Topic: 73 750 K3 - replacing fork seals, confirming all that is needed

[Chachi]

I have weeping fork seals on both sides. I was thinking I could get through this spring/summer before I had to deal with them, but saw a large amount of fluid on both sides of front rim, so I can't put it off. And of course it showed up as soon as I buttoned up all of my spring work like powder coated fenders.

Anyway... I want to confirm what all is good to replace since I'm going in.

1 - Seal, one for each fork, correct? Honda OEM or All Balls OK?
2 - Cir clip, usually OK to re-use?
3 - I'll probably put a fresh set of gaiters on
4 - If I use gaiters, do I also have a dust seal?

I am not that familiar with all of the fork components. I am also going to change out fork ears with some smaller aftermarket headlight brackets. I guess I'll see what condition tubes are underneath. Just looking for confirmation of small parts so I have everything I need at once and heads up on anything to look out for, etc.

[CycleRanger]

you'll want these too.  At least, I did.   

WASHER (8MM)
 90544-283-000

Actually, I listed a buncha more stuff  but my post got messed up.

RING, PISTON
51437-329-010
GASKET, FR.
90543-273-000
O-RING (23X2.8 )
94608-50000
RUB, FR. FORK COVER
51622-292-010
RUBBER, FORK COVER
51601-300-000
RUBBER, FORK COVER
51601-300-000

http://www.westernhonda.com/fiche_section_detail.asp?section=2560092&category=Motorcycles&make=Honda&year=1973&fveh=132837

[flybox1]

Check out the youtube video forum member dino (hackaweek) posted.

[Chachi]

CycleRanger... see fiche attached... part #22? My Honda shop tech confirmed it. He said it's a copper crush washer. Sound right?

[PeWe]

If you want the good not leaking ones, order from David Silver.

https://www.davidsilverspares.co.uk/parts/by-part-number/hpart_91255341305/

91255-341-305 (13mm without washer)
Superceeded by:
51495-425-830
If 14mm height is with washer?
In that case thin seal...

 

I got the information about 91255-341-305 in  this thread
http://forums.sohc4.net/index.php/topic,131619.msg1549866.html#msg1549866

This is the seal that Honda described as the new ones 1974 in the Service bulletin I have attached.

It is very strange that most sellers sells the old weaker model of fork seal. I mounted  a pair of those and got huge leaks direct with new fork pipes from CycleX 2013.
Bought the good ones from David Silver and no more leaks. This is the same seals I bought early 80's to my bike. Much stiffer and have double lips. No doubts wich side up.

I have them in my K6-76 so they fit the entire range from early to late CB750

Also available here with spec
https://www.partzilla.com/product/honda/51495-425-830

[CycleRanger]

CycleRanger... see fiche attached... part #22? My Honda shop tech confirmed it. He said it's a copper crush washer. Sound right?

Yes, copper washer. I don't like reusing them. See my updated post above for the rest of the parts.
I mean while you're there why get everything?

[ekpent]

You will need the proper size allen head tool for the bolt in the bottom of the fork and maybe a pry tool and some heat to carefully get the old seal out. A piece of pcv pipe and the old seal works well to 'drive' in the new one.Depending on your method maybe a broomstick to do the allen,best to at least break it loose while the spring is still in. Good luck on the original tubes being good under the fork ears, most all the 750's I have done are pretty rusty and pitted and require some wet sanding etc. to dress them up before re-installing. None were presentable to go 'naked'.
  Don't loose the D washers in the top triple and if none are there do a spacer,especially important on K2 or older.  Have Fun !!
PS-Look for any notchiness in the steering and if it feels bad do some tapered bearings to increase the fun factor 

[Stev-o]

I usually put oil in it too! ATF works....

[Duke McDukiedook]

Graduated cylinder to measure the right amount oil.

[Stev-o]

Long nose funnel

[Chachi]

Thanks for all the info.

My Honda shop has this kit in stock:
https://www.davidsilverspares.com/parts/by-part-number/partnumber_9507/

51490-KBH-305

It has a seal and what I think is part #18 in fiche - cushion, fork cover. I wonder if there is a way to tell if the seal in that kit is the same one that PeWe mentioned?

His thread has this for seal based on a service bulletin:
91255-341-305 -- 35x48x13.2

Service bulletin lists it is for K1 and K2, I'm K3. Bulletin came out in 74 after the K3 release.

When you search my model on DSS, you get:
91255-KBH-003 -- 35x48x11

And CMSNL parts fiche lists several superseded part numbers, but I think this was the last one:
91255-KBH-003 -- 35x48x11

For fork ears... I may luck out that things look good underneath, but I may not. I get that. If it looks good the plan is to remove stock ears and use Joker Machine top gaiter boot collars and smaller brackets.

http://jokermachine.com/products/cafe-racer/honda-cb750-parts/cb750-fork-boot-collars.html
https://www.denniskirk.com/emgo/universal-headlight-mounting-bracket-66-35830.p217659.prd/217659.sku

[CycleRanger]

I usually put oil in it too! ATF works....

ATF?!  Heaven forbid! 

Use this instead.  http://www.belray.com/bel-ray-high-performance-fork-oil

[Stev-o]

I usually put oil in it too! ATF works....

ATF?!  Heaven forbid! 

Use this instead.  http://www.belray.com/bel-ray-high-performance-fork-oil

Ok, you started this.

What is the best fork oil to use?!

[Chachi]

I just watched the hackaweek video. That thing was great. I had no idea they existed. I need to watch whatever else he has. Although I noticed that he installed what I think is the same Emgo headlight brackets I am looking at, but I thought you had to use the shims on 35mm forks? I wonder if he's using a different set of forks vs. what is stock to a 73/K3? And I am currently using Bel Ray fork oil. I have the weight written down somewhere. I plan on refilling with the same.

[ekpent]

 I have not done it but have heard of people using later year 750, like 1980-81, DOHC fork seals I believe. Probably a thread about it around here.

[CycleRanger]

I usually put oil in it too! ATF works....

ATF?!  Heaven forbid! 

Use this instead.  http://www.belray.com/bel-ray-high-performance-fork-oil

Ok, you started this.

What is the best fork oil to use?!

Anything that's not ATF.