Topic: Yamiya CB750 K1 Painted Body Sets

[ZTatZAU]

The K0 gauges have chrome bottom covers and black plastic housings and plastic lenses. Your K1 instruments are virtually identical, except they have metal housings and glass lenses. Honda still sells the bottom chrome for the K0 but they are sort of “universal” and fit  BOTH speedo AND tach. The bottom cut out is designed to match both. They should fit your K1 too.

I ordered a set for my Sandcast project but when I saw them, I had to have the originals rechromed. The originals are left and right. If you’re interested, I can dig out the new ones for a part number?

Thanks John, for the info and your offer.  Before you go digging though, let me pull my bottom covers and have a look at them.  If they were chrome, I can't imagine I would have painted them without scuffing up the finish... but that was fifty years ago, so you never know what I may have done back then.

Yamiya tanks petcocks as K0-K4.
K5 got one on the left side, one spigot for hose. A threaded bung on tank.

Thanks again PeWe!  I appreciate the info.

EDIT-Follow-up:  John, I haven't pulled my bottom covers yet, and it's hard to tell from the picture you posted, but when you say "universal" (in addition to the bottom opening), do the replacement covers you have, both have holes for the speedometer's trip meter knob?

ZT

[BenelliSEI]

I will have to look.i know they fit both gauges fine, but we’re identical. The originals on the S/C and my 1970 K0 were  each different, one for the speedo and one for the tach. Next time I’m in the shop (Thursday or Friday) I’ll dig them out and show you.

[ZTatZAU]

The good news is, I received my Candy Ruby Red Body Set from Yamiya today! And, as you all predicted, they look great!



The bad new is, my K1 is a long way from being worthy of wearing these beautiful new skins!

My rims are cleaning up quite nicely but the spokes are a different story.  Likewise, the chrome engine covers shined up pretty good but the engine cases, cylinders, head and rocker cover are going to need more than the GUNK wash and rinse,  I did a while back.  Any suggestions on brightening up the engine while it's still in the frame?

I also have a new set of fork boots that will go on when I install the new red fork covers.  What is the minimum I need to take apart to install the new fork boots and covers?

Any other suggestions appreciated!  ZT

[denward17]

^Looks awesome.....

[BenelliSEI]

Wow! You will have to pull the tubes out of the tree to install the fork ears. Clean them out and do the fork seals while you have them out. Spokes are only $30 for your rims and nothing improves the bike like a new set!

[PeWe]

That tank set will look fine in your living room!

Maybe your bike will need new fork tubes too (if scratched and very rusty) and all stuff around the fork ears.

Do not use aftermarket gators if yours look old and ugly.
They do not last, they crack quickly and do not withstand fork oil. I lubed my fork seals on the upper side to not let them glide dry. The gators did not like that, swelled. The cracks happened anyway, no oil there.

That bike will get new Honda gators this winter. Hopefully good quality, not bad rubber as aftermarket.

When bike get such good looking parts it might bring a general upgrade to match the tank set.

[newday777]

The good news is, I received my Candy Ruby Red Body Set from Yamiya today! And, as you all predicted, they look great!



The bad new is, my K1 is a long way from being worthy of wearing these beautiful new skins!

My rims are cleaning up quite nicely but the spokes are a different story.  Likewise, the chrome engine covers shined up pretty good but the engine cases, cylinders, head and rocker cover are going to need more than the GUNK wash and rinse,  I did a while back.  Any suggestions on brightening up the engine while it's still in the frame?

I also have a new set of fork boots that will go on when I install the new red fork covers.  What is the minimum I need to take apart to install the new fork boots and covers?

Any other suggestions appreciated!  ZT

ZT
Nice! How many days from when you ordered them?
As John said, get a set of spokes and relace the wheels.
And yes you have to drop the fork tubes out of the triple trees to get the new seals, accordion boots and headlight ears in place.(no other way period) and as PeWe said, don't use aftermarket accordion boots.
As far as brightening the motor, it'll be very hard to paint in the frame. You'd have to mask off everything. Far better to remove the motor and put it on an automotive engine stand so you can sand it well(prep work is the most important step to get a quality job that will last) and to mask off the areas you don't want to paint. Having the motor on the engine stand allows you to rotate the motor for sanding, taping off and for painting using the bar of the stand to rotate it without getting your hands on the cleaned prepared surfaces.
I used Duplicolor DE1615 aluminum color paint.
For the strongest paint on the motor to protect against gas, final spray over the color with 2K Clear.
Once painted, the following day carefully remove the tape then let the paint harden for at least a week after painting before moving it.

