Author Topic: What is going on here? Front fork oddity 71 JDM K1  (Read 1721 times)

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Offline DesertKyorugi

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What is going on here? Front fork oddity 71 JDM K1
« on: March 13, 2020, 09:52:47 PM »
Now that we got the USDM 71 K1 up and running we turn our attention to the JDM 71 K1.
We were looking at swapping out the unicorn/gauges and noticed something very different on the forks. What are we looking at here? Is this how it is supposed to be? I can't find anything in the factory parts diagram.
Thanks
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Online bryanj

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #1 on: March 14, 2020, 01:37:07 AM »
Not standard, seems to have schraeder valves for air forks and maybe taper head brgs pushed trees farther apart needing bigger spacers
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline pjlogue

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #2 on: March 14, 2020, 02:24:58 AM »
Tapered steering head bearings were installed on the head and the wrong spacer was used.  The only cure I know of is to use the stock ball bearings for the top bearing or mill the top bearing recess further into the head so the tapered bearing sits at the correct height.  Using the OEM top bearing is what I do as the forces on the top bearing are minimal during normal riding.

-P.

Offline Kevin D

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #3 on: March 14, 2020, 03:28:58 AM »
K1 has painted fork ears and headlight shell, not chrome ears and black shell.
71 CB750 K1
104,000 miles
Original Owner
———past———
70 SL100/125/150
70 Candy BlueGreen CB 750 K0
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Former Honda parts kid/counter kid/do all
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Offline lash

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #4 on: March 14, 2020, 05:47:15 AM »
Look like that is the bottom rubber for the fork ear installed on the top.
Analog mind in a digital world..

Offline 754

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #5 on: March 14, 2020, 09:04:04 AM »
The bottom rubber is inside the headlight ear... or should be.
Maker of the WELDLESS 750 Frame Kit
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Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline DesertKyorugi

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #6 on: March 14, 2020, 11:00:42 AM »
Tapered steering head bearings were installed on the head and the wrong spacer was used.  The only cure I know of is to use the stock ball bearings for the top bearing or mill the top bearing recess further into the head so the tapered bearing sits at the correct height.  Using the OEM top bearing is what I do as the forces on the top bearing are minimal during normal riding.

-P.

Thanks guys. How do I fix this? We are going to return it to stock. Is the air forks just a mod to the top caps? Getting new stock caps and stock steering head bearings should get me back to stock? Is the bike safe to ride the way it is? I am assuming it is since the PO left the bike the way it is and parked it.

I am still learning so here's a stupid question, why tapered steering head bearing? What is the benefit?

Originally we bought this bike for the exhaust, then we found out she is a JDM model and almost all the pieces are there so we decided we are going to save her. The PO was a big Harley guy, she has a lot of mix and match pieces. It is going to take time but eventually, we will get all the mismatched pieces to swap out. It is just a little harder now that we have two K1s that we have to source the correct parts for.
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Online bryanj

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #7 on: March 14, 2020, 11:19:27 AM »
Lots of people say taper rollers last longer and dont "notch" my personal opinion is the only reason to fit them is price but recently original type cup and cone sets have turned up on ebay at a good price.
Tapered rollers as a rolling bearing are fantastict but the head races don not roll but move through a limited angle and from experience they do still "notch"
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline 69cb750

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #8 on: March 14, 2020, 11:22:55 AM »
Quote
Is the air forks just a mod to the top caps?
No after market parts

Quote
Getting new stock caps and stock steering head bearings should get me back to stock?
See next post

Quote
Is the bike safe to ride the way it is?
Probably

Quote
I am still learning so here's a stupid question, why tapered steering head bearing? What is the benefit?
Original races get dents from ball bearings around 10,000 miles, tappered rollers last longer but not original.


