Topic: 74 CB750K A Bike For My Pops

[HondaMan]

A box of goodies came in the mail and included was an 18 tooth front steel sprocket from JT. I replaced the front sprocket but I have a couple of questions about the install. I know on the later years (77-78) they ran a 630 chain and the front sprocket had an offset to it. This means it could only be installed facing one way. Is this the same for the earlier 530 chain sprockets? because I couldn't tell a difference one way or the other but I could be wrong. Secondly, What is the rule of thumb for setting the chain oiler? Is it hand tightened or torqued to a specific range?

The 530-size sprocket on these earlier bikes is "spaced" by that spacer washer (or a shoulder on the sprocket, if you got that type) to offset it. If the sprocket does not have 2 [big] washers with it, put the washer BEHIND the sprocket to push it outward a little bit (2mm, technically...). Then slip on the little toothed plate.

If you have a fine-stone grinder handy, try modding that JT countersprocket a little and be rewarded with smoother operation, quieter chain, and longer life: trim the tips of every tooth about 2mm shorter, and then apply a 45 degree side angle between the egdes of each tooth and the sides. This only takes about 10 minutes (at least, after I have done about 20 of them lately) and will make you chain much happier and will reduce the tendency to pitch off the lube as it is running.

The oiler: Honda set them at 1.5 turns out from closed on the 1974 and later bikes. That often let the chain run pretty dry, though. The little rubber seal on the screw is probably shrunk from age by now, so it may oil well at that setting today?

[Lazerviking]

Really digging this build and your attention to detail. I need to add a small blaster and a powder coating system to my basement. Do you use a booth for blasting your parts?

[FridgeRaider]

Really digging this build and your attention to detail. I need to add a small blaster and a powder coating system to my basement. Do you use a booth for blasting your parts?

Hey Lazerviking thanks for the reading! At the very least home blasting is the way to go.  I built a big blasting cabinet that can house a motorcycle frame (still haven't built an oven big enough to compliment it  ).



I use a modified powder coating gun from harbor freight and a small wall oven to cure them in. 90% of the final finish is in the prep work so I can get great results (not professional, but close) for a fraction of the cost. Plus, I can say I did all the work myself. 

The 530-size sprocket on these earlier bikes is "spaced" by that spacer washer (or a shoulder on the sprocket, if you got that type) to offset it. If the sprocket does not have 2 [big] washers with it, put the washer BEHIND the sprocket to push it outward a little bit (2mm, technically...). Then slip on the little toothed plate.

If you have a fine-stone grinder handy, try modding that JT countersprocket a little and be rewarded with smoother operation, quieter chain, and longer life: trim the tips of every tooth about 2mm shorter, and then apply a 45 degree side angle between the egdes of each tooth and the sides. This only takes about 10 minutes (at least, after I have done about 20 of them lately) and will make you chain much happier and will reduce the tendency to pitch off the lube as it is running.

The oiler: Honda set them at 1.5 turns out from closed on the 1974 and later bikes. That often let the chain run pretty dry, though. The little rubber seal on the screw is probably shrunk from age by now, so it may oil well at that setting today?

Awesome advice! I had to run into the garage at 1 a.m. to modify the sprocket. It took me a little more than 10 mins but overall it was pretty easy.

Before:



After:



I would have posted this earlier but I had a lady friend fly into town the next day so she took precedence over motorcycle work. Let me know how it looks!

[FridgeRaider]

This is method I used. I pulled out my digital caliper and locked it to 2mm. It has a depth gauge that extends out of the bottom which can be used to mark each tooth. I sharpied the 2mm but came to realize that it is easy to lose the mark when going at it with my dremel. I remedied this with painters tape as a mark of what not to grind.









Tips grinded down, before chamfering them:



Final results:





The fine grinding bit on my dremel started giving them a bit of a rounded bevel a couple teeth in due to wear (hopefully that wont affect performance). Ultimately I'm happy with the results and with the teeth being 2mm shorter, I think i can put the crankcase protector (against broken chains) back on without clearance issues. Thanks HondaMan!

[Brittreynolds93]

Wonderful project. Great attention to detail, can't wait to see the finished project!

[FridgeRaider]

Front of the bike mocked up before tire install:





Decided to go with stock tire sizes that came on the bike in 1974. Avon Roadriders seemed to get nothing but awesome reviews from you guys so it was an easy choice. 

