Topic: CB750 K1 Resurrection

[ZTatZAU]

Despite some unavoidable delays I've finally gotten back to my K1 resurrection and have the carbs back together.  I recently received a pack of 8 new O-Rings for the fuel connector tees from Parts-N-More (# 48-0791) though I'm not sure what these O-rings are made of.

I'm looking for recommendations on the best O-Ring Lube to use on the fuel connector tees when joining the bank of four carbs together?  Any suggestions?

ZT

[Tracksnblades1]

Missed you back in January.

Enjoyed your presentation.
While in qrammer school, I learned to ride a Cushman also. An Eagle 2speed with a foot clutch. Still have it in the family.
Still with my best girl friend and after 42 years thinking she may be the one..😜

Welcome.

[MauiK3]

I usually use a silicone lube very sparingly. On brake systems I use the lube that came with a kit.

[ZTatZAU]

Missed you back in January.

Enjoyed your presentation.
While in qrammer school, I learned to ride a Cushman also. An Eagle 2speed with a foot clutch. Still have it in the family.
Still with my best girl friend and after 42 years thinking she may be the one..😜

Welcome.

  Thanks Tracksnblades, for your nice welcome and comments!

I usually use a silicone lube very sparingly. On brake systems I use the lube that came with a kit.

  Thanks MauiK3!  I appreciate your reply.

ZT

[grcamna2]

Welcome to the forum ZTatZau.

[newday777]

Despite some unavoidable delays I've finally gotten back to my K1 resurrection and have the carbs back together.  I recently received a pack of 8 new O-Rings for the fuel connector tees from Parts-N-More (# 48-0791) though I'm not sure what these O-rings are made of.

I'm looking for recommendations on the best O-Ring Lube to use on the fuel connector tees when joining the bank of four carbs together?  Any suggestions?

ZT

I have some red grease I use on orings to lube them. My shop isn't here at the house so I can't tell you if it's just a bearing grease or what. Just need a little coating for them to slide in easier.

[newday777]

Doing a web search this turned up on lube for fuel orings

[ZTatZAU]

Welcome to the forum ZTatZau.

Thank you kindly, grcamna2!

I have some red grease I use on orings to lube them. My shop isn't here at the house so I can't tell you if it's just a bearing grease or what. Just need a little coating for them to slide in easier.

Doing a web search this turned up on lube for fuel orings

Thanks Stu!
I saw similar warnings and cautions, depending on the type of rubber, when I searched the web.  But not knowing what these aftermarket O-Rings are made of is why I asked for suggestions here.

Parker Super O-Lube is widely used in the aviation industry and likely a good choice; but at about $40/oz, I'm thinking a light coating of bearing grease or even motor oil would do just as well in this application.

I appreciate your thoughtful replies.
ZT

[MauiK3]

Often it's good to use some of the fluid in the system the o rings are for.
Forks-use fork oil
Brakes- use brake fluid
You get the general idea.
Not always easy, fuel systems come to mind as an exception

[ZTatZAU]

Often it's good to use some of the fluid in the system the o rings are for.
...
Not always easy, fuel systems come to mind as an exception

Thanks again MauiK3.
I wound up using a product called Seal Lube, I happened to have on hand, on my fuel connector tee o-rings.  Popular in the aviation industry, the following description is from Aircraft Spruce's website...

"SEAL LUBE: Formulated especially for lubricating seals, gaskets, and o-rings.  This pure silicone lubricant will greatly improve the life and sealing ability of door seals and rubber gaskets (such as gas caps) and is ideal for lubricating the o-rings on the primer pump."

My connector tees, with lightly lubed o-rings, went together nicely!

I now have another problem and I'm not sure if starting a new thread for subsequent questions would be preferable to continuing on in this thread with additional questions as my K1 resurrection proceeds.  Any advice on this is appreciated.

For now, I'll continue on here and put this new issue out there for any advice and suggestions.

After a good ultrasonic cleaning and reassembly, the individual carb slides operating up and down quite freely when raised by hand and dropped back down to the closed position on their own or with an ever so slight downward push.

However, once the four carbs were joined together and mounted securely on the "carb rack", the carb slides did not operate so freely when moving the actuator linkage by hand.  I should point out that I did not disassemble the actuator linkage assembly but cleaned the rack and linkage as a unit in the US cleaner.  The linkage operated smoothly and effortlessly before installing the carbs on the rack; but once the carbs were mounted i found considerable difficulty raising and lowering the slides via the actuator linkage.

Without the lower return spring installed, the linkage worked smoothly to raise the 4 slides 3/4 to 7/8 of the way up where it became difficult (but doable) to rase them to the fully open position.  Then, on the way down by operating the actuator linkage, the slides moved freely at first then seemed to get more and more difficult until a point about half way closed and then (almost) seemed to snap closed without much pressure at all.

