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

[SOHC4 Cafe Racer Fan]

Lovely port work. Mike is an artist. 

[edwardmorris]

PSA: Allen's Fasteners now has stainless ARP flange bolts in those pesky extra long lengths used by the CB750 crankcases. When I checked few months back, no one except for baller-bolts.com had the long length ARP flange bolts in stainless. I had an order with baller-bolts that went nowhere for weeks. After some searching around, turns out the vendor is VERY hit or miss (lot more of the latter) and extremely poor communication wise. Some have had excellent luck with them, others have cursed their lungs out. Just thought I'd share, my exp was definitely bad.

ARP stuff looks pretty cool! I had a minor concern about the flange size, so I tested it out. The stock ones are obviously larger, but the ARP ones seem to cover up sufficiently well. Should I worry?

[MessnerMoto]

SS bolts don't have same strength like stock ones. Don't use SS bolts around main crankcase bearings. For rest of crankcase bolts I am not sure. Try to dig other people experience

[evanphi]

You could always put a bit of thread sealer or Permatex Ultra Black Form-A-Gasket No. 2 (non-hardening) around the head?

[edwardmorris]

SS bolts don't have same strength like stock ones. Don't use SS bolts around main crankcase bearings. For rest of crankcase bolts I am not sure. Try to dig other people experience

Main bearings are getting APE HD studs and nuts, this thread is missing an important update from when I wasn't able to upload pix, I will add those tonight for sure. Rest of the crankcase bolts are all 6mm and need a measly 96in-lb torque, I was assured ARP SS h/w is plenty strong

[edwardmorris]

You could always put a bit of thread sealer or Permatex Ultra Black around the head?

I might just do that (very lightly) on the few bolts on the lower crankcase may be near oil, not too worried about the upper ones. The flange does cover the hole completely, just not above and beyond like the stock ones....

[evanphi]

You could always put a bit of thread sealer or Permatex Ultra Black around the head?

I might just do that (very lightly) on the few bolts on the lower crankcase may be near oil, not too worried about the upper ones. The flange does cover the hole completely, just not above and beyond like the stock ones....

Forget the Ultra Black - use the Form-A-Gasket No. 2 (non-hardening)! My bad. Same stuff used for the cam tower pucks. I would figure it would be better than thread sealant because there's no threads near the flanged head?

[edwardmorris]

You could always put a bit of thread sealer or Permatex Ultra Black around the head?

I might just do that (very lightly) on the few bolts on the lower crankcase may be near oil, not too worried about the upper ones. The flange does cover the hole completely, just not above and beyond like the stock ones....

Forget the Ultra Black - use the Form-A-Gasket No. 2 (non-hardening)! My bad. Same stuff used for the cam tower pucks. I would figure it would be better than thread sealant because there's no threads near the flanged head?

Pretty much knew what you meant

[timbo750]

Trying to decide on electrics, was looking around on Rick's stuff and it seems they have a starter solenoid too? Any feedback on that? I'm thinking about

Rick's RR
Rick's Starter Sol
Hondaman fuse unit
Hondaman safety unit bypass plug
Stock winker relay

Ed, did you end up getting a HM safety unit bypass plug? i have been looking for one but HM doesn't have one listed on his web site, i ma happy to wire one up myself if I can get a schematics.

[edwardmorris]

......
Ed, did you end up getting a HM safety unit bypass plug? i have been looking for one but HM doesn't have one listed on his web site, i ma happy to wire one up myself if I can get a schematics.

Yes, I don't have it here yet, but I did ask for it along with a few other things I'm getting from Mark. Its a pretty simple bypass, pretty sure its in the FAQ or in older posts somewhere here.

[edwardmorris]

Missed update from a while back...........

Box 1 arrived from JMR with the cylinders all done and these goodies. Megacycle hardweld rockers, HD timing chain, APE adjustable sprocket, yami FJ sprocket bolts, APE bearing studs, Kibblewhite cyl studs, Barnett springs, MLS head gasket, viton coated metal base gasket.

[calj737]

SS bolts don't have same strength like stock ones. Don't use SS bolts around main crankcase bearings. For rest of crankcase bolts I am not sure. Try to dig other people experience

Rest of the crankcase bolts are all 6mm and need a measly 96in-lb torque, I was assured ARP SS h/w is plenty strong

(ARP) Only about 170,000-190,000 psi for their tensile strength. If you can muster that much torque, you deserve your own TV show. Plenty strong and much stronger than stock bolts.

[evanphi]

You could always put a bit of thread sealer or Permatex Ultra Black around the head?

I might just do that (very lightly) on the few bolts on the lower crankcase may be near oil, not too worried about the upper ones. The flange does cover the hole completely, just not above and beyond like the stock ones....

