Topic: 1973 CB750 Four K3 -- Project "Terry's Fault" -- BUILD RESUMED

[seanbarney41]

I really dont know.  I was under the impression that the only real difference in the faces was the redline rpm.  I would compare as many part numbers as possible between 550's and 750's.  All I can really tell you for sure is if you slap a stock 550 tach on a stock 750, it will report an obviously too high rpm.  This I have done.

[calj737]

The tach drive gear is different between 500/550 to a 650/750. To use a 550 gauge on a 750 motor, you need to change the gear. I have not heard of simply changing the face to correct the readout. Guess we will know soon...

[edwardmorris]

The tach drive gear is different between 500/550 to a 650/750. To use a 550 gauge on a 750 motor, you need to change the gear. I have not heard of simply changing the face to correct the readout. Guess we will know soon...

If you're talking about the gear under the valve train cover, that's what I had asked earlier, would much rather do that if possible, but looks like a full redo is in order.

[edwardmorris]

Progress has pretty much stalled out because of this awful mindset I'm struggling to get out of. Had to deal with a super schitty vendor who'll promptly take your money but treat you like schit when there's an issue. I have nothing nice to say on the matter, so I'll end the rant there.

Finally felt motivated to get back to it, so started putting the trans back together. Was about to finish installing new SKFs then noticed that one of the snap rings isn't seating fully flush like the rest of them. Its on the main shaft, easy enough to get to as long as the bearing isn't on there. Held off on installing the bearing for now, what do you guys think? Find a replacement or this'll do?

Other than that, it went pretty smooth. Assembled using motor oil directly this time as this may not be sitting out much longer if things go well.

[Davez134]

I know once you get moving with progress, you don't want to stop. Been there many times. But, I would not re-use that snap ring. It looks deformed, and can get magnified while moving. Just my non-scientific opinion.

[edwardmorris]

Thanks Dave, that's my concern as well, especially at high RPM shifts, I'll look for a better one.

[02z06dave]

Thanks Dave, that's my concern as well, especially at high RPM shifts, I'll look for a better one.

Let me know if you need one. I have a few sitting around, I'm sure

[edwardmorris]

Thanks Dave, that's my concern as well, especially at high RPM shifts, I'll look for a better one.

Let me know if you need one. I have a few sitting around, I'm sure

I do! PM incoming, thanks Dave!

[edwardmorris]

Got the bearings installed for all except the crank case and main shaft, will get to that after the snap ring is sorted. Please take a look at pic 4, I can't recall exactly from the K2, but does this bearing sit slightly proud like this?

[MRieck]

I'd replace that snap ring......and make sure the sharp edge is facing outside.

[edwardmorris]

Thanks Mike, going to wait for a better one for sure.

Today I thought I'd get one of the top three least fun things out of the way, damned redo of the gauges. I had a set of brand new faces and lenses from Marcel that I was saving for another set of gauges but decided to use it now. Totally abandoned the custom faces I had made for this build on the first round of gauges. Carefully took them apart without hurting any of the nice powder coat done by Marc. Found a relatively cheap set of correct K3 gauges and put them together. The old incorrect set from the lesser honda will stay disassembled because I could care less right now. Have some new rubbers on the way for these, will also redo the wiring with new sleeving and refresh the terminals. Nevermind the dirt/spots, they're on my phone, not on the gauges.

[Stev-o]

Nice!  Just received my K1 guages back from Marcel, his parts and workmanship are second to none.

[edwardmorris]

Nice!  Just received my K1 guages back from Marcel, his parts and workmanship are second to none.

Thanks, saw that yesterday and decided to get mine out of the way too! Getting better at it, this one was done within 6 hrs.

[SOHC4 Cafe Racer Fan]

The sight of those minty-fresh Marcel gauges gave you meter-envy, so you decided to break the seal on yours!   Very, very nice gauges!

[edwardmorris]

The sight of those minty-fresh Marcel gauges gave you meter-envy, so you decided to break the seal on yours!   Very, very nice gauges!

haha, no, I don't like working on these at all since I don't have whatever magic tool Marcel uses to do the crimping. I had to find a set and start over because the ones I had ready to go were deemed incompatible with the 750s. I'm waiting on a snap ring for the trans to arrive, as soon as that's here I'll be readying the cases to go back together...

[Stev-o]

The sight of those minty-fresh Marcel gauges gave you meter-envy, so you decided to break the seal on yours!   Very, very nice gauges!

 I don't have whatever magic tool Marcel uses to do the crimping.

I'm guessing he had that tool custom made.  I've been told the Honda gauges were not intended to be opened up. Thats kept me out of them!

[edwardmorris]

The sight of those minty-fresh Marcel gauges gave you meter-envy, so you decided to break the seal on yours!   Very, very nice gauges!

 I don't have whatever magic tool Marcel uses to do the crimping.

I'm guessing he had that tool custom made.  I've been told the Honda gauges were not intended to be opened up. Thats kept me out of them!

Most likely to keep people from tampering numbers, but 40 years later no one seems to care anymore. We need that special tool states side and possibly a local service for the work and save intl shipping.

