to have the transmission repaired a second time I took it out and put in a manual adjuster. This is not a hot rod, just a commuter.

nice to see a shovel being worked on.....40 yrs to upgrade , why change a good idea👍

Excellent lesson ..thank you

Do you ever come to the UK, I want you to service my road king. Top Man

Doc a guy called Hayden came out with one in 1980s uses double coils works fabulous I have 88 lowrider with one for 75 grand and good as day one

Perfect explanation. Thanks

Awesome job on the video. Many thanks Doc.

Brilliant. Thanks for the instruction Doc.

Bingo !! Thank you. !!

Thanks Doc, you just made myself adjustment day, Great Again.

So this is why I can't find information on adjusting the primary chain on my '14 fxdf 103" Thanks!

2019 Road King….. main shaft bearings on the trans toasted and trans had to be completely rebuilt due to that stock adjuster. Pulled the stock adjuster and installed a new baker attitude adjuster….problem solved.

My 08 road king primary chain was so tight, it tore up my starter. Had the starter rebuilt, and took out the junk oem tensioner and put in a hayden. Now my bike runs quieter, and goes in gear without a loud clunk, and its easier to find nuetral. Was a cinch to do.

Another wonderful and very informative video. Thanks to both Doc Harkey and to Low Country Harley. Keep them coming. Oh, can you make a video about the oil transfer. I have seen the Harley solution and the aftermarket fix. I want to see which fix I will do on my bike.

Super video.

Interesting vid, doc. Stock adjuster on my 98 Ultra works fine and easy to check.

thank you for the info, my 2011 street glide has 55k and I am planning another trip to Sturgis from Portland, Oregon I am guessing 3000 miles total or so and I will be taking my bike to the local dealer to do a service on it.

The B was the third automatic tensioner if I understand correctly? The A was the second, and is the one installed in my 2009. From what I hear, the B tensioner should solve most problems. Still not sure I feel reassured since Doc here mentioned the aggressive throttle getting a to tight chain. Oh, and the chain TIGHTENS when the bike gets warm. Which means I have a hard time starting my 2009 again after filling gas... (Also seems plausible this tensioner of mine might be why it sounds like the compensator is on it's last legs. Haven't opened it up to check yet, will when I get a new tensioner. )

you say they changed in 06, was it late 06? I have an 06 ultra, it still has the inspection cover and the manual gives you instructions on adjusting. Haven't taken it apart to check, but its in the plans. Need to pull primary to change drive belt(53k miles on her), shifter shaft seal, and shifter arm. May have to look into the retro fit upgrade.

Well explained procedure... Thanks Doc!!

Yes talking about the automatic primary chain adjusters. Be careful how you ride actually you know as well as I do they get entirely too tight. They’re hard on the transmission the bearings everything on that side with them things get so Tight. Better to be a little loose than that tight. It was nice on the older boys we had a little cover to take off a couple minutes and you’re on your way. Now compensators bearings very hard on them. They should have a hydraulic set up for something. But they keep taking shit off . Even better would be is to make it a gear drive. You know like there’s other people. Yeah no chain to worry about. I know that slapping around none of that over tightening just a couple Carrier sprockets. That would be a nice set up strong to if it’s done right. My opinion enjoy your show

There is a newer version of this tensioner now, 39929-06C. Could you check this one out and tell us the difference? Appreciate the great videos, you're the BEST!

Always great content, informative, and to the point.

Thank you🙏 from the Netherlands 🇳🇱

Great Information! Thanks DOC

I couldn't find water pump on my 03' fxdx, but I did replace the primary chain adjuster with 06' Auto-adjuster an now every once in a while it slammed gears on startup. I've asked an told it's new auto adjuster slamming, Go back to manual adjustment! What do you think about this auto adjuster an starting slamming?

