71ish CB450 build

[boddy]

I decided to dive into the engine and see how good or bad things are. The bike sat since 1982 in an unheated garage and I disassembled it about 8 years ago and brought everything into the basement. I did a compression test and got about 165 on both sides. I know this is borderline so I decided to go ahead with an overhaul.

The outside was pretty dirty from sitting around for almost 40 years. There is some pitting on the side covers that I'm hoping to clean up before painting.


Over the past few months I managed to acquire a complete gasket set, oil seal set, DID 219T cam chain, additional cam link (for those unforeseen situations!) valve guide seals, new piston circlips and center cam chain roller. Hoping that the only thing left will be a new set of rings.

 

[ancientdad]

Well, you have the best cam chain and a new center roller, hopefully the tensioner roller will still be soft. Since you're going to be in there (and likely only this once), I'd replace the wristpins too. Compression of 165 stone cold isn't bad at all. Remember to break the chain and lift the head off before starting the disassembly of the head so you can turn the cams until there are no followers with tension.

 

[boddy]

I took off the valve covers and the cams seem to be in good shape with only slight scoring.

I then ground down the master link and removed the chain.


I tried to separate the head from the cylinder, but it just would not come apart. I tried some heat and used a plastic hammer on the top mounting bolts but could not get the gasket to let go. I decided to remove the cams and followers to reduce the weight and then pulled off the head and cylinder as a unit. Once on the bench I laid the assembly on its front and gently tapped in between the base of the cylinders where there are no fins. After a few good hits it finally separated.

Rocker arms all look to be in the same condition. This one is from the left intake.
Should I try to clean up or just leave it alone?

The cylinder bore has what looks like some rust staining but I can't feel any ridges or pitting. Hopefully it will clean up by honing.


One concern are the pistons. They both have some scoring, probably due to some contaminants in the oil. Should these be replaced?


Thanks all for your help.

 

[ancientdad]

That piston is a bit scuffed up but looks usable as long as the ring lands are clean and within spec. If you can't feel the rust marks in the cylinder it should clean up with a hone, but you should get the cylinders and pistons measured to see how much wear there is. You can use a fine stone to dress up followers when they have light scoring, then polish up with fine emery cloth. Don't bother to replace the rubber cam chain damper rings on either side of the cam sprocket, they're there to quiet the chain noise and will eventually get hard and brittle and break up into pieces anyway, I never replace them.

 

[boddy]

That piston is a bit scuffed up but looks usable as long as the ring lands are clean and within spec. If you can't feel the rust marks in the cylinder it should clean up with a hone, but you should get the cylinders and pistons measured to see how much wear there is. You can use a fine stone to dress up followers when they have light scoring, then polish up with fine emery cloth. Don't bother to replace the rubber cam chain damper rings on either side of the cam sprocket, they're there to quiet the chain noise and will eventually get hard and brittle and break up into pieces anyway, I never replace them.

Good to know. Next step will be to clean everything and verify all is within spec. Good point about the damper rings. Mine are still intact but not that pliable. Better to remove before they disintegrate.

Another question on a leak down test - should this be done with the torsion bars installed or with the valves just sitting in the head with no tension on them?

 

[ancientdad]

Torsion bars installed, you'd check valve leakage on a coil valve spring head with the springs installed there too. Check the torsion bars for equal tension when you remove and reinstall them, sometimes when a 450 engine sits a long time with one valve held open the torsion bar loses some strength and in some cases you can slip the torsion bar up onto the knock pin with your fingers (not good). Bill Lane altered a socket to fit over the end of the torsion bar to use with an inch-pounds torque wrench to measure the tension

 

[boddy]

Torsion bars installed, you'd check valve leakage on a coil valve spring head with the springs installed there too. Check the torsion bars for equal tension when you remove and reinstall them, sometimes when a 450 engine sits a long time with one valve held open the torsion bar loses some strength and in some cases you can slip the torsion bar up onto the knock pin with your fingers (not good). Bill Lane altered a socket to fit over the end of the torsion bar to use with an inch-pounds torque wrench to measure the tension

I was fortunate enough to buy the torsion bar socket and a homemade oil filter wrench off a guy selling a bunch of parts - $10 for both!
I have a foot-pound torque wrench (0 to 150 range), I suppose this will not be accurate enough for the 3.7 to 4.63 ft/lbs specified for the torsion bars

 

[LongDistanceRider]

Sounds like an inch/pound torque wrench is in your future.

