Honda Twins banner

1 - 13 of 13 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Hi everyone, thanks for looking.

I have a 1984 Honda CM450E that I bought with 39,xxx km on it and have put 12,000 km on it since. It's hardly needed anything in the way of maintenance. So far I've put a new rear tire on it, done 5 or 6 oil changes, changed out the plugs, new air filter, new exhaust, put a new valve cover gasket in, and adjusted the valves 3 or 4 times. She's been great with very little problems so far.

Fast forward to the last time I checked and set the valves: I had a tapping noise in the head, that after adjustment had gone away. A few days later, the noise was back. Fearing that I hadn't set the valves quite right (despite triple checking the clearances), I pulled the valve cover off, and it was immediately apparent that my right side exhaust valve lash clearance was too loose. Weird, I thought, but perhaps I hadn't tightened the locknut quite snug when I set them. So I set the clearance, checked it and all the others again, and threw the cover back on. The bike sounded much better.

~2200 km later, the noise was back. I pulled the valve cover off, and no surprise, it was immediately apparent that the right side exhaust valve lash was the source of the noise. It is supposed to be set at 0.006 in (0.14mm), and it was easily twice that. So, I set it to the appropriate clearance, and threw her all back together.

Looking at the factory service manual, it says I should be inspecting and adjusting the valve clearances every 6,400km. Now, I do ride daily, commuting as well as pleasure cruises, in dusty areas and the occasional downpour. The service manual mentions that in these conditions you should service more frequently, but I feel that 2,500km is still likely too frequent... Am I correct in assuming this?

After talking to a few friends and shop gurus, a few things have been said that trouble me. Unfortunately, most of them were a little over my head and I can't quite remember the ins and outs of what was said. One person mentioned that the valve might be "burying" itself in the seat (told me to look for a new head for the bike), another person mentioned the possibility of the valve stem stretching, another still mentioned something about my valve keepers falling and dropping the valve into the cylinder... I don't know what to think however. There is no noticable loss of power in the bike.

I'm really hoping you guys have the insight to help me out on this one. Has anybody else had to adjust their valves (or one specifically) far too frequently? What could possibly be going wrong, and how can I identify the problem? I've never done more than oil changes, chain maintenance and valve lash adjustment, so I'm not mechanically adept but I'm certainly inclined.

Thanks in advance, and let me know if there's any more info I can provide!
 

·
Registered
Joined
·
9,796 Posts
Welcome to the forum. Great to see another 400 series here. Got any pics of it?
Have a look at your right exhaust cam lobe. It sounds like it is worn past the hardening and needs a new camshaft and rocker arm.
PM sent for manual.
 

·
Premium Member
Joined
·
24,208 Posts
I agree with Dan, cam/rocker wear since the clearance is increasing. The other scenarios mentioned would result in the clearances tightening.
I do my valves at @10K mile intervals. Yeah Honda says more frequent and even more so under adverse conditions. Really though adverse conditions like dust and rain have no bearing on the internals of the engine.
My adjustment intervals are based on the modified valve train oiling in my engine though.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #4 ·
Hey Dan and Jim, thanks for the warm welcome and quick replys! Working on getting some pictures of the bike, should have them uploaded later today or tomorrow.

So I opened the valve cover up again yesterday after reading your posts, thinking I would be able to visibly see wear on the cam lobe (lol), and then after reading the relevant section of my manual, realised that we're talking thousands of an inch difference between a good cam and a bad cam... There's no marks or pitting or anything like that that I could really see. However after looking at the valve train and thinking about it I definitely agree with you guys, I can't see any other way that clearance would be INCREASING instead of decreasing.

Just to rule something out, I removed, inspected, and swapped the adjusting screw an locknut with the one on the other exhaust valve. Both look a little beat up where they make contact, but they are worn evenly. So I'll take a look in another 100km or so to see if the right side is still a problem.

So, more questions.

