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Discussion Starter · #1 ·
Alright, so I've finally decided to try to fix the noise in the engine of my cl350. Ever since i got the bike it had some top end clatter, but i just rode it and said whatever. Now, under a heavy load or whenever lots of torque is needed (like accelerating from a stop going up hill) I get a nasty knock coming from what I'm pretty sure is the top end. Also, the clatter has gotten worse but its still just kinda of af a metalic "******-*****" humming just aubidly beneath the exhaust. I think there might be a slight loss of preformance, but I dunno if its because of this. But before I go tearing the whole thing apart I just wanted to get some opinions on what could be the problem.
 

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my 360 made a clinky clink noise for about 2 miles before the tappet adjuster screw backed out and caught in a valve spring, siezing the engine and bending two intake valves...

I'd stay on top of noises like that

first thing I'd do is check the clearance of your tappets, then take up any slack in the cam chain, and while you're at it, remove the tensioner housing and inspect the rollers, it could also be an exhaust leak, depending on how clinky vs clunky the sound is

how many miles are on the engine?

also, if the sound doesn't go away after doing those operations, I'd pull the right crankcase cover and inspect the oil pump screen, make sure it's not blocked and check to make sure the cam is getting oil by backing out the nut on the left side to the rear of the points cover, if oil is pushed out, then pressure is okay and the noise might be your conrod small end bearings
 

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While these engines tend to be a bit noisy, any extreme clatter should be dealt with before parts are destroyed......Could be anything from loose tappets or camchain to actual cam or rod damage......Only disassembly/physical inspection will tell.....
 

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Discussion Starter · #4 ·
The engine just reached 20,000 miles. I checked the oil filter recently, and I guess the cam chain rollers are probably past their prime. But I'll check all those things and see if anything helps.
 

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Discussion Starter · #5 ·
So I got the engine on the workbench and started to tear it down. I think I found the culprit already. The rocker arm all the way to the right (not sure which valve that controls) wobbles about a millimeter in either direction along the long bolt that holds it. Thing is i just had surgery on my hand so even using a screw driver is hard, but as soon as my hand gets outta this cast I'll see whats going on. Are the rockers positioned with shims or washers or something like that? What do you guys think, this the likely candidate?
 

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Not necessarily.... tappets which are not being acted on by the "bump" of a cam lobe WILL be loose and sloppy......
 

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Discussion Starter · #7 ·
I thought the tappets were not adjustable? But that rocker arm should definitely not be loose like that, right? I'm very new to this so bear with me if these are some noobish questions :roll:
 

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Tappets and rocker arms are essentially two terms for the same part.... They DO have a means of adjustment....some have bolts and locknuts, some ride on excentrics, some use shims and cups..... Check the manual for your bike....
 

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You're talking about a CL350, yes? If so, the rocker arms have a lot of play if the cam lobe isn't bearing on it. In fact, that is how I check to ensure that the valves are closed during an adjustment (cam chain, valve, etc). They really wiggle!
 

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Discussion Starter · #11 ·
Heres the open top. All the other rockers don't have any play, so thats why it seems like this one could be making the noise. Its the one in the back and on the right (in the picture, not relative to placement in the bike) and it wiggles side to side, along the bolt that holds it. I just cranked the engine over, and regardless of where the cam is pushing all the other arms are stable and this one wiggles still.
 

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I had a terrible engine noise in my CB350.

It was a clacking, metallic sound, without rhythym (meaning it wasn't tied to rpm or anything like that.)

Imagine if you put a few large nuts in a tin can, and then shook it.

Turns out the cage on my crankshaft end bearing (ball bearing) was gone into pieces, and all the balls were spinning freely around the bearing. They're not supposed to do that!

71hondacbtwin
 

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Did we run without oil?....What was the cause?.... Got pix?....
 

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Hi
Im no expert with this engine, however it looks reasonably oily, and assuming that there is sufficient oil in the engine, the cams and followers seem in the correct position and there doesn't seem to be any ""blueing or "yellowing" (excess heat) of the bearing surfaces. I would be looking at the cam chain to see it was at the correct tension and tappet clearence. There was a good suggestion to check over the cam chain tensioner to see if it is functioning correctly. If these are good then I guess you might be looking at the small end piston movement.
 

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have you checked the valve adjustments to ensure they are within spec? that's were I'd start. there's nothing obviously wrong i can see from the picture. do the valve adjustment job and let us know what you find.
 

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Discussion Starter · #16 ·
I've been slacking with this whole thing, but I finally got my hand outta the cast, so hopefully I can make some progress now. But I kinda forgot to measure the valves before taking the engine out... :? And I also never got compression readings, just did the thumb method when I was getting it running. But it did usually smoke out the breather pretty good so I just figured the compression is on the low side. Also, it ran low on oil for a short while, but it was changed often and only ran low due to a brief, unchecked leak. The noise distinctively came from the top end, so hopefully the big end bearings are ok. I'm now stuck on the screws holding on the housing for the tach cable and the end of the cam. I tried an impact driver, blow torch, liquid wrench. They are sorta hard to reach and I'm trying really hard to not strip them. Anybody ever encounter this problem or got a good idea how to get them out?
 

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Not to argue with Nigel, but the cam lobes do look "blued' to me...(at least the one to the right of the pic)....It is likely that if the lobes got hot enough to "blue", the cam journals are shot....
 

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66 I too see what you mean there, but I did think that it was the reflection from the casting as there didnt appear to be any apparant wear.
I guess the best thing would be to ask if the bluing is there, or not, as photos can be a little decieving sometimes.
It certainly seems to have a fair covering of oil in the gallery.
Gill over to you my friend.
 

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Nigel, I agree, pix can be deceiving....But it IS the "points' side and that's usually the one that goes bad first...... I guess we'll wait on Gill.....
 

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I have to admit that I do not know this engine so well. Most of my experience is general bike engines and specific to the 450. There are many of you guys out there that are much more familliar with these engines and like you say knowing how the wear starts and where it heats up first.
Also I would have thought that perhaps Gill would have said about bluing when he first looked inside as it would have looked odd.
Hoping that Gill will clear up this and lead us to help put him in the right direction, sort out the noise and get him back riding.
 
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