Topic: CB550 head questions

[nbcam]

Hey I bought a CB550 cheap off FB and started to work on it, kid I bought it off said he done the head on it. Timing was way off so I had no faith in the work he done so decided to pull the head off the bike.

Here’s what I found


Looks like he took a dermal to the head and the pistons





Just wondering what the best options would be, Is it best get the head surface remachined and the valve seats and seals redone

I did not take the jug and pistons off yet but I’m thinking I will probably want to check these for wear and get new rings and cylinder block honed or rebored.

Is there anyone on this site that provides a service like this and how much would it typically cost if I brought it to a machine shop ?

Thanks


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[dave500]

was it running?

[nbcam]

No it wasn’t running when I got it, that’s why I decided to pull the head off because I didn’t trust what he had done


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[dave500]

it all looks intact,mightve just needed ignition settings going over and carbs sorted?when you say the timing was way off what timing was that?

[nbcam]

The timing was way off when I got it, at TDC per the manual the key on the cam should line up with the face of the head mine was nearly 90 degrees off

I lined up the cam correctly and checked the valve clearance all looked good, cranked it over a few times and was averaging about 90psi on the cylinders

Do you think it would be wise to get the head surface redone or does it cause any issues, just thinking while i have it off would be nice to get pistons and head checked at machine shop


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[dave500]

you sure it wasn't 180 degrees out?if it was it would've been ok,if you had the engine running like you said in an earlier post it would've been fine,id guess you've pulled the head for nothing?

[nbcam]

The bike has never being running while I had it, when I first got the bike I cranked it over by hand. I checked valve clearance and it was off, I also checked the compression and had very little compression across any of the cylinders.

I pulled the valve cover off and noticed at TF1.4 the key on the cam was off, see pic below of approx location marked in red


I lined the cam up correctly and put the cover back on. Checked the valve clearance again and it measured correct for intake and exhaust on each cylinder.

Cranked it over a few times and was averaging about 90 psi across the cylinders, at this point I had no faith in any of the work that was done prior to me so I pulled the head off the bike and was looking for recommendations on the next step I should take ?

To me the surface of the head seems rough, looks like he took a dermal to the head and the top of the pistons


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[Little_Phil]

90 deg off would probably bend the valves at a minimum. As Dave says 180 deg off is ok.

[DaveBarbier]

You could PM MRieck, he’s in Mass and does engine work. And by “does engine work” I mean he’s amazing with these old bikes. My 674cc project was done by him as many other peoples’ bikes on this forum.

I’m with you that I wouldn’t trust the previous owner’s work. But you could check the head on your own with a straight edge and test the valve’s ability to seal. Or bring it to Mike and he’ll get you on the right track. Be careful or you might end up ported and polished.