Topic: My CB750K2

[willbird]

In 1972 model year my dad bought a new 750K2. I and my sister rode with him on the back of it. I remember him adjusting valves "they have to be done with the bike COLD, as in has not run today cold", and him building a mercury manometer setup to synch carbs. Dad put a windjammer III on it and had some ugly to me saddle bags on it too at one point. It also got an action 4's 4:1 header installed when the factory pipes rusted out.

Dad died in 1986 and I got the bike then. At one point somebody had stolen the bike briefly and taken the gas tank and side covers. Dad got a used gas tank but was unable to get our local dealer to order side covers. Once it was mine I did manage to got those and paint it all matching. In 1992 or so I stripped it to the frame and had frame plastic media blasted and built the bike back up. Rode it until 1996 or so and then got side tracked and it sat until about 5 years ago.

I got a battery then and fired it up but left it sit it AGAIN.

So now I am getting it squared away again. Pulled the gas tank off today and found out that when I left it sit idle since 2018 or so I left fuel in the tank  . Oops so that is a mess I was not looking forward to LOL.

Ordered some Evaporust to deal with that mess.

Bike has an oil leak between cylinder and head but that is going to wait until next winter. Focus now is getting it running and riding so I can enjoy it this summer. I have fresh license plates and a new battery so no excuses  .

Bill

[BenelliSEI]

Hey Bill..... great story! I tend to move my bikes on, every few years and my Dad never had any interest in cars or bikes. My son loves to ride an old K3 we’ve had for 10-12 years (second from left in the photo). I keep it clean and safe, but have never torn it down. My plan is to pass it on to him and hopefully one day he’ll have a tale to tell too. Have fun with your bike.

P.S. if that petcock was “drooling” for those years, pull those floatbowls and clean out all that muck before you try to start it up!

[willbird]

Hey Bill..... great story! I tend to move my bikes on, every few years and my Dad never had any interest in cars or bikes. My son loves to ride an old K3 we’ve had for 10-12 years (second from left in the photo). I keep it clean and safe, but have never torn it down. My plan is to pass it on to him and hopefully one day he’ll have a tale to tell too. Have fun with your bike.

P.S. if that petcock was “drooling” for those years, pull those float bowls and clean out all that muck before you try to start it up!

That is one thing we can thank the SOHC higher powers for, the petcock kept that fine aged E10 in the gas tank. During the 5 years ago work I had removed carbs and cleaned them thoroughly. Whatever fuel was in the bowls then dried up and did not leave too much mess in there thankfully. I have a petcock rebuild kit in hand.

I'll post a picture of the bike tonight. Frame, swing arm, tank, and side covers are all a corvette blue called Dark Cloisonne Metallic. Maybe not anybody but my cup of tea but it was what I wanted and I'm still fond of it :-). That was a Vette color for years 94-96 maybe. The Vette colors to me all jumped right out of the book at the paint store. I had the bike done in a vette red for a few years too.

[willbird]

I lied about the swing arm, it stayed black 

[rocket johnny]

i like that color of blue ,,  and its your bike so any color you like !

[newday777]

Hey Bill
You have a worthy bike to get back on the road again and good memories I'm sure. I like the blue you used(I'm parcel to blue, my K5 is the Planet Blue)
I have a 76 K6 that was my dad's but is a full restoration project that I took apart in 2015 as the motor was frozen from mice pee in 2 cylinders (and some seeds of some type??). I set the bike up new from the crate when I was parts manager at the local Honda shop in 76 for my oldest brother, with a Windjammer and bags, a year later my brother had to sell it to move to Chicago for a job so my dad bought it and rode it a couple years(I did the maintenance on it and I rode it a few times on some late sleepless hot summer nights and some fall excursions which the faring was great for keeping the chill off). Dad rode it to work mostly to save gas and occasionally he and mom would venture out for a few hours of riding until mom got scared by a cager just missing them so when a friend of mine was looking for a 750 dad sold it to him. I stopped by my friend's house in 2014 for a visit after not seeing him since about 1979 when I moved to Colorado. I'd forgotten he had bought it and his new wife mentioned that Pete had a bike, I asked what he had. It was sitting in his shed since 94 from the head leaking oil all over his dress pants on the way to work one morning. Mice had build a 2 story condo under the air cleaner and above the battery and tool tray. If you enlarge the picture you can see the nest under the carbs. They peed on the frame(rusted and needs filling) and crawled in the RC header and peed in the 2&3 cylinders. I didn't have enough income to rebuild the motor yet so it took the back burner after I bought the K5 I bought from another friend's estate in 2018 that was an easy get back on the road purchase. Maybe, hopefully, this year will be the the K6 turn to get back on the road.
BTW the head leak is usually the rubber pucks that have shrunk from lack of riding often.
Have fun getting yours back on the road again.

