Honda CB450 Twin project

[clrrk]

Well, where do I start? I've wanted a project bike for a cafe racer build for a couple of years now but never saw the right bike for sale at the right money. During this period my friend had bought a US import CB450 Twin that somebody else had started as a project and never finished. He bought it, painted the tank, removed the wheels and started to polish a few bits before setting it in a corner and forgetting about it.

Recently he decided that he had too many projects going on and was going to let some of them go so I jumped at the chance to buy this. Not sure of the year currently as he is still hoaking me out the Nova paperwork but its somewhere between 1968 and 1973, most likely a later year due to having disc brakes up front rather than drums front and rear.

When I collected it, it was basically an engine in a frame and the rest was in a box of parts, so the first job was to get it built back into something at least resembles a bike.

It's probably worth noting at this point that the only bike I've ever owned was an Aprilla SR50 scooter over 15 years ago, so this whole project is a massive learning curve for me.

Now that it vaguely resembled a bike again the plan was to get it running again first, before getting stuck in to the fun stuff. My friend had taken the cover for the valve cam follower off and accidently removed the cam follower as well. This meant that the rocker arm had fallen off so the first job was to pull the carbs off and get in, remount and clearance the rocker arm correctly.

Next job was to take a look over the wiring. The rectifier wiring looks like it has seen better days and I found a few other broken wires which I've now repaired.

The bike, in theory, is now in a position where I can attempt to start it, just need to get some oil and a battery and hopefully I can get turning over. Fingers crossed.

 

[Slimsbikers]

Best of luck with it.Not a bad way to pass the lock down.

 

[dub]

Subbed, love a home built café racer thread. Once I get my dad's workshop cleared out I can see us getting a wee project in the space.

 

[S2K-Aaron]

Fantastic! Great base lad! Looking forward to seeing the progress

 

[clrrk]

Update: Attempted to get it running last night and it wasn't to be. Made some fuel lines and connected them up to a temporary tank (coke bottle) to fill the carbs and they immediately started to leak, pulled them apart and the seals were rock hard so have ordered a rebuild kit and will give them a complete overhaul.

 

[Peter]

Brilliant, will be keeping an eye on this build! Would really like one of the CB's next as a project. Check out Classic Octane on Youtube, he restores a lot of Honda CB's.

Classic Octane

Austin, TX. Follow along as I build classic bikes, cars and a few late model projects as well. Classic Octane gear (Shirts and stickers) - https://classicoct...

www.youtube.com

 

[clrrk]

Brilliant, will be keeping an eye on this build! Would really like one of the CB's next as a project. Check out Classic Octane on Youtube, he restores a lot of Honda CB's.

I've actually watched a few of his videos already. Seems to be a ton of CB how-tos on Youtube in general. Between it, hondatwins.net and a PDF of the workshop manual I found on Google I've been learning a lot.

 

[dub]

Brilliant, will be keeping an eye on this build! Would really like one of the CB's next as a project. Check out Classic Octane on Youtube, he restores a lot of Honda CB's.

Classic Octane

Austin, TX. Follow along as I build classic bikes, cars and a few late model projects as well. Classic Octane gear (Shirts and stickers) - https://classicoct...

www.youtube.com

Well there's my evenings gone watching that channel now lol!

 

[martymim]

Class, Looks to be great project.
Would love to get stuck into one.

 

[clrrk]

Time for a decent update, been working away at this over the last few weeks.

I started to look into making some plans for pieces I would need to fabricate, first up was the electrics tray. Given that at this stage the wiring was very much a hard mess of unknowns the plan was to rip the wiring for everything other than the ignition system and replace it with new wiring controlled by a Motogadget M-Unit which could be hidden under the seat along with a combined regulator/rectifier as I want to be able to run a small lithium battey under whatever rear hump style I go with. So mocked up this cardboard template which I'm going to attempt to bend out of 1mm mild steel and then rivnut in place.

Soon after I got a call to say the wheels had be found and to come collect them. I also got the original import paperwork which confirms that the bike is a 1970 K3 which was exported from California in 2015.

