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Discussion Starter · #1 ·
I am reposting some stuff from the MSN group here so we don't loose it forever.

From: bobm (Original Message) Sent: 1/18/2008 10:45 AM
I am in the process of tuning a '73 CB 450. Starting with the valves, I have not been able to find a .0012 feeler gauge in any auto shop. The best any of them can do is .0015. Any thoughts on where to get one?
Thanks.


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Recommend Message 2 of 7 in Discussion
From: MSN Nicknamestillstanding462 Sent: 1/18/2008 10:59 AM
I'll probably get flamed for this, but I always use a tight .002 on these bikes.
I don't think.0012 is even achievable for most of us, and a tight .002 seems to yield no more noise or wear.

bill

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Recommend Message 3 of 7 in Discussion
From: MSN Nicknameoldcycle Sent: 1/19/2008 2:17 AM
0.03mm Starrett feeler gage is available at the link below for about $4.00.

http://www.use-enco.com/CGI/INSRIT?PMAKA=990-2365

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Recommend Message 4 of 7 in Discussion
From: MSN Nicknameelvis__evans Sent: 1/20/2008 11:44 AM
I've always used 0.0015". It's close enough. Elvis

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Recommend Message 5 of 7 in Discussion
From: aries_58 Sent: 2/7/2008 9:20 PM
Don't know if this will help at all. Wish I could say I have tried it but my bike started acting funny so I never got the chance. I found this on a website and it sound like it might work.


The old Honda 350 and 450cc twins had what are called eccentric rocker arm shafts. That is, the center of the shaft is ground off center so that as you turn it, the rocker arm that rides on it, moves back and forth. This increases and decreases the valve clearance. If you adjust the valves on these engines the regular way with a feeler gauge you will be ok But, there is a better way.

Start and warm the engine up enough so that it idles good. Loosen each valve adjuster lock nut and turn the adjuster shaft with a screw driver. The valve will get noisy and the engine RPM will go up. You want the highest engine RPM with the lowest tappet noise. Do this on each valve. You will notice that the engine RPMs go way up. Sometimes as much as 1000 to 1500 RPM gain. Now back the idle down with the throttle stop screws and do it again. We want the highest RPMs and the least tappet noise, with the emphasis on the RPM. Yes, they will be noisy but, where do you think that RPM is coming from ? Stock clearance too tight ? I learned this trick from a factory mechanic when I worked in a Honda shop in 1968. I have never heard of it from any other source. It works though. I've used it on a lot of 350s/450s with no ill effects.

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Recommend Message 6 of 7 in Discussion
From: MSN Nicknamestillstanding462 Sent: 2/7/2008 10:07 PM
I'm sorry, but never, EVER do this on a 450.
Works OK with a 350, but not a 450 - you'll toast your followers and cams.
We did it on 350's all the time back in The Day, but I've seen the results on a 450, not pretty.

In point of fact, tight intakes on a 450 will cause uncontrollable reving - I've seen it more than once.

bill

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Recommend Message 7 of 7 in Discussion
From: MSN Nicknamehonda3370 Sent: 2/8/2008 12:14 AM
I agree with Bill Lane, his suggestion is valid,when you give the rocker & cam lobe more room, there is MUCH better oil flow between the too. I have been using 004 on the intakes and 005 on the exhaust, for 14 years now, always trying to get better oil flow thru these motors, and if you think the motor is making noise, you can always tighten them up, nothing will be hurt by trying it. I never have been able to figure out why Honda made the clearance so tight ( that would be a good subject of discussion on the site ). maybe someone out there knows for sure ...with out guessing.
 

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honda3370 is the name Terry Naughton of Team Hansen uses at the 450 Forum.......
Listen to him, he knows as much about 450's as anyone still alive.
 

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Is there a "simply stated" step by step valve adjustment procedure for a CL450 K1. I have the Honda Service manual, but I'm hoping there's an easier to understand way to do it.
I'm under the impression that the bike was adjusted last using the "warm" method that is only supposed to be used on 350's and I want to do it the right way asap.

Thanks for your help.
Bob
 

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Flugtechnik, The messages at the MSN CB450Dohc forum will not be lost forever.

I have been downloading and indexing all of the tech messages (and most of the general messages) from MSN forum since it was announced that they would be shutting down the forum in February.

You can find these messages at : http://www.cdacycle.com/cb450forumsrch.aspx

This CDACycle.com site was updated today, and is scheduled to reindex this evening, so all recent messages will be searchable by tomorrow.

