Topic: Cleaning Forks CB750 K6

[oldhatt45]

Hey Guys,
I'm still getting the hang of posting and which forum sections I should be posting to, so please forgive me if this isn't the right section.

I'm finally (after 26 years) into restoring my CB750 K6 which I've owned since it came out of the box.
Have started into restoring the forks.  Have used the paint stripper to get the old clear coat off and then on to sanding.
First with 220, then 400, then 800 and finally 1200 grit.  Still finishing up the left fork leg.
Next step from what I have read is to buff the legs.  I have a choice of buffing compounds (from Harbor Freight) Course (black), Medium (Red) and Fine (White).  Which one should I be using after the sanding?
Then I thought I would put a clear coat back on and the leading contender for  that seems to be the Eastwood Clear Coat. 
Would appreciate any help and/or guidance in getting these forks back to reasonable shape.
I've attached a couple of pictures of the 750 and the forks so far.

[dhall57]

Hey Charlie and welcome. Many members here but only a handful that are the original owners of their sohc4 bikes. Congrats and if I could I'd shake your hand  for holding on to your bike all these years. I've got a K6 also but didn't get until 2009 and I think Im the 3rd owner. Your K6 looks like it just needs some TLC and it will be back to its glory. I hope the 341's pipes are still in good shape. Good job on the one fork. Johnie a member here has got the polishing down to a art. Im sure he could give you advice and tips for the best results.

dhall

[oldhatt45]

dhall,
Thanks for the welcome!
My K6 is one of the things I don't think I'd ever let go of.  LOL
The 341 pipes are in good mechanical shape, but I will be replacing the seals and whatever needs work after I get them looking right.  The picture of the forks show the one on the left after 400 grit sanding, so it looks a little better now.
Would love to hear any advice from Johnie or anyone else.  I need all the help I can get!
Getting these forks done is just the first step in the long road back.
Thanks again
Charlie

[dhall57]

Do you have any more pics, past(back in the day 70's or 80's) or current. If so love to see some of them. I just bought a 1974 Boss Maroon CB750 from a guy that had it stored away in his basement for 30 years because his doctor told him not to ride it anymore because of back problems. Why did you park yours 26 years ago?

[CoachDoc]

Your plan is just what I did to bring my forks back to life, and I did not use any clearcoat after completion. It's been three years, and I just buff them up every 6 months or so by hand with Mothers metal polish to restore the shine. They still look like new so it's working. Good luck with your restoration.

[edwardmorris]

220 grit is a bit too aggressive IMHO. I'm sanding all my covers now, there are some pix in my build thread if you'd like to check them out. I consulted with Johnie, and with 73Nancy who offers professional polishing services on this board. From what I gathered, if there aren't too many blemishes, hitting it straight with the red compound and letting it work will yield good results (Johnie's method?? I may be wrong). If you're going for a mirror finish, then incremental grits up to 2000 are needed, but don't start as low as 220 if you don't have unavoidable deep gouges. Then, black, red, white and jeweller's rouges should do the trick. If you're going for a stock look, then incremental sanding upto 1200 is sufficient, and you start with the red rouge, then the green/stainless compound and check how close it is to the stock finish before deciding if and how much to apply of the jeweller's rouge.

Personally, I'm still sanding away as I make time, so I can't say I've tried either of the buffing approaches just yet, but my plan is to go for a stock look, so I will be stopping at 1200 (started at 500 since most of the covers were unharmed) and going with red->green->check and proceed approach. Hope this helps.

[oldhatt45]

dhall57,
I know I have some pictures still in a box down in my basement.  Over the next couple of weeks I'll try and find them and get them into digital format and post.  Can't promise, but I'll try.
As far as parking her for 26 years goes, the parking started when my ex and I split.  Wanted to take the bike with me but didn't have a place to store it.  Then for the next 3 years, she wouldn't let me come get it.  When I finally got it back it looked like she had hit it with a hose and I just didn't have the time to get it shined up and on the road until now.  Actually it was my current better half that suggested I get it going again.  LOL

edwardmorris,
I know that the 220 sounds pretty aggressive on the forks, but they were really badly oxidized and pitted.  Good news is they are coming up pretty nice.  I would like to get it looking pretty much stock, so I'll take your advice on that.  I can start with the Red rouge then I'll need to get the green/stainless compound.  Any particular brand???  Or place to get it?  Also will need to get the Jewelers Rouge as well.  Same questions for that as well.  Also, which buffing wheel to use for which rouge?  I have 3 different wheels.  One is a 1 inch sewn wheel, then I have a spiral wheel and finally a loose wheel. 

