1969 CL450 US Barn Find Restoration

[MrDavo]

Thanks for looking but no, a bit of a pig in a poke that one, if I lived nearer to the Frog dude I would maybe go and take a look, but not on just those photos.

[AshimotoK0]

I wouldn't recommend my softening brew for critical internal engine parts Dave. I wouldn't do it on any of mine.

I think I read about removing the damper rings initially from Chris Saxby on Honda Twins and he was given the info by Pete Watson who used to race them and is reputely the guy that Ken Ives copied the red 'Ken Ives' Special from and also prompted Honda UK to sort out the Bomber flat spot in the carburation. Sadly Pete is no longer with us but seems to be  held in pretty high regard by people I talk to who are multi-Bomber owners (I think one of them owns about 14 !). There is good and bad info on all internet forums I think, you just have to trawl around to get the best info filtered from the not so good stuff.

This is a letter between the two of them ...interesting reading (sorry if it's a slight hijack). Also in my file on the Bomber was this period photo with Lord's Denbigh & Litchfield on their Bombers ...The Litchfield one was a red 'Ken Ives' special. Lord D also owned the Brighton Bike 750 pp gold bike ...probably traded this bomber for it (he's the one with the trendy stripey pants on  )

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[K2-K6]

I've been reading through the twins forum thread on setting the valve clearances,  no wonder there's so many issues reported about these. Seems to have quote a few traps built in that must catch out a fair proportion of people without specific knowledge.

http://www.hondatwins.net/forums/55-engine-discussion/12171-450-500-valve-adjustment.html

Also seems that the exhaust (is the cam rotating across the follower towards the rocker pivot point?) would have its peak load go highest just as the spring load peaks in comparison to the inlet which is reducing. No surprise that any wear is first seen on the exhaust lobes!

Looks like you can set the rocker eccentric adjuster two ways also (180 degrees out), which would further raise the peak load if incorrect as the fulcrum moves toward the camshaft centre line,  which disadvantages the geometry.

Seems like the design is very near the knuckle load wise. Needs very meticulous setup to avoid problems.

[MrDavo]

I was going to scan through that now, but realised that its just the 11 pages?  It looks as if there is a lot to possibly go wrong.

I had wondered if I could set it up carefully on the bench first, then check it again once the head is installed. However the timing marks give me TDC left side intake stroke, not where I want to be. A bit of geometry would be needed to make your own timing marks to do the tappets, and then probably not accurately enough. I'm guessing I build it with loose clearances, then worry about it once the chain is timed up.

There will be a delay while I wait for the parts now, as some are coming from the US, some are on special order.

I just got back from a trip to the Parcelfarce  sorting office, another £20.26 to pay for the VAT plus collection fee on the 500T stator cover, and no they don't take cards, it is only the 21st Century after all, so it was off to find a cash machine.  The cover looks nice though, much better than the badly scrawped one that came with the bike, if technically not the right Honda logo.

[K2-K6]

Pages 1 then 9,10,11 are the most interesting. The others are just problems around the core.

Seems that if you've moved the valves back into the head at all during grinding etc,  then you may run out of valve clearance so worth going through it before fitting head in case you need to alter valve length.

[MrDavo]

Playing around with the stem length sounds scary, what about the hardening? Lets hope not.

Anyhow, I suppose its not beyond the wit of man for me to mark the back of the cam base with small paint marks (I can use the yellow paint pen I bought for my CB750, that's another thread altogether) then see if I can get the gaps about right with the head off the bike, better than finding out once I've built it.

This looks good, valve gear assembly step by step, with photos that haven't been screwed over by Photobucket:

http://www.hondatwins.net/forums/1-project-logs/11792-cb450-cl450-valve-train-assembly-pictorial.html

[royhall]

That's a very good thread on the head assembly. I'm watching this thread closely as I'm about to start work restoring my Bomber. Was looking forwards to it, but am not so sure now. As your finding, there's a lot of learning to be done.

[jensen]

I pm’d Jensen, so he should see this

A late response since work, work and work consumes all the time I have at the moment.

