Topic: 1971 CB750 K1 Restoration Project

[Oly]

I pulled the trim off the fuel tank and brushed off the rust under it and other locations with a soft brass brush.  I have rust removal gel headed my way and will finish its clean up in prep for painting then.

Continued pulling parts off working towards getting the engine removed, as I'd like to start going thru it ASAP.  Did a compression test (Cold engine & no carbs) with the following results: #1-90, #2- 90, #3- 115, #4- 120.

Also, I'm looking for someone that has ordered the Qty 100 "wear resistant 4mm I.D. double sided rubber grommets" thru amazon that are for sealing the top portion of the carb slide rod and would like to sell me a dozen of them.

And if someone has a good suggestion for a set of JIS screwdrivers and JIS bits for an impact driver, Id really appreciate any input.  Thx!

[Shtonecb500]

im happy you are keeping the stock paint job, I try to save every tank I can with decent paint....no matter how bad it looks inside....they always clean up.

[newday777]

The bottom of the tank looks good. I'm glad it is solid.

Vessel makes great jis screwdrivers.

https://www.amazon.com/Screwdriver-JISPH1-Japanese-Standard-Screws/dp/B07DPSDQMD/ref=mp_s_a_1_21?dchild=1&keywords=vessel+jis+impact+screwdriver+set&qid=1612028374&sr=8-21

[Oly]

  During the cleaning of my carbs I noticed that all my main jets were 120 and the slide needles were clipped into the 3rd slot, which is in conflict with Hondaman's book that states the K1's had 115 mains and needles clipped into the 4th slot.  Because my bike's build date was 8/70 (old factory build) is it possible they mixed and matched components (i.e.: carb assemblies) from earlier K0 builds into the early K1 builds?
 I also noticed that the sprockets on my bike are 18T (front) & 48T (rear) when they are supposed to be 17T & 48T.  I guess the PO could have changed them out as he and his wife did a lot of touring and the 18T X 48T would give them better touring performance.
  As I tear the bike apart after 43 years of ownership,  I'm always surprised on what I find its true configuration is  vs. what I believed the bike's configuration should be.  I guess a lot could have altered in the first 7 years of its life by PO.

[Oly]

I dropped the swing arm today and the center collar looked like this...deep gouges thru the surface plating into the base metal and spots that look overheated. 
Also a picture of the the bearing opposite the collar's worst gouges.

I see lots of options for the bearings but not so many for the collar (#52141-300-000).  Any ideas would be greatly appreciated.

[newday777]

If it was running good the last time you rode it just clean the jets and brass parts in a soak cleaner or ultrasonic if you have one and leave it set the way it was, then run it a while to see how it goes. The 120 should be fine with today's gas.

The gouges in the swingarm spindle could be filled and resurfaced to size then new bushings to size.

[bek1966]

I'm so glad to hear that you're keeping the original paint.  You're making fantastic progress!  Thanks for sharing.

Brad

[Oly]

The gouges in the swingarm spindle could be filled and resurfaced to size then new bushings to size.
[/quote]

Newday... I wasn't aware that the collar could be refurbished.  Is this something you have done or had done?  Do you know the details of the process required?

[Kevin D]

  During the cleaning of my carbs I noticed that all my main jets were 120 and the slide needles were clipped into the 3rd slot, which is in conflict with Hondaman's book that states the K1's had 115 mains and needles clipped into the 4th slot.  Because my bike's build date was 8/70 (old factory build) is it possible they mixed and matched components (i.e.: carb assemblies) from earlier K0 builds into the early K1 builds?
 I also noticed that the sprockets on my bike are 18T (front) & 48T (rear) when they are supposed to be 17T & 48T.  I guess the PO could have changed them out as he and his wife did a lot of touring and the 18T X 48T would give them better touring performance.
  As I tear the bike apart after 43 years of ownership,  I'm always surprised on what I find its true configuration is  vs. what I believed the bike's configuration should be.  I guess a lot could have altered in the first 7 years of its life by PO.

My 11/70 K1 came with 120/40 jetting and 18/48 sprockets. I can’t say about the needle setting: I have never had them out. I put 115/38 jets in after years of plug fouling that came with in-town riding. I also switched from NGK to the Denso plugs x24esu? It’s been so long since I have bought new Densos I may have forgotten the number.

[BenelliSEI]

I dropped the swing arm today and the center collar looked like this...deep gouges thru the surface plating into the base metal and spots that look overheated. 
Also a picture of the the bearing opposite the collar's worst gouges.

I see lots of options for the bearings but not so many for the collar (#52141-300-000).  Any ideas would be greatly appreciated.

I’ve seen a lot worse. I’d chuck that shaft up in a small lathe and knock any high spots off with a wide, flat mill file. Then polish with finer emery cloth. As long as there are no high spots, you won’t damage new end bushings. Lube it well and reassembled. Keep it lubrications.....

[Oly]

Kevin...thanks for the feedback.  Your Denso P/N (X24ES-U) was correct from other postings I've seen.  I may try once I get things going back together.

