Topic: The Runcible Racer - maduncle's CB450 project

[maduncle]

Heck, I may as well post this project here as well as on the Honda Twins forum as you guys are always good for advice.

My second bike project is another Honda, this time it is a 1965 Honda CB450K0 Black Bomber. The bike came to me from Colorado where a friend of mine found it when hunting for cars to ship back to Australia.

So in September - I got this pile...



Missing carbs, a seat, a proper tank, and a few other bits - but it is mostly there and there are a few bonuses.



TLS hub and rolled rim for the front, I can find a rolled rim for the rear to match.

I started on the frame by stripping it down and then cutting off all the tabs, brackets and holders I won't be needing. Then just threw some primer on the bare metal parts and put it aside for stripping later.



Next up - tackle the engine. It wasn't turning over so I got stuck into finding out why.



First look inside was okay...

... but can someone tell me what the M1 or MI embossed on the head stands for? I have not seen it on any other CB450 head.

Then I got the head off.





Two pistons rusted in place.

I cleaned up the head to assess the damage, most of it was rust on top of the carbon deposits, so the only pitting in the metal is to one edge of one chamber.



So what am I doing with this?

The plan is to fit the K0 tank I have and I will make my own seat pan. I want to do a cafe racer seat with a tail that has the same lines as the tank, wit the ridge across the top.

Black tank and seat, Chrysler Blaze Red frame, clubman handlebars, headlamp with single digital gauge in it, race rims, Marzocchi of Ceriani forks if I can find them, and plenty of polish.

Next challenge - free up the pistons (currently soaking in ATF/Acetone) and undo the 'special nut' inside the oil filter so I can get the bugger off!

[grcamna2]

Nice find ! You've got quite a project on your hands & it WILL come together.

[maduncle]

The weekend was very productive:

1/. Finally got the pistons out and the engine fully dismantled. I did have to "tap" the pistons with a cold chisel which kind of dented them, but then I am replacing them anyway. Last thing left to do before I get the engine casings hydro-blasted is to try to get the long connecting rods out, any ideas folks?

2/. I got my box of bits from America, including the CB450 triple. I decided to remove the instrument mounting posts as I will have one gauge in the Bultaco headlamp bucket I am using, and then I tried my hand at polishing - wow! I now have a mirror finish top triple.

3/. I dismantled the starter motor, cleaned ot all the oil and dirt inside it (is this common?) resoldered one broken connection, cleaned each component and reassembled it. I probably need to put 12v across it now to test it and make sure it works.

4/. Late on Sunday I went out and collected the VT250 forks and the CB450(?) head and other parts I got off eBay, and this is where it gets interesting...

This new head I picked up matches my other head by about 90% in casting design, slight variations in vane thickness, different external shapes here and there and a much rougher cast overall. But the interesting thing is the chamber and valve seat sizes - the measurement across the chamber edge on each cylinder is 5mm wider than my 450 head, and the valve seats in the chamber are also 5mm wider.

So I am wondering - do I have another CB450 head with slightly different dimensions internally - or do I have another head that fits that might be off a CB500?

[maduncle]

Some photos to follow up my last post with.



Polished triple (bling bling).



Cleaned up starter (hope it works).



CB450K0 head.



And - is this a CB500T head? ( I hope so).

UPDATE - a very learned fellow from the Honda Twins forum told me to use a magnet on the chamber, if it did not stick then the chamber is aluminium and therefore a 500T head (as 450 heads have a steel 'skullcap' inserted in the head for the chamber).

Yay - it is a 500T head.

[grcamna2]

maduncle,
     Have you tried fitting your CB450 head gasket to see if the valves will have clearance on your CB450 cylinders ? I hope they will...it will have a bunch more performance w/ that CB500T head;what kind of condition are the CB500T valves, seats & guides in ? How is your frame coming along ?

[grcamna2]

Nice job on those polished parts also...what type of clear coating will you be using ? I want to polish some of my parts & haven't really found a very tough coating that will endure gasoline,etc. for years...any ideas ?

