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Author Topic: Stiction horrible! Time to upgrade, HELP!  (Read 1107 times)

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Offline 1976cb750f836

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Stiction horrible! Time to upgrade, HELP!
« on: September 03, 2019, 11:46:55 am »
I have a 78F front end on my 76F bike( due to a T-boned crash repair). I now have comstars and twin disk up front. It was a bolt on with modern stem bearings. I'm sooo  tired of feeling every bump in the road. I'm looking  for a plusher ride 1st. And if cornering and dive are better, well that's ok too. My plans are emulators and low stiction seals? All recommendations welcome. I'm going to gather parts for a winter build. Fork tubes are 35mm, so i order emulators for that! What about seals? I've read somewhere that a ysmaha something 36mm seal will work and cause less friction? Or was that before modern teck made a decent seal for the cb? All help welcome.

Offline calj737

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #1 on: September 03, 2019, 11:53:35 am »
Proper weighted single rate springs, quality valves, and the correct amount of oil are cornerstones of good handling. You can also tinker with preload spacers to fine tune your ride. It's a 40 year old bike, so its only going to be so "good". You should also invest in a quality rear shock. You will be surprised at the difference it all makes.
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Offline Bankerdanny

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #2 on: September 03, 2019, 12:39:18 pm »
Your bike and mine are very similar, Blue 76F with 78F front end and Lesters.

Emulators are definitely available for our bikes. I have vintage Koni's on the back of mine.
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Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki 80 (K11 probably, it's been 30 years), '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline 1976cb750f836

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #3 on: September 03, 2019, 01:46:34 pm »
I have hagons on rear, bought new during build 10 + years ago, not many miles though. They are Much better than  oem stock rears!  The front does Not Move At All under light up and down pressure? I'm after a plusher ride, softer more responsive to bumps. Are the emulators the way to go without swapping. Front ends?  I also have a 81 gs750(My other favorite bike), that is MUCH softer ride. It has 35mm forks a also. Way less stiction. It moves under the slightest road irregularity. Educate please. Also on a budget, no $ to waste.
Just today I got fed up with the harsh ride. I loosened all tree and axle bolts, front fender also, bounced front up and down, couple times, bolted all back, test rode, some better, but not much?   Help.

Offline Bankerdanny

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #4 on: September 03, 2019, 02:03:06 pm »
My forks are stock. I would drain all the oil out and refill with fresh oil. My preference is fork oil. The manual calls for ATF I think, but I don't know how common dedicated fork oil was in the 70's.

I weigh ~240 lbs and run 15wt in my forks (I ran the same weight in my 550 forks), if you weigh less then 10wt might be best for you. If that is still too stiff, then try ATF, which is slightly lighter weight. I use a measuring cup to put the oil in, correct specs are in the repair manual. Using less oil than stock will also help at the cost of less rebound control.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki 80 (K11 probably, it's been 30 years), '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline Erny

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #5 on: September 03, 2019, 02:25:10 pm »
....  The front does Not Move At All under light up and down pressure? ....

I have EXACTLY the same issue on my 750 K7 and also even worse on 550 K1. I'm mad out of that. Oil change (Motul 10W, I have ~80kg) did not help at all..
Also I put some washers under the springs (they are bit out of service limit, so too short) help a bit on 750 but not at all on 550...

I tried to find low friction seals, but did not find them for 35mm Honda forks

Sorry I did not help but will look at this thread if some solution will appear ;)
CB750K K7 USA model (1977)
CB550K1 USA model (1975)

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #6 on: September 03, 2019, 02:52:28 pm »
Hey Danny, what volume did you put in your's?
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline scottly

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #7 on: September 03, 2019, 09:33:46 pm »
Guys, I'm also a member of the Stiction club. >:( I've had it with K7 forks, and F2 forks. I've experimented with springs, different fork oils and ATF at different volumes. The springs and oils only come into play after the stiction breaks loose and things move. I recall someone recently claimed using motor oil instead of fork oil or ATF made for less stiction?
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Offline jgger

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #8 on: September 03, 2019, 10:01:16 pm »
What is the chance that the axle spacers are either too short (pulling the forks together) or too long (spreading the forks apart)? I dont think it would take much to cause an initial bind. With the wheel off and caps and springs removed see if it slides freely, then bolt on the wheel and try it again.......Just a thought.
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Offline 1976cb750f836

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #9 on: September 04, 2019, 05:11:12 am »
What is the chance that the axle spacers are either too short (pulling the forks together) or too long (spreading the forks apart)? I dont think it would take much to cause an initial bind. With the wheel off and caps and springs removed see if it slides freely, then bolt on the wheel and try it again.......Just a thought.
I did just that yesterday. A tad of improvement but not much. I'm going to pull them apart and c exactly where the sticking  or friction is! It takes at least 10 lbs of force ,or pull, to get them to began to move? I will gladly pay the $ for emulatore, if they reduce the friction and make them more sencitive to bumps and dips. I currently have 10w fork oil. Im tempted to try them with no oil at all? I weigh 180, with me on bike i get bout 2in of sag in front.

