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Discussion Starter · #1 ·
Hi all. I started my bike up this evening.... No drama for a minute or two as it burbled away then a nasty noise started up like a hard fluttering sound. This came and went until the bike had warmed up completely at which point the noise disappeared again. I don't have much experience with CXs but I guess this is the cam chain tensioner going west? The bike is one of the late uk models with an auto tensioner so there is nothing externally to adjust.



Am I right in assuming it's now an engine out job and replace the chain etc before something expensive happens?
 

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It could be a number of things

what model, year, milage?

Are you in the UK?

Late UK with auto tensioner ususally means Eurosport or an import

more info would help folk make better guesses
 

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Discussion Starter · #3 ·
Hi, yes I'm in the UK - Stoke on Trent. The bike is an 81 model Eurosport and showing 24500 on the clock but I can't comment on how genuine that figure might be. The previous owner told me the engine had been split recently for a new stator but this was before he purchased it in early 2010. I,ve not had the rocker covers off as there is no tappet noise and whilst I wouldn't say the carbs are perfectly in synch its not running badly. I tried killing the ignition a couple of times and restarting it this evening. Once the noise resarted instantly and once the engine was quiet again for a short period. Revving had the same effect - sometimes the noise went sometimes not.



Cheers



Daz
 

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What model and year of the bike? Alreday asked.
 

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So it is a Euro, thought it might be

Guesses

The noise may be the exhaust, has it a 2-2 ( original) or 2-1 (Motad)?

My Motad often makes odd noises after startup which after I realised what it was I ignored.

I;d check your exhaust is secure and gas tight



If the cam chain tension was at the end of its travel due to worn chain or broken

I think the noise would be constant rather than intermittent and

generally speaking, ir doesnt go away until its fixed.

Ditto broken chain guide.

The noise isnt what I'd call a flutter though, its distinct, mechanical and has been described as a 'machine gun rattle'

I cant recall of the 500 Euro has a mech or electric fan

If its the mech type its worth checking as they can self destruct and have also been known to hit the surround.

I have a 500 Euro motor in my bike but its a bitsa so not much good as an example.

Clutch and transmission rattle is common as well



Its not easy describing noises on a forum or making guesses based on a description

Any chance you could post a vid on youtube?
 

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Discussion Starter · #6 ·
Funny you should mention You Tube - I had a look last night and found a couple of rattly CX posts - mine definitely didn't sound like the ones posted. I've come to work on it today - IPhone at the ready to record the noise. Guess what? yep not a murmur from it today. It ran superb from start to finish. I'll try again later.



By the way it has a pattern collector and Jama silencers which I think are actually designed for the A or B type CX.
 

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Pattern collector?

Do you mean the 'H box' underneath the motor between the pegs?

Possible AHA ! moment here as some of them suffered from poor internal spot welds

on the baffles which caused a cam chain like rattle.

I know a guy in Leigh lancashire and a lass in Shrewsbury who had these problems

with aftermarket H boxes.

Rod in Leigh eventually cut his open and welded them down
 

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interesting thread... I have noticed many many postings regerding mystery noises. As an Audio Engineer, I can promise that the audio on you tube in most cases is not really a good way to Guess judge what is really going on.



One of the least mentioned components in this forum is the exhaust syst. I'll bet more than one CXer is having issues due to a partially obstructed or leaky Exhaust. I pulled an Ex syst from a 78d last week. Maybe a pound or more of rust chips came out of the "power chamber" ( h box)





My left side heat shield is rotting away and at certain speeds began to sound like something way more serious like the fan grenading or the cam chain slapping around.



The noise maker was temporarliy fixed with a foot of bailing wire... a ten second two cent job.





I wonder why Honda calls it a "power chamber"






Edit: one day I'll take the time to spel chek my posts... "regerding"
 

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I've had exactly the same problem with one of my collector boxes.The internal pipes came away e.g the small spot welds at the front inside causing a rattle at Idle.I didn't want to open it up so my solution was pretty easy.I drilled a couple of M6 holes in the top through both the outer wall and the inner pipes.Then bolted a small M6 bolt and nut up to draw the pipes up tight against the upper part of the collector.

Neither one has shown any signs of exhausts leaks but if they did I was just going to put a bit of exhaust putty on them.



HTH
 

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Discussion Starter · #10 ·
Hi all,



Thanks for the input so far.



As requested here is a link to You Tube - http:brum brum clatter clatter clunk



The audio isn't bad - at least not on the IPhone I recorded it on anyway..... you can here the noise pretty well.



As of 12.30am UK time the link isn't live as You Tube are still checking the content for terrorist threats and illegal immigrants




Interesting thoughts on the exhaust system though - mine is kind of a bitsa of aftermarket parts.



Cheers



Daz
 

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Boy that does not sound good. Even when you reved it up it sounded like the chain rubbing. Timming chain. Thats my impression. The tentioner my have gone out. I would say no riding till that is checked out.

Just my thoughts.
Exhaust leak would be the easy fix.
 

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Time to drop the engine and open up the rear.



I cant tell you what it is but I have thoughts. And it involves checking out the cam chain and guides.
 

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good video Daz

hmmm

Really not sure about that intermittent sound.

It might be the cam chain is worn and the tensioner flapping ?

guide broken or breaking up?

possible starter clutch rollers grabbing?

rotor or advance unit loose and dancing about?