I have heard lots of complaints about the auto tensioner problem and many recommend aftermarket brands. I as of yet haven't had a problem. I am not looking forward to researching which one to use. I guess the mileage when it goes down will be a factor. I change the big 3 every 3000 miles. I also hear about issues with the compensator too :^( ~ this is going to get expensive fast!

Can you provide any insight into the newest version? The 39929-06C. I notice the ramp that was metal on the A and B version is now polymer like the shoe on version C. Is this strictly a cost cutting measure per usual from Harley or do you think the teeth being plastic will shear if the belt becomes overly tight by the ratcheting? Thank you

Fabulous - thank you!

I'm having starter banging clunking noise from auto adjuster too tight! I'm going back to manual, investigating what brand best?

Simply fascinating info Doc....Many Thanks!

Another Great Video... Thx...

Doc, what's your opinion about the hydraulic tensioners?

Hi Doc. Does the same hold true for the 2019 FLHC-107...I have herd a lot of night mares about the chain adjusters on the cam side and the primary side...

I think instead of buying a manual adjuster to replace these, a lighter spring in that wedge might help.. these things make the slack “banjo tight,” as Kevin would say

Great video Doc has it going on....:)

Great video...many thanks for all the helpful info! 👍

Hi i recently had to change the Teflon tensioning foot for the third time. while checking i discovered that at 5/8's cold on the tight spot it is approximately 9/16 difference from tight to loose. i have 1 1/8 on the loose spot.

I am having to replace my third inter primary bearing at 70000 miles, in your opinion could the auto adjust be my problem, getting chain to tight?

Doc, I found the electrical problem, I will write on that blog what the story is. You're gonna be astounded to hear what it is. Now my issue on Primary Chain Tensioners. My bike is an 2003 so it had the standard chain tensioner. well, adjusting the Primary Chain every 10,000 miles isn't something I wanted to do so, when I completely redid the primary at 60,000 miles, I spent the $125 for the updated latest model of Harleys Automatic Chain Tensioner. Now I read about this thing over tightening the chain and causing excessive force on the crankshaft, bearings and transmission bearings. So, I went from a manual adjust that wasn't causing any harm to a part that now causes harm and I got to pay $125 for it. Does Harley do anything the correct way from the beginning.??? I've had nothing but problems with this bike over 20 years....$19,000 for the purchase and $20,000 in additional parts and service on it. So, do I have to check this damn automatic tensioner every 10,000 miles and if so, off it comes and I'll just go back to a manual adjust one. At least I know its not going to over tension the chain and cause more damage and more money spent on parts.....This was my first Harley and its my last....Goldwing...!!!!!

doc thank you so much for sharing your expertise, appreciate so much your technical advise am an avid follower i have a street 500

I want Doc working on my bike!

another great video. didn't realize my 2004 FXDWG had an adjustable primary tensioner. going to check it this weekend. thanks again.

Only recently discovered you Doc am really enjoying your tech videos. I don't own a Harley but if I did I'd certainly want you working on it. I'd really like to hear your thoughts on Rekluse clutches, if you haven't already covered it?

Thanks

great video

Great video, I have been looking at a manual tensioner like the SE manual and others. I see lots of compliments about the SE manual primary chain tensioner AND others. To the point of people removing them shortly after install. Why are the manual tensioners more noisy and what if anything can help quiet them down? I know it's also a subjective thing but there are too many online posts about manuals being very loud. Looking forward to your thoughts Doc. Keep up the great videos!

Thanks Doc!

How wood one you just yourself like the old style would work in my 13 Limited

Great explanation, is it the same on a Street bob 114? I noticed yours is a chain, and mine is a belt.

Thank you Doc!

Yes! Thank you Doc. Never heard any recommend checking the slack through the derby cover. Going to do that soon. Is the old building still a deli? Always liked that place.

did the baker manual chain tensioner install on '12 ultra as well during the bump up to a 110 big bore kit, ported heads, HF injectors, 259 cams, S&S cam plate, TC3 oil pump and inner bearing work...to include a SE compensator and clutch pack....the new comp is way too noisy...clack clack clack, now going to install a man o war comp...anyway, baker manual chain tensionser is thumbs up!