 

[boddy]

Sounds like an inch/pound torque wrench is in your future.

It certainly does, LOL.

 

[12ozPBR]

Bill Lane altered a socket to fit over the end of the torsion bar to use with an inch-pounds torque wrench to measure the tension

I am glad this topic came up. Making one of these had gotten lost in my mental to-do list. It will be a good near term task and small, but fitting tribute to Bill and all the knowledge he shared over the years.

 

[LongDistanceRider]

I am glad this topic came up. Making one of these had gotten lost in my mental to-do list. It will be a good near term task and small, but fitting tribute to Bill and all the knowledge he shared over the years.

And that would be a good sticky topic on how to make one.

 

[ancientdad]

And that would be a good sticky topic on how to make one.

We should just copy Bill's and reword a bit, they'd never know. Interestingly - and we've condemned this here previously, and rightfully so - in another post over there while I was looking for the one about making a socket to measure torsion bar strength, I saw that Bill actually endorsed adjusting the 350 valves by ear while running. A strong caveat was to never use that method on the 450, but essentially the only difference between them is follower vs rocker arm and a tighter lash setting (that actually equates to .002" at the valve tip). I was surprised to see that. He added that 350 tune-ups were gravy then in large part because of setting the valves while running.

 

[boddy]

And that would be a good sticky topic on how to make one.

My socket is a genuine Honda tool, so I took some measurements for those that want to make one. As per Bill's post, the inside diameter is 3/4", the notch is 7/16" wide and 5/16" deep.

 

[Dutchess]

Is the torsion bar socket just to get it realigned to install the dowel pin or is there an inspection point to evaluate the "springyness" of the torsion bar? If it is the later, I have not been able to find this in the FSM.
Lee

 

[ancientdad]

Is the torsion bar socket just to get it realigned to install the dowel pin or is there an inspection point to evaluate the "springyness" of the torsion bar? If it is the later, I have not been able to find this in the FSM.
Lee

You can use a wrench (14mm IIRC) to simply lift the torsion bar onto the dowel pin. I can't recall if it's in the FSM somewhere or not and haven't looked as yet, but the late 450 expert Bill Lane said at least 60 inch/pounds of torque required is what he likes to see using the tool on a torque wrench to check spring strength.

Torsion bar tool

 

[Dutchess]

You can use a wrench (14mm IIRC) to simply lift the torsion bar onto the dowel pin. I can't recall if it's in the FSM somewhere or not and haven't looked as yet, but the late 450 expert Bill Lane said at least 60 inch/pounds of torque required is what he likes to see using the tool on a torque wrench to check spring strength.

Torsion bar tool

Nevermind.

 

[ancientdad]

Will do. I could certainly make a tool, and have a digital wrench that starts reading at 5.9 lbs. I just got everything back from my machinist and but the cams, rockers, pistons and valves inspected in spec. I know he checked the eccentric shafts, journals, guides and bosses on the head covers and they were in spec. I don't know that he would have checked the torsion bars for strength. Certainly something I can do. In retrospect, I wish I had had him replace the guide orings while he was at before recutting the seats and fitting the valves. Hopefully that oversight does not come back to haunt me.
Lee

Do you have an engine repair thread going here? If not, you should start one since this is boddy's thread. As for the o-rings on the valve guides, do you mean the machinist removed the guides or are you referring to the valve stem seals on the top of the guides? If you mean valve stem seals, they're easily replaceable and will not affect anything done by the machinist.

 

[davbib]

Do you have an engine repair thread going here? If not, you should start one since this is boddy's thread. As for the o-rings on the valve guides, do you mean the machinist removed the guides or are you referring to the valve stem seals on the top of the guides? If you mean valve stem seals, they're easily replaceable and will not affect anything done by the machinist.

That would be great, because I'm about ready to get my engine on my bench and start taking things apart and while I've done lots of bike maintenance over the years I've never opened an engine up before.

 

[ancientdad]

That would be great, because I'm about ready to get my engine on my bench and start taking things apart and while I've done lots of bike maintenance over the years I've never opened an engine up before.