3.25-19 Front 4.00-18 Rear



I spent a month or so waiting out the holidays hoping they would go on sale but never did.  Darn you tire manufacturers and your set prices!

Beautiful tires none the less and were much easier to work with as compared to the old stiff tires I took off. With a little bit of elbow grease, tire spoons, and a product called Ru-glyde:

[SOHC4 Cafe Racer Fan]

What's with the Saran Wrap -- protective against fingerprints or some layer of minimal protection against dings/abrasions?

[FridgeRaider]

What's with the Saran Wrap -- protective against fingerprints or some layer of minimal protection against dings/abrasions?

  The thought was to try and keep polishing/media blasting dust off of it for as long as I could. 

[FridgeRaider]

Since day 1, the bike didn't want to roll when in gear with the clutch pulled in. This issue was always in the back of my mind and on my checklist of things to troubleshoot. With the front end of the bike buttoned up (for the most part) and a replacement clutch handle in my possession (original was broken), the clutch was up next. I originally figured that after sitting so long with the oil drained that the friction plates had simply fused together. I was correct, but had a little extra surprise to go along with it.

Blue RTV silicone is always a sign of PO modifications to come:


No surprise here, friction plates were dried out and stuck together:


The surprise:


Previous owner apparently lost the 4th bolt for the lifter plate/clutch springs and decided to instead use a bigger SAE size and jam it in sideways. This effectively ruined the threads and I'm honestly surprised it didn't crack the lifter plate to boot. So now I get to go on the hunt to replace the stripped base plate. Luckily Stev-o lives right down the road from me and said he might have something stashed away in his batcave.

This was his answer:


Stev-o is an exceptional guy but I think I have him in the looks department. 

From the the two sets of friction plates and an entire clutch assembly, I was able to hand pick the parts still in spec and install them in the bike. I wish I could say it was easy to do but ended up being a 4 hr+ job. The base plate in the clutch basket didn't sit flush at first and it ended up being a couple mm short for the clutch plate. Finally figured it out and got it installed correctly.

Clutch plate polished with new SS fasteners:

[Stev-o]

Stev-o is an exceptional guy but I think I have him in the looks department. 

Ha!   Glad it worked out for you, want to see this on the road when you are done with it. 

[Brittreynolds93]

I can vouch for others who are curious, you are quite the handsome man FridgeRaider

[FridgeRaider]

I can vouch for others who are curious, you are quite the handsome man FridgeRaider

Take a girl on a motorcycle ride and look at the results, I should have gotten one a long time ago 

Stev-o is an exceptional guy but I think I have him in the looks department. 

Ha!   Glad it worked out for you, want to see this on the road when you are done with it. 

I'm hoping to get it running before my return to Florida, even better if I can get it on the road to Austin for a visit. The full engine tear down and M-unit install is on hold till I can set up shop with my dad.

[Brittreynolds93]

Let's be honest, you just got lucky with me! Also don't pretend that you only took me on your motorcycle once. 
Now get to work on that beautiful motorcycle

[Stev-o]

Let's be honest, you just got lucky with me!

All of a sudden, I feel like an awkward third wheel!

[calj737]

And then some, Stev-o. Didn't realize it had flipped from SOHC to eHarmony overnight!

[FridgeRaider]

And then some, Stev-o. Didn't realize it had flipped from SOHC to eHarmony overnight!

Saves me the trouble of joining eharmony   

Now get to work on that beautiful motorcycle

Yes ma'am!

I forgot to mention in my previous post that I followed HondaMan's clutch basket modification and drilled 8 holes total as opposed to the 4-6 he suggests. Thanks again to Stev-o, I do have an extra clutch basket if that turns out to be a little to much modification. I'm still trying to figure out what after market friction plates were put in the bike. I believe OEM Honda were small straight cut (those were the ones I put back in) and the later ones were slanted cut. The friction plates I pulled out were straight cut into quarters. Any idea who makes those?:



This is a great walkthrough by 72hondacb750 for rebuilding oil pump & countershaft oiler:
http://forums.sohc4.net/index.php?topic=78643.0

I replaced the O-rings as well the oil stopper seal (provided by Elan). The original stopper was still pliable and in good shape so I saved it for a rainy day.