Thinking I may have an alignment issue on the mounting rack or perhaps some distortion in the slide barrels with the retaining rings too tight (tightened only by hand), I removed the carbs from the rack and verified the slides all still moved freely as did the disengaged actuator linkage.

Unfortunately, upon reassembly, I experienced the same difficulty, described above, when operating the actuator linkage.  Any help or suggestions to resolve this issue (if indeed it is a problem) will be appreciated.

ZT

[ZTatZAU]

It's been several days since my last post but please disregard my last question as my carbs now appear to operate feely as they should.

I may have gotten better response (or any response) if I had posted my question in a new thread.  Still not sure which approach would be best... I.E New question - New Thread OR New Questions in my original thread for continuity.  PLEASE ADVISE!

For now, I'll post this question here and see what responses I get.

My carbs are now mounted on rack plate but not yet installed on the engine.  I have installed NOS rubber insulators.  But before I get ahead of myself... Should I be installing the air filter box before installing the carbs?  OR, is it possible to install the carb assembly, and then the air filter box?

Thanks!  ZT

[newday777]

The carbs go on first w/loose clamps, then the airbox goes on, bolts in the upper mount loosely,  the hold up the carbs so they are straight to the airbox and tighten clamps and airbox bolts.

Yes you can ask here to keep it together and you can also ask separately in addition if you need an answer right away.

So what was hanging up the carbs?(you didn't say above other than disregard)

[ZTatZAU]

Thanks for your informative reply, Newday777 (Stu).  I'll follow the steps you set forth.  Once that's done, I assume the rubber velocity stacks are inserted into the airbox... then pulled back out to seat them on the carbs and at the airbox holes.  Is that what you recommend?

As for my prior carb issue, I think it was simply a matter of dry slide bores and the lack of the lower return spring which seemed to help get past the mid point of the downward slide.  A little squirt of WD40 up into and around the slides seemed to help too.  Thanks for asking!

ZT

[newday777]

Put the air horns in the airbox on your bench before you put the airbox in place.

[Scootch]

I found that it worked well for me if I had the carbs mounted, had the velocity stacks inserted into the air box, then rotated the air box up into position slipping the stacks onto the lower part of the carbs and working them in place then installing the air box screws. But probably a matter of personal preference as to what works best for you. Also you can reach into the air box and rotate the stacks to help coax them onto the the carbs...

[newday777]

WD40 attracts dirt and gums ip eventually so if it gets sticky, clean it out with contact cleaner, then lube with dryslide

[ZTatZAU]

I found that it worked well for me if I had the carbs mounted, had the velocity stacks inserted into the air box, then rotated the air box up into position slipping the stacks onto the lower part of the carbs and working them in place then installing the air box screws. But probably a matter of personal preference as to what works best for you. Also you can reach into the air box and rotate the stacks to help coax them onto the the carbs...

Thanks for those tips, Scootch!  I'll see what works best for me.

WD40 attracts dirt and gums ip eventually so if it gets sticky, clean it out with contact cleaner, then lube with dryslide

Thanks again for your help, Stu!  I'll keep the Dry Slide in mind going forward.
ZT

[ZTatZAU]

Carb Install Questions

I really should have taken more pix when I took my K1 carbs apart so I wouldn't have so many questions as I reinstall them.  But here goes...

1)  AIR BOX CONNECTOR TUBES

Put the air horns in the airbox on your bench before you put the airbox in place.

Any suggestions on achieving the proper orientation of my NOS Air Box Connecter Tubes as i insert them into the Air Box?  Other than the mold lines, there doesn't appear to be any indexing marks on the K1 tubes as I've seen on other models.  The tubes are pretty snug and difficult to rotate once they're in there; so, I'd like to get them pretty close to correct as I install them in the Air Box on the bench as Stu suggested.



Any suggestions on this?

2)  CARB DRAIN & VENT TUBES:



I've found some pix and tips for other models where all six hoses are routed down through the clip at the swing arm but my K1's OEM vent tubes aren't long enough to go all the way down there.  So, my question here is... Should the two carb vent tubes be routed up and over the top of the Air Box?  Or something different?

As always, I appreciate your expertise and assistance as I work toward getting my K1 back on the road!
ZT

[BenelliSEI]

On my K1 the bowl vent tubes (2) just go up and over the airbox.

[BenelliSEI]

Regarding the airbox connectors, they all have to have the front openings parallel, when installed. From memory, I think I have all mine pointing “down” (out the front),before mounting the top of the airbox (the bottom 1/2 goes on when everything else is done).

Or it might be”up”? Should be obvious when you line yours up to the top mounting bolts……

[BenelliSEI]

Don’t be afraid to list all your questions in your “Project File” here. Plenty of us like to follow your progress and you’ll get lots of responses. More pics the better.

