The International CBX Owners Association

I have a cylinder head I am preparing for use and it has a lot of carbon deposits in the combustion chambers. I was thinking of maybe soaking it in a liquid to remove the stuff. Anybody ever done that? What did you use?
Yes, I know, I can blast it.

Mike,

I never had any luck with chemical cleaners on carbon deposits. I either buffed them off or blasted them off. If you find something that works, let me know.

Cheers, Tom

Same as Tom....

I actually turned the head upside down, with spark plugs installed to close the holes, and poured Chemtool carb cleaner into the combustion chambers. I let it sit for a day and the crud softened up quite a bit and scrapes off easier than before. Not perfect but a step into the right direction.

EMS wrote:I have a cylinder head I am preparing for use and it has a lot of carbon deposits in the combustion chambers. I was thinking of maybe soaking it in a liquid to remove the stuff. Anybody ever done that? What did you use?
Yes, I know, I can blast it.

OK, thread hijack time: I'm having major angst about not popping the top off my engine before I reassemble. PO swears it ran great, didn't smoke or use oil. I'm tempted to pull the head and cylinder to inspect, decarbon, replace valve seals, lap the faces etc, but knowing me, if I do that, it'll be new slugs, rings, 3-angle valve job, yadda yadda, yadda. Somebody talk some sense at me. please. Motor has ~30K miles on it. This is all over my head, I'd have to outsource. Opinions and advice welcome.

N.

Nils, I totally understand your concerns. Once you start digging into something, you will have a hard time stopping before it is getting out of hand. I was at the same crossroads last year with a BMW R100S that had sat for over 12 years. I wanted to pull the heads off to check for corrosion or other potential problems in the cylinders. A friend in the BMW club, an old "Airhead" expert, told me not to worry and just run the bike. I did and it goes like a scalded dog.
Now point well taken, the BMW Boxer heads are coming off much easier than that of a CBX and there is no time really wasted, but....
I face the same decision with the resurrection of the 80 CBX I got during the Winter meeting. But I think I have already decided not to take the head off. In your case, I would trust the previous owner. And 30,000 miles is not really that much...

Nils:
I would leave it as is for now. Do all the cosmetic stuff to the engine you need to, plus the normal tune-up stuff. Do a valve adjustment and make sure the camchain tensioners are free and working correctly. Chances are it will be just fine. I did a rolling chassis '80 a few years ago with unknown mileage and it hadn't ran in 20 years. It ran great. And the engine in the 80,000 mile '80 I did last year needed nothing but a tune-up and some paint. It runs great and uses about a quart of oil in 1000 miles.

Don't worry a thing about the internals of the engine - it will be just fine.

Dave

The only weak areas that I find with older CBX engines are stripped threads because of overtorquing. These are mainly the threads in the cam caps for the valve cover bolts and the threads for the front bolt of the small cam chain tensioner.

Nils -

Put it back together and ride it.

Steve