RD04 Rattle - the video !!

[c13tay]

Following on from my thread I think ive got as far as I can with trying to describe the rattle / tick or whatever you want to call it !!

so , here is a video

http://www.youtube.com/v/KQihbCbAZsc

[jochembele]

Wow, strange. It runs smoothly on idle! A lot nicer than mine.
Does the ticking begin at a certain rev everytime?
Someone should be able to tell you what it is.. I wouldn´t give it away for that..

[c13tay]

Yes its very strange

Tickover is perfect.

The noise starts very quietly at around 2300 revs then gets louder, peaking at about 3500 revs

Still cant identify exactly where it is coming from but think its top end


Chris

[africajim]

Sounds very much like a camchain not tensioned. Either the camchain tensioner is worn or shot or the camchain has stretched over the limit of the tensioner?

Answer? Simple, remove tank, remove cylinder head covers, check valves, tappets and camshaft for any signs of wear, remove camchain and tensioners and replace any worn parts.

Ok, easier said than done but it can be done following the workshop manual in a couple of evenings or a weekend.

I'm sure someone else will come along with their diagnosis and between mine and other opinions you'll single out the problem. Best of luck!

[c13tay]

Thanks for the reply

I initially thought that but was put off the scent by my local Honda dealer saying "its not cam chain related or it would do it on tick over and when coming off throttle"

[Zenarchy]

I'm not really very experienced mechanically, so this could well be way off the mark, but have you checked the exhaust, and also the seal around the area where the shiny part of the can cover joins the black part of the can underneath.

I noticed mine (also an rd04) was making a bit of a noise kind of like that (not exactly but a similar sort of pingy sound like it was tied to the revs), and it turned out to be the exhaust blowing very slightly (almost imperceptibly) from where the shiny metal cover joins the exhaust underneath (you know the shiny metal plate under the heat guard). I stuck some putty stuff in it along the edge and it sorted it. I could have sworn the noise was coming from the engine itself, but I don't think it was as after sealing the exhaust it stopped completely. My guess was that it was a sort of high pitched whistling blowing on each cycle of the engine through the can in some tiny little hole somewhere, giving the impression that it was the engine itself.

Just a wild guess, but perhaps this might explain why it's only happening when revved (pressure increasing in the exhaust), and why it gets louder as you rev up higher, then tails off after a while (as the pressure changes).

[fergus1964]

on the video it sounds like a spark jumping an air gap - try disconnecting one coil, in turn on each cylinder, and see if that makes a difference, or hold the spark plug cap a short distance from the plug, and see if the clicking is in time with the noise

[Steve T]

. . . says the wife!!!

SWMBO says it sounds like a tappet - she has been know to be right about these things

[BobA]

Yeah, strange.

Out of interest, have you tried a compression test? That would certainly prove a busted or sticky ring, and would also possibly highlight a valve problem (burnt out and not seating correctly)

A visual inspection of the valvegear would also be worth it, perhaps even taking the plugs out and cranking the engine as well to see if any foreign objects get spat out.

Failing that, it could possibly be a small end bearing, which is actually much preferable and cheaper to rectify than a problem in the bottom end.



Bob

[c13tay]

Well to try to answer a few of those

Exhaust - well the neighbours were happy - I ran the bike without exhaust - still rattles

Tappets - have adjusted these about 4 times now - im a bit of a muppet with a spanner so not sure if I did it right but didnt seem to make any difference - at one point though the noise had changed but that may have just been wishful thinking !!

Not done a compression test yet but poured a load of redex down the plug holes the other night. Put a rag over hole hand cranked the engine - it nearly blew my hand off !!! and covered everything in redex !!

Im off to Japan on Saturday for a week and think a week away from the bloody thing will do me good.


BobA - What is involved in repairing/relacing small end bearings ?? thought that was pretty terminal / un-ecconomical repair ??