[ZTatZAU]

On my K1 the bowl vent tubes (2) just go up and over the airbox.

Thank you, BenelliSEI!

Regarding the airbox connectors, they all have to have the front openings parallel, when installed. From memory, I think I have all mine pointing “down” (out the front),before mounting the top of the airbox (the bottom 1/2 goes on when everything else is done).
Or it might be”up”? Should be obvious when you line yours up to the top mounting bolts……

Thank you!

Don’t be afraid to list all your questions in your “Project File” here. Plenty of us like to follow your progress and you’ll get lots of responses. More pics the better.

And, thank you!  I appreciate the replies.
Stay tuned.  I ain't done yet.
ZT

[ZTatZAU]

GAS TANK & PETCOCK

My rebuilt Carbs and Air Box are now installed on the bike and the twist grip throttle operates the slides from idle to full quite nicely.

My next step is to ensure a reliable supply of clean fuel to the rebuilt carbs.  To that end, I'd like to address some light rust in the gas tank and rebuild the petcock which currently does not deliver any fuel at all with the fuel valve in the reserve position.

I disassembled the petcock and there was so much gummed up and hardened crud built up, all the way up to the base of the taller RUN position tube, I couldn't determine where the RESERVE outlet port hole was, down inside the valve body in the area indicated by the small pick in the picture below.



I started with carb cleaner spray and the small pick; digging out as much of the crud softened up by each application of the carb cleaner spray.  It was pretty slow going and eventually, I put the disassembled valve body into a Gunk cleaner basket for about twenty minutes and then cleaned out the rest of the two oval cavities through which the mounting screws pass.

I should mention here, hoping that it may help others, that I was quite concerned about stripping out the Phillips head screw caps or worse yet, snapping the screws off at the nut plates inside the tank. The petcock had never been removed and the two screws were very tight, and I couldn't budge them with as much pressure I was willing to apply with a screwdriver.

I considered using a handheld impact screwdriver but decided I didn't want to bang that hard on the bottom of the tank.  So, after fully draining and venting the tank, I sprayed some PB Blaster down onto the nuts inside the tank.  After a good soak, I then applied some heat (with a heat gun) to the valve body and the heads of the retaining screws and was finally able to remove the screws, and the valve, with a good fat handled Phillips screwdriver.  I then ran a 6mm tap through the nuts inside the tank to clean up any corrosion in the threads and likewise ran a 6mm nut up and down the mounting screws to clean up those threads.

I've now ordered a petcock rebuild kit, that I saw here in another thread, which contains everything I should need to reassemble a serviceable fuel valve.



As for the rust in the tank...

I've previously used Evapo-Rust with good results in a much smaller 2.2 gal. tank when restoring my 1973 XLH 1000 but I don't have enough Evapo-Rust on hand to completely fill the 5.5 gal. K1 tank and don't particularly want to go through the hassle of rotating the tank periodically as the Evapo-Rust does its thing.  At $30/gal, I don't want to spend another $90 to stick with the E-R and now considering the use of household vinegar or perhaps "The Works - Toilet Bowl Cleaner" as I've seen on a few YouTube videos. 

In researching my options, I did find an interesting thread where someone filled their tank with golf balls to reduce the volume of rust remover to fill the tank; but I'm not sure how many golf balls would be required, what they might cost (I'm not a golfer), or how the golf balls would stand up to whatever product is used.  Any suggestions are welcome!

ZT

[RAFster122s]

Vinegar and acids that are aggressive eat both bad and good metal. I dislike them for that reason. I prefer to use electrolysis of oxalic acid which chelates the rust like Evaporust and similar products and. Just use it in a warmed to hot solution and let it work for a few days. You can buy powdered oxalic acid 5 pound bag and mix it with 5 gallons of distilled water... Given you need 5.5 gallons I would just add the water to top up the tank. Golf balls are a good solution. Check with a driving range and tell them why you want them, they might give you a deal on balls with divots or slices or enough balls tohelp fill the tank.

Electrolysis works well too if you have a battery charger that can run manual mode and don't mind cleaning the rebar or other sacrificial steel anode often.

Using acids that eat good steel just makes the tank metal thinner and etches the rolled steel finish leading to faster rust issues in future unless you line the tank with Caswells or POR tank liners.

[newday777]

I agree with David about doing electrolysis. I use washing soda 1/2 cup to 5 gallons water and an electrode made from 5/16" all thread bar nutted w/fender washers to a cut down paint can cap.
Positive lead to electrode, negative to the tank at the hump rubber mount flange (sand off paint to expose fresh steel for connectivity).
This is after a couple days, clean it off and go again a couple more times. 

Edit... The paint cap insulates the positive from the tank so the electrode draws off the rust from the tank and attracts the rust to the electrode.