If the lobes are ok, just can re-use this cam. Make sure you polish the edges a bit, so that no extra material brakes out.
I can't give you an advice about using the rubber rings in general or not. I only can say that I prefer them, makes the head noisy without them, just replace them when re-build an engine with fresh, original Honda rubber rings. Personally I only saw issue's with these rubbers on old engines with no history of rebuilding what so ever. I think it's wise to replace them within 20 years or so 

In this particular case I would't use them, there is a lot of material gone to keep the rubber in place, that could be a risk.

Jensen

[MrDavo]

Thanks for the reply Jensen, I appreciate your input. I have ordered new rings, these are nearly 50 years old and rock hard. It would be horrible if they started to break up in service after such a long sleep.

I am glad you think I can reuse the cam as otherwise it is perfect.

The valve seats were done with grinding paste but not recut. Let’s hope I won’t need to use your expertise on shortening valves and guides to get acceptable clearances.

[K2-K6]

Just picking up on Laverda120 post earlier ( i wouldnt in this example here as the lobes area so good) but for others looking in its worth gaining the opinion of the indicated supplier to see what they could offer. Some of these services in the past have offered wildly varying results (I've no knowledge of that supplier though, so no reflection of their work) .

http://www.common-motor.com/Honda-CB350-CB360-CB450-CB500T-CB550-Rebuilt-Camshaft-Rocker-Arms

Found the above though which indicates some specialisation in these components, unsurprisingly if anyone has direct experience of them.

[AshimotoK0]

Just picking up on Laverda120 post earlier ( i wouldnt in this example here as the lobes area so good) but for others looking in its worth gaining the opinion of the indicated supplier to see what they could offer. Some of these services in the past have offered wildly varying results (I've no knowledge of that supplier though, so no reflection of their work) .

http://www.common-motor.com/Honda-CB350-CB360-CB450-CB500T-CB550-Rebuilt-Camshaft-Rocker-Arms

Found the above though which indicates some specialisation in these components, unsurprisingly if anyone has direct experience of them.

I believe Kettle738 has used Newman Cams in the past for CB450 cam parts and said they were OK..  Mick is fairly picky so I trust his opinion and I think I would use them if needed.

[AshimotoK0]

If I am interpreting Jensen's reply correctly he is advising that you miss off the dampening rings on the exhaust cam because of the damage but says engine is noisier without them. Pity the metal can't be built up and machined but I am no expert on brazing chilled iron castings or if it's even a possibility. I have definitely seen CB250K sprocket mount lugs welded up though. I wonder if someone like Newman cams could advise. The USA Bubbas would probably build it up with JB Weld   

[MrDavo]

In that case I may look for another decent camshaft, there are a couple on the bay, the best ones are in the US, so subject to stupid carriage plus taxes, but I’ll keep looking.

I don’t want to build a noisy engine, it would bug the crap out of me. The alternative would be to build it with dampers but keep whipping the cover off to see if it is spreading, although they are a lot of work to install, they should be a 10 minute job to cut and pull out.

[royhall]

If it was mine I think I would hold off on a cam replacement decision until the new damper rings arrive.....To my mind there's not much left to hold a very soft rubber ring in place. If they turn out to be a fairly hard rubber they may have enough integrity to hold in place....... But that said don't forget, even turning at half crank speed the cams are still fairly whizzing around, and with clearly brutal damage like that (looks like hammer rash from the photo) there could be hidden cracks that may lead to structural failure...... Although you could easily get the cam crack tested, my gut feeling would be to wait until something better comes up and change the cam for an undamaged item...... You have gone to so much trouble getting this engine mechanically and cosmetically perfect it would be a shame to compromise, and it's going to leave a nagging doubt in your mind.

[AshimotoK0]

+1 Roy .. how about a quick call to Newman cams though Dave ?  They must have seen damage like that or broken bits ... bet they have seen CB250/350K and if its any consolation that cam is really rare in decent nick compared with 450 even though they made a million of them.