Topic: 1970 CB450 restomod

[Maurice]

I've done some work on this find:



I will try to document here as I restore it close to stock. Maybe change a few things, nothing more than: bars (400F), rims (black powdercoated), shorter rear fender/small light, "modernized" electrics (regulator/rectifier this looks like 2 + 1-phase + PMA?).

Now I am taking it apart ever so slowly. So far no snapped bolts, only quite rusty.

Forks tubes look like #$%*e, I'm looking for new/good ones in case these are too pitted. I think these interchange with CB750 K0 -> K2? If so that would make the search easier.



I took many pics as I went, for when the time comes to do the reverse.











Not too confident in this capacitor but I'll probably re-use the coils.



Finally:





The motor is surprisingly "light", I just lifted it off the frame and set it aside without having to tip the frame over.

The right side exhaust is toast, I found a cheap stock replacement.

Took a pic inside the valve covers (sorry no pics) and things look quite nice in there.

This is exciting, almost as exciting as my first time in a biplane this week-end (giggled like a 4 yo the whole time), even got to "pilot" for a bit:

[strynboen]

im in the final vith my cb 500t..it is a "low buged restoration"..rattelcan paint..no
recroming...paint instead..and veldet holes in exhost system..most at back side vas rodden..and viring vas a mess..

the engine sits low in frame...ca 10 cm lower then in a 500 four..feel a bit heavyer then my 550 four..but power are likely

[Maurice]

Nice! These machines are rattle boxes, great for backroads, highways not so much

Wiring is so simple though, I'm thinking I might just make a new one if this one is bad. It does use a few fancy round connectors, I'll see how to re-use those. It's completely stock so I have that going for me.

Good luck!

[strynboen]

i have shortned /thangeda fev vires..and pun nev konnektors on..the 500 have elektronic volt regulators..not like the 450..but use the same 2 fase generator..or is it a 3 fase..2+1...
i like the 450 looks better then the 500..but think most is the same..just stroke and krank and some bearings are thanged..think the fork tubes are 550. or 500.have it all apart..and it looks like..

[Maurice]

Yes engine/frame is lower, surprisingly so. It can, now, and it should, it doesn't have 4 piston crank + alternator rotor + points sticking all the way out

Not a big fan of the 500 seat, I guess that's easily "adjusted". The tank looks great though. Are the pea shooters stock? A good thing about these pipes is you can swap a lot of different ones on there in case...

[cheftuskey121]

Nice start! Those look like stock pipes. I have some 450 parts from a 71. Anything in particular you're looking for. Might have for tubes for you.

[Maurice]

Chef, I read your resto thread, it's a great inspiration man.

Thanks for the offer, if you have the tubes I'm interested. Maybe the master cylinder/brake lever (lever definitely, it's bent), I'll take it apart maybe just needs rebuilding. I don't think I'll need anything else it all seems there but I'll let you know. Maybe some (a ton of) advice

[Maurice]

Finally made some progress on this.



That's pretty much it...

The plan for near future is to install swingarm with bronze bushings, mock up fork/shocks/wheels and redo motor top-end. Compression was ok when I measured, but pulling some pieces shows the gaskets crumbling. Not sure I want to split the cases we shall see when I pull the clutch and get a peek at the shifting mechanism, shifting by hand seemed fine but there's only one way to find out...

[Maurice]

Doing some clean up. I was dreading tackling the carbs, it's always a major PITA to get them clean. However this time it's not so bad.



This is just from spraying with simple green, toothbrush and about 10 minutes at it. Both carbs now look much better and the insides are intact, no degradation from fuel sitting in the bowls.

Also cleaned up the motor some, but forgot to take pics.

I think I will just run it as is, it is not showing any sign of issues, no noticeable leak, oil looks clean, ports look decent, cam chain has good tension (i.e. tensioner far from all the way in), shifts just fine by hand and most of all compression was good and even. I'll measure it again before attempting to start, do the tune up measurements and closely inspect the oil that comes out. My reasoning is that the factory likely did a better job at assembling than I will ever do, and if things are within spec. and gaskets hold this should last a bit. If not then pulling this motor back out is a 10 minute job that I can still do without even having to lay the bike on the side.