[MauiK3]

Great upcoming project!
I couldn't help but notice the cedar siding on the shed the fairing is hanging in. I just did some woodwork with cedar, it's gone through the roof in price!

[willbird]

Ok here is the carnage, kicking myself, washed out with dish soap, rinsed with hot tap water, and loaded in 2 gallons of evaporust.

[willbird]

Thinking I will need small fuel tank for doing stuff like syncing carbs, and to fire bike up while cleaning tank. Amzon reviews said the ones out there kinda suck so I ordered a threaded spigot Honda Petcock, pretty cheap. Making a bulkhead fitting to use with a rubber washer in some kind of tank to hang from ceiling.







I'll see if our TIG wizard at work can TIG that washer on there for me :-).

The Honda tank spigot thread is I am sure a metric thread, I CAN chase a metric thread but it kind of a PITA to swap the lathe over. In this case 5/8-18 is close enough in this short engagement so I was able to use grade 5 all thread.

[Stev-o]

Great story!   

I have one of these for sync'n carbs....

https://www.amazon.com/AnNafi-Auxiliary-Servicing-300Ml-Accessories/dp/B09C8NNN7C/ref=asc_df_B09C8NNN7C/?tag=hyprod-20&linkCode=df0&hvadid=587365484771&hvpos=&hvnetw=g&hvrand=16262374551016038993&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028314&hvtargid=pla-1648577278078&th=1

[willbird]

Great story!   

I have one of these for sync'n carbs....

https://www.amazon.com/AnNafi-Auxiliary-Servicing-300Ml-Accessories/dp/B09C8NNN7C/ref=asc_df_B09C8NNN7C/?tag=hyprod-20&linkCode=df0&hvadid=587365484771&hvpos=&hvnetw=g&hvrand=16262374551016038993&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028314&hvtargid=pla-1648577278078&th=1

Reviews on those were kind of mixed.

[newday777]

Ok here is the carnage, kicking myself, washed out with dish soap, rinsed with hot tap water, and loaded in 2 gallons of evaporust.

I've found that you need to get 5 gallons of Evaporust if you are going to use it.
I would highly suggest you do an electrolysis cleaning method first then follow up with 5 gallons of Evaporust.
You'll get far better results.

[willbird]

Ok here is the carnage, kicking myself, washed out with dish soap, rinsed with hot tap water, and loaded in 2 gallons of evaporust.

I've found that you need to get 5 gallons of Evaporust if you are going to use it.
I would highly suggest you do an electrolysis cleaning method first then follow up with 5 gallons of Evaporust.
You'll get far better results.

Another gallon showed up today from amazon and went in for a total of 3.  In for a penny in for a pound at this point :-).

[RAFster122s]

That much corrosion I think I would be using electrolysis... that's pretty scaly rust inside the tank.

[willbird]

That much corrosion I think I would be using electrolysis... that's pretty scaly rust inside the tank.

I appreciate the advice, looks like the process is working, I am going to give it time. I'll study on the electrolysis in case I need to do that but it is something I have yet messed with.

Bill

[MauiK3]

It's pretty gentle and effective.