[ekpent]

Only 7 days since you posed that question. I would say that was a nice quick and smooth transaction for you considering it came from Japan. Glad it all arrived as promised and in good condition.

[MauiK3]

Cleaning an engine in the frame is pretty tough.

[Lucien Harpress]

If you're painting the motor, I would strongly advise against using any kind of clear coat on your engine.  While 2K clear might be a different story, I put a coat of Dupli-color clear on my engine last time I refurbished it, and it started turning yellow/brown after only two (short) rides.  After having to mask and re-paint my top end with it still in the frame?  I can confirm, it's an absolute pain.

[newday777]

If you're painting the motor, I would strongly advise against using any kind of clear coat on your engine.  While 2K clear might be a different story, I put a coat of Dupli-color clear on my engine last time I refurbished it, and it started turning yellow/brown after only two (short) rides.  After having to mask and re-paint my top end with it still in the frame?  I can confirm, it's an absolute pain.

That us why you need to use 2K clear

[ZTatZAU]

Thanks everyone!  I appreciate the nice comments and advice!

Yes, Yamiya's turn around time was nothing short of amazing!  I placed the order on Monday the 4th and had the new parts on Saturday the 9th.  (I sure wish Busso would get it together on shipping the no-stamp exhausts.)

Everyone's advice on OEM Honda fork boots is well taken and I've had a new set on hand for a while.  I'll need to have a good look at the 750 Shop Manual to see how to go about removing the fork tubes.

Wow! You will have to pull the tubes out of the tree to install the fork ears. Clean them out and do the fork seals while you have them out. Spokes are only $30 for your rims and nothing improves the bike like a new set!

Thanks John, is there just one seal on each fork tube?  other than new boots, is there anything else that should be replaced while the tubes are out?  And yes, nice shiny spokes is something I always notice when ya'll post pix of your beautiful restorations.  How about suggestions on sourcing the spokes and fork seals.  Are they available and best sourced from Honda or from other suppliers?

And thanks for the primer on painting the engine Stu!  Your painted engine looks great, though I'm not sure I'm ready to commit to that much work.  Here's what mine looks like after a good wash and rinse with GUNK...



The cases really don't look all that bad, but I was hoping to brighten up the top of the cylinder head and rocker cover with some aluminum polish and a bit of elbow grease.  Maybe I'm kidding myself?

I would like to touch up a few spots on the frame though and would appreciate suggestions on the best paint and color for the frame?

As always, thanks for your help and advice!
ZT

[BenelliSEI]

I buy inexpensive spokes from vintagecb750.com. They have fork seals too. If you order stuff from a dealer it’s a good idea to replace the sealing washers on the fork drain plugs and the Allen screws that go in through the bottom (recessed in above the axle shaft). Most guys order the fork boots from Honda, but I’ve had good luck with the ones from vintagecb750.com. I touch up the frame with any good brush on enamel and then polish the original finish with a bottle of plexiglass polish I happen to have on the shelf. Any cheap automotive wax would do too.

[newday777]

The rocker cover can be hand polished with Semichrome polished. I used it on my bikes back in the 70s and still use it today.
Pull the tank off to have the most access to the rocker cover, it'll take time to cut through the grime by hand and polish it, it can be done. The covers all came with a clear coat over the polished aluminum so that will the hardest part to get through if doing by hand.... 
The very top of the head can be polished too. It came painted from the factory.

[PeWe]

Flashing new/repainted/polished parts will make the before OK parts to look bad
Same when restoring appartment or house and other things/chicks

[ZTatZAU]

Looking for advice on ordering new fork seals for my 1971 K1750...

Do you guys recommend paying extra for Genuine Honda fork seals which may have been sitting on the shelf for years and gotten hard or the new manufacture generic replacement fork seals which are quite a bit cheaper?

Thanks!  ZT

[PeWe]

Honda labeled for my bike.
PITA to replace the cheap soon cracking ones.

[bryanj]

Fork seals i use any good brand, fork gaiters only Honda

[PeWe]

Gaitors Honda.
More about the seals. I found my old post where I referred to another one.
http://forums.sohc4.net/index.php/topic,156338.msg1791143.html#msg1791143

It seems that all sellers today sell the earlier seal, not the improved thicker Honda started with later.

[newday777]

Gaitors Honda.
More about the seals. I found my old post where I referred to another one.
http://forums.sohc4.net/index.php/topic,156338.msg1791143.html#msg1791143

It seems that all sellers today sell the earlier seal, not the improved thicker Honda started with later.