Since you've never done an engine rebuild before and you're starting with one of the more unusual engines, I'd absolutely recommend it. Go here and start a new thread for it.

https://www.vintagehondatwins.com/forums/newthread.php?do=newthread&f=57

 

[davbib]

Since you've never done an engine rebuild before and you're starting with one of the more unusual engines, I'd absolutely recommend it. Go here and start a new thread for it.

https://www.vintagehondatwins.com/forums/newthread.php?do=newthread&f=57

Thanks will do. Will snap a few pics when I get out into the garage so everyone can see where I'm at.

 

[boddy]

After almost 2 years I think it's time to post something on this build.

Admins could you change the title to '71ish CB450 build'

I think I will consolidate everything here and not just the engine build

thanks...Brad

 

[boddy]

Thanks for the title change. The reason I say 71ish is because the chrome fork ears and 7" headlight shell are from a 1972. The tank I had was pretty far gone so I picked up a used one in good condition but it also was from a '72 since it had the chrome strip at the bottom. My side covers are original paint but with a couple of scratches that I think I will leave alone. The tank I bought was also red but had some '70's pin striping done that I think is a nice throwback to that era. I think I might keep the tank and side covers as is.





When I got the bike it didn't have any flashers so I had to purchase both front and back flashers and mounts. The fork ears were a little rusty but they polished up fairly well - a few small pits.

 

[ancientdad]

Hey, at least the headlight ears weren't bent from a turn signal stalk during a fall. It all looks like good used stuff, should look nice together.

 

[boddy]

It won't be concourse material but should look good from far lol.

Over the last year or so I have been tackling the items one by one. I started with the front forks which I took apart cleaned and then polished the aluminum. I also changed the seals, drain bolts and sealing washers. One item off the list.

I next


I next tackled the wheels. The rims were quite rusted from sitting on concrete in an unheated garage for about 30 years.



I ordered new rims, spokes, bearings, retainer rings, tubes and tires. I had to cut the 50 year rubber off the rims as the tire beads were hard as rock. I took everything apart and cleaned and polished the hubs. New bearings were installed. I then laced up the new rims and spokes. I lightly sanded the disk and repainted the center black. Next was to install the new rubber. I had already bought the Dunlop K70's before I read here on VHT that the more modern tires such as the Shinko's were better handling.

 

[Flyin900]

Nice progress and polish job on the aluminum bits for sure. I just came across your thread and will keep following the progress. The paint on the tank and side covers looks decent overall for a 50+ year old machine.
As far as the Dunlop K70 tires the bike will feel right at home. On these older machines any decent name brand tire is superior to the stuff from 50 years ago.

 

[ancientdad]

I ordered new rims, spokes, bearings, retainer rings, tubes and tires. I had to cut the 50 year rubber off the rims as the tire beads were hard as rock. I took everything apart and cleaned and polished the hubs. New bearings were installed. I then laced up the new rims and spokes. I lightly sanded the disk and repainted the center black. Next was to install the new rubber. I had already bought the Dunlop K70's before I read here on VHT that the more modern tires such as the Shinko's were better handling.

Everything looks great, new rims and spokes always look excellent. You're missing the rubber dust seal over the left wheel bearing (sprocket side) on the rear wheel. They call it "retainer cap", it's the cap over the bearing retainer.

CAP RETAINER for CB450K4 U.S.A - order at CMSNL

✓Get the CAP RETAINER ✓Manufacturercode: 42633-283-000 ✓Quality part

www.cmsnl.com

 

[boddy]

As far as the Dunlop K70 tires the bike will feel right at home. On these older machines any decent name brand tire is superior to the stuff from 50 years ago.

Thanks. For the type of riding I intend to do I think the Dunlops will suffice.

 

[boddy]

You're missing the rubber dust seal over the left wheel bearing (sprocket side) on the rear wheel. They call it "retainer cap", it's the cap over the bearing retainer.

Good catch, I didn't even realize it was missing. I've been pouring over the parts fiches looking at what might be missing or need replacing and never noticed. Some parts of this bike have been apart before judging by what I am discovering. The dust cover is one thing and I'm also missing the chrome cable holder that goes on top bridge. I'll start a new parts list...

 

[boddy]

Sent some bits and pieces out to be zinc plated and picked them up. They told me they blast all the parts, prep and then zinc plate. I even had some small 5mm screws that were not lost.

 

[12ozPBR]

The plating looks really nice boddy! Was it fairly affordable? I need to find a place to plate things for one of my next projects.

 

[ancientdad]

The plating looks really nice boddy! Was it fairly affordable? I need to find a place to plate things for one of my next projects.

