Author Topic: 1970 CB450 restomod (Read 7627 times)

Maurice · « **on:** October 22, 2014, 07:15:13 AM »

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 · « **Reply #1 on:** October 22, 2014, 08:13:42 AM »

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 · « **Reply #2 on:** October 22, 2014, 08:19:57 AM »

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 · « **Reply #3 on:** October 22, 2014, 08:25:36 AM »

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 · « **Reply #4 on:** October 22, 2014, 08:37:46 AM »

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 · « **Reply #5 on:** October 22, 2014, 10:09:39 AM »

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 · « **Reply #6 on:** October 22, 2014, 10:35:06 AM »

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 · « **Reply #7 on:** April 21, 2015, 11:31:16 AM »

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 · « **Reply #8 on:** April 27, 2015, 06:13:18 AM »

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 · « **Reply #9 on:** April 30, 2015, 05:23:26 AM »

CBX performance bronze bushings, shame they will be hidden.

Maurice · « **Reply #10 on:** May 04, 2015, 11:36:06 AM »

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 · « **Reply #11 on:** May 09, 2015, 01:20:51 AM »

Quote from: Maurice on October 22, 2014, 07:15:13 AM

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 · « **Reply #12 on:** May 11, 2015, 06:40:11 AM »

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 · « **Reply #13 on:** May 11, 2015, 11:13:55 PM »

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 · « **Reply #14 on:** May 12, 2015, 03:49:13 AM »

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 · « **Reply #15 on:** May 12, 2015, 10:09:09 AM »

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 · « **Reply #16 on:** May 12, 2015, 11:07:55 AM »

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 · « **Reply #17 on:** May 14, 2015, 06:36:28 AM »

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 · « **Reply #18 on:** May 14, 2015, 03:42:21 PM »

Quote from: Maurice on May 14, 2015, 06:36:28 AM

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 · « **Reply #19 on:** May 18, 2015, 05:50:11 AM »

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 · « **Reply #20 on:** May 20, 2015, 08:34:51 PM »

Quote from: Maurice on May 18, 2015, 05:50:11 AM

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 · « **Reply #21 on:** May 21, 2015, 07:51:35 AM »

Quote from: faux fiddy on May 20, 2015, 08:34:51 PM

Quote from: Maurice on May 18, 2015, 05:50:11 AM
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 · « **Reply #22 on:** May 21, 2015, 07:58:29 AM »

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 · « **Reply #23 on:** May 21, 2015, 09:59:29 AM »

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

Maurice · « **Reply #24 on:** May 21, 2015, 10:55:50 AM »

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...

Maurice · « **Reply #25 on:** May 21, 2015, 10:57:20 AM »

This plug still works, believe it or not. I will probably not ride with it, but somehow I knew one day this was going to happen. Those damn nuts are always on so tight.

Maurice · « **Reply #26 on:** May 29, 2015, 06:25:20 AM »

Almost popped a hernia trying to get the oil plug out. Sonofa. Had to use heat around it, then it came out. It's not the best design, directly underneath the bike, oil sump integral to the lower case, and a huge diameter guarantees oil splashing everywhere...

Also cleaned the inside of the tank, which was not too bad at all.

Before:

After:

WD-40 inside right now.

Waiting for muffler gaskets/clamps, I figured I'd rehabilitate the front brake. Expecting a rusted out piston, this is what came out:

Master was stuck, now rebuilt and bled. I'm still using the old hose, slingshot is closed for now...

The caliper paint is so-so, but I'll take care of it when the new hose is here or I'll get fluid on it. Also hopefully I can find the same color paint, it looks like a nice change from the black.

Maurice · « **Reply #27 on:** June 01, 2015, 12:36:57 PM »

I got to start it over the weekend.

First I rigged up an old battery, turned the motor around to lube up the cams. It really does not take much to build up oil pressure, soon there was oil pouring out the cam lobes.

Starter motor is not hooked up, so I kicked. This motor is high compression (I measured 170 and 160 PSI by leg), it takes some doing. Second kick it sputtered to life, then shut down. I tried to start it again to no avail, then lost some time rigging up proper exhaust since PO put longer shocks and the axle contacts the mufflers...

