What Did You Do With Your Nighthawk Today?

[Bob H]

I've never seen an ultrasonic cleaner used like that before.  I have the HF one and just fill it with whatever cleaning solution I'm using.

I put some plain water in the ultrasonic cleaner, placed the bag of parts, then added more water to the "max" line. 

I got the idea to contain parts  in zip lock from several Adv Rider threads and researching ultrasonic in general (as I am a newbie). I heated the water before putting it in zip lock, then also heated the surrounding water in the ultrasonic, and also ran the heater during the cleaning process.
The following thread is pretty interesting where a guy puts parts inside of a beaker, suspending parts in the solution https://www.advrider.com/f/threads/ultrasonic-cleaner-whos-got-one.1614611/
There are all kinds of opinions on how long to run the ultrasonic, from 20 minutes to an hour.
My cleaner has a timer with max of 8 minutes (480 seconds on the display) so the zip lock quart bag enabled me to "flip it" 4 times to ensure no bubbles preventing contact to the passages.
The bag can hold very small parts. And it contains the initial grime that comes off the parts, so you have less junk getting on the ultrasonic machine initially.

People that clean their carbs describe stuff coming off like "smoke" during ultrasonic, and I did see that.
Some technical references say OK to use hard pyrex beakers, but not plastic that can absorb vibrations. Suspend the containers from bottom of ultrasonic cleaner.
I had some concern about the plastic zip locks, so after the 4 sides were done with pine sol solution I ran the carb bodies and larger parts in plain water, not using a zip lock. I didn't see more contaminant coming off the parts but it gave me a warm and fuzzy feeling that the parts were cleaned.

[mollusc]

Ah!  I didn't realise that the tub was filled with water and the bag was sitting in that.  I thought you just had the bag sitting in there on its own.  Seems like a good approach.

[Gene]

 I finished completely rebuilding my carbs, (all 4 of them) and also got the choke plunger/adjustment rod straightened out and installed. This past weekend I installed them, (It's very difficult for someone not used to it) and I would have completed the bike but, my wife and I went and got a puppy, and I ran out of time and complicating things was it started to drizzle/rain.
 
Things to still do:

Hookup the throttle cables, (not easy)
install the seat.

Hope it runs!

[Larry Fine]

In my opinion, it's much easier to attach the cables before putting the carbs back in place.

[mollusc]

Completely agree.  Connect the cables to the carbs before sliding them into place in the cavity, then fight with getting them into the carb boots, then attach the box-side boots.
Choke cable is easy to install after everything is done though.

[Bob H]

...Things to still do:
Hookup the throttle cables, (not easy)

Consider lubricating all your cables, including clutch while they are easy to access.
My motion pro lube tool suggests lube from carburetor end, and yours are uninstalled.

I just did that as I wait for vacuum diaphragms, which had about 10 day delay from Honda to Partzilla and have not been shipped to me yet.

I got this lube tool a few years ago and really like it. Takes a bit to wrap your head around how to use it, but it worked better than the older "clam-shell" type tools. Costs more.
https://www.motionpro.com/product/08-0609
Do you have a manual? Agree with Mollusc, all my manuals say to install cables while the carb assembly is loose.
I have silicone lube for brake work (syl-glyde) which eases the push onto carb boots.
It is friendly to rubber, such as brake caliper seals so it is fine for rubber connectors to your carbs.

[Bob H]

Got everything put back together and she runs!
I pulled the California emissions junk, and the 110 Main Jet.
Replaced with Main jet size 115 and 1 shim for each Slide Needle as recommended by Pete and the folks at carbjetkits.com for stock exhaust, stock intake. I also replaced the pilot jets as they came with the kit, but my old ones were OK.

Running up through 3rd gear was great, a slight flat spot was gone 4,000 to 5,000 RPM and the run up to redline was smooth.

My real test was 4th gear where my bike tended to be gutless - so I punched it and the clutch slipped!!!

Could not believe it. Kind of a joy and sadness. Glad that it had more power, sad that I have yet another project. But the clutch is not urgent, under normal riding it is OK. I thought it would have lasted more than 38,000 miles because the bike has been taken care of, not abused or hot rodded.

I will sync the carbs next (have a Morgan Carbtune) now that I know it runs OK and that I can get it up to operating temperature.

While I was waiting for vacuum diaphragms to arrive, I replaced the slowly leaking valve cover. The manual says to use Hondabond only at the half-round moon shape things and about an inch beyond. Screw that. It is known that this is a problem leak area for this model, so I put a "thin" layer of Hondabond around the entire gasket, both sides.

Part of that decision was based on how immaculate the cams look, and automatic adjusters. I hope I never have to pull that rocker cover off, it will be glued on - but the only reason to pull it would be to fix a leak. So now it basically can't leak.

I also replaced spark plugs while everything was opened up.
They looked like new after 25,000 miles since last change.

[Pete in PA]

That's great!  on the clutch I think there is also a time quotient in the fiber plates. They age too.

Read up on doing the clutch, there is a special nut that needs a special tool.  Order a new nut from Honda and now it's a regular hex nut.  30 years too late Honda.

I also think you don't need the clutch holder tool. I think you can put it in 5th gear and hold the brake. or leave in neutral and buzz it off.