Wow, it must be an upgraded approach for the next one, you're famous for the quick and dirty (but mechanically solid) runners!

 

[boddy]

The plating looks really nice boddy! Was it fairly affordable? I need to find a place to plate things for one of my next projects.

For me it was reasonable considering to replace some of the bolts you are looking at about $4-5 each, if you can find OEM. The cost all in was $80. Of course I came across another box of parts that need plating and was happy to learn that the plater accepts small batches of items.

 

[ancientdad]

For me it was reasonable considering to replace some of the bolts you are looking at about $4-5 each, if you can find OEM. The cost all in was $80. Of course I came across another box of parts that need plating and was happy to learn that the plater accepts small batches of items.

That price is well worth it, and in hindsight I wish I'd looked into that for my 450 build back in 2017. I overdid the vinegar treatment and lost plating on more than a few bolts and nuts which are now dark and ugly.

 

[boddy]

I have a small batch of items to bring, I'll see if it's still cost effective.

 

[boddy]

Sorted through all the bits I got back from the zinc plater and put it together with pieces I bought in order to organize everything. I used the parts fiche bolt/screw dimensions to know what piece went where. I ended up buying a lot of washer, nuts and screws as the originals in some cases were a little too far gone.



Also organized some of the engine bits

 

[jensen]

The plating looks nice, but I don't understand why these should be blasted before plating ? It makes the surfaces rough and dull. Looking closely, I see just a few parts are blasted, most where not I guess ? I miss the muffler hangers ? do you paint them ? Springs came out good ! Here in the Netherlands I pay 50 euro for 10 kilo or so, but only when it's clean and de-rusted. I also take the old layer of zinc plating off (chemically).

 

[boddy]

The plating looks nice, but I don't understand why these should be blasted before plating ? It makes the surfaces rough and dull. Looking closely, I see just a few parts are blasted, most where not I guess ? I miss the muffler hangers ? do you paint them ? Springs came out good ! Here in the Netherlands I pay 50 euro for 10 kilo or so, but only when it's clean and de-rusted. I also take the old layer of zinc plating off (chemically).

The platers told me that the pieces to be plated didn't have to be super clean but not greasy. They said they would blast/clean them before plating. Maybe they chemically cleaned them, I will ask next time I bring in some pieces. My muffler hangers were painted black.

 

[boddy]

I looked at my transmission components and would like the opinion of the members as to what should be replaced. Based on marks on the crankcase halves the engine has definitely been opened before and looking at the shift forks I would say they have been replaced.


The counter shaft looks ok to me aside from some scuffing in the groove where the shift forks rest.



The main shaft is a little more scuffed up - should I try to smooth that out?


The bigger concern is the "star". There seems to be quite a bit of wear on the points of the star. Should I start a search for this piece? The neutral detent is a little rough as well. The pizza cutter and neutral stopper arm were changed because they is no play in the wheels.

 

[ancientdad]

The bigger concern is the "star". There seems to be quite a bit of wear on the points of the star. Should I start a search for this piece? The neutral detent is a little rough as well. The pizza cutter and neutral stopper arm were changed because they is no play in the wheels.

The detent star definitely needs repair or replacement. If you can't find one, you might look for the CB500T shift drum complete as it comes with a new one attached, that's how I was able to replace mine. As long as you're sure the pizza cutter has zero shaft play then you'll be good, the neutral stopper arm/roller is still available as they don't wear out as easily. Here's the part of my maintenance thread where I replaced the parts.

Maintenance time 3, now 4, continuous years in

Oh, good! I didn't realize you could access the shift detent parts without splitting the cases, but it's good to know. I've only split cases once and hope those cases can stay together for a long while now that it's behind me!

www.vintagehondatwins.com

 

[boddy]

Thanks AD. I will start the search for either the star or a complete 500T shift drum.

 

[ancientdad]

Thanks AD. I will start the search for either the star or a complete 500T shift drum.

David Silver has the complete shift drum like I bought to get the star, but it's about 40% more now of course...

David Silver Spares

David Silver Spares Honda Part Number Search

www.davidsilverspares.com

 

[boddy]

David Silver has the complete shift drum like I bought to get the star, but it's about 40% more now of course...

David Silver Spares

David Silver Spares Honda Part Number Search

www.davidsilverspares.com

I also see the CMSL also has just the star, at $67 Cdn plus $41 for shipping. At those prices I think I might try and get it repaired.