For a top end rebuild this DOHC engine requires a couple risky things IMO: splitting cam chain, and potentially changing cam bearing specs (gasket thickness may require shimming differently and getting it wrong there means spinning camshaft bearings...). I'll do it if it's really required.

[Maurice]

CBX performance bronze bushings, shame they will be hidden.

[Maurice]

Starting to put things back together.



This was a PITA. I do not like to manipulate loaded springs with pliers. Managed without losing an eye.



Now I'm looking over the ignition, plug caps have infinite resistance, and condenser does not look good. Points and coils check out ok, stator looks pretty good and I'll test it next (although that is not critical to get it started), so hopefully I can soon plonk the motor back in and attempt to fire it.

[faux fiddy]

Forks tubes look like #$%*e, I'm looking for new/good ones in case these are too pitted. I think these interchange with CB750 K0 -> K2? If so that would make the search easier.

You may get lucky and have clean travel area, but those do look crusty as does most of the other chrome.  You obviously know by now they are clean enough?

I started with  some fork ears that started out square; much worse looking than those. I used a pipe that fit just inside it and another thinner pipe skewer, hung 'em between blocks and tapped them with a hammer for about a whole weekend.

The earlier '70's 450's (yours)  has a different narrower bolt in the end of the shock that holds it whereas the '74 450 KO had a pinch bolt on the Triple clamps which holds the tube. Fork ears and Fork seals are a bit different between the two, also. In all I think they changed the forks three if not four or more times in the ten year history of the 450.

From what I understand the later pinch bolt is one that interchanges with the 500/550, but with mods and a whole front can be changed.

[Maurice]

Do you mean this bolt here?



With the D washer in the middle?

The tubes do not look too terrible once cleaned up, I'll take some pics post them. One is pitted a bit I will smooth it with JB weld or something like that. The sliding bits are intact. They came out easily. Maybe paint them so they don't rust again, in case I can't find good tubes. I really would like to re-use as much as I can from the parts I have.

[faux fiddy]

I didn't see the picture that shows yours has pinch blocks.

I don't know if for some reason they did something different on the CL models or if mine somehow got out of the factory in '71 and '72 or were both swapped out, both  with something more like this:

http://www.ebay.com/itm/HONDA-OEM-TOP-BRIDGE-TRIPLE-TREE-FORK-CB450-CL450-CB-CL-450-1968-1969-53230-292-/171780283079

Instead of a pinch bolt on top it just has a bolt sticking in the top end of the fork as a mount and filler hole.

[Maurice]

Ah I see. I have the classical one. Looks very 750K0-ish, which is why I was under the impression I could simply swap K0 top tubes. When I pull them apart I'll ask if one of you lucky K0 owners can compare them.

Rotor and brake caliper are the same, but tube part numbers are not...

[faux fiddy]

The pinch blocks are absolutely a better way to go. As it is,  I think you will might have luck swapping forks with a 500 or 550 with 35mm forks if it's even necessary, and depending on the spacing of the wheel.  750 might work just as well, but it seems it's never as easy to swap stuff as it may appear.  Here is the link and a partial list of their 35mm trees :

http://www.caferacer.net/forum/project-builds/14059-triple-tree-fork-conversion-chart.html


Upper: 26 x 48.5 x 15.2
 Lower: 30 x 50 x 14.4
 Honda C250N (79)
 Honda CB250 (Early Models)
 Honda CB250RS (80-84)
 Honda CBX250RS
 Honda CM250T Rebel (82-84)
 Honda GB250F/F2
 Honda MVX250 (83-84)
 Honda VT250F (83-86), VTR250 (88)
 Honda CB350F/F1 (73-74), CB350G (73), CB350/ K2-K4 (69-72)
 Honda SL350 /K2/K3 (69-73)
 Honda CB360 (74-76), CB360GT (76), CB360T (74-77)
 Honda CJ360T (76-77), CL360 (74-75
 Honda CB400A (74-75), CB400F (75-77), CB400TI/TII (78-79), CB400T (80-81)
 Honda CBX400F
 Honda CM400A/C/E/T (79-81)
 Honda GB400
 Honda CB450/K1-K7 (65-74), CB450T (82), CB450SC (82-86)
 Honda CL450 /K2-K6 (68-74)
 Honda CM450A/C/E (82-83)
 Honda CB500/K1/K2 (71-73), CB500T (75-76)
 Honda CX500 C/D (78-81)
 Honda FT500 Ascot (82-83)
 Honda GB500F/F2
 Honda GL500/I (81-82)
 Honda VT500 Ascot (83-84), VT500ED, VT500C/FT (83-84)
 Honda CB550K/K1 (74-78), CB550F (75-77), CB550SC (83)
 Honda CBX550F (82-83)
 Honda CB650 (79-82), CB650C (80-81), CB650SC (82-85), CBX650ED/SCD
 Honda CX650C (83), CX650ED
 Honda GL650/I (83)
 Honda VT700C (84-85)
 Honda CB750K (69-78), CB750A (76-78), CB750F (75-78)
 Honda VFR750C (83)
 Honda VT750C (83)
 Honda GL1000 (75-76)
 Honda GL1000L (76)