[Bob H]

OK, while it is opened up I likely should replace springs as well so everything gets a fresh reset.
I'm sure the steel plates are OK but would need the surfaces to be sanded which is a time suck.

I am inclined to do the Barnett $200 complete kit with 7 frictions, 6 steels, and 4 springs
https://www.barnettclutches.com/343/honda/0/0/1993-honda-cb750-nighthawk.html

I think I am going to wait until my next oil change. If I am replacing the steels, no harm is really being done if there is occasional slipping. The clutch appears 100% OK until I grabbed a fist full of throttle in 4th.

Time to start getting the parts ready, including that hex nut and a new cover gasket.
I will get a cheap ebay tool to remove the existing nut.
I see what you are saying on the replacement nut, now it no longer needs a special tool. It has that outer flange that you punch into the keyway.

[Larry Fine]

Remember to soak the new fiber plates in engine oil before assembly.

[Pete in PA]

I've been wondering which cheap Chinese tool to get off Ebay. It's going to be a one time use.

Mine isn't slipping (yet) But it's a 92 at 21k miles.

I'd probably just do the fibers and springs myself.

https://youtu.be/R9pOtHRzJM4  This guy is in the middle of doing his clutch. Still 1 or 2 more videos to do.

[Bob H]

I did the carb sync yesterday using the Morgan Carbtune, and took it for a longer ride. It is like a completely different bike, with power everywhere (not a liter bike, but at least not gutless and runs like a 750 should). 
I think the main reason for that is changing the main jets from 110 to 115.   I don't think the slightly torn diaphragms were causing too much trouble. While I was waiting for the new ones I started the bike up with the old ones and gave it throttle, watching the slides move up and down. 2 of the diaphragms had small slits, but they moved up and down similar to the undamaged ones. Likely it would have gotten worse over time.

I just use a large syringe for temp fuel, with a cheap plastic petcock. Have the safety stuff ready if needed.


The few times I had to switch on reserve, it was awkward with gloves riding down the road. Fumbling around for the petcock valve.
You start to realize that the "reserve" is just making you run out of gas, while a lot of gas is sitting there in "reserve".
Modern motorcycles do not have a reserve, and if you don't watch the dash or tiny warning light you could run out of gas.

A couple years ago I started leaving my petcock on RESERVE and simply watch the miles. I zero out the trip meter when I fill up.
So yesterday I decided to re-orient my petcock. The original position puts the fuel line where it is very awkward to reach, this makes it much easier for removing the tank.
If you don't need to access the handle thing for reserve, you can orient it wherever you want.
The vacuum line can be re-oriented by removing the 4 screws and aim it where you want.

[mollusc]

I always consider Reserve as similar to carrying a spare gallon bottle of fuel.  It's there if the tank runs out.  Give how much variability I had with the mileage on my 700S, I don't trust relying on the tripmeter -- rather, I use that as a backup for the gauge.  I know that not all bikes have gauges though.

[Bob H]

I always consider Reserve as similar to carrying a spare gallon bottle of fuel.  It's there if the tank runs out.

Right, being in control of fuel is much better than being stranded.
Sometimes I ride with a guy on an MT-07 that gets better mileage than I do despite 1 gallon smaller tank. His Fuel injection verses Carburetor's.

I have had to fumble around for reserve while my bike sputters along the road. So I just leave the "reserve" on 24/7 and fill up before my Trip Meter hits 110 or 120 (it can go 137 miles, but fill up sooner)

I always have saddlebags (small air pump, flat fix kit, etc.) and if going out more than a couple hours I bring a gallon of fuel, sometimes 2 if going very remote.
I got these 1 gallon containers from Tractor Supply, they fit my saddlebags perfectly with a bit of room to spare (made by "Midwest")

[Pete in PA]

I did the carb sync yesterday using the Morgan Carbtune, and took it for a longer ride. It is like a completely different bike, with power everywhere (not a liter bike, but at least not gutless and runs like a 750 should). 
I think the main reason for that is changing the main jets from 110 to 115.   I don't think the slightly torn diaphragms were causing too much trouble. While I was waiting for the new ones I started the bike up with the old ones and gave it throttle, watching the slides move up and down. 2 of the diaphragms had small slits, but they moved up and down similar to the undamaged ones. Likely it would have gotten worse over time.

I just use a large syringe for temp fuel, with a cheap plastic petcock. Have the safety stuff ready if needed.


The few times I had to switch on reserve, it was awkward with gloves riding down the road. Fumbling around for the petcock valve.
You start to realize that the "reserve" is just making you run out of gas, while a lot of gas is sitting there in "reserve".
Modern motorcycles do not have a reserve, and if you don't watch the dash or tiny warning light you could run out of gas.

A couple years ago I started leaving my petcock on RESERVE and simply watch the miles. I zero out the trip meter when I fill up.
So yesterday I decided to re-orient my petcock. The original position puts the fuel line where it is very awkward to reach, this makes it much easier for removing the tank.
If you don't need to access the handle thing for reserve, you can orient it wherever you want.
The vacuum line can be re-oriented by removing the 4 screws and aim it where you want.

Glad it runs better!   How's the idle? Where did you set your pilot screws at?  Did you get your tool yet?

Mine already broke😡😡 It's like the inside of a speedo cable with a screwdriver tip crimped on it. Going to play with it and try to fab. it into something that works.