Offline my name is nobody

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #10 on: September 04, 2019, 07:02:20 am »
If I remember correctly, the front fork seals for a Yamaha IT175 (part no. 48Y-23145-00) may work.
Their dimensions are 36X48X10.5 mm. I saw this in part of a magazine article titled "Updating the Honda 750" in Motorcyclist Magazine from 8/81. It used to be posted here on the site, but the link for it is no good, so I cant verify my memory is correct. Those seals are supposed to be a tad larger, and provide less tendency to "stick". I'm gonna put them on my k5

Offline slikwilli420

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #11 on: September 04, 2019, 07:23:19 am »
If there is stiction, oil, springs or emulators will not help. Something is causing the binding and it needs to be fixed first. It sounds like a spacer issue. Are you running fork brace?  They tend to cause more harm than good unless installed carefully.
All you gotta do is do what you gotta do.

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Offline maxheadflow

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #12 on: September 04, 2019, 08:17:37 am »
What is the chance that the axle spacers are either too short (pulling the forks together) or too long (spreading the forks apart)? I dont think it would take much to cause an initial bind. With the wheel off and caps and springs removed see if it slides freely, then bolt on the wheel and try it again.......Just a thought.
I did just that yesterday. A tad of improvement but not much. I'm going to pull them apart and c exactly where the sticking  or friction is! It takes at least 10 lbs of force ,or pull, to get them to began to move? I will gladly pay the $ for emulatore, if they reduce the friction and make them more sencitive to bumps and dips. I currently have 10w fork oil. Im tempted to try them with no oil at all? I weigh 180, with me on bike i get bout 2in of sag in front.

Emulators are not going to fix your problem.   If it takes 10 lbs to move the slider on the tube, you either have the wrong seals or the tube/ sliders are damaged.   You should be able to remove the seals to see if they are the problem.  The damping rod might be bent. remove the bolt and slide it out, see if they improve.  If everything slides well but sticks when assembled, get the front end up, assemble the  forks without springs and as you add fenders, caliper/ wheel, check the movement. If it gets tight you found your problem. 

Offline Bankerdanny

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #13 on: September 04, 2019, 09:50:37 am »
If I remember correctly, the front fork seals for a Yamaha IT175 (part no. 48Y-23145-00) may work.
Their dimensions are 36X48X10.5 mm. I saw this in part of a magazine article titled "Updating the Honda 750" in Motorcyclist Magazine from 8/81. It used to be posted here on the site, but the link for it is no good, so I cant verify my memory is correct. Those seals are supposed to be a tad larger, and provide less tendency to "stick". I'm gonna put them on my k5

There is a full transcript of the article in this thread: http://forums.sohc4.net/index.php?topic=38253.0
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki 80 (K11 probably, it's been 30 years), '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline Redline it

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #14 on: September 04, 2019, 10:31:13 am »
get ahold of Terry Cable, (Terry Davis) of hesperia ca. he used to be focused in the off-road industry and couldn't be beat in fork suspension and cables. it's possible he shifted to the harley davidson lines for the bulk of his sales. he's the guy to talk to about dampening. he'd turn a damper rod out for you, that'd be tailored to your needs.  and get some cable while you're at it, I think they're on the high side of price, and again, they're the smoothest cable you'll find.

Offline my name is nobody

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #15 on: September 04, 2019, 11:56:57 pm »
also, the axle nut should be threaded on correctly, (hex end of nut installed first toward wheel.
Not the other way round)

Offline 1976cb750f836

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #16 on: September 05, 2019, 07:35:21 am »
If there is stiction, oil, springs or emulators will not help. Something is causing the binding and it needs to be fixed first. It sounds like a spacer issue. Are you running fork brace?  They tend to cause more harm than good unless installed carefully.
No fork brace. I ran it without fender just to test, No difference.  Axle nut on correct. Theirs nothing left externally to do. I'm tearing them completely apart( I never have, only changed oil and seals during build). I'll first pop the seals out while still assembled on bike to test. Then their coming down. If nothing is bent, I have a bench polisher, going to give the tubes a new finish. Ive found low stiction seals to order. Ill report findings as i dissassemble.