Getting the bike back on two wheels meant I was now able to take it over to a friends dad. We dug through the wiring and got everything connected up properly but still no spark. So we started to dig deeper and found that the points were slightly corroded and completely out of timing. After cleaning the corrosion and setting the timing we had spark and decided to give the freshly rebuilt carbs some fuel and attempt a kick.



Bike kicked over and even managed to maintain idle for a little while. Went round feeling the exhaust to check that both sides of the engine where firing and found that the right side exhaust was cold. After a check again of spark we realised that I had adjusted the float level too high and it wasn't getting fuel. Quick adjustment and all was good.

Pleased to know now that it runs - it will need some fettling to get it to run nice but for now all I wanted was clarification that the engine was good before invest any money into the bike.

 

[fabiostar]

a 450 is a rather rare thing these days, the classic racers love them. at one stage they were called the black bomber.

 

[Dave..]

a 450 is a rather rare thing these days, the classic racers love them. at one stage they were called the black bomber.

I tried to do a deal on one last summer.

The Honda CB450 Black Bomber - Motorcycle Classics

Two cylinders, twin cams and loaded with technology, the Honda CB450 put the world on notice: Honda was at war, and planned to win.

www.motorcycleclassics.com

 

[fabiostar]

ay they are a hard bike to buy these days.

 

[clrrk]

I've been furloughed from work again so I've had plenty of time to work on this. Decided to try and get all the labour intensive stuff done while I have time on my hands. First step was to get the bike back home again...

Now that the bike was running again I decided to take a look at the wiring. As I plan to go for an M-Unit a lot of the wiring will need to be redone, so I ripped out every wire that wasn't needed for the bike to run. I also picked up a combined regulator/rectifier to replace the separate units as this will be required anyway for me to run a small lithium battery.

Although I never plan on selling this bike I thought it would be a good idea to document the wiring incase anything went wrong in the future and I needed to trace my wiring again. This will get expanded in the future when I add all the accessories but for now here is how it looks. Still need to add a new main fuse now that I've deleted the starter motor.

With the wiring sorted the next step was to get the engine out so I could get it prepped and painted. It was a heavy brute of a thing to get out by yourself but after about 15 minutes of wrestling I had it set on a pallet. Want to replace all the gaskets while it is out but the gasket kit is on back order at the moment so will have to wait.

Plan is to paint the majority of the engine black, with polished stator cover, cam covers, oil filter cover and fins. Tested this on a few pieces, really enjoy the contrast...

Looks so weird without the engine in...

 

[dh1079]

Great project and coming along nicely, great job

 

[S2K-Aaron]

Now that the bike was running again I decided to take a look at the wiring. As I plan to go for an M-Unit a lot of the wiring will need to be redone, so I ripped out every wire that wasn't needed for the bike to run. I also picked up a combined regulator/rectifier to replace the separate units as this will be required anyway for me to run a small lithium battery.

Bikes coming on really well mate, just one thing. Make sure you get a Reg/Rec that is compatible with a Lithium battery. Many aren't.

Basically a Gel or AGM Battery charge at higher volts, if the Reg/Reg charges a Lithium at them volts it will Fry it! Trust me i've been there!

Lots of Brands tell you their charging points and same with the Battery so it's important to match the two correctly.

 

[clrrk]

Bikes coming on really well mate, just one thing. Make sure you get a Reg/Rec that is compatible with a Lithium battery. Many aren't.

Basically a Gel or AGM Battery charge at higher volts, if the Reg/Reg charges a Lithium at them volts it will Fry it! Trust me i've been there!

Lots of Brands tell you their charging points and same with the Battery so it's important to match the two correctly.

Cheers for this. Was actually something I looked into a bit before I bought it. Ended up going for this one goes to a maximum of 14.4DCV so it should be fine.

 

[S2K-Aaron]

Cheers for this. Was actually something I looked into a bit before I bought it. Ended up going for this one goes to a maximum of 14.4DCV so it should be fine.