In February, when the MSN site ceases to exist, I will be giving our moderator Bill (tbpmusic) a copy of all messages that were posted on the MSN forum since it was started in 2003. I will also provide the MSN Moderator - Jordan (Polishbeer) with a copy should he decide to move the forum to another site. However, I have no plans on shutting down the index at CDACycle.com, at least until Bill or Jordan have a suitable alternative in place.

Later,
Ted
 

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bobelliot said:
Is there a "simply stated" step by step valve adjustment procedure for a CL450 K1. I have the Honda Service manual, but I'm hoping there's an easier to understand way to do it.
I'm under the impression that the bike was adjusted last using the "warm" method that is only supposed to be used on 350's and I want to do it the right way asap.

Thanks for your help.
Bob
Never, EVER, use the "set the valves by ear" method on a 450.
It's only acceptable on a 350, and only then if you're very experienced.

Do it with a stone cold engine.
First set the cam chain adjuster, as outlined in the manual.

Bring the left side to TDC compression stroke, line up the "LT" mark and hold it there (kind of a feat in itself).
Adjust both left side valves to 0.002". Adjusters should make the valves tighter when rotated away from the head (meaning turned towards the front on the exhaust, or towards the rear on the intakes).

Do not attempt to set them to 0.0012" like the book says, you'll never make it and there's a real danger of getting them too tight. Tight intake valves will cause an uncontollable high idle, and tight valves in general will toast your top end parts.

Turn the engine 180 degrees to TDC compression stroke on the right side, line up the "T" mark, and set the right side valves to 0.002".

The adjusters may try to move on you when you tighten the nut down, so double-check after locking them down.

That's all there is to it.
 

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Discussion Starter · #6 ·
Thanks Ted! I was not aware of your work. These were just a few of the threads I've found very helpful as I tune my bike and thought they should be posted here.

Bob,
It is pretty much as simple as Bill says. The smallest feeler gauge I could find anyway was 0.002". The hardest part for me was getting the covers off. Especially the intake side as the lower screws will hit the top of the carbs. I also tried to hold the adjusting screw in position as I tightened the nut since tightening it moves the adjusting screw. It took a couple tries for each one to get it right.
 

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Well, they do give you 0.0012" feelers in the little Honda tool kit that comes with the bike.
They're like tinfoil, they last about one or two valves - and that gap is totally unreasonable for normal humans to achieve. I've done it a zillion times, and I'm not comfortable with it.
I just use 0.002", no noticable increase in noise or wear. I use precision "shim stock", I get it in 25' rolls, because even 0.002" feelers don't last long. I just cut off a new piece whenever I need to. I get it in 0.002", 0.003", and 0.004" to do most Hondas out there.
Like Terry mentioned, he regularly goes to 4 or 5 thousandths on his 450's.
 

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Just to add all the possibilities I will post this --- but hasten to add I have used it only two or three times when in a corner. Usually I use the Honda workshop manual method but with a .0015 feeler.
With the covers removed tighten the gap till it is no longer possible to move the cam follower from side to side then increase the gap till the follower will slide from side to side freely but with no appreciable up and down movement. Tighten the cam adjustment nut and check to make sure it has not moved and you are done.
 

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Just so that all possibilities are considered I will post this --- but hasten to add I have used it only two or three times when it was not feasible to do it by the book.

Normally I use the Honda workshop manual method but with a .0015 feeler.

With the covers removed tighten the gap till it is no longer possible to move the cam follower from side to side then increase the gap till the follower will slide from side to side freely but with no appreciable up and down movement. Tighten the cam adjustment nut and check to make sure it has not moved and you are done.

I suggest that when Mr Honda says .0012" (.003mm) he means zero clearance ie. the cam follower is not touching the cam but there is no appreciable gap -- WHEN COLD. When the motor warms up the clearances increase to what Mr Honda considers optimum.
 

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Rich Ard said:
Would like to suggest this be made a sticky or be rewritten as one. If the latter is the way to go I'll happily take care of that, pending an expert's proofreading. :)
Good idea Rich, if you'd like to rewrite it in a concise format that includes all the main points of this thread that would be great. Once you're done, create a new post and I'll make it a sticky. Feel free to bounce your version off some of the forum experts for a proofread. Let me or any of the moderators know when its done so we can sticky it. Thanks.
 
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