CoachDoc,
Thanks for the info.  Being the somewhat lazy person I am in terms of keeping things pretty much low maintenance, I'm really thinking that clear coating would work out better for me, but the good news is I can still change my mind.   
I take it that you haven't had any pitting since you restored yours???  And Thanks, I'll need all the God Luck I can muster.  Unfortunately to date, if it weren't for bad luck I wouldn't have any luck at all.  LOL

I appreciate all the HELP!!!! 

[edwardmorris]

edwardmorris,
I know that the 220 sounds pretty aggressive on the forks, but they were really badly oxidized and pitted.  Good news is they are coming up pretty nice.  I would like to get it looking pretty much stock, so I'll take your advice on that.  I can start with the Red rouge then I'll need to get the green/stainless compound.  Any particular brand???  Or place to get it?  Also will need to get the Jewelers Rouge as well.  Same questions for that as well.  Also, which buffing wheel to use for which rouge?  I have 3 different wheels.  One is a 1 inch sewn wheel, then I have a spiral wheel and finally a loose wheel. 

I forgot to mention, I used aircraft stripper to get rid of the factory clear coat before sanding. The yellowish gunk might be that, not oxidation but since you're already past that, keep going. As for the compounds and wheels, I ordered Eastwood's 6" Aluminum and Stainless buffing kit, has all four compounds and associated wheels and comes with a handy guide. Here is a buffing 101 article,

http://www.dimecitycycles.com/dccdiatribe/2010/09/aluminum-polishing-101-with-the-herminator/

check that out since you already have the wheels.

[Stev-o]

....and I did not use any clearcoat after completion.

+1 I do not use clear coat on my polished parts either. It can yellow over time. 

This would be a good time to change the springs and fork seals too.

[oldhatt45]

edwardmorris,
The polishing 101 article is great!  Explained a lot.  Thanks.
Ordered the Green Stainless compound and the Jewelers Rouge.
Need to get another spiral sewn wheel.
The only thing the article did not talk about was the wheel to use for the White Compound and the use of the Jewelers Rouge and wheel.

Stev-O,
I'm gradually coming to the realization that I will likely NOT use the Clear coat and just bite the bullet and go with the polish.
I also have in hand new fork seals and will be ordering new springs.  Problem with the springs is that I originally put in S&W progressive rate springs.  The specs were 28/48 and I really liked the handling.  The New progressive rate springs I see from "Progressive Suspension" are 30/50 and I wonder if this will make any appreciable difference?

And talking about suspension parts, I have Koni's on her right now and I think I'd like to have them rebuilt.  I read a thread about a guy named Koni King but have not been able to locate him.  Any suggestions on a Rebuild of the Koni's?  When she came out of the box, the shop I bought her from suggested putting in the S&W springs and the Koni shocks and I was Really happy with that set up.  I also had Continental tires on her.  Put them on right out of the box on the advice of the guys at the shop.  THe old tires are  RB2 (3.25) front and K112 (130/80) rear.  Apparently Continental no longer makes the bigger rear tire in the K112 tread pattern.  So, I ordered Continental Go tires.  Hoping they perform as good as the RB2/K112 tires.

Thanks Guys!

[edwardmorris]

The only thing the article did not talk about was the wheel to use for the White Compound and the use of the Jewelers Rouge and wheel.

Eastwood's guide here http://www.eastwood.com/images/pdf/13143_instructions.pdf

has a table for compounds, metals and wheels to use. Google is your best friend

[oldhatt45]

Edward,
Thanks.  That is what I needed.  Yes Google is Our Friend.  Although I sometimes have trouble and get too many useless results.  LOL
Charlie

[Stev-o]

Stev-O,
I'm gradually coming to the realization that I will likely NOT use the Clear coat and just bite the bullet and go with the polish.
I also have in hand new fork seals and will be ordering new springs.  Problem with the springs is that I originally put in S&W progressive rate springs.  The specs were 28/48 and I really liked the handling.  The New progressive rate springs I see from "Progressive Suspension" are 30/50 and I wonder if this will make any appreciable difference?