Good man, I unfortunately didn't and ruined both a Lithium battery and a Reg/Rec.

Looking well keep it up

 

[clrrk]

Time for another update.

With the engine out, degreased and sanded back it was time to get some paint laid however most of the country was out of stock of Black VHT as everyone has been going mad with the fire pits over lockdown. I eventually tracked some down, masked up the bits that I didn't want painted and give it a coat of paint...

AND I HATED IT! It was nowhere near as dark as the Halfords Engine Paint I had used on the chain cover and it looked more like primer than a final finished. Sure it might darken down after the engine has been ran a few times and its had a chance to cure but I really hated it.

Spoke to a friend of mine who is a painter by trade, who has done a few bikes in his time, and he recommended just giving it a a light coat of satin black over the top to make it blacker... so I did.

Much happier with it now. It remains to be seen how it lasts and if it will react any once the engine runs and the VHT cures, but I'm happy for now.

You may have noticed in the photos above that I'd started to polish up a few of the covers. I bought myself a Sealey bench polisher last week and a couple of different grades of pads and couple of Menzerna polishing compounds. Surprised how well they are coming up, the stator cover was corroded and had some deep gouges in it so I went sanded it from 80 grit up-to 800 and then hit it the the polisher.

It's not perfect, I still need to refine it a little more as I didn't spend enough time on each stage so you can still see some of the sanding marks round the edges.

 

[dh1079]

Great progress buddy

 

[clrrk]

Almost a month since my last update. Sadly now that I'm back at work progress has slowed somewhat. The last month has been a lot of ordering parts, waiting, finding out the parts are wrong and reordering new stuff.

I got a gasket kit for the engine and polished up the rest of the covers so its now ready to be put together for the final time.

I've also been doing a lot of work up front. I decided I didn't like the clip on's that were on the bike as there was no height adjustment and given that I'm 6ft2 I felt they sat too low. I also ordered some controls as the bike didn't come with any. Original plan was to go for some expensive Motogadget push buttons but the more I thought about it the less I could justify £160 for some buttons, so ended up going onto Amazon, ordering a set at a tenner and painting them to get rid of the horrible red graphics. Bonus to this was that I was able to do away with the horrible throttle assembly that was on that bike when I bought it and use the OEM tube with the new controls.

Another addition up front was some bar end mirrors and indicators. Typical it's one or the other with these, but after a bit of Googling I found a way to modify them so that I could run both. By drilling out the inside of the mirror mounts to a size large enough to accept the indicator and chopping down the inserts I was able to get both mounted together.

I also bought a Headlight, which I love, and some brackets to mount it, which I hate and will be replacing soon.

Last update for the July is the frame hoop. I ordered one of these from Wish 2 months ago with an upsweep and an integrated tail light but when It arrived I found out that where I measured the 210mm frame and where they measured it were too different things. Having hunted for ages to try and find a 1" (25mm) upswept 210mm frame hoop this side of the Atlantic I gave up and ordered a flat one from The Netherlands which I will have my own upsweep added to eventually.

The flat hoop unfortunately did not come with a built in light, so decided to bust out the grinder and try and be delicate for once...

And that's us for now. Next step is to get the bike over to Landspeed Auto House. I've been talking to Noel about a custom tail piece I want made, so hopefully the next update will be something a little more exciting.

 

[clrrk]

Don't think I'm going to put any fabricators out of business any time soon, but I have an electrics tray...

 

[Dave..]

Don't think I'm going to put any fabricators out of business any time soon, but I have an electrics tray...

View attachment 288507

Looks good.
Are you keeping those tyres? I had simillar on my Z750 (came on the bike) and they had very poor grip in the dry and wet and didn`t give me any confidence.

 

[clrrk]

@David.S Absolutely not. Will be changing to a more retro style tyre after I refurbish the wheels, like a Firestone Champion Deluxe or similar.

 

[Dave..]

@David.S Absolutely not. Will be changing to a more retro style tyre after I refurbish the wheels, like a Firestone Champion Deluxe or similar.

The wee bike will look well when it is finished.