I'm actively looking for a new (used) camshaft, which I'll probably have to source out online. Any tips on not buying one in the same (or worse) shape mine is in?

Thinking about it, am I in danger of damaging the bike at all if I keep running it? From what I can tell the valve will only be opening later and less in the cycle, so I shouldn't have to worry about the valve making contact with the piston or anything, right?

My major concern, however, is WHY the cam lobe has worn so much (and continues to wear). It strikes me that 50,000km seems awful early for a replacement of a major engine part. Is this normal wear and tear?

Thanks so much for your help guys. Wonderful community you've got going!

Cheers,

James
 

·
Premium Member
Joined
·
24,208 Posts
The cam. rockers and adjustment screws all can be wearing, may be a combination or just one. Cam wear is first seen on the toe area, the highest end. The rocker pads should have a gentle convex curve to them, not flat or concave as well as being perfectly smooth. The adjuster screws should have a smooth surface that will have shiny lines on it showing a slight wear pattern. The right screw in this is ruined and the other 2 were worn enough I replaced them
201_4493.JPG
Can't find any rocker pad pictures but this is what a good used cam looks like 201_4552.JPG
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #6 · (Edited)
Thanks for the help Jim, I appreciate those pictures you took! Sorry for the lack of pictures of my bike, I've had some family in town and it's been a very busy week. I'll get around to uploading them this evening or tomorrow, I promise!

I found this camshaft on eBay, but it has some pitting, does it look worth picking up?

I've also sourced out a couple of CM400 engines locally, are the camshafts and rockers interchangeable between the CM400s and the CM450s?

I've put a couple of hundred km on my bike since swapping the adjusting screws for the exhaust valves, and it's a little hard to say but honestly I think the tapping is back, and after less than 300km, it sounds like I have to adjust the valves again... I was planning on heading on a road trip this coming weekend, about 700km round trip, but now I'm really having second thoughts.

What could possibly be causing only the cam lobe and rocker arm on the right exhaust valve to be wearing so fast?? Could it be from idling on the side stand?

edit: I also bought a micrometer today, so I plan on pulling the camshaft and rockers out and measuring them whenever I have time, hopefully an evening this week.

Cheers,
James
 

·
Premium Member
Joined
·
24,208 Posts
That cam is junk. You can use any manual transmission cam 1978 through 86 400 or 450. They are all the same.Rocker are 450 only items
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #8 ·
Yeah I figured as such, it looks pretty gross. Thanks for the tip. Are you sure about the rocker arm being a 450 only part? Partzilla lists 14430-413-830 as for both the CM400s and CM450s... (and to my surprise a couple of CBs in there as well)
 

·
Premium Member
Joined
·
24,208 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #10 · (Edited)
Sorry, I'm a little confused by that last post. So 14430-413-830 isn't the rocker I'm looking for, you're saying I should be after 14430-413-315? Or are you saying that 14430-413-315 is for the 400s only?
 

·
Premium Member
Joined
·
24,208 Posts
That number is superseded to the 315 number but no worry there since the part will come from Honda and it'll automatically be supered over to the latest greatest one.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #12 · (Edited)
Ohhhh ok I think I'm getting it now. So wether I ask for an 830 or a 315, I'll get a 315, and the 315 takes the place of several different unique rockers?
 

·
Premium Member
Joined
·
24,208 Posts
Close, it's just a new number reflecting a design or material or manufacturer change of the original design.
The part is listed a NLA thru US Honda and I checked a major source in the UK also that shows NLA. You can contact your local Honda dealer and ask them to do a nationwide parts search of dealers and possibly there'll be one that has it sitting on the shelf somewhere. Be aware that the list price on these things no longer applies in this case and the price is whatever it is.
However now that you know the engine it applies to you can expand your search for a good used one. Left and right are the same part.
You will find the part listed as available through different sites, call them first before ordering to verify because many times it's old information and after they charge you they inform you it's NLA and it takes a week or more for the charge to be reversed.
 
1 - 13 of 13 Posts
Top