1967 CB450K0 Black Bomber Rebuild - By Royhall

[royhall]

Thanks Ash. I refer you back to my earlier comment. Also, "it worked out much better than I had planned". Standards cant be very high.

[AshimotoK0]

Thanks Ash. I refer you back to my earlier comment. Also, "it worked out much better than I had planned". Standards cant be very high.

I only posted the text& pics because you couldn't initially find the relevent bit Roy... don't worry.....  I won't be bodging it like that   

[royhall]

I wouldn't have expected a bodge like that on one of yours Ash. A little more elegant solution is always available, gaffer tape is a get you home repair. Can you imagine after a couple of years, some heat, and engine vibration what that's going to look like.

[royhall]

Finally got some parts back for the Bomber. I have been waiting 4 months now for painting, chroming, and powder coating. It's been a bit frustrating during the lockdown as I had time on my hands to get this project finished but no parts. That said, the only parts to come back so far is the powder coating.

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I don't think the powder coaters did too bad a job on it. There's a few spots that could have been slightly better but fortunately they are in hidden away areas. Looking closely at the frame you can see just how poorly the welding was done, with uneven snaking about welds and spatter just painted over. Obviously it's meant to be like that so that's how I have left it.

My plan now is to get the engine back into the frame. This is not going to be an easy task as the engine weighs an incredible amount, I would wager it's as heavy as my CB750 engine. So the problem is to get this into this.

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The plan of action for later this morning is to lay the engine on it's side on the bench and lower the frame over it and secure with thread bar as the real bolts are still at the platers. I have taken the precaution of taping up the frame as it's going to get banged that's for sure.

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Wish me luck, will send some photo's from A&E.

[Bryanj]

They aint that heavy, or at least they wernt when i came out of the navy in 74

[Laverda Dave]

At least you have some of it back Roy and can crack on. Hopefully it went OK and the engine is in by now.
I feel your pain with the chroming, I've been waiting for 16 weeks now for mine to make a return.
Like you I had to resort to fitting the engine back into the frame using studded bar. I wish I hadn't, l couldn't fit the engine in via the laying on its side method as the engine plates were in the way (it's my Triton rebuild). I placed blocks of wood under the frame with the inevitable consequences of the frame tipping over when I tried to lift the engine into it. I wish I'd waited for the Covid lockdown to have ended and got a mate around to help with the lifting instead of damaging my back, knees and frame!
Keep the posts coming, I'm enjoying the rebuild thread👍.

[AshimotoK0]

Looking good Roy .. Have you got both silencer brackets as I can only see one .. I may have one spare if not. Shouldn't the rear brake torque arm be zinc plated? (although I have to admit ...  it would be much better protected against the weather with PC). I also have one of those spare too if you need one.

EDIT whoops just saw two brackets DOH ! 

[royhall]

Well the engines in the frame. Today I wish I had a bit more patience and had waited for a friend to give me a hand. But no, Mr Cant Wait had to go ahead alone and now is suffering from a back strain. Anyway, job done and the back will be good in a couple of days.

I started out by making some thread bar studs as the correct bolts are still away at the platers (possibly to return some time before the Sun goes Supernova)?

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I had a good old struggle getting the engine out of the home made engine stand, it's been in there that long it didn't want to be shifted. I then laid the engine on it's side, after fitting an already damaged alternator cover, with the head and barrels on an old cushion and covered the rest of the bench with towels. I removed the clutch actuator cover and supported the engine with a piece of 3*2 cut to the right length, need to be careful there as the gear change shaft is now unprotected. All three of my manuals say to put the engine in from the left side so that's the plan. It is a bit closer to the edge of the bench than I would have liked but needed the room so the frame misses the garage wall.

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I carefully lowered the frame over the engine and helpfully the bottom mounting fell straight into place so I slid a long stud through and fitted nuts hand tight. It was then just a matter of lifting the headstock to get the second long stud through, then an easy job fitting the top and front brackets.

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At this point I needed to stand the frame up. I was planning to have the frames bottom rail still on the bench so I could roll the frame upright and slide it on to safety, unfortunately it was overhanging. This is the point where I realised I should have done this on the floor, thick or what. Anyway, the easy alternative was pick the whole lot up and heave it onto the bench. That was probably the back ache moment.

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Now the next big heave was off the bench onto the beer crate I always use to do the build up. So no messing about just got hold of it and with the assistance of gravity plonked it on the box.

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So there it was in the frame, and in position. At this point I fitted the other plates and tightened all the studs. It became clear whilst tightening the front plates that something was wrong. The rear lower fixing had a large gap between the engine and the plate and the other three bolts tightened correctly (you can just see it on the last photo). On checking, the front mount on the lower crankcase had been machined 5mm out of true (so much for Honda quality control). So for now I packed it out with washers that I will replace when I get chance to make an aluminium spacer, probably when I change the bolts.