Online Don R

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #10 on: March 14, 2020, 01:35:06 PM »
 I've had tapered bearings notch as well as stock ones. DSS had some nice K1 fork ears, I used a set on a k1 that I sold back to them.
No matter how many times you paint over a shadow, it's still there.
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Offline 754

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #11 on: March 14, 2020, 01:50:04 PM »
Don't expect your reflectors to fit in K1 fork ears, they use smaller reflector with a smaller thread..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline DesertKyorugi

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #12 on: March 14, 2020, 02:05:17 PM »
Fork caps - https://www.ebay.com/itm/Genuine-Honda-Chrome-Fork-Bolt-Caps-CB450-500-550-750-MT-XL-CR250-See-Notes-H13/232070296837?hash=item360877b505:g:7usAAMXQC-tTBQme:sc:USPSFirstClass!49006!US!-1
Race 50301-268 - https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=50301-268&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=50301+cb750
Race 50302-268 - https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=50302-268&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=50301-268
Race 53212-250 - https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=53212-250&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=53211-269
Race 53211-268 - https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=53211-268&_sacat=0
Red head light bracket - https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_144_77&products_id=1494
Gold head light bracket - https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_144_77&products_id=1486

Thank you @69cb750. As I mentioned in other threads before, we are going to ride the bikes. Our first priority is to get the bike running safely, ride while we slowly swap out the incorrect parts. For this bike, we are planning to purchase the complete Yamiya Body Kit in Candy Ruby Red but that is going to be further down the road.

The headlight bucket is from something else but it works so we will leave it alone for now. I am going to take some pics so you guys can help me identify all the incorrect parts.

Thank you all in advance

« Last Edit: March 14, 2020, 02:11:53 PM by DesertKyorugi »
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline DesertKyorugi

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #13 on: March 14, 2020, 07:23:00 PM »
Not standard, seems to have schraeder valves for air forks and maybe taper head brgs pushed trees farther apart needing bigger spacers

I am not seeing anything different between my 2 K1s. Am I looking at the wrong thing? I don't see higher height causing the extra spacers/rubber.

Could it just be wrongly installed?
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline low-side

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #14 on: March 14, 2020, 07:48:10 PM »
Lower triple tree appears to be riding a little low in the first pic, so probably the TRB conversion issue mentioned above.  That's enough space, though, that those might be 550 fork ears.  Have you measured the height of the fork ears between the two bikes?

Offline DesertKyorugi

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #15 on: March 14, 2020, 08:02:07 PM »
Lower triple tree appears to be riding a little low in the first pic, so probably the TRB conversion issue mentioned above.  That's enough space, though, that those might be 550 fork ears.  Have you measured the height of the fork ears between the two bikes?

That is probably it. The headlight ears and headlight bucket must be from a 550. That would explain the odd shape of the headlight bucket. I will measure and verify it tomorrow. Thank you

**Update: I went on CMSNL and it looks like it is from a CB500
« Last Edit: March 14, 2020, 08:57:45 PM by DesertKyorugi »
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline 754

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #16 on: March 14, 2020, 10:52:28 PM »
Your front brake looks like maybe Mark Zero brand . Looks cast iron, probably stops well. Nice front rim too.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline DesertKyorugi

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #17 on: March 14, 2020, 11:16:49 PM »
Your front brake looks like maybe Mark Zero brand . Looks cast iron, probably stops well. Nice front rim too.


Good eyes. Front rim is alloy, shod with 4.1x19 tire
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Online Don R

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #18 on: March 19, 2020, 09:01:57 AM »
 Somebody loved that bike enough to spend some time and money on it at some point. I like them original and/or modified, you have to appreciate the aftermarket parts and the effort to make it a better version of the bike. 
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline DesertKyorugi

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Re: What is going on here? Front fork oddity 71 JDM K1
« Reply #19 on: March 19, 2020, 10:16:37 AM »
Somebody loved that bike enough to spend some time and money on it at some point. I like them original and/or modified, you have to appreciate the aftermarket parts and the effort to make it a better version of the bike.

I was told the PO is a bonafide biker guy. Loves making the bike goes faster, stops better and looks better. Not sure what happened to the side covers and gas tank though, everything else is either polished or upgraded. The bike is up and running now, just need to sort out all the safety checks before I am able to go for a test ride.
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running