Forget the Ultra Black - use the Form-A-Gasket No. 2 (non-hardening)! My bad. Same stuff used for the cam tower pucks. I would figure it would be better than thread sealant because there's no threads near the flanged head?

Pretty much knew what you meant

Mostly for others reading. Big difference between the two!

[MessnerMoto]

I see that they are using some other stainless alloy. I was thinking that they are from A2/4 stainless...

[edwardmorris]

Front brakes on the car were almost shot, so that took up most of today Finally got those pesky 6x10 screws for the fork drains, finished assembly on the front forks with new progressive springs. Balanced the wheels, was going to assemble them and hit a blocker with the rear wheel axle getting chromed too thick (K2 deja vu), gotta take that back and thinned out next week. Was going to do the front wheel and realized I need to work on the speedometer drive first, oh well, there's still part of tomorrow left to get what I can done. Sure as hell can't go riding because of this incessant rain

[edwardmorris]

Stuff back from Cryo, glad to see it come back packed as good as I sent it, even better actually. But so friggin tired of packing and unpacking stuff, time to begin assembly! Gotta clean it all up one more time, not sure what the somewhat sticky lube is on the parts...

[edwardmorris]

Progress has stalled for a bit due to a blocker, and lately good weather + free time has been translating to riding the K2 at every opportunity. A while back I was looking for alternatives to stock handlebar levers as I did not want to polish up the rather rough ones that were on the bike. I ended up finding a set of chromed "dog leg" styled aftermarket ones. On of my stops at the local bike shop, we were chatting and the owner (who LOVES the K2) said to me "You've got too large hands for them bent things". I told him others have said that too, but I really don't want to keep up with the polishing (the K2 is enough work ), so he asked me to drop off my old ones next time I came by. I did, then forgot about it for a long time. Went by there today, and loooky! All smoothed out and chromed up! I don't even know what these are going to cost me but damn they look cool

[edwardmorris]

So, I'm a little worried about something now. This K3 originally came with a set of CB450 gauges which wasn't going to work, so I bought a set of 73 750 gauges on ebay last year. The 450 gauges felt like they were sort of force installed on the top triple and I didn't want to worry about its structural integrity. So I asked the same ebay seller if he had the triple that went with the gauges. He said he had it, so I bought them together.  Guages got rebuilt using goodies from Marcel, and I forgot all about the triple. I didn't realize that I already had another spare 73 top triple laying around, so I just got that powder coated and threw the ebay one in my spares pile. Now this I call pure luck, because I was reading this thread today

http://forums.sohc4.net/index.php/topic,157454.msg1804674.html#msg1804674

and went back and checked to make sure my triple was correct. Thankfully the spare I got powder coated is the correct one, but the ebay spare that came with the gauges is from a friggin 550! My worry now is that I may have rebuilt 500/550 gauges and I'm not sure if they'll work as a drop in on the 750? When I worked on them, they looked like they were 750 gauges. I'll have to go through my old boxes and see if I still have the old gauge faces to confirm the red line. IIRC, the ebay listing had tons of pix of the gauges and I'm fairly certain they are correct, but just in case they aren't, what can be done besides finding another set?

[seanbarney41]

speedo will work fine...550 tacho will read incorrect as the drive gear on the camshaft has a different amount of teeth

[edwardmorris]

DAMMIT! Looks like they were 550 and I completely missed it


@Sean, are the innards on the tach different or just the gear under the valve cover? Would hate to redo those so close to assembly time

[seanbarney41]

Unfortunately, I think the tach innards are identical...it's the gear on the cam itself that is different.  I guess you could run a 550 cam and...oh wait, nevermind.

That sucks.  I have made similar mistakes, just without the rebuild.  Currently having tach problems myself as I just literally wound the needle off the one on my gold bike.

[calj737]

Cam gear is different. Clocks are different innards too. Find a new set.

[edwardmorris]

Cam gear is different. Clocks are different innards too. Find a new set.

Will swapping the tach gear at the cam with one from a 550 not work? I'm getting conflicting reports, some have used 500/550 tachs on 750s as is and claim they work, some say just the tach gear needs to be changed, others say there is no way to get it work at all...

[seanbarney41]

As is?...it will work but will read 500 or 600 rpm too high.  Swap the gear in the valve cover?...I dunno?  I know that the gear on the cam cannot be swapped.

[edwardmorris]

As is?...it will work but will read 500 or 600 rpm too high.  Swap the gear in the valve cover?...I dunno?  I know that the gear on the cam cannot be swapped.

OK, more digging and it turns out the face markings for the RPMs are different, so using a 750 face (which I did) should correct that, provided nothing else changes (not even the gear under the valve train cover) right??