Topic: 1976 Honda cb750K

[BenelliSEI]

I pay about $20/ 4 litres for the stuff I buy. Wear eye protection!

My local farm supply store doesn't carry phosphoric acid. Only muriatic acid at $19/4L. Will call around.

Bill….. Try Amazon.ca. This looks the same to me?

[BenelliSEI]

Not sure I picked the right tank, but it had some wear marks that match skuffs on the frame……

Found the missing oil line and gave them a good scrub. When they are totally dry I mix a bit of paint thinners and a flat black paint and give the material covering on them a quick coat.

[BenelliSEI]

Next up is to scrub down the main wiring harness and do a few small repairs. Dismantled the airbox today and astounded by how hard the velocity stack/ carb connector rubber bits have become. I had to carefully cut them up to get them out. Absolutely rock hard.

Note the bit of towel under the brake hose to metal line connection. Spotted a tiny drop of BF hanging there. I hate doing stuff up too tight, but 1/8 of a turn more solved the problem.

[Nightshift]

I pay about $20/ 4 litres for the stuff I buy. Wear eye protection!

My local farm supply store doesn't carry phosphoric acid. Only muriatic acid at $19/4L. Will call around.

Bill….. Try Amazon.ca. This looks the same to me?

Hmmm, not sure John. It doesn't indicate what grade it is but for $26/4L I'm guessing its watered down when it only lists it as a concrete/grout cleaner. The Food Grade stuff at 85% or even 75% is $140/gal and it does indicate its a rust remover. Gotta do some more homework to make sure I'm buying the right stuff.

[BenelliSEI]

I pay about $20/ 4 litres for the stuff I buy. Wear eye protection!

My local farm supply store doesn't carry phosphoric acid. Only muriatic acid at $19/4L. Will call around.

Bill….. Try Amazon.ca. This looks the same to me?

Hmmm, not sure John. It doesn't indicate what grade it is but for $26/4L I'm guessing its watered down when it only lists it as a concrete/grout cleaner. The Food Grade stuff at 85% or even 75% is $140/gal and it does indicate its a rust remover. Gotta do some more homework to make sure I'm buying the right stuff.

Good point. I’ll check what concentration my stuff is, next shop day.

[BenelliSEI]

Darn….. Had two oil tanks on the shelves and Stu tells me I fitted the wrong one! Will  redo it next time. Now I will have two really clean tanks. The second one will go on the Rickman soon enough.

[PeWe]

Breather spigots and hose thicker on K6 than earlier.

[BenelliSEI]

I pay about $20/ 4 litres for the stuff I buy. Wear eye protection!

My local farm supply store doesn't carry phosphoric acid. Only muriatic acid at $19/4L. Will call around.

Bill….. Try Amazon.ca. This looks the same to me?

Hmmm, not sure John. It doesn't indicate what grade it is but for $26/4L I'm guessing its watered down when it only lists it as a concrete/grout cleaner. The Food Grade stuff at 85% or even 75% is $140/gal and it does indicate its a rust remover. Gotta do some more homework to make sure I'm buying the right stuff.

Bill…… Here iswhat I have. Can’t find the acid % anywhere on the label. Will be interested in your conclusion.

[Nightshift]

Thanks John for digging that out. Here is the MSDS for that product. Looks like its a blend of phosphoric and nitric acid. Note they say its not compatible with aluminum, mild steel (gas tanks), etc. Cheers, Bill

[grcamna2]

Thanks John for digging that out. Here is the MSDS for that product. Looks like its a blend of phosphoric and nitric acid. Note they say its not compatible with aluminum, mild steel (gas tanks), etc. Cheers, Bill

Can it be slightly diluted in strength to allow you to use it in your fuel tank safely ?

[BenelliSEI]

Thanks John for digging that out. Here is the MSDS for that product. Looks like its a blend of phosphoric and nitric acid. Note they say its not compatible with aluminum, mild steel (gas tanks), etc. Cheers, Bill

Bill….I don’t use it on aluminum. I dilute it at least 12:1 and it works fine in tanks too. Thanks for the sheets, I printed them off for info in the shop!

[BenelliSEI]

Finished up all the electrical today and forgot to take a picture. Looks tidy.

Stripped down the airbox and threw all the black plastic in the dishwasher.
Apparently they “stink”?

[BenelliSEI]

Electrics  back in place. Need to find a ground cable and test everything next time.

[denward17]

^Very clean look, great job John.

[BenelliSEI]

^Very clean look, great job John.

Thanks Den. Looks like you were doing the same today! There is a very small bit of rust and “scale” on this bike, but it’s so good I’m determined to preserve all the original finishes.

[PeWe]

John, do you have the long breather hose to this bike?

I have not found a stock hose.
From valve cover back to passenger footpeg + a little down.