[maduncle]

Hadn't thought much about a good clear coat yet - other than keep 'em dry and keep 'em shiny!

I will test clear coat the starter - the triples should not need it being aluminium.

And as far as the engine goes, I will be either boring out the sleeves or replacing them with 500T sleeves, as this has ben done before in race engine builds.

[grcamna2]

Oh Yeah, that one should run good when you're on the road or Track.

[Terry in Australia]

Subscribed. 

[maduncle]

So someone at work heard I was into old bikes and gave me this suitcase full of magazines that he found whilst clearing out a relatives house as they had passed away recently.



I think I hit the mother load on bike magazines from the late 40's to the early 60's (most of them in the 50's).

Nothing in them on the CB450 as far as I can tell so far, there are not that many as recent as 1965, but it is a fantastic collection to now be the curator of.

[Retro Rocket]

Awesome score there Cliff.....

[grcamna2]

+1 on that NICE Vintage lit. collection !

[Terry in Australia]

I just want to jump in that suitcase and roll around in those vintage mags like Scrooge McDuck in his money bin!

[faux fiddy]

So someone at work heard I was into old bikes and gave me this suitcase full of magazines that he found whilst clearing out a relatives house as they had passed away recently.

Cool friend you got to give you that stuff.

As far as  '65 model the drum brake on the front indicated older. If the rim is a 19" you may have a scrambler or CL. I learned some people replaced the up pipes because the cb are lighter , and or more available.  Serial numbers?

I will look at mine and see if there is any M on the heads and post back. I have a 71 CL  (turd wrangling thread here in other bikes) and another '74 that there is a thread here.

Your upper triple may be a later replacement, also.  One of the big complaints of the 450 twins was vibration and to resolve the issue the later bikes (unsure of years) were fitted with triples that have rubber bushings in them. Mine have turned mushy or always were, and machining some delrin replacements may be in the works.

Keep us updated!

[maduncle]

Hey fiddy,

Frame number and engine number are both CB450K0 numbers - I checked all that before I bought the bike.

The front wheel could be off a different bike, as the forks and triples were, but it is a good TLS hub and rolled rim, so I am very happy to use it.

The triple I polished is off a K3, and the rubbers are in good condition so I should be okay for handlebar vibration.

I have found a reputable company here in Ballarat that can re-build my engine using the 500T head, new bigger pistons, new sleeves, and a lot of other new parts to replace worn parts - but I am looking at around $3,000 for this, so I will need to save up for a while.


And Terry - you are more than welcome to borrow any of the magazines for a read when ever you like (just don't roll around in them - bad mental image there).

[Terry in Australia]

Thanks Cliff, I might borrow some, I love to read old mags, I gave away a big box full of 1970's "Two Wheels" mags many years ago and I still regret it. 3 grand seems like a rip to rebuild a twin, I reckon you could do much better than that!

[maduncle]

Three gees is just my first quote - I reckon I can do better too!

[tbpmusic]

And - is this a CB500T head? ( I hope so).

UPDATE - a very learned fellow from the Honda Twins forum told me to use a magnet on the chamber, if it did not stick then the chamber is aluminium and therefore a 500T head (as 450 heads have a steel 'skullcap' inserted in the head for the chamber).


Yay - it is a 500T head.

Maybe yay, maybe not.
The 500T has the same bore as a 450, it was just a longer stroke.
The 500T head will deliver lower compression due to it's design.
Lots of 500T guys opt for a 450 head, to get higher compression, therefore mo' betta' performance. Very seldom do you see guys going the other way (500T head on a 450 bottom).
The valve seat area itself has to be steel - aluminum valve seats would make for about 500 miles between rebuilds........
500T was basically de-tuned from 450 specs - 450's are actually better performers, despite less displacement.

You may just be noting the difference between a 4-speed 450 head and a 5-speed head......

[maduncle]

Thanks tbpmusic, I will investigate this further.

To be honest - I don't mind using the original 450 head anyway - it is a lot 'nicer' cast and all I would need to do is get the broken fins fixed.

Latest score - a set of Betor 35mm shocks in excellent condition for $50 at a swap meet last weekend.