I also noticed that the barrels are offset to the frame centre line, probably due to one side of the engine being heavier than the other. But it looks weird and I can't say I have seen that before on any other bike I have owned. Now the engine is in, it's easy to see the things that should have been done first ie. fit the starter motor cable that has to thread through the front plates, under the frame and be clipped under the engine. I will probably look at that as well when I take off the plates to change the bolts.

For now I think I will go sit in the big chair and make use of the Warsteiner that was evicted from the crate. OOOHHH my poor old back.

[royhall]

I put the clutch actuator cover back on and fitted the rear mounting plates.

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The next job will be to tackle the electrics. This is a job where I am way out of my depth so may need plenty of help and advice. Already spotted a couple of problems, the new wiring harness that came from Thailand looks a bit different to the original. I was wanting to keep the original really but it has been butchered. Also, the Selenium rectifier that came with the bike has leaked quite badly and clearly can't be re-used. I think I have another in a box of bits I bought off eBay just for the rear brake torque arm (Ash, I powder coated it as it was already black painted probably a mistake). The whole box of bits only cost me £12 so if the rectifier is good, what a bargain.

Will post some pictures of the wiring harness differences later when I get back into the garage.

[royhall]

Roy just a thought regarding the front plate gap. It's clear from the pics that the mounting lugs on the frame are longer on the top than on the bottom, could Honda have machined the front plates so they were handed and you've just fitted them upside down or on the wrong side?

Looking at the pics before they were fitted there does appear to be a recess and spacer fitted on them.

Yes it does look so in the photo but the frame lugs do measure exactly the same. Also tried the plates the other way and no difference.
When measuring the casting it is 5mm out top to bottom and with a square across the casting it's all on the one side hence three bolts line up perfectly and the gap is just in the one place. A spacer is the way to go.
Don't forget as mentioned earlier in the thread, this is a replacement bottom casing as the original was badly cracked.

[royhall]

Anyway back to the proper thread. As I'm going to be asking lots of dumb questions about the electrics I thought best to post a wiring diagram.

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This is the best one I could find (credit the Clymer manual) but it does show a single coil and points where mine is duel coil as per the later bikes. Not sure why that is, maybe the single coil was very early bomber that was changed whilst still on the 4 speed. Not important as it doesn't really change any wiring.

I am going to be using a stator from a K4, a glass mat battery, a new wiring harness that the colours are not quite correct, and Pamco electronic ignition with electronic advance. Because of that I think it would be prudent to install a regulator into the circuit as per the later bikes. I was thinking of a combined regulator/rectifier in place of the Selenium unit, maybe something like this   [size=78%]https://www.classicbikepartscheshire.com/electrical-c3/ammeters-voltage-regulators-c20/rectifier-regulator-12v-for-classic-motorcycle-p1483/s1500?cid=GBP&gclid=EAIaIQobChMImdrq8ZTC6gIVcYBQBh0z3QQMEAQYASABEgL-jPD_BwE[/size]

Any comments or advice at this point before I order the wrong thing would be appreciated.

[Bryanj]

Thats only a single phase unit, not sure how the 450 generator is wired, perhaps hiding a zener and heat sink off a 70's triumph would be better

[AshimotoK0]

A 3 phase regulator will not work on a twin. Best to fit a 3 wire regulator from a CB250/350K G5 or a later 450. Lots of them about , extremely reliable and don't cost a lot Unlike the Honda 4 3-phase voltage regulators they are totally solid state and no contacts to wear out. Same function as a Zener diode on a late 60s Triumph but a lot more sophisticated and precise current dumping to prevent overcharging of battery.

[royhall]

My plan was (if correct) to take off the Selenium rectifier and fit the combined unit into the same location.

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Then wiring should be the two yellow wires connect to brown and yellow (either way), the red goes to red, and the black to ground (these wires are already at the rectifier so no need to cut the harness). Then the pink wire from the stator is joined to the yellow when the lights are switched via the ignition switch to give the lights a boost. Some recommend permanently splicing the pink and the yellow after the stator, however I am not sure of the need as it already joins (switched) before the rectifier. So to my mind it could stay as is, or would the switching in whilst the alternator is turning somehow damage the unit. Sounds like a perfectly good plan to me or is all that just a dumb scheme?

BTW. Ash, this one is single phase, any reason that wouldn't work on a Honda twin?

[AshimotoK0]

Sorry didnt realize that one is single phase. I dont have any experience of that unit and its reliability. This is what I am fitting to my Bomber K0 http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=333178554350&category=177955&pm=1&ds=0&t=1594370188615&cspheader=1 If you trawl through my Dropbox incomplete Honda Bulletins I posted recently they discuss Honda fitting low output generators prior to the solid state regulator being introduced. If you are using a later stator that will be a high output one designed for the solid state regulator introduced on the CB250. Also there is evidence that after 50 odd years the permanent magnets will have lost magnetic flux. I would get the bike running and monitor the charge current with lights off  and if it is low then permanently connect the night charging coil.