Offline Erny

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #17 on: September 05, 2019, 01:49:24 pm »
What are low friction seals yoi found? Can you pls share some info?
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Offline scottly

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #18 on: September 05, 2019, 08:00:12 pm »
I found an old magazine ad for the 1980 CB750F which states "low stiction forks". The 1980 used 35mm forks similar to the 77/78F, and the seal dimensions are the same , but DMS lists different part numbers?
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Offline 1976cb750f836

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #19 on: September 06, 2019, 05:26:52 am »
The add says 60% reduced friction over oem seals! These are 36mm to use on 35mm forks, as per cb750 upgrade thread states . They are for a 1976 Yamaha dirt bike, and many others.
EBay link.
https://www.ebay.com/itm/Leakproof-Pro-Moly-Fork-Seals-5206-Kawasaki-Yamaha-Suzuki-Honda/312728825755
The same brand also comes in 35mm.
https://www.ebay.com/itm/Leak-Proof-Seals-5209-Pro-Moly-Fork-Seal-35mm/192414558946
Read the description on the first link.
I'm going to try the 36mm first, and if they leak then use the 35mm.
Update on teardown. I removed the dust seal, loosened axle pinch bolt, upper tree clamp bolts, and center stem nut. No difference, still takes bout 10 lbs force to began movement.
I got the bike up on my homemade bike table and will begin teardown later today, gotta c my Dr this morning first.
I've decided the stiction devel has me by the nads,  my forks stick, my clutch sticks(hard to find N), and my carb slides sometimes stick. Think I'll have the Whole bike dipped in teflon,LOL.

Offline Erny

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #20 on: September 06, 2019, 09:27:33 am »
.... still takes bout 10 lbs force to began movement....

Curious to know, how do you measure force needed to begin movement?

I'll be waiting resulf of your experiment with seals. I'm totally fed-up with mine.
Suspension is for me by far the weakest part of CB550/750 four K, having it better will make bike just perfect!

EDIT: trying to google them and found some reviews - but all very negative, all report they started to leak very fast... so I'm not very optimistic
« Last Edit: September 06, 2019, 09:35:16 am by Erny »
CB750K K7 USA model (1977)
CB550K1 USA model (1975)

Offline Bankerdanny

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #21 on: September 06, 2019, 02:23:33 pm »
.... still takes bout 10 lbs force to began movement....

Curious to know, how do you measure force needed to begin movement?

I'll be waiting resulf of your experiment with seals. I'm totally fed-up with mine.
Suspension is for me by far the weakest part of CB550/750 four K, having it better will make bike just perfect!

EDIT: trying to google them and found some reviews - but all very negative, all report they started to leak very fast... so I'm not very optimistic

A seal diameter greater than that of the tube wouldn't seem like it would be very leak resistant.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki 80 (K11 probably, it's been 30 years), '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline 1976cb750f836

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #22 on: September 07, 2019, 05:58:38 am »
I'm estimating the 10lbs it takes to move with my arm push or pull.
Seals are smaller ID than the tube they fit, (that's why the stiction ). I'm sceptical also, but I'm going to try them.

Offline 1976cb750f836

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #23 on: September 08, 2019, 07:54:12 am »
After reading some of the reviews, I'm beginning to think they may be a mistake?
I'll decide after teardown, I may find other problems.

Offline PeWe

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Re: Stiction horrible! Time to upgrade, HELP!
« Reply #24 on: September 08, 2019, 11:15:45 pm »
Interesting thread about fork issues.
I noticed when fixing the front wheel flat on my CB750K2 a few weeks ago that I had to bend forks together to get the front axle correct and tighten all 4 nuts. I did not see that before since I assembled the front fender after the wheel (the very irritating way doing it). NOS virgin Honda fender that needed to be forced in place.

That bike has a little bit bumpier ride at front than my K6 that has a smoother action.
I'll loosen all bolts that tighten the tubes at lower and upper tree and see if it will change.

I think the new fender might bend it outwards and need to be adjusted.
« Last Edit: September 08, 2019, 11:17:16 pm by PeWe »
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