Next day I used a good battery, the motor fired up almost immediately, then went into too high an idle. Quickly adjusted the idle stops. Oil immediately started coming out one of the valve lash adjusters, I had forgotten to tighten it. Oops... Let it cool a bit, set the super tight lash (0.03mm, almost impossible to slide the gauge without wrinkling it). Runs fine now but smokes a bit under throttle, I'll see whether rings settle or it needs torn down. Compression looks ok so hopefully it's residual oil I poured in after I got the bike.

This engine revs quick, and was surprisingly easy to get to run ok initially. Kickstarter lever did leave the bottom of my foot sore from testing compression and starting, short lever and high compression: ouchy.

No time for pics or anything, it's all jumbled together anyway, was not expecting the exhaust to be such a PITA...

faux fiddy · « **Reply #28 on:** June 01, 2015, 01:17:50 PM »

Quote from: Maurice on June 01, 2015, 12:36:57 PM

I got to start it over the weekend.
(0.03mm, almost impossible to slide the gauge without wrinkling it).

There is a thread at HondaTwins.net that has a re-posted discussion of valve adjustment. Guys that worked with Team Hanson (Daytona winners back in the day) say a tight .002" is the way they do it. Another guy who I met at Barber says the same.

I did mine that way, as far as I know they might have never been adjusted since factory. It ran much better afterwards.

Not sure how that converts to MM off hand.

tbpmusic · « **Reply #29 on:** June 02, 2015, 08:37:10 AM »

Yeah, we all use 0.002" - the setting the manual calls for is nearly impossible for a normal human to achieve, and it's way too easy to be too tight. And I wouldn't suggest a real tight 0.002", but a moderate one. That gives a good margin of safety and still minimizes clatter.
Many folks who race them (like Terry Naughton at Hansen) actually use up to a 0.005" gap - but then they have plenty of parts available.

Maurice · « **Reply #30 on:** June 02, 2015, 08:55:47 AM »

Ah ok. The gauge I used is marked 0.0015", I'll go with .002 should be much easier. The engine does run quieter than I expected.

Started it up again and it did not smoke a bit this time. We'll see, need to clean the carbs again I think, after a while I could not start and was not getting any gas into the cylinders. The pilot circuit is a weird setup where gas comes in from the main, through a hole in between the towers and then into the slow jet tower. I was perplexed when cleaning the pilot and finding no hole at its tip

Is some starter freewheel noise normal when kicking while testing for compression for example? Once running I cannot hear any such noise.

tbpmusic · « **Reply #31 on:** June 02, 2015, 10:23:24 AM »

Quote from: Maurice on June 02, 2015, 08:55:47 AM

Ah ok. The gauge I used is marked 0.0015", I'll go with .002 should be much easier. The engine does run quieter than I expected.

Started it up again and it did not smoke a bit this time. We'll see, need to clean the carbs again I think, after a while I could not start and was not getting any gas into the cylinders. The pilot circuit is a weird setup where gas comes in from the main, through a hole in between the towers and then into the slow jet tower. I was perplexed when cleaning the pilot and finding no hole at its tip

Is some starter freewheel noise normal when kicking while testing for compression for example? Once running I cannot hear any such noise.

It could have been smoking because the tappets were a bit tight......

You are correct, ALL fuel for BOTH the main and idle circuits passes through the main jet first on these carbs, an unusual situation.
The "idle jet" that has the "38" stamped on it isn't a proper jet at all, more or less just a cover for the cross-drill between the two passages. The real idle jet is underneath the one stamped "38", and it's too small to bear any sort of stamped number.
Attached is an annotated diagram of how these carbs work......

If the starter is quiet when the engine runs, you're golden.

faux fiddy · « **Reply #32 on:** June 03, 2015, 10:50:57 PM »

I think I know the noise you're talking about when kicking. I haven't had anything crater. I've put half the mileage on the bike at 12k miles and it's done it from time to time.

Sometimes you'll hear the starter disingage and wind down, too.

tbpmusic · « **Reply #33 on:** June 06, 2015, 06:29:33 PM »

When the starter clutch starts to go out, you'll know it - thing will start "whooping" and howling like crazy......

Maurice · « **Reply #34 on:** December 04, 2015, 11:57:22 AM »

Bike has been done for some time, maybe I'll cut the rear fender it's all dented anyway. Nice little bike has a lot of get up and runs great.

Next I'll be working on a '76 750, almost finished a DOHC 750 looks nice. I just don't feel like posting here anymore, sorry.

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Author Topic: 1970 CB450 restomod (Read 7627 times)