24304292350: CENTER GEAR SHIFT Honda - buy the 24304-292-350 at CMSNL

✓ Get the CENTER GEAR SHIFT ✓ Manufacturer Part Number: 24304-292-350 ✓ Quality part

www.cmsnl.com

 

[ancientdad]

I also see the CMSL also has just the star, at $67 Cdn plus $41 for shipping. At those prices I think I might try and get it repaired.

24304292350: CENTER GEAR SHIFT Honda - buy the 24304-292-350 at CMSNL

✓ Get the CENTER GEAR SHIFT ✓ Manufacturer Part Number: 24304-292-350 ✓ Quality part

www.cmsnl.com

I didn't even check CMSNL, didn't expect them to have one. Their shipping can be ridiculous to the US, and I'd imagine Canada as well based on that crazy quote. For me, they are a last resort.

 

[12ozPBR]

I also see the CMSL also has just the star, at $67 Cdn plus $41 for shipping. At those prices I think I might try and get it repaired.

24304292350: CENTER GEAR SHIFT Honda - buy the 24304-292-350 at CMSNL

✓ Get the CENTER GEAR SHIFT ✓ Manufacturer Part Number: 24304-292-350 ✓ Quality part

www.cmsnl.com

Unless it was friend of yours it is hard for me to imagine who could do a quality repair job on the shift drum center (star) for less money than that. More than the cost, I’m surprised they actually have one available.
I never have gotten around to version II of my shift drum center grind repair jig. I wish I had it perfected so I could offer you a repaired replacement. If you do end up replacing yours I may be interested in purchasing your old one as a core to repair down the road at some point.

 

[boddy]

Unless it was friend of yours it is hard for me to imagine who could do a quality repair job on the shift drum center (star) for less money than that. More than the cost, I’m surprised they actually have one available.
I never have gotten around to version II of my shift drum center grind repair jig. I wish I had it perfected so I could offer you a repaired replacement. If you do end up replacing yours I may be interested in purchasing your old one as a core to repair down the road at some point.

If I do purchase the star, you would certainly be welcome to the old part.

 

[boddy]

Decided to smooth out the ridges on the star detent, so I took it apart and used a small grinding stone in the drill press to take down the ridges. I figure it's not precision gearing here, just a detent to hold it in the gear selected, one mm less is not going to make much of a difference.


While I had the grinding stones out, I decided to do the oil transfer piece mod to allow a better flow.

 

[boddy]

I bead blasted the engine cases, head and cylinder a while back. I washed everything in the parts washer twice, with lots of compressed air between washes. I then washed in hot soapy water followed by a cleaning of the outside surfaces with laquer thinner. I then painted with VHT aluminum caliper paint and baked for the 1 hour at 200F.

If you zoom in, you can see many blemishes and pin holes from corrosion. I was not completely satisfied so I decided to re-do the cases. For the areas that needed filling, I took Flying900's advice and used SteelTech epoxy filler.

In order to apply the filler I had to remove the paint. I was surprised how easily the "cured" paint came off with a rag and some laquer thinner. I think once done I will use the VHT paint but clear coat with a 2K sating finish. I'm not sure the VHT caliper paint would have stood up to any gasoline leaks. I may be a while before I get back with any updates as it is too cold here to do any painting in the garage.

 

[12ozPBR]

Decided to smooth out the ridges on the star detent, so I took it apart and used a small grinding stone in the drill press to take down the ridges. I figure it's not precision gearing here, just a detent to hold it in the gear selected, one mm less is not going to make much of a difference.
View attachment 28600

Nice detail work on smoothing out the ridges. I will be interested to hear the results when you get it all back together and can test it. As long as the pizza cutter rolls smoothly and is not out of round it may work just fine.

 

[boddy]

As long as the pizza cutter rolls smoothly and is not out of round it may work just fine.

The pizza cutter and neutral arm were both replaced and there is no slack in either so I'm confident it should work fine. If not, I can always replace the star after the fact as it's easily accessible from the clutch cover.

 

[boddy]

Still a bit on the cool side for painting the cases so decided to look at some of the engine components. The oil pump has some light scratches but more wear from the pin that holds the plunger on the connecting rod. I can feel a slight catch with my finger nail. Since the pin floats in the plunger, is this wear normal from the connecting pin?