Benelli...I was thinking that I'd need to get a new collar seeing that it was gouged thru the surface hardened platting.  I'm thinking about sending it to Hondaman for his expert touch, as I like the idea of keeping the original design but with his custom internal bronze bushing setup.  I'll run my existing damaged collar by him to see if his process can use it modified as you've suggested.
OFF subject but---Congratulations on the great find you made during your road trip to get the Chopper!

I've whittled most parts off the frame except the engine, but need to clear some bench space to place it on before continuing.

[BenelliSEI]

Thanks..... one other detail I do on my “riders”; pull out those silly Honda oil fittings. Drill and tap for a proper Zerk fitting, so you can pump in grease. That shaft looks like that, because nobody ever did.

[Oly]

Benelli..10 4 on the Zerk.  I can see that would help keep it lubed properly.

[Oly]

I've been attempting to remove the original mirror on my front brake assembly for the past few weeks. Alternating PB Blaster soaks & movement...then heat but ultimately it failed and twisted off.  Are there any tricks to getting it out?

Also, as I was dismantling the front fender Assy. I discovered one of the fender braces had cracked at a fastener location.  Has anyone ever repaired this or is it easier to source that original part?   

[Oly]

Near completion on the carb rebuild.  Trying to run down the final staggered float setting.  After reading Hondaman's input on an older post, I'm trying to figure out the exact point to take my float measurements.

[Oly]

I'm also breaking down the front forks for rebuild, but was real surprised at what I found. 
Does anyone recognized this type of fork setup?

[BenelliSEI]

I've been attempting to remove the original mirror on my front brake assembly for the past few weeks. Alternating PB Blaster soaks & movement...then heat but ultimately it failed and twisted off.  Are there any tricks to getting it out?

Also, as I was dismantling the front fender Assy. I discovered one of the fender braces had cracked at a fastener location.  Has anyone ever repaired this or is it easier to source that original part?

Only..... excellent progress! That broken mirror stem can be a real bugger. Try drilling it ou to about 75% of the original stem diameter era and then an “easy out”. They look a bit like a tap, but really just a wedge shaped rod with 4 backwards cutting flutes. You drive it in the hole and turn counter clockwise. I’d also get that “stump” really hot with a propane torch......

I have a rack of 10-15 of those fender braces, if you can’t find one locally. I’m not sure how you would repair it?

[BenelliSEI]

Near completion on the carb rebuild.  Trying to run down the final staggered float setting.  After reading Hondaman's input on an older post, I'm trying to figure out the exact point to take my float measurements.

Those carbs look great! I set them up so the float hinge pin side is “up”. Now tilt them up about 45 degrees from straight sideways. This way, the float pad is resting just lightly on the fuel valve. Not compressing the centre pin. Measure in this position. I use a plastic cut out gauge that just passes over the floats. Or you can measure from the gasket base to the float.

[BenelliSEI]

I'm also breaking down the front forks for rebuild, but was real surprised at what I found. 
Does anyone recognized this type of fork setup?

Same as mine. Earlier style, find a 1970 parts book or manual. Unlikely anything is very worn. Replace the seals and move ahead. Looking good!

[BenelliSEI]

Actually, that corner of the green manual (in one photo) is one of th “early” ones. Isn’t that fork design shown there? Does your set up have the seals “double stacked”?

[Oly]

Actually, that corner of the green manual (in one photo) is one of th “early” ones. Isn’t that fork design shown there? Does your set up have the seals “double stacked”?

John...thanks for sending me back to the original green manual.  I was stuck on the Hondaman book illustration showing the early vs later fork design breakdown and I wasn't seeing the lower hollow tube and damper bolt on the early version.

By "double stacked" are you referring to the style of seal or that two seals are stacked on each other?

[BenelliSEI]

That’s it! I thought there was an excellent drawing in there. I though you might have a double wiper seal in there (two wiping seals in one part)?

[Oly]

  Well after a 2 year medical hiatus I'm finally back to my project.  I'm working on changing out the front /rear wheel bearings and was about to order them from "All Balls Bearings", but noticed that they offer a standard All Balls bearing kit (25-1307/25-1362) and a Pivot Works premium bearing kit (25-1307-P/25-1362-P) for considerably more money.  If anyone has experience or knowledge of the real differences between these two grades I greatly appreciate any input. 

[newday777]

  Well after a 2 year medical hiatus I'm finally back to my project.  I'm working on changing out the front /rear wheel bearings and was about to order them from "All Balls Bearings", but noticed that they offer a standard All Balls bearing kit (25-1307/25-1362) and a Pivot Works premium bearing kit (25-1307-P/25-1362-P) for considerably more money.  If anyone has experience or knowledge of the real differences between these two grades I greatly appreciate any input.

Welcome back Oly
I didn't know they were offering a more expensive set. Do they say made in Japan or USA??
Take your bearings to a local bearing supply and get them there.

[BenelliSEI]

Welcome back Oly! Good to see you back on it. +1 to above. I have a good shop locally and buy Timken or SKF Bearings from them. The counter people are knowledgeable and they don’t sell any crap. Not sure if I save any money, but I like the place.

A year ago, when I wanted new bearings for the s/c headstock, the guy gave me a bag of 0.250” balls for free and problem solved!