Topic: 1973 CB750 Rescue

[CycleRanger]

Those shocks cleaned up nicely. I'd use some paste wax or something similar to seal up the pin holes in the chrome otherwise they'll start to show corrosion again eventually.

[Stev-o]

I hooked that portable to my helmet to give the bike a quick test drive.

Need to see a pic of that Johnny!

Nice job on the shock, j343. Can you do the exhaust?!

[Johnie]

Here you go Stev-o. This was one of the blue/green KO bikes. I just couldn't wait for the tank...you know how it is for the first start up...LOL

[grcamna2]

Here you go Stev-o. This was one of the blue/green KO bikes. I just couldn't wait for the tank...you know how it is for the first start up...LOL

I love that blue/green color Johnie. Lol 
Removing the stock tank for adjustments is a pain,I can see how a short ride w/o it is quicker to adjust things when returning back from a ride.
I use a little OEM Honda stock plastic CT70 fuel tank/test tank that I bungee to the top frame rail.

[BenelliSEI]

Here you go Stev-o. This was one of the blue/green KO bikes. I just couldn't wait for the tank...you know how it is for the first start up...LOL

Well done! My wife and I laughed for 5 minutes. She was convinced there was only person in the universe that was actually that stupid. Now she knows there are at least two. Thanks!

[Stev-o]

Here you go Stev-o. This was one of the blue/green KO bikes. I just couldn't wait for the tank...you know how it is for the first start up...LOL

HA!  It looks like it is your Camelbak drink bottle!!!

[Schnell]

"HA!  It looks like it is your Camelbak drink bottle!!!"

Now THAT's an idea!

[j343my]

I hooked that portable to my helmet to give the bike a quick test drive.

Need to see a pic of that Johnny!

Nice job on the shock, j343. Can you do the exhaust?!

The exhaust is too big for my bucket of Evaporust, so I'll have to figure something else out.

Here you go Stev-o. This was one of the blue/green KO bikes. I just couldn't wait for the tank...you know how it is for the first start up...LOL

This is too funny.  What could possibly go wrong...

[RAFster122s]

I hooked that portable to my helmet to give the bike a quick test drive.

Need to see a pic of that Johnny!

Nice job on the shock, j343. Can you do the exhaust?!

The exhaust is too big for my bucket of Evaporust, so I'll have to figure something else out.

Here you go Stev-o. This was one of the blue/green KO bikes. I just couldn't wait for the tank...you know how it is for the first start up...LOL

This is too funny.  What could possibly go wrong...

Will the mufflers end fit in a 4" plumbing pipe? If so you could derust the chrome building a tube to soak them in. Won't help on the headers, but the exhaust can part could slide into a large plumbing or sewer pipe with endcap.
A heavy plastic garbage bag can be used for odd shaped parts in a box filled with objects to take up room around your derusting project piece. Fill bag with evaporust and let it work.

[grcamna2]

I hooked that portable to my helmet to give the bike a quick test drive.

Need to see a pic of that Johnny!

Nice job on the shock, j343. Can you do the exhaust?!

The exhaust is too big for my bucket of Evaporust, so I'll have to figure something else out.

Here you go Stev-o. This was one of the blue/green KO bikes. I just couldn't wait for the tank...you know how it is for the first start up...LOL

This is too funny.  What could possibly go wrong...

Will the mufflers end fit in a 4" plumbing pipe? If so you could derust the chrome building a tube to soak them in. Won't help on the headers, but the exhaust can part could slide into a large plumbing or sewer pipe with endcap.
A heavy plastic garbage bag can be used for odd shaped parts in a box filled with objects to take up room around your derusting project piece. Fill bag with evaporust and let it work.

The Evaporust website mentions wrapping certain items with an absorbent material soaked with it(rags,etc.)and then taping(I imagine shrink-wrap will work good)them over,then putting them in an airtight container/bag,etc.
The Evaporust does evaporate if it isn't kept air-tite.
Evaporust works faster,the higher the temperature of the parts,but then it evaporates faster.

[MauiK3]

Nice progress
The fuel tank hanging from the helmet trick is the ultimate in determination!
I've never seen anything like it.
If the exhaust doesn't work out and you're not up to waiting for a stock 4-4 system maybe Delkevik?

[j343my]

Will the mufflers end fit in a 4" plumbing pipe? If so you could derust the chrome building a tube to soak them in. Won't help on the headers, but the exhaust can part could slide into a large plumbing or sewer pipe with endcap.
A heavy plastic garbage bag can be used for odd shaped parts in a box filled with objects to take up room around your derusting project piece. Fill bag with evaporust and let it work.

The Evaporust website mentions wrapping certain items with an absorbent material soaked with it(rags,etc.)and then taping(I imagine shrink-wrap will work good)them over,then putting them in an airtight container/bag,etc.
The Evaporust does evaporate if it isn't kept air-tite.
Evaporust works faster,the higher the temperature of the parts,but then it evaporates faster.

These are both good ideas.  I'm not particularly big on this exhaust system though, so there is only so much effort I'm willing to put into saving it.

[j343my]

Working on the front end now:


The stanchions look about how I was expecting:


I managed to make quick work of the forks.  The damping bolts were stuck in both, but the impact got them out relatively easily.  The fork seals were also the hardest to remove that I've ever experienced.  I blow torched them until they were smoking and then they came out with the seal puller.

They got a thorough cleaning, new crush washers, seals, and some 10 weight fork oil.

The sheath on the wiring harness to the headlight was very brittle and cracking more every time I turned the bars:


I carefully cut it off and replaced it with some split loom I had leftover from a previous project:


Now that the front end is in the air, I was able to get a good idea of the condition of the steering bearings.  And they are bad... The bike was obviously sitting with the wheel straight ahead as there is a big notch right in the middle that basically locks it into place.  I already have tapered roller bearings, so thats the next item on the todo list.

[denward17]

Are you going to clean up those tubes and re-use?

[SOHC4 Cafe Racer Fan]

That front "stand" looks a little sketchy. Don't bump it! 

[grcamna2]

That front "stand" looks a little sketchy. Don't bump it! 

a pair of long ratchet straps to an upper ceiling support wouldn't hurt

[HondaMan]

The sheath on the wiring harness to the headlight was very brittle and cracking more every time I turned the bars:


I carefully cut it off and replaced it with some split loom I had leftover from a previous project:


Now that the front end is in the air, I was able to get a good idea of the condition of the steering bearings.  And they are bad... The bike was obviously sitting with the wheel straight ahead as there is a big notch right in the middle that basically locks it into place.  I already have tapered roller bearings, so thats the next item on the todo list.

Good call on the wiring! Once, long ago, JerryRXman and some friends rode up here from southern Colorado, and one of the bikes (I think it was an "F", but with a K6 kickstarter lever, I remember) kept blowing the main fuse during their long ride - they had ridden along the Front Range all day. It turned out to be intermittent shorts between several wires right where yours had the broken wire harness jacket from steering movements, where the jacket had carved off the insulation of several wires right there. They had stopped at the Safeway near here (for fuses, I think?), so I rode home and got some electrical tape to shore the wires apart with, so he could get home (Jerry - was that your bike? I don't remember...). Later he got a new harness to fix it up.

The PVC jackets on these harnesses were supposed to last 10 years, I think they made it?

[j343my]

Are you going to clean up those tubes and re-use?

Yes.  They are a bit pitted at the top, but they're straight and the sections the seals touch are in great shape.

That front "stand" looks a little sketchy. Don't bump it! 

It's actually very stable. 

Good call on the wiring! Once, long ago, JerryRXman and some friends rode up here from southern Colorado, and one of the bikes (I think it was an "F", but with a K6 kickstarter lever, I remember) kept blowing the main fuse during their long ride - they had ridden along the Front Range all day. It turned out to be intermittent shorts between several wires right where yours had the broken wire harness jacket from steering movements, where the jacket had carved off the insulation of several wires right there. They had stopped at the Safeway near here (for fuses, I think?), so I rode home and got some electrical tape to shore the wires apart with, so he could get home (Jerry - was that your bike? I don't remember...). Later he got a new harness to fix it up.

The PVC jackets on these harnesses were supposed to last 10 years, I think they made it?

Mine definitely made it.  It was intact when I got the bike back in December.  The first time I turned the bars full lock it started cracking.

[j343my]

Got a bit more done this week.

Steering bearings were first:

The lower race gave me some trouble, but otherwise it was smooth sailing.  The old bearings didn't look as bad as I was expecting given how notchy the steering felt.  The grease was very dry though.

Went with the All Balls bearing kit.  From what I read, it looked like everyone uses the thinner spacer at the bottom. Mine was no exception.



I also did the front wheel bearings and tire/tube:


The front bearings were much better shape than the rear.  Probably had a bit more life left in them, but I already had the new bearings so they got replaced.

For the front tire I went with a Duro HF317.  I couldn't find a 3.25 x 19 anywhere in Canada, so I went with a 3.5".

Currently Evaporusting the headlight ears so the rest of the front end will go back together when they are done.

[SanDogDewey]

I gotta ask…why the zip ties?

[RAFster122s]

Zip ties are to help mount the tire to the rim ... That's one technique used...

[j343my]

I gotta ask…why the zip ties?

Zip ties are to help mount the tire to the rim ... That's one technique used...

Yeah, just makes it a bit easier to mount the tire.

[j343my]

Made lots of progress this week.

Got the front end reassembled.  Used the engine hoist to get the front wheel back on:


When I was taking apart the front fender, one of the fender stay grommets completely disintegrated.  I dug through my box of wire grommets and found one that was pretty much the exact size.  The outer diameter is a little smaller, and I had to sand it down a bit to make it thinner.  I'll probably replace all 4 at some point but for the time being it worked perfectly:


I also got the front brake done.  Ended up doing the caliper piston seal, rebuilding the master cylinder, and new brake lines.


Bleeding:


In theory I now have a rideable bike.  I'd have to do the old hang the auxiliary fuel tank from my helmet trick, but it could happen.

[newday777]

Coming along nicely.  Go for the helmet mount but get good documentation! Pictures are a must have!

[BenelliSEI]

When I was taking apart the front fender, one of the fender stay grommets completely disintegrated.  I dug through my box of wire grommets and found one that was pretty much the exact size.  The outer diameter is a little smaller, and I had to sand it down a bit to make it thinner.  I'll probably replace all 4 at some point but for the time being it worked perfectly:

FYI...... I’ve noticed that vintagecb750.com is selling fender mounting hardware now. Looks like they have yours.