[willbird]

Grabbed 2 more gallons of the EvapoRust from TSC. They have it on sale -$3 from regular price. That filled tank to top and there was a bit left in the final gallon.

The TIG dude at work was gone until Monday so my inner machinist took over and I whipped this up from billet unknown steel alloy I had laying around. This took about 1 hour start to finish. When the tools needed are at hand and you keep it at it the finished part within a bar of stock is rapidly exposed for all to see LOL. TSC had the rubber washer in the Hillman drawers of parts. Clamp thread is 3/4-16. The petcock thread for a tank spigot is IMHO M16-1.5mm so I turned the dia .625 and ran a 16 threads per inch thread on it. My Grizzly lathe will run a metric thread but one has to take gears off the left side, add other gears, then swap back. It is the right thing to do for some jobs but in this case .0625" lead instead of .0590" is fine for the task the thread does. 


Parting off this deep can be scary LOL, it went OK..many years ago I was parting off a part on a lathe way back in the corner of a dingy dark shop, the lathe had a 4' fluorescent light above it. The cutting tool dug in and the part climbed up on top if it, the HSS cutoff blade shattered and the shards of it burst both tubes in the light overhead leaving me %^%$#& in the dark LOL.






I have a TIG welder of my own I bought about a year ago but I have not practiced with it, I need to make that happen so I can TIG 10% as well as I can run a lathe and milling machine LOL.

Bill

[BenelliSEI]

Lovely piece of work! A large aluminum water bottle would look good with that in the bottom (assuming it passes through the neck).

[willbird]

Lovely piece of work! A large aluminum water bottle would look good with that in the bottom (assuming it passes through the neck).

I ordered a container made for mixing 2 cycle premix from Amazon that might work maybe. We will see what that looks like.  32oz.

[willbird]

Big progress day yesterday. Goals for that day were.
1. Wake up at 2:45AM, be at work at 3:30AM
Not achieved, set alarm to 245PM and woke up at 3:45AM, no biggie, got there at 4:30 and worked until 10:30.
2. Mow lawn, done.
3. Drain oil from oil pan and tank, done
4. Grab a Dorman 090-040CD Oil Drain Plug Standard M20-1.50 from O'Reilly and drill and tap it 1/8 NPT to install a fluid filled pressure gauge I had. Done.
5. Remove spark plugs and squirt a little engine oil in each cyl. Done
6. Add new oil, had Mobil 1 5-30 on hand from an a vehicle I no longer have so used it, goal is just to warm it up with that oil in there a few times and drain. Done.
7. Crank to achieve oil pressure, Done, 450 lbs cranking.
This was really as far as I thought I would get yesterday  , the rest is bonus.

8. Replace spark plugs, forgot how much fun the inner two are to get to.
9. Hook up no gas tank fuel feed. Done
10. Check each float bowl, rinse out with brake clean, done.
11. Turn on fuel and start engine, got it to run on 3, cyl 1 pipe not warming up. Removed that float bowl, bone dry, needle was stuck up. Removed needle and seat, cleaned, then it ran on 4 cyl but cyl one carb overflow was dribbling. Float was dragging on one side and could not go fully up, fixed that and it runs on 4 now. 80PSI oil pressure anything over 2krpm or so. The Dorman plug leaks oil. The oil drain plug gasket included plainly is not designed for anything but static pressure. Will reinstall stock galley plug once I get a new O ring for it. Just wanted to make sure I had oil pressure to begin with before I fired the engine. Had never checked it's oil pressure as long as I have had it.

Mice had moved into my Windjammer years ago when I did a resurrection of the bike and I had made some new wires and something is amiss there, ordered a 6 pin Deutsch connector pigtail from the zon of am and will redo that stuff. My H4 bulb was burned out too so grabbed one of those from Mao mart, and an 1157 LED tail-brake, and I have two accessory tail lights that take 1156, put LED in them too. Buddy game those to me and when I got them they had 1156 in them which were SUPER bright but IMHO too much amperage draw so I had found a smaller bulb that fit 1156 socket, the LED 1156 should be fine though.
 

