calivette2003

2005 F-12X stock except Mac-boost chip. Been a great, fast, and basically maintenance free craft for years until 2010.

Last year at the lake it acted up, but after a 10 minute cool down, while riding my 650SX, it went away completely (rode for another hour wide-open throttle no problems, now it's back!

First off: just finished yearly maintenance, new plugs, new filters (oil and air), lubed all fittings, emptied and flushed the fuel tank, just put in 91 octane.

Tested on the trailer with cooling hose attached

Tried disconnecting the boost chip, last year at the lake and now, no difference so that's not it.

Idle is normal 1200 (+-100), at 2000-2500 starts to stumble, does not appear to be the motor (hope to God), i.e. no metallic noise when I used my mechanic's stethoscope. Somewhere in the back compartment there is a clunking noise, Had thought the shaft bearing may be bad allowing the impeller to hit the outer ring when the engine torques or spins up but if so why would it do it and then stop and run fine, that makes no sense.
Other thought is the turbo unit, maybe the waste gate or WGS is bad and it bleeds off all pressure. The unit is well preserved, lubed regularly and the waste gate opens/ closes by hand.

So unsure what the hell it is. Problem is it is beyond me to diagnose. And I can't afford to take it to the local dealer, Fun Bike Center, as they charge $200 just to diagnosis it. I just retired from the Navy and am unemployed so that's not an option till I find work.

So I'm going to take it out to the beach and see if the problem persists (I know it will) but better to try and have to spend 4 hours cleaning then a $600.00 bill I CAN'T AFFORD, I can at least enjoy my 650SX.

Any advice would be helpful.

David

jrinjax

I would start off with a new set of plugs and remove the waste gate soleniod.
CAREFULLY unbend the tiny tabs that hold it together and open it. Check and see of it shows obvious corrosion inside of it. There is a quick check without disassembly on PWCTODAY.COM.
The rattling is usually just the necessary slack built into the driveshaft spline and goes away once it is in the water and warmed up. Besure to control corrosion in the engine bay or it will kill your Honda, especially in the salt.

angiegood

Hi David-

It sounds like we have the same issues. I don't have any odd noises. I get all my service done at Motoworld. If you can't figure it out and have to take it in call Brent in the service department. It will run you about $100 to get a diagnosis. I get a pretty good discount with them on parts and labor. If you need to go in there tell Brent you know me and he will extend my discount to you. Hope you find your problem soon

I spent about 900 dollars at FBC on a seadoo boat I have, it turned out to be a $5 dollar sensor but they couldn't figure it out and just kept replacing parts, it was very frustrating.

calivette2003

JRINJAX:23714: Thanks found that thread and printed it out. I have new NGK IR plugs already. Will try the quick blowing into the WGS while off and while running and then from there will take it off and disassemble as necessary, seems this is the Achilles’ heel of these Hondas. Appreciate the feedback!
David

Angie, I actually bought my Honda from ECC back in 2006, I just went to FBC becuase it isn't so far for me (50+ miles). I hope you have found the culprit.

Thanks to both.

calivette2003

Found the WGS for $74 with shipping, will try to fix first but after that I'm ordering.

jrinjax

That is a very good price on the WGS. The salt air is picked up by the turbo's induction and blown into the WGS which bleeds air off of the Waste Gate actuator to build boost pressure.
Some of the salt remains inside the solenoid corroding it. If you fog your engine by spraying fogging oil through a pinpoit straw into the tiny hole [after removing the tiny phillips screw] in the top of the center inlet, it pushes the fogging oil into the WGS. I just periodicly open and clean mine very carefully with CRC 656.

calivette2003

Per chance where exactly is that tiny phillips screw in the "center inlet"?

David

jrinjax

Where the air tube slides on to the center inlet of the turbo's compressor wheel housing, if you look very closely there will be a rusty dot, which is actually a small phillips head screw. Use a jewel's screwdiver to remove it and fog it with engine fogging oil while it is running. It will smoke like a mosquito fogger and shut it off. I bought my fogging oil from Home Depot.

calivette2003

Thanks, appreciate the info.

David

calivette2003

Just finished the ski last night.

1. Was not able to take off the small screw in the compressor inlet, not rusted at all but frozen and stripped so I removed the flex boot and fogged the turbo while running (killed the motor).

2. Moved the WG rod easily, lubricated with CRC-656.

3. Removed the WGS, shot some CRC electronics cleaner thru it. I could not blow thru either WGS hose tees. I also used a vacuum hand pump for this test, outer hose tee held 20" vac., inner tee got to 20' vac. but decreased rapidly. I then re-installed WGS, and with motor running was able to blow thru both solenoid hose tees, the outer hose tee held 20" vac. till I reved over 2000rpm and then the vac. dropped immediately to 0". Inner tee would not hold vac. at all, vac. pump needle bouncing all over the place. So I never took the WGS apart as it passed all your tests, hope this means the WGS is good. SHOULD I BUY A NEW WGS ANYWAY?

Idle is baby smooth now, 1200rpm +- 50. Reved the motor several times (ON A TRAILER w/ flushing water), smooth acceleration up to 6500rpm. Over 6500rpm has a stumble, maybe this is because the motor has no load on it. I do not remember a stumble before, but I'm not sure if I ever exceeded 6000rpm before on a trailer nor it is wise to rev. motor this high without a load on it. (possibly spin a bearing?). So I hope I fixed it.

As always appreciate your advise.

David