As you mentioned in your first post and as others have said

it may be worth playing safe and dropping the motor to check.
 

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Add me to the engine out and open rear up crowd. I can't imagine that being exhaust at all. Sounds like a piece of the guide or tensioner or the like has broken, and is flopping into the chain path intermittently. May not have snapped off all the way and is hanging, tossing about into the chain. Any other of those rear case pieces, such as gear shift bits might be doing the same, such as Reg mentioned. Only way to know will be pop the case.



Lets HOPE you have not chewed the block up too bad. At least the parts are available.



Check your oil for silver shavings, that could lend a thought for chewing of the block casing by the sloppy chain. And photo journal the stuff as you go along.

You will have great support here in getting it back in shape. Nice looking bike by the way. From what I could see.



Good luck!

Joel in the Couve
 

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good video Daz.and a nice looking bike,i agree with the others....that engine could do with coming out.when you do, i think the problem will be obvious
 

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Discussion Starter · #16 ·
Hi all. Well that seems quite conclusive then. I'll attempt an engine drop on Sunday. One thing I picked up from the manual is the need for a Honda tool or " a 20 mm bolt of the correct thread pitch" to get the alternator off. Does anyone know if this is just a standard m20 thread?



Something else the bike did on start up last night - when I hit the starter first time round it didn't engage. The starter just span then sounded as though it was catching against the starter gear as it slowed. I had this once before on a Suzuki Savage 650, that time round it turned out to be 3 broken teeth on the starter ring gear. If that is the case here what would the chances be of a tooth fragment ending up in the stator or around the cam chain guides?
 

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Hi all. Well that seems quite conclusive then. I'll attempt an engine drop on Sunday. One thing I picked up from the manual is the need for a Honda tool or " a 20 mm bolt of the correct thread pitch" to get the alternator off. Does anyone know if this is just a standard m20 thread?



Something else the bike did on start up last night - when I hit the starter first time round it didn't engage. The starter just span then sounded as though it was catching against the starter gear as it slowed. I had this once before on a Suzuki Savage 650, that time round it turned out to be 3 broken teeth on the starter ring gear. If that is the case here what would the chances be of a tooth fragment ending up in the stator or around the cam chain guides?
darren,the bolt you will need is about 2 inches long,20mm by 1.5mm pitch.easy to find in the uk.


here are a few threads,which might help you.

http://choppercharles.com/cs/forums/126066/ShowPost.aspx



http://choppercharles.com/cs/forums/149387/ShowPost.aspx



http://choppercharles.com/cs/forums/154093/ShowPost.aspx

good luck
 

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Something else the bike did on start up last night - when I hit the starter first time round it didn't engage. The starter just span then sounded as though it was catching against the starter gear as it slowed. I had this once before on a Suzuki Savage 650, that time round it turned out to be 3 broken teeth on the starter ring gear. If that is the case here what would the chances be of a tooth fragment ending up in the stator or around the cam chain guides?
darren,i wouldnt pre-empt anything,an hour after getting the engine out,i think it will be obvious.
 

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Just had a listen.I agree with above comments.Engine out job.Most likely cam-chain related.Do now and save the engine.



Plenty of info on what you need to do here,



http://choppercharles.com/cs/forums/126066/ShowPost.aspx



http://choppercharles.com/cs/forums/193248/ShowPost.aspx



More CX/GL engines have been ruined by worn cam chains than by anything else.It's also not a hard job just a little daunting 1st time.You will get plenty of help and support here.Most cam chains seem to last around 50k to 70k but there are reports of them doing 100k.Pre-emptive oil and filter changes and adjusting the tensioner bolt(Manual Cam- chains) go a log way to extending the life of the chains.



The Water pump engine side Oil-seal should be replaced and care taken when re-fitting the rear case so as not to damage it.
 

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Darren

As said, dont be daunted by 'dropping the lump'

One of the reasons I, and I suspect many others, stick with a CX is

they're so easy to work on.



From memory:



Seat off, tank off, put away safe

drain oil and coolant, examine oil and possibly filter for particles

remove exhaust



Disconnect plug leads and electrical connections to engine

Working backwards, remove inlet manifolds ( bolts twist and pull off) then carbs , leave airbox rubbers in place

remove 2 8mm headed bolts at rear of starter

use a screwdriver to gently tease the thing out the case then turn it towards yourelf to remove the

10mm headed nut and cable.



While your there, stick a finger in the hole and try pushing the starter ring about

It should go downwards easily but lock as soon as you try and push it upwards

If it doesnt keep this in mind when its opened up.



PUll the rubber boot back and remove the 12mm headed long bolt that holds the drive shaft in place

then ease the shaft off the motor



SUpport motor, remove bolts and its out !

I find a trollay jack very useful and another pair of hands is nice and probably advised

when dropping and lifting the motor.



Rear cover:

Remove Water pump cover first then impellor

note and keep the small washer under the impellor safe

Remove Pulser cover then advance unit

Pulsers can stay in place



Once you've removed the bolts and cracked the case, open it carefully and dont drag the gearchange shaft

out with the cover, many of us have first time and its better to tap it back in gently as you pull the cover.



Take your time

Stop for tea biscuits, bacon butties etc whenever you feel the need

Take lots of pictures
 
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