[Maurice]

I kinda prefer the bigger rotor that is on there right now, brake is actually pretty good that way, especially on the 450. Hence trying to replace just uppers...

Thanks for the list, great to see the possibilities

[Maurice]

Ok so here's the shape of the tubes I have. I did not clean too hard either, just want to start mocking up and I will address the forks after motor/electrical is in good shape.

This is the worst piece. Pitting is there, not too deep I will try to salvage by smoothing with JB weld or something like that.



Other side is ok. Chrome is gone but metal is almost intact.



Travel area on both fork legs looks like this. I will see more when I take them apart but this is good so far. They do not appear to leak, assuming there is still oil in there



Believe it or not, these are the fork lowers after simply wiping them down.



Another crappy picture, showing the layout of the bolts, this looks like 750 K0 to me.



I just sold 2 bikes, getting ready to pick up some speed on this project.

[faux fiddy]

This is the worst piece. Pitting is there, not too deep I will try to salvage by smoothing with JB weld or something like that.

It looks like your fork travel areas are pretty clean. I would use a stone on any burrs that may be on the travel area. It  will likely need fork seals once you start putting miles on it, but if they don't leak run it is what I usually  say.

Mine had pitting under the fork ears  but not quite that bad.

I used a wire  wheel and then primered them  and used some silver automotive paint as a touch up.  I did the same with a wheel three years ago and had the tire off this week. It looked as good as when I did it.

[Maurice]

I wish all bikes were this easy when pulling out/installing the motor.

Took a whole 5 minutes to go from here:



to here:



No need for fancy jacks or any contraption, just pick up the engine, lift tilt a bit, done.



Engine bolts look good enough for re-use.



PO must have seen some fireworks when pressing the start button:



I'm not a big fan of electric start, this will stay out and the starter motor will come out eventually as well.

Going over electrical the harness is in great shape, hopefully I can clean the brass in the carbs this week and attempt to start it, see if the engine needs to come out again.

[faux fiddy]

I wish all bikes were this easy when pulling out/installing the motor.

I had one of the bottom skewers on mine stuck and spent a lot of time on it. Finally heat and two hours beating on it with a large hammer and a drift and it came loose.

[Maurice]

I wish all bikes were this easy when pulling out/installing the motor.

I had one of the bottom skewers on mine stuck and spent a lot of time on it. Finally heat and two hours beating on it with a large hammer and a drift and it came loose.

Hate it when that happens. Went through the same on a swingarm bolt, luckily didn't have to cut anything.

This bike has been good so far, only had to grind a slot in 1 screw so far, came out easily with the impact driver after that.

[Maurice]

Stock harness is old but mostly intact. Only one loop connector was broken, easy to replace.

I plugged it to test the ignition. Turns out this POS is shorting:



It was crap 45 years ago, a solid state one is going to take its place. Apparently you can also install a $25 mower regulator/rectifier and combine both outputs from the generator (stock only turns both with the lights on...).

Quick faking of the kill switch on:



Plugs/plug caps and condenser are new, points look good, coils we'll trust and presto we have nice blue spark. Will static time and be ready to fire when carbs are on.

[SOHC4 Cafe Racer Fan]

I'm enjoying seeing another one of your bikes come together Maurice!

[Maurice]

Thanks Don. This won't compare to any of yours, not even close

I sold my 550 last week and still getting over it... A dependable bike that was.

Last photo:



I put 2 bikes for sale and they were gone in less than a week, didn't even have time to deal with the usual CL bullsh*t. Tough to see them go...