Per
Does the link work for you?
The David Silver link for me is no good now so it needs to be changed(on first page see picture) (it might be because of the UK link and I have the USA link??)
(https://www.davidsilverspares.com/parts/by-part-number/part_91255341305/) is the dead link. 91255-341-305 has been superseded by 51495-425-830 seal set (with spacer). I haven't seen the new seals to verify if it is still the same dbl lip.
New link so you can edit the post if you want is
https://www.davidsilverspares.com/parts/by-part-number/part_91255341305/

[PeWe]

I have edited that old post.
I added the screendump from DSS above.

91255-341-305 (35x48x13)
Superceeded by:
51495-425-830 (35x48x14)
14mm is with thick washer
So, no upgrade...

https://www.ebay.com/itm/364154582692?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=FAFPPfGgRUK&sssrc=4429486&ssuid=XgCEg0CPSya&var=&widget_ver=artemis&media=COPY


I have not tested the 51495-425-830
If that seal is thin 11mm seal +washer to make 14mm?
If it is, a downgrade back to the old the Honda bulletine show when upgraded to
91255-341-305  1974.

The seals I bought winter 1979-1980 when my K6 got new +6" fork tubes were really tough to mount as well as the old stock to take out.
Risk to crack the lowers when bending them out.
Same feeling with 91255-341-305 that might be the same I used back then.

Here photos of 91255-341-305 (I have 2-3 sets ordered years ago from DSS UK while still available)
and weak thinner less lipped
91255-KBH-003 (11 mm thick)



I should test this if located closer to me.
Might be like the 91255-341-305
https://www.denniskirk.com/k-and-s/35x48x13-fork-seals-16-1055.p1401947.prd/1401947.sku

[Stev-o]

I have done frame touch-up painting and it turned out nice.  I used semi-gloss black paint, sorry forgot what brand but just buy high quality. Some guys have used appliance paint with good results.

[ZTatZAU]

RE: The "thin vs. thick" oil seals...
At first I thought I understood what PeWe was talking about but now I must admit I'm quite confused.  As most here may recall, I am working on the K1 (12/70) CB750 that I bought new in 1971.  Tthis is the only CB750 I've ever worked on.  I've been relying upon a downloaded "CB750 - CB750K1 - CB750K2" parts manual made available "Courtesy of Honda4Fun" when trying to find the correct replacement part numbers for my K1 750.  Perhaps I should be looking for a better, newer, parts manual.

The best I can tell, this parts manual shows (on page 87 & 89... Slide (?) E8 & E9... in drawing no. (?) F-8) the correct oil seal item #27 as p/n 91255-300-013 (35x46x11) for the K0... and 91255-300-023 (35x48x11) for the K1.  So I assumed this was the "early thin vs. later thick" that PeWe initially mentioned.

I didn't check with Honda but started searching online for the 91255-300-023 oils seals.  I wound up ordering a set of seals from Everett Powersports OEM p/n 91255-KBH-003 which (on other sites) showed the dimensions of this seal as 35x48x11 and said to be correct for my 1971 K1 CB750 on the Everett ebay website... mostly because Everett shipped the seals for free along with the set of aftermarket spokes and nipples I ordered from Everett.  I should have these parts tomorrow (Thursday) and can only hope the seals are correct for my K1 as I didn't consider, (as I am now), these oil seals may have been superseded by the 35x48x13/14 seals that were later mentioned here in this thread.

As I've said this all new and confusing for an old fart like me, and hope you all can help me understand...

1) Where can I obtain a parts manual that might show any later superseded part numbers for my K1?

2) What does the "KBH" in the 91255-KBH-003 part number indicate?

I'm still in the learning process and appreciate any help I can get!

I have done frame touch-up painting and it turned out nice.  I used semi-gloss black paint, sorry forgot what brand but just buy high quality. Some guys have used appliance paint with good results.

Thanks Steve-O!  I appreciate your reply!
ZT

[seanbarney41]

fork seals generally do seal type things...the 14mm Honda double seal ones generally overkill and just add more stiction...just my experience and opinion

[Stev-o]

1) Where can I obtain a parts manual that might show any later superseded part numbers for my K1?

2) What does the "KBH" in the 91255-KBH-003 part number indicate?

1.  I just used one of the online fiche such as this one...

https://www.partzilla.com/catalog/honda/motorcycle/models-with-no-year/cb750k1-a/front-fork

Also helps with assembly.

2. Have never seen a part number like that! The 3 middle number is typically the model designation, K1 is 300.  However, the fork seal cover many models...

https://www.partzilla.com/product/honda/91255-KBH-003