Power valve flapper removal
 

Hello,
A little bit of history with my 2009 EC300. As temperatures started to get little higher around here I decided to drop down the needle. As I did it, I went for a test ride and the bike was running fine mid and high rev, but poor bottom and idle. It was idling too high, and if left like that for some seconds it would stall. Started fiddling with the air and idle screws but then I noticed the air filter tube (or whatever it is called) was loose from the carburetor and was sucking air. I put it back in place, but it didn't make a difference. I went back to the "original" settings, and still the bike has no low end power and idles like crazy. I know it's a classic lean situation (and the color of the plug proves it), but I just can find a damn air leak!!! Pilot jet is 45, and I ride mainly between 1500 and 3000 feet altitude (500-1000 meters).

Because of all that, I'm going through a full service - repacking the silencer (noticed excessive spoonge, even at its front end), power valve cleaning, reed checking, carb cleaning, etc.

Now, I disassembled the power valve mechanism (getting the flapper pivot rod was such an odyssey!), but the flapper just wouldn't go out of the exhaust port. Is there a special position it should be in? The tech article says only to remove it. The French site http://translate.google.com/translat...staticID%3D133 also doesn't mention anything peculiar, but the SOB just floats there, going about 1/2" out. I swear it's like it's begging me to smack it really good from the inside...

Help and advice much appreciated.

P.S. If I pull the choke the idle gets better, but then the mid and high end power is messed up.

You said it.

You had an air leak. You probably still have an air leak somewhere. Check the carb boot and the rubber joiner between the cylinder and the carb. Try spraying a bit of wd40 around and see if the idle races up higher again.

You also mucked around with the air screw so reset that back at 1/1.5 turns out from closed.

No dirt or crud in the float bowl/pilot jet? Will also cause the lean condition and restrict fuel flow.

(quite possible if you rode through some dirt/dust while you had the air leak on the filter side carb boot).

Back on the power valve I read today to do it with out removing the cylinder you can turn the engine over until the piston is at its lowest. drop the flapper down, turn it sideways, and pull it out through the exhaust port.

flapper does come out through the exhaust port. it takes quite a bit of finagling.

your idling problem seems alot like mine... i just found that my reeds weren't closing fully anymore.
gonna replace the reeds and see then...

Got it out! The key really is to turn is slightly sideways. Thanks for emphasizing on that.

Do you think I can sand blast the parts to get the carbon off them? The thing is like stone, of course, and the wire brush only tickles it.

As for the air leak, reeds seem OK. Looked through them towards the sun, and didn't see any light inside. This is the legitimate test for them, right?

The rubber boot between the carb and cylinder is OK, even though with some surface cracks. Successfully passed a blowing test - pressed it firmly with my palm towards my mouth and blew hard - no leaking.

Has anyone figured a test for the other rubber boot? I have a couple of suspicious points, but haven't been able to verify them. Will start reassembling in the next few days and commence with live tests.

- Sand blasting shouldn't bother the flapper.
- You may be over-tightening the clamps on the carb. boots.
- As mentioned, with the engine idling, spray WD40 or carb. cleaner at seams where there might be a leak. Your idle speed will change if the WD40 is sucked in through the leak.

The boots are dirt cheap, I change them out with a top end and/or reeds. Its the same part that was on the old RAD valves and can be had from Boyesen. They tend to develop fine cracks over time and there have been guys over the years thad had them fail and leak. Another trick: bond the boot to the manifold with Honda grip glue, snug (not too tight) the clamp and you have a very good seal. Now you can't disturb that joint if you wrestle the carb out.

Ether (starting fluid) works real wel for air leaks. Also check your ignition side crank seal.

My PV is usually real clean, but what carbon is there comes off with a wire wheel on a bench grinder after degreasing with contact cleaner. Some guys use oven cleaner with good results, makes sense to me but I never tried it.

Sure sounds like a crank seal to me. Pull the ignition cover, if you see any goop you got a bad seal. While the cover is off, start the bike, pull the choke to bring the RPM's down, and spray carb cleaner behind the fly wheel. if the bike revs up you need a new seal.

Well, crank seal is next on my list if all other checks fail.

By the way, how closed should be the power valve when engine is not running? When disassembling it, I looked through the exhaust port and it was covering no more than 20-30% of the aperture.