When did the b version of the tensioner come out?

The primary on my 2013 Fatboy Lo seems to be loud inside of there. I think I need to check it.

Hey doc.. I’m Farely new rider got my 2008 ultra back 1 1/2 years ago and have a question.. when I go to start my bike people have said it grinds as I start it and I should have it looked at.. had a mechanic come out at Harley and listened to it.. he heard what my friends were talking about and said he had an ultra that did this and never figured out the problem.. it starts fine but he did say it may be the chain tensioner may be loose reason why I’m listening to this video and want to know your opinion on it.. when I first got my bike the guy I bought it from had a stripped ring gear.. I replaced it and then that one stripped I caught it quickly and put on a new one back on again and rebuild starter thinking it was the starter and has been fine but what would make the starting part grind as it starts.. not sure if you have a way for me to send you a sample video.. but I’m at a loss.. thanks!

I Love your channel Doc, I have picked up so many Tips and Tricks, Your the Man! I would like to hear what you think about Hydraulic Tensioners? I’ve had the Stage V Tire Shredder Kit installed and I Love playing with all that extra power! I will check with long screwdriver!

Doc.... Could u make a video on clutch adjustment on Softail with M8 engine?... Thanks

I believe that the 39929-06B primary auto adjuster didn't appear until 2009 or 10 models so the early adjuster is on 06 Dynas and all 07-09's. Also the 40063-05B retro for earlier models which I also have comes in two pieces (but is weirdly stamped as 39929-06B > go figure?)

soooo My dyna street bob is an 09. I have the factory service manual. It doesnt show any service interval on the primary chain adjuster. [or I didnt see it since I was looking for something else] I bought her used with only 12K miles on the clock. I actually ride it [daily] Im already at 20K miles. Its basically stock and its transportation I dont race it or ride it like I stole it. When or rather if I should be concerned about that primary chain adjuster? I change all fluids monthly because its cheap insurance and see no metal or nylon in the fluid when drained. Bike is stock EXCEPT for a gear drive and cams, pipes and a remap. Like I said its transportation and ridden as such.

HD is a slow innovator. And I use the term innovator very loosely. Auto primary chain adjusters were available in the after market well before HD used them. I installed an aftermarket auto primary chain adjuster way back in the day in my 96 RK. Triumph and BMW have had ABS and traction control (of course HD doesn't call it TC) available for their bikes for years before HD introduced them.

I just converted over to an automatic chain tensioner. I do like to hot rod and have a heavy hand. Should I switch back over to a manual?

I am very surprised Dr Harley works on old Harleys 👍😎

Do a video on battery voltages, bike off and on. What voltage should be. How throttle affects voltage. How to tell if your battery is good or bad.

What about the faulty adjusters overtightening the primary and causing bushing and shaft failures?

This is so topical for me right now. I was just wondering about these the other day!! I was looking at the online catalog for SE options and this was there. So, for my stock but stage one 04 Softail...Hope you can answer: 1. Is there much threat of the ratchet up issue on mine with the auto-tensioner? I’m middle of the road or less on aggressive throttle. Again, Stage-One, TC88B which is otherwise bone stock. 2. In two years, with only 11,000 miles still on the bike, I need PC Chain tightening every service. Is this typical? Thanks so much for your videos, I really enjoy and learn from them every time.

Great Video, and happy I found your Channel 👍...I don’t know if you will see this? I have a 2006 Road King (ex Police Bike) Mine has a Manual Adjuster... Thoughts? Also when shopping for parts, and I scroll through the Model Selection... It always has an option for the Road King Police... What’s the difference between the normal Road King and the Police Model ? 🤔🛵

i was going to put one in my 03 Road King. 95ci. 100hp 107lbft. ill go with a Hayden M6-BT01