I have ordered 5m NBR hose, ID 10mm, OD 14mm from China (eBay).
I do not have the rear bracket for my K6.
Saw old photos that I used a strap aroubd rear triangle and hose that was dry and hard.
Bracket went with the 341 4-4 40 years ago.
My K2 will probably get a longer hose too, T- connection with oil tank breather.

[BenelliSEI]

John, do you have the long breather hose to this bike?

I have not found a stock hose.
From valve cover back to passenger footpeg + a little down.

I have ordered 5m NBR hose, ID 10mm, OD 14mm from China (eBay).
I do not have the rear bracket for my K6.
Saw old photos that I used a strap aroubd rear triangle and hose that was dry and hard.
Bracket went with the 341 4-4 40 years ago.
My K2 will probably get a longer hose too, T- connection with oil tank breather.

Per….The hose was on the bike and in good shape. It is a long one and is very thin wall. Want me to take measurements?

[PeWe]

John, do you have the long breather hose to this bike?

I have not found a stock hose.
From valve cover back to passenger footpeg + a little down.

I have ordered 5m NBR hose, ID 10mm, OD 14mm from China (eBay).
I do not have the rear bracket for my K6.
Saw old photos that I used a strap aroubd rear triangle and hose that was dry and hard.
Bracket went with the 341 4-4 40 years ago.
My K2 will probably get a longer hose too, T- connection with oil tank breather.

Per….The hose was on the bike and in good shape. It is a long one and is very thin wall. Want me to take measurements?

That would be fine

[BenelliSEI]

John, do you have the long breather hose to this bike?

I have not found a stock hose.
From valve cover back to passenger footpeg + a little down.

I have ordered 5m NBR hose, ID 10mm, OD 14mm from China (eBay).
I do not have the rear bracket for my K6.
Saw old photos that I used a strap aroubd rear triangle and hose that was dry and hard.
Bracket went with the 341 4-4 40 years ago.
My K2 will probably get a longer hose too, T- connection with oil tank breather.

Per….The hose was on the bike and in good shape. It is a long one and is very thin wall. Want me to take measurements?

That would be fine
[/


Per….. The hose that runs from my cam cover vent to the right side passenger foot peg is the original hose. It’s approximately 15mm OD. and has a 3mm wall thickness. OA length is about 92 cm. Happy New Year, John D.

[BenelliSEI]

Finished up the airbox this afternoon and added new rubber connectors/velocity stacks from vintagecb750.com. They are very soft and pliable and fit perfectly. Meguire’s “Back to Black” polish sure makes a clean ‘box shine!

Also cleaned out the correct oil tank! Photos next time.

[PeWe]

John, do you have the long breather hose to this bike?

I have not found a stock hose.
From valve cover back to passenger footpeg + a little down.

I have ordered 5m NBR hose, ID 10mm, OD 14mm from China (eBay).
I do not have the rear bracket for my K6.
Saw old photos that I used a strap aroubd rear triangle and hose that was dry and hard.
Bracket went with the 341 4-4 40 years ago.
My K2 will probably get a longer hose too, T- connection with oil tank breather.

Per….The hose was on the bike and in good shape. It is a long one and is very thin wall. Want me to take measurements?

That would be fine
[/


Per….. The hose that runs from my cam cover vent to the right side passenger foot peg is the original hose. It’s approximately 15mm OD. and has a 3mm wall thickness. OA length is about 92 cm. Happy New Year, John D.

Thank you for the hose details good to know.
I have found a nitrile hose ID 10mm, OD 14 that I hope will work without kinks.
5m
I think it will sit tight enough on valve cover spigot, a strap will help.

https://www.ebay.com/itm/175723417741?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=DB4AXMZjTt6&sssrc=4429486&ssuid=XgCEg0CPSya&var=&widget_ver=artemis&media=COPY

My K2's airbox might get some black polish too. It is my K6 original box

[BenelliSEI]

Per….. That looks like a good solution. It’s hard to find the right “thin wall” pipe. One of the guys I race with runs a very busy, local garage. They do a lot of FORD truck engine replacements. The new ones come crated with all the electronics, ECU and hoses. I always strip out all the vent and fuel lines before the old ones get scrapped! Lots of good stuff and free!

[PeWe]

I'll report how it will work.
My K2 might be updated to K6 long breather style too

[BenelliSEI]

I'll report how it will work.
My K2 might be updated to K6 long breather style too

Per….. I fitted the “correct” oil tank today (top in photo). It only has one hose from the tank that goes back to the rear vent on the transmission casing. The internal pipe in the tank goes up pretty high inside, so I guess in theory, if the tank is over filled, it will also act as an overflow. The only true vent is the long pipe from the cam cover, back to the right passenger foot peg. I wonder if that is enough?

[BenelliSEI]

Fitted the correct oil tank today and finished up the airbox, including a new filter. Went through my notes and I did fork seals and fork oil back when I bought it. Only rode it 28 miles before borrowing the motor for the Rickman…….