[edwardmorris]

The circlip for the main shaft came in from Dave B, so main shaft got put together. Installed the bell over the reman primary and put the new clutch in the marinade, will button it all up tomorrow. New rubbers for the gauges got here today, need to finish those up soon. Next up is thread chasing the crankcases and installing studs/kickstarter etc. in prep for closing them up.

[edwardmorris]

Clutch went together, now I can't remember what happened with the K2. With that "fat" washer under the inner hub, the whole thing isn't sitting flush with the shaft. I took it off and tried, then it sits flush. I know the big washer can't be skipped, but wanted to double check that this looks ok. Have it tied up for now, but torque it down after confirming nothing is off.

[edwardmorris]

Also looking for recommendations on a cam degreeing wheel, would be ideal if I could find a clear one that I can use on the ignition side as opposed to the dynamo side.

[HondaMan]

Clutch went together, now I can't remember what happened with the K2. With that "fat" washer under the inner hub, the whole thing isn't sitting flush with the shaft. I took it off and tried, then it sits flush. I know the big washer can't be skipped, but wanted to double check that this looks ok. Have it tied up for now, but torque it down after confirming nothing is off.

The hub must sit outbound of the splines, or else the dished torque washer has no way to torque it to the mainshaft. So, the hub does not sit flush with those splines down inside. If all is well, installing the dished washer (dome toward you) will flatten somewhat to 'spring out' the mainshaft into the heart of the clutch hub. This helps establish the all-important distance to that troublesome 4th gear on the other end: if the nut ends up just about flush when torqued onto the mainshaft (to hold the basket), then the mainshaft will be the same length it was when Honda's techs installed the shim on the other side of the 5th gear, against the far bearing, and the 4th gear spacing will come out just right.

Once in a while, I have seen where swapping the primary sprocket out for a new one changes this distance. The result can be either a very stiff shift into 4th gear, or no 4th gear at all (or it jumps out of 4th), as we have sometimes seen in posts around here. If the distance between the primary sprocket and the 4th gear is such that the 4th gear splines do not clear 5th well, it is hard shifting and needs a thinner shim on the other side of the 5th gear. Vice-versa if 4th gear tries to disappear.

If (you do this and) you have the old primary sprocket in this case, measure the thickness where they meet the mainshaft. If they are identical, great! If they vary more than 0.5mm, you may have to play the 'spacer game' on the other end of the mainshaft, against that bearing over there.

[edwardmorris]

Thanks Mark, for that awesome detail. Mine sat flush at 35ft-lbs, everything looks to be working smooth (and the trans is backcut) so put it all together.


I've been struggling lately, I don't know why but it has been really difficult to focus on finishing up this build when I'm so close. A lousy experience with a vendor started the derailment, I fought it off and kept working on it until I got the primary shaft sorted (above). After that, for almost 3 weeks, I simply couldn't get myself to do anything further and I can't explain what's wrong. Was keeping busy with work and the long weekend was coming up, so I decided to shake off this nonsense and power through the engine assembly. Took some time off, got the cases ready, assembled the crankshaft, installed the new main HD studs (installed height method with red loctite, don't ever do these with the "bottoming out" method, guaranteed set up for failure), then began collecting everything to close up the cases.

It was bad enough I was struggling with the build, my house decided to drown me, chimney leak is back with a vengeance (5, FIVE! roofers have looked at it quoted me unrealistic amounts, they pretty much know I'm screwed now) AND the sewer decided to back up, slowly leaking back into the basement's lowest drain. Quite a bit of money literally down the drain but the sewer situation is contained, still working on the roof, may have to DIY patch it again to kick the can down the road till I find a decent roofer.

That burnt through much of my time off, so back to the check list and now, for the life of me I can't find the large retaining ring that goes on the final driven shaft, and the retaining pin for the kickstarter shaft. As painfully organized as I am, and can recall bright as day in my head two ziplock bags marked with those parts, I have yet to find them after almost 36 hours of ransacking the place. So the engine assembly has stalled out, making my mindset MUCH worse now. I've started looking for replacements as there is no point wasting time looking for them, they'll turn up if they're still here, but I have a feeling they've shifted to another dimension.

Sorry, I know its not quite the anticipated update, but I really am struggling and needed to vent. I know I'll finish it, I just hope I get my drive back soon.

[edwardmorris]

OK folks, could really use a motivational speech right about now. Its been a challenging summer to say the least. Work, family, home, pretty much anything that could, got in the way and the build had stalled out. The power plant is at 95% completion, needs the cam degreed to finish it up. Should be rolling smooth after that I hope, but lets just see. The above mentioned sewer and roof repairs are finally underway once I secured some down payment and financing arrangements, just need to refocus on the build while the rest keeps going....

[mashfu]

Well if these are what you need i got you sir!

[Terry in Australia]

I don't know about motivational speeches Rafi, but like you said, you're so close now, you just have to get it done so you can ride it before your winter sets in!

Here on the other side of the pond the weather is slowly improving, and even though my CB750's are safely ensconced in my garage in Melbourne (I work 400 miles away in Canberra) I'll be doing some work on my old K1 in the weekends leading up to summer, not to mention finishing Mike's Café Racer so I can give it back to him at long last. Luckily I've got my Yamaha FJR1300 and Honda VFR750 here in Canberra to keep me amused.

Take a leaf out of Nike's book mate, and just do it! Cheers, Terry.