Topic: Look, squirrel! Or, how bike projects shift quickly; new CB750 K6 project for me

[gearsoup]

I've got a Vevor 30L ultrasonic, carb clear solution for the ultrasonic  (https://www.kmcarburetor.com/products/sc-20-ultrasonic-cleaning-chemical-1-gallon?_pos=1&_psq=sharpe&_ss=e&_v=1.0)
Also, I should be wrapping up my Vapor Blast cabinet this week 

[BenelliSEI]

Perfect match. They’ll be spotless inside and out!

[gearsoup]

Well...looks like there's something missing here (I think).

[gearsoup]

PO added 2 into 1 exhaust on the bike, rather rusted out. I thought it would be good to replace with a Delkevic 4-1 exhaust, but it appears that I need to have some collectors and exhaust clamps 

https://www.ebay.com/itm/225647409329?itmmeta=01HRW918RPSVYSV4P21NGR9YH9&hash=item3489a238b1:g:~FYAAOSwH49i7dR0&itmprp=enc%3AAQAJAAAA8Cu8rhn1e9o1nTH8qdtewuTHmAWnVkG%2FHH6AiZgJUu6ZaOea7Lf3pXU5KOJfKupTbwJQDprZX%2FCKysTl04PzCcbagmpMXNlPdy75G7WBayOuzxOkUdd5jxGfk6WojTDxKVCTckft0ucUAX9%2Fo10SY6nSSCuhPISYmT2llQxAAkPubVfJGnwW%2FCyeQUTUvDTGcC6o7Z8l%2BXqrJKL6xeb1r8ciZz9szYSwdi7Vk4jnt0Og9XCyy%2FkMo0Gh5M3uNyCrKq5fCxJGCNIRN%2B9PD54AJFUBQvF1iU3UPbaNDxIm6UloXJYbRMlCq5PTJax0PNnlfw%3D%3D%7Ctkp%3ABk9SR7SMhYnHYw

https://www.ebay.com/itm/175865387865?itmmeta=01HRW9J5QPS4HEEWCFMPMTWK7W&hash=item28f264db59:g:3u4AAOSwbrlk3~AQ&itmprp=enc%3AAQAIAAAA8HCIliKgGcUnXgqJjgnPv7jui%2BvOASX0%2BGryTQd4%2BhBrhxWn6%2Fu5uPDasW8nE1vMNX46ts%2FpBtSeqLxexgf%2BfjfWnLBf0x2pkP0U%2FkmX%2B%2BghIa8oN1m82GOe1UMhK%2FdZTMWgs1tK1FVBWjG%2FaRrP%2B21pUWpIsOUieGWOxLSwsipTLOakP7h3n%2FwZdEMR1FTy9JjoPd4B7jgWiLy%2B7RGmuXEdXuYNjHPc4rWEdZId%2FSyyW7o1ww6FSIwMXemBQLlI9csDHQ1PK7JmnWCzfXATr0a99DaGGEyhu14HDyXaT7hPC7lFijx7cXFZ8Vd5AkzvTg%3D%3D%7Ctkp%3ABFBM9tvIicdj

[gearsoup]

What's interesting is that the pipes they offer for the "F" bike do have the bits and bobs I need....
https://delkevic.com/full-system-to-fit-cb750f-super-sport-1975-1976-with-classic-straight-universal-muffler-and-stainless-steel-4-1-headers/

[gearsoup]

There's nothing on the frame or the overall design that leads me to suspect this was an F bike converted to look like a K. Is there any easy way to check to see if this motor is from an F bike? Or is it more likely that many years ago, the PO just ditched the collectors and clamps when they installed the 2 into 1 pipes?

Do you folks think I'd be better off returning the 4 into 1 kit that I have and getting the F model, or just buying the parts needed to make this set of pipes work? I suspect that (if I do have a K bike front to back) there are bolt holes that aren't going to line up at all.

[seanbarney41]

You can identify your frame and engine number by using the guide at sohc4.net.

[seanbarney41]

f you need clamps and split collars, clamps are available as a reproduction and a nice visual upgrade over rusty originals.  You will have to source the spit collars used, I think.

[gearsoup]

You can identify your frame and engine number by using the guide at sohc4.net.

Good idea. Frame and engine numbers both line up with K6 expectations

[gearsoup]

f you need clamps and split collars, clamps are available as a reproduction and a nice visual upgrade over rusty originals.  You will have to source the spit collars used, I think.