And talking about suspension parts, I have Koni's on her right now and I think I'd like to have them rebuilt.  I read a thread about a guy named Koni King but have not been able to locate him.  Any suggestions on a Rebuild of the Koni's?  When she came out of the box, the shop I bought her from suggested putting in the S&W springs and the Koni shocks and I was Really happy with that set up.  I also had Continental tires on her.  Put them on right out of the box on the advice of the guys at the shop.  THe old tires are  RB2 (3.25) front and K112 (130/80) rear.  Apparently Continental no longer makes the bigger rear tire in the K112 tread pattern.  So, I ordered Continental Go tires.  Hoping they perform as good as the RB2/K112 tires.

Sorry, unfamiliar with the S&W springs, but I think you will be happy with the Progressives. Recently put them on my K4.

Not sure if you know, Koni was sold to an Australian company and is now known as Ikon [name has slight change of letters]. Apparently, there are rebuild kits available. I have a set and have considered it, but may just purchase new shocks instead? Never heard of the Koni King.

http://www.ikonsuspension.com/index.shtml

Continental is still making the K112, I think 130mm is too wide for the stock rear rim.
4.00-18" is the correct size. Too wide of tire creates a large pinch angle, the tire will eventually "square off", and cause odd handling in turns.

https://www.denniskirk.com/continental/rear-k112-conti-twin-4-00h-18-blackwall-tire.p54181.prd/54181.sku

Good to see you working on this bike, I love seeing them road worthy once again. I am currently working on a K7, it's been off the road for 15 years.

[oldhatt45]

Stev-O,

Thanks.
I knew about Koni being bought out by Ikon.  I'm just not sure about me rebuilding them myself.  LOL
There are just a couple of things I try to stay away from working on.  Automatic Transmissions and Air Conditioning.  LOL

I had the K112 (4.00) on from Feb 1976 until March 3, 1976 then changed to the K112 (130) from March 4, 1979 through Dec. 1988 when she went to sleep.  She definitely handled better with the 130 on the stock rim.  Never had a problem with "squaring off".  Wonder where the "squaring off" thing came from?  Hope the tires I ordered work out as well as the RB2/K112's.

What tires do you have (or gonna have) on your K7???

Also, I used Belray 30 wt oil (150 cc) in the front forks with the S&W springs.  I see that a lot of folks use lighter weight oil (ATF & 10 wt) in their forks these days.  So, I wonder if the newer Progressive Springs will perform like the S&W's if I continue using 30 wt???

The best (or maybe worst - LOL) part of restoring my old gal is that there was no OP to blame for anything, and knowing exactly what was done to her and when.  While I am looking forward to getting her back on the road, I'm going to take my time and hopefully do it as right as I can.  I am very glad I found this group.  Lots of good info and Good people!!!!!

Thanks Again
Charlie

[Stev-o]

I agree, I'm not planning on rebuilding the Koni's myself. I'm sure we could do it with the correct tools, though. 

I have a 130mm tire that shows the squaring off, I'll shoot a pic when I get a chance.

The K7 came to me with tires in good cond, so I will not be buying for this one.
I bought Bridgestone BT45's for my K4....excellent tires.

There is no doubt this is a great forum, we are share the passion for these bikes and are more than happy to share our experience.

[oldhatt45]

Today I got to work on the Left fork leg and start the 1200 Grit sanding.
Thought I would take a picture or 2 of 1200 vs 800 grit finish just to show those that wonder what it might (or maybe should) look like at different stages. 
In the picture where you can see the sandpaper laying on the middle of the leg, the 1200 grit is to the left, the 800 grit is to the right of the paper.  The nice looking spot to the right is where the inspection sticker used to be so a small section looks pretty good at 800.  Down a little further (to the right is where the 800 grit really is.  LOL
My order of sanding was 220, 320/400, 800 and finally 1200.  After I get this leg done I will begin the polishing and buffing.

The hardest of the sanding was the 220 grit.  I was a little nervous about using that heavy a grit, but it got the pits out without destroying the leg or taking too much material off.

All in all, it took me about 8 days per leg.  5 days doing the 220 (Yes, I'm slow but I only worked on it about 5 or 6 hours per day) then about a day each for the other grits.

Hope this helps someone out there.

[Wollongongwolf]

On my 550 I used Mothers and 0000 grade steel wool, then used Mothers with a Mothers Power Cone on a drill and finished by hand again with Mothers and a soft cloth. Mine shine like chrome and I know nothing about polishing, very happy with results.I know others would do a better job, but for a bum like me, much better than expected. Was going to clear coat, but a quick polish with Mothers, look great. Will post a pic if I get around to it.