O-ring in the countershaft oiler was replaced as well. The four screws were a PITA and took at least an hour because I stripped everyone of them even with my impact driver. New fasteners were a must:

[FridgeRaider]

Why can't rebuilding carbs ever be easy 



The carbs aren't anywhere near the worse I have seen/dealt with, outside is grungy with minimal old gas residue in the float bowls and jet passages. I guess I wasn't paying attention when removing the slow jet on the #2 throttle body because the top portion was unknowingly cemented in the passage and I managed to torque it in two. I ended up having to drill it out, I believe I got it all out but I cant be 100% sure. I can spray carb cleaner through it and thread in one of my still good slow jets. Best case scenario is I have to source out a new 40 Slow Jet, worse case is I have to replace the whole #2 carb body.





Another learning experience is unlike the carbs off of my CB550s and later style PD carbs, Honda staked in the linkage rod which I should have drilled out before fully disassembling.



Currently dipping the parts in Berryman's chem dip and will finish the outside of the throttle bodies with soda blasting.

[FridgeRaider]

I decided to take a break from the carbs until I figure out how I should proceed with them and got the entire rear end disassembled:



All new rubber parts were bought a while back in anticipation for this step in the restoration from http://www.vintagecb750.com/ (except passenger foot pegs, they were out of stock  )



Both front and rear foot pegs got a home powdercoating from yours truly in super gloss black and the original fasteners got a quick shine. The result is probably one of my favorites for the bike so far because it cost me next to nothing and looks absolutely top notch.



I have always had mixed feelings about the rear shocks. I know that popular opinion for them is that they have been the weak link (performance wise) since Honda rolled them off of the factory floor. Many suggest upgrading to Koni, Ikon, Progressive Suspension, and others for better performance and handling but those come with a hefty price tag. Even still they don't have the stock look that I want with my restoration(ish). I decided that I would try to see how well the original shocks cleaned up before shelling out a good portion of my budget for aftermarket shocks. Here's one of the rusty shocks ready for disassembly:



I was all ready to make a spring compressor similar to the one in the Honda workshop manual until I was digging around my buddy's tool cabinet for a drill bit and came across his custom bearing puller (ends were grinded down to fit narrow openings). It ended up being exactly what I needed. Word of advice: set the shock to the lowest compression setting before compressing the spring (you would think this would be obvious but I didn't realize until after I had them disassembled that I could have made it easier on myself):





40 years taking it's toll:



The shields are rust magnets, before pic:



After media blasting the insides (blue painters tape to protect the chrome for any wayward slag):



It's hard to believe that this is the end result after cleaning the rust off (more proof Quick-Glo works under the right conditions) and polishing the parts up:



Final conclusion: With the exception of minor imperfections the shocks now look almost NOS. I'm still open minded for arguments towards upgrading the rear shocks but I highly doubt that my Dad will push the bike past the ability of the stock shocks to warrant losing the original look and the accompanying price tag that goes along with them.

[Restoration Fan]

Love the way those shocks cleaned up! 
The good thing about your approach towards keeping the original shocks is that the shocks area very quick and easy piece to replace if you do decide to upgrade.

Great job with the bike.  I'm really enjoying all the photos of the progress.

[SOHC4 Cafe Racer Fan]

Cosmetically, they look great, but they are still 40 year old springs.

[FridgeRaider]

Love the way those shocks cleaned up! 
The good thing about your approach towards keeping the original shocks is that the shocks area very quick and easy piece to replace if you do decide to upgrade.

Great job with the bike.  I'm really enjoying all the photos of the progress.

Thanks! I've been following your build from the sidelines, anxiously waiting to see the engine back in the bike and running!

Cosmetically, they look great, but they are still 40 year old springs.

40 year old springs on a 40 year old bike 

What are my alternatives that don't break the bank? I have a pair of cheap EMGO shocks sitting in a drawer collecting dust but they are bulky and longer than stock. They wont work for my vertically challenged father. This thread here http://forums.sohc4.net/index.php?topic=27343.0 is a tad bit old but andy750 has a similar mindset as myself on the matter.


 

[FridgeRaider]

As with the front, the rear wheel got a full rebuild. I switched out the bearings with a new kit from All Balls and replaced the old sprocket with a 48 toothed one from JT. The rest of it got a good polish.