Like these? https://4into1.com/chrome-exhaust-pipe-joint-cylinder-set-honda-cb750k-1969-1976/

Or these: https://www.vintagecb750.com/products/7/exhaust/109/gaskets-mounting-hardware

(I think the images below are what I need, based on looking at CMSNL)

[BenelliSEI]

Those are what you need. The studs come out and they are held in by a Philips head counter sunk screw. I prefer alternates I buy locally that are stainless and use an Allen key.

[gearsoup]

Those are what you need. The studs come out and they are held in by a Philips head counter sunk screw. I prefer alternates I buy locally that are stainless and use an Allen key.

Good call, I think my local hardware store will have those.
Jeez, hope I don't break any studs on removal. PB Blaster, some heat and proper torque, they should come out ok...... :pray

[BenelliSEI]

Look like this….

[grcamna2]

Look like this….

You've got a good bolt supplier John.

[BenelliSEI]

Look like this….

You've got a good bolt supplier John.

Bill…. Bolts + is relatively new in Canada and I have a store only a few miles away. Fantastic selection and very knowledgable staff. If you look at the picture, they actually had the stock Honda length and also gave me 8 that were 6 mm longer. I cleaned out the threaded holes and was able to use the extra grip length. Great place.

[gearsoup]

Bill…. Bolts + is relatively new in Canada and I have a store only a few miles away. Fantastic selection and very knowledgable staff. If you look at the picture, they actually had the stock Honda length and also gave me 8 that were 6 mm longer. I cleaned out the threaded holes and was able to use the extra grip length. Great place.

Do you recall the pitch and overall length of those? I might just hit up McMaster-Carr, need some other items from them at the moment

[BenelliSEI]

Bill…. Bolts + is relatively new in Canada and I have a store only a few miles away. Fantastic selection and very knowledgable staff. If you look at the picture, they actually had the stock Honda length and also gave me 8 that were 6 mm longer. I cleaned out the threaded holes and was able to use the extra grip length. Great place.

Do you recall the pitch and overall length of those? I might just hit up McMaster-Carr, need some other items from them at the moment

I think I bought a few extras, will look tomorrow and measure them up.

[gearsoup]

Eh, it's all good. I bought some from McMaster once I found the part on CMSNL, added on a few mm. Figure if they're too long and I can't chase the threads, I can always machine them back if needed.

[BenelliSEI]

Eh, it's all good. I bought some from McMaster once I found the part on CMSNL, added on a few mm. Figure if they're too long and I can't chase the threads, I can always machine them back if needed.

Good solution. I used a bottoming tap and cleaned out what was there and a bit more.The extra grip is reassuring.

[gearsoup]

Finished up my vapor blast cabinet the other day. My wife was skeptical about the whole thing, couldn't wrap her mind around why I wanted something like that. Well, the results speak for themselves, so she understands now 

This was just a rough pass on some junk carbs I picked up to practice on, figured if I destroyed them it wasn't the end of the world. Upon total dissassembly, I'm fairly certain the left most carb is toast, the next one in is "maybe" (something heavy dropped on it at one point in its life).

[gearsoup]

Left most carb and the bowl (only blasted the bowl thus far)

[BenelliSEI]

Amazing! That might be the cruddiest carb I’ve seen.

[grcamna2]

Amazing! That might be the cruddiest carb I’ve seen.

Same !   

[Stev-o]

Nice...I love vapor blasting!

[gearsoup]

So, good news and bad news

The good: I disassembled and vapor blasted the carbs and carb rack, they came out beautiful! 


The bad: "OEM" bottom brass was not OEM, it's aftermarket. The rebuild kit I have is Keyster from vintage750.com. The slide needle is OEM, so...yay? (It's set on 2nd clip from bottom, leave it be?)

I DO have a set of junk carbs (see my vapor blast photos above), but 2 of the carbs are absolutely nasty, the brass is....sketchy at best.  I'll likely just head on over to jetsrus.com and get what I need. Should I replace everything with OEM, or are some of the bras bits okay to leave? Just replace the jets?

Now, onto my second question:  Floats; set them to 26mm. Okay, but from where?
If I look at the service manual, it shows them using a gage, it appears to be resting on the outside lip of the upper body (Not where the bowl sits)
In some videos and pictures I've found, I've seen folks using card stock that fits between the float and the lip where the bowl meets. Which one is correct?

In the attached photos, ignore that the carbs are not tilted back. Having only two hands, I wanted to simulate the measurement process and take photos at the same time. When setting the floats, they will be tipped back properly (just enough to rest on the float needle)