[tbpmusic]

Thanks tbpmusic, I will investigate this further.

To be honest - I don't mind using the original 450 head anyway - it is a lot 'nicer' cast and all I would need to do is get the broken fins fixed.

Latest score - a set of Betor 35mm shocks in excellent condition for $50 at a swap meet last weekend.

Betors are good stuff.
Shocks are high quality Koni copies, the forks were high quality Ceriani copies - good find.
You'll like them way better than stock - but then a pair of twisted rubber bands would be an improvement over stock 450 shocks........

[maduncle]

Thanks tbpmusic, I will investigate this further.

To be honest - I don't mind using the original 450 head anyway - it is a lot 'nicer' cast and all I would need to do is get the broken fins fixed.

Latest score - a set of Betor 35mm shocks in excellent condition for $50 at a swap meet last weekend.

Betors are good stuff.
Shocks are high quality Koni copies, the forks were high quality Ceriani copies - good find.
You'll like them way better than stock - but then a pair of twisted rubber bands would be an improvement over stock 450 shocks........

(Facepalm) I should have said:

Latest score - a set of Betor 35mm FORKS in excellent condition for $50 at a swap meet last weekend.

[cbfnut]

First year black bomber!  Awesome.  Btw, does anyone know if the 450 K0 motor fits in a 400f frame?  Thanks.

[maduncle]

 
Hey cbfnut - send me a picture of a CB400F frame and I will be able to tell you if a 450 engine fits (somehow I doubt it).

Meanwhile - big day today.

I dropped off the 450 head, jugs and crankcase halves and the frame and swing arm to The Blast Factory in Coburg for some work.

Andrew there can blast the engine parts, then drop them into this huge vibrating bucket full of ceramic beads in a polish paste slurry, which then polis the parts to a very smooth and clean surface that will not absorb oil or petrol spills and can be wiped clean.

Amazing.

And he can do this ceramic coating process that bakes on this grey ceramic paint which is then polished using the vibrating tubs, and the parts come out looking like polished steel, even though they are paint.

I love this finish.

Meanwhile - the frame and swing arm will have the paint removed ready for me to begin re design and rebuild work on them.

Best bit is - I needed to get the three broken fins on the head repaired, and Andrew put me onto 'Dave' at Precision Welding around the corner from him, who does this sort of work. So Dave has the head and then it goes to Andrew.

Ah Coburg, so full of useful and helpful subject matter experts all keen on bikes!

(BTW - the other head I have that might be a 500T head or a 450 5 speed head will remain in stock, it is actually sand cast so that just adds to the mystery).

[Terry in Australia]

G'Day Cliff, I rode my K1 over to your place on Sunday arvo but you musn't have been home, so I chatted to a little blonde kid on a bicycle who told me how much he loved my bike, and we even had a "race" down the alley (I kicked his arse......) so that was worth the ride, ha ha!

I'm looking forward to seeing the finished parts mate, if they come out nice and shiny I might take some of my 750 parts to get done. I think (but I don't know for sure) that most Honda heads of the era (certainly all CB750 heads) were "Sandcast", it was just the cases that were diecast. Cheers, Terry.

[maduncle]

G'Day Cliff, I rode my K1 over to your place on Sunday arvo but you musn't have been home, so I chatted to a little blonde kid on a bicycle who told me how much he loved my bike, and we even had a "race" down the alley (I kicked his arse......) so that was worth the ride, ha ha!

I'm looking forward to seeing the finished parts mate, if they come out nice and shiny I might take some of my 750 parts to get done. I think (but I don't know for sure) that most Honda heads of the era (certainly all CB750 heads) were "Sandcast", it was just the cases that were diecast. Cheers, Terry.

Hey Terry sorry I missed you, we were away for two days in Walhalla, got back Monday arvo.

I got told today that CB450 heads were die cast and sandcastle, but that could be wrong. When you see the mystery head and my 450 head together - one looks good and the other looks like it was carved from play dough using a spoon!

Lucky for me the 450 head is the good looking one!