Buying all new SS spokes from Buchanan's would have been nice but I decided long ago to just spend the extra time on the old spokes. Plus it seems that some members are having fitment issues with them in rear hub (granted I think it's with the later year hubs).







Trying to remove the casting marks from the inner portion of the rear hub was an absolute pain and I still didn't get it all sanded out! It still looks good though! Lacing and truing went fairly smooth but I didn't run into a problem until I got to putting the new rubber on. The IRC motorcycle tube I bought to use was for tire sizes ranging from 4.00 to 5.10, which meant that it was within limits but still on the large size for the 4.00-18 Roadrider. I think this was a big factor in me pinching a hole in the tube when working the tire onto the rim. I sat there for a good 10 mins in denial trying to inflate it. 









The big powersport dealership in town had a tube more in the range I needed.

[FridgeRaider]

Next up: Changing the grease zerks in the swing arm bolt to a more modern one that fits an American style grease gun. My swing arm bolt had the earlier style press in grease zerks so it required me to tap new threads. Honestly this modification was fairly easy despite my lack of experience. Here's a list of things needed:

• Irwin Tools 2727- 3 Piece Set - 6.0 mm - 1.00 mm
• Schroder 4.006.4 Ratcheting 1/4-Inch Tap Wrench, 3-1/2-Inch Long
• 6mm Assorted Grease Fittings Set (cheaply sourced from local auto-parts store)
• 5mm Drill Bit (I substituted a close equivalent SAE sized one)
• Cutting Fluid (helpful but not 100% necessary)
• Blue loctite

I decided to keep it metric, mostly because I can reuse the 6mm tap set on other parts of the bike. If I had used a 1/4" tap, it most likely would have just collected dust in a drawer. After practicing on a couple of times on scrap piece of metal I had the confidence to tackle the swing arm. I don't have access to drill press (that would have been nice) so I put the bolt in a vice and eyeballed the drill bit straight. In hindsight I should have put a piece of tape on the drill bit for a visual for maximum depth because before I realized it, I was quite a bit deeper than I needed it to be. Next up was to use the tap set to cut the threads. I didn't have any cutting fluid on hand so I just used some of the assembly lube I used earlier for the front brake, it worked well enough. Steady torque and backing the tap out a bit after every 1/4 - 1/2 turn was the key.



The bolt liked to turn with the tap so I had to rig it to stay in place. This was my solution so it wouldn't be marred by the vice:


Once the threads were tapped, I sprayed out the extra metal filings with some carb cleaner (I had previously cleaned the grease passages out with a Q-tip). Last step was to put blue loctite on the new 6mm grease zerks and gently screw them into place. Here is the finished piece, read to be installed and pumped full of grease.

[FridgeRaider]

Making progress and giving myself a mild heart attack in the process. The swing arm is too big for my oven so I had to forgo giving it a powder coating, I did however replace the stock OEM bushing with brass ones from ebay seller "kenosha_kid". Great product for the price and surprisingly fast shipping considering it was coming all the way from Germany.



I was playing around with my new grease gun and the swing arm bolt when again inexperience got the best of me. I didnt quite understand how to remove the grease gun from the zerk after done pumping grease into it (simply unscrew the tip to release pressure). While I was trying to separate the two, I snapped the zerk in half:



For half a second all hope was lost and I considered abandoning ship. Good thing for my sanity the fix was simple, all I had to do was grab a small EZ Out and the broken fragment I had Loctite'd in place unscrewed itself out. A new grease zerk went back in and now I have real world knowledge on how fragile these things are.

This is the high pressure grease I'm going with:

[FridgeRaider]

I've been busy squaring away the rear of the bike. The underside of the rear fenders got the same Caswell coating treatment as the front fenders, rims, and tank did. Hopefully they will all stay rust free for another decade or two.







As per the suggestion of Hondaman in his book, I purchased a Diamond Powersport 530 chain. I purchased the 100 link based on the fact that the original chain count was 100. In hindsight, I should have bought the 102 link one instead. I find the 100 ct. is about as short as you could physical use on the bike and pulls the rear axle forward of the first adjuster notch on the swing arm. This in turn makes me have to choke up on the rear brake actuator to get it to engage. I later found out that it is suggested purchasing the 102 ct. for this exact reason, here's a thread for reference http://forums.sohc4.net/index.php?topic=77514.0.







And it's a roller: