Power valve end play, side to side movement, rattle...
 

Hi all

I recently bought a well used 2004 EC300. The engine seems to be in good condition. It was running a bit rough but after adjusting the carb it's running sweet now.

My last remaining issue is a terrible rattle, it's very noticeable on overrun, for example rolling down a steep bank with the throttle shut.

I removed the left and right power valve covers and also the exhaust. The power valve seems to be well adjusted, it sits against the closed stop and has no slack in the mechanism.

I stuck my fingers up the exhaust port, I could feel a lot of side to side play/movement of the power valve. When I move it left/right I also hear the horrible rattle that I hear on overrun.

Questions:

1. Is there anyway to remove the sideways movement of the power valve (possibly with shims?) and thus reduce or eliminate the horrible rattle noise that I have?

2. Is it possible to remove the power valve unit without removing the cylinder head/barrel from the engine?

Thanks and best regards, Dave.

Yes, you can remove the power valve without removing the cylinder. You will need to remove both PV side covers and get the piston at BDC. It should come out the exhaust port. I would remove the head so you can push the flap out.

Not sure about 2004, but on my 2014 i removed most of the side to side movement by pressing the left hand side bearings in a bit more (just a tad, maybe less than 1mm, if i press them more the PV get's stuck probably on the left exhaust valve).

p.s. Did you check the rocker arm on the right side or the bell crank hitting the case ? It's pretty common for them to bang on the cylinder or case, to check remove the right side PV cover, put the pipe back in, start the bike and rev it a tad, you will see the rocker arm moving and rattling, make sure it's not banging on the cylinder (if it's banging on the case, you should see marks on the case, you have to drain the coolant, the case oil can stay in just lean the bike on the left side when removing the case cover). Here is a video on youtube that helped me out a lot in removing most of my rattles at high rpms https://www.youtube.com/watch?v=dI0fUUHaDjQ

you sure it is not the exhaust o-rings that are worn?

My experience has been that they are just noisy old 2 strokes. The pipes can rattle against the spigot, against the mounts if not aligned correctly. The rads/braces can vibe up against thing. Plastics can clatter. Bash plates will rattle. Everything is always way more evident on decel because:
a) the exhaust isn't making any noise to cover it up, and
b) as the revs fall it always goes through the range where the crank is least balanced. This increases the vibes, felt, heard, etc. Under throttle you tend to have a load on the piston and also move through this area faster.. Find it and hold a steady throttle and it'll buzz away through the bars and pegs more than most would enjoy.

Thanks for the advice and suggestions.

I'm a bit busy at the moment but as soon as I've investigated it more I'll post feedback.

All the best, Dave.

Fixed!
 

Finally had time to look at the exhaust power valve today.

I removed the left hand side power valve cover. I pushed the power valve bearings all the way in and then, using my digital caliper, measured the gap to the retaining washer, or rather the face that the retaining washer sits on. It was 1.8mm.

Luckily, I found a suitable washer 1.6mm thick. I placed the washer between the inner bearing and the part that pivots and turns the power valve. Thus leaving 0.2mm clearance to avoid jamming the system.

It worked great, the rattle has gone. Just been for an 60 minute ride and all is fine. :)

I think this is self explanatory, but if anyone needs to see a photo then just ask.

All the best, Dave.

Power Valve photos
 

Hey Dave,

I think I am experiencing the same issue with my EC300 2014.

Looks like the spacing washer has worked for you!

Do you have any photos to show your success?!?!

Regards
Liam.

Hi Liam, I'm sorry I don't have any photos. My bike's at my house in France but I'm over in the UK at the moment.

All the best, Dave.

I appreciate this is an old thread but can I just confirm that the original poster has inserted an extra washer/shim alongside the one shown by the arrow?
(or was his missing and he replaced it?)




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