[HondaMan]

Temp tank: I have the Motion Pro version, it is top-notch. Someone sent me one after I rebuilt his engine.

I can 100%+ recommend the 3-step tank coating system POR-15. Just one thing to watch for: insert 2 long 6mm screws/bolts, coated with grease into the 2 screw holes that hold the fuel petcock onto the bottom of the tank, using them to close that hole with a small piece of tin or aluminum for the process. Then when the POR-15 sets up it creates a shell around those 2 holes so you can unscrew those long screws and then install the 2 shorter ones that hold the petcock on. If this step isn't done, it is nearly impossible to remove the POR-15 from those in-tank nuts so as to reinstall the petcock. The POR-15 is impervious to anything you can put in the tank that will run the engine, too, even race gas mixed with ethanol or a touch of nitro.

[willbird]

Temp tank: I have the Motion Pro version, it is top-notch. Someone sent me one after I rebuilt his engine.

I can 100%+ recommend the 3-step tank coating system POR-15. Just one thing to watch for: insert 2 long 6mm screws/bolts, coated with grease into the 2 screw holes that hold the fuel petcock onto the bottom of the tank, using them to close that hole with a small piece of tin or aluminum for the process. Then when the POR-15 sets up it creates a shell around those 2 holes so you can unscrew those long screws and then install the 2 shorter ones that hold the petcock on. If this step isn't done, it is nearly impossible to remove the POR-15 from those in-tank nuts so as to reinstall the petcock. The POR-15 is impervious to anything you can put in the tank that will run the engine, too, even race gas mixed with ethanol or a touch of nitro.

Good to know on the coating, I hear of so many bad reports about some products out there. A co worker said that Napa has a tank coating material avail he has used for leaking Mopar gas tanks.

The tank is looking pretty good, I just left the EvapoRust in there for what ended up about a week total.

I picked up a HF 20 lb pressure blaster today and grabbed some "medium" coal slag blast media from TSC. The stuff is dirt cheap so I figured it was worth a shot, $14 a 50 lb bag vs nearly a dollar an lb for other stuff.

I took apart the front caliper, made a fitting to use a grease gun. NAPA has in stock a metric brake fitting adapter designed to let one use a 3/8 USA tube flare nut into the 10mm metric flare socket. I just flat bottomed the hole and ran in a 1/8-NPT tap then threaded in a 1/8-NPT grease zerk. Piston came right out with a Dewalt 20V grease gun :-). I did hit it with compressed air a bit before trying grease and was getting no motion, did not feel like bouncing the piston around the shop while creating a huge cloud of DOT 3 brake fluid LOL.



Hit the aluminum parts with some TSC tractor matte black rattle can. I was kind of on the fence about just reassembling but just could not bring myself to put new piston and seal in scabby looking parts LOL.

Folks speak of a Red Rubber Grease to use inside the bore on assembly, it does not seem to be sold in the USA ?? Supposed to be DOT bralke fluid compatible ?? I have some of the purple stuff made for automotive caliper work.

https://shop.advanceautoparts.com/p/permatex-purple-ceramic-extreme-brake-lubricant-236ml-can-24125/16160018-P?navigationPath=L1*14924%7CL2*15038%7CL3*16152

I'm not thinking that the seal and piston need anything other than brake fluid, but thinking about the portion of the piston that is out past the seal, and the other metal parts involved.

Here is an example, I cannot see needing as much as they used..kinda SMH there LOL, but a little wipe of it to protect the piston out past the seal might be good.
https://www.redrubbergrease.com/tips-how-to-brake-caliper-failure-repair-with-rebuild-kit.html

[newday777]

Amazon Castrol red rubber grease

[willbird]

Amazon Castrol red rubber grease

Is it good stuff for that purpose??

Bill

[BenelliSEI]

I just coat that portion of the cylinder (where it’s exposed). A small amount of any good silicone grease will work. Last two, I used a stainless piston, from a guy in Germany...... need to check if he still sells on EBay. Well made, beautifully finished.