Topic: Force needed when removing valves (CB550)

[wmajinw]

So I'm rebuilding the top end and when I was removing the valves from the first cylinder, I needed to use some force.

Other valves came out easy and when I tried inserting the into the first cylinder valve place they went in easy.

The valves from the first cylinder were difficult to insert into any other cylinder valve places.

Any easy remedy for this or should i just buy 2 new valves (exh and inl) for the first cylinder?

Any ideas why this happened?

[bryanj]

Either that or top end was mushroomed which means you have reamed out the guides oversize, check for side play with fitting valve, also inspect the guides closely for cracks

[Tracksnblades1]

Either that or top end was mushroomed which means you have reamed out the guides oversize, check for side play with fitting valve, also inspect the guides closely for cracks

+1

Mechanics 101,  remove  and chamfer worn rolled over mushroomed valve tips with a file before removing..especially non-hardened valve stem tips..

^^^^^^^what he said above….new valve guides and valves will bring it back to like new specs anyway. And you won’t be disappointed with it smoking during high intake vacuum conditions…

[wmajinw]

Either that or top end was mushroomed which means you have reamed out the guides oversize, check for side play with fitting valve, also inspect the guides closely for cracks

Possibly this, because the tip of the valve, when inserting, is already getting stuck.

Any tips on replacing valve guides?

[bryanj]

Yup, get a decent, reliable shop to do it as the guides need reaming and seats cutting

[wmajinw]

Once fully inserted the valves do move freely in the intended range (meaning that they open and close with the camshaft movements).

Any serious problems if I leave them just as is?

Don't know any shops around who would take on this kind of work and buying new guides and /or valves will sink me further down the hole.

[Tracksnblades1]

Once fully inserted the valves do move freely in the intended range (meaning that they open and close with the camshaft movements).

Any serious problems if I leave them just as is?

Don't know any shops around who would take on this kind of work and buying new guides and /or valves will sink me further down the hole.

What is your stem to guide clearance where it moves freely?  How does it compare to Honda’s specifications..?

The stem only wears against the guide within the distance the camshaft moves it.. Above or below the wear area should be as assembled. What no one knows is the damage the guides incurred while driving the valves out..?

The down side to excessive stem to guide clearance is blue smoke and short valve job life…

Mike Rieck does performance porting and cylinder head work here.

Cycle Exchange does cylinder head reconditioning stock and performance.

Any machine shop providing service to your local motorcycle dealerships should provide you with competent service..

Why did you disassemble the head in the first place..?

[denward17]

Once fully inserted the valves do move freely in the intended range (meaning that they open and close with the camshaft movements).

Any serious problems if I leave them just as is?

Don't know any shops around who would take on this kind of work and buying new guides and /or valves will sink me further down the hole.

If you tell us what part of the country you are in, some guys might know of a good machine shop.

[wmajinw]

Once fully inserted the valves do move freely in the intended range (meaning that they open and close with the camshaft movements).

Any serious problems if I leave them just as is?

Don't know any shops around who would take on this kind of work and buying new guides and /or valves will sink me further down the hole.

What is your stem to guide clearance where it moves freely?  How does it compare to Honda’s specifications..?

The stem only wears against the guide within the distance the camshaft moves it.. Above or below the wear area should be as assembled. What no one knows is the damage the guides incurred while driving the valves out..?

The down side to excessive stem to guide clearance is blue smoke and short valve job life…

Mike Rieck does performance porting and cylinder head work here.

Cycle Exchange does cylinder head reconditioning stock and performance.

Any machine shop providing service to your local motorcycle dealerships should provide you with competent service..

Why did you disassemble the head in the first place..?

It all started when I removed the engine to paint it. When removing one of the spark plug came out with a bit of thread from the head, so I decided to take a peek at the cylinder so down the rabbit hole I went...

When I say I needed to use some force, it means it was quite hard to remove by hand and it not come out easily or smoothly. I did not use any excessive tool force or hammer.

I'm in Lithuania (Europe) and while there are reputable local machine shops, but they're used to dealing with cars and don't want to get their hands dirty on old bike parts.

I haven't yet checked the valve to guide clearances or if the valves move side to side excessively while in the guides.

I'm thinking maybe if I just use some different grit sand paper to take of a bit of the material on the top of the valve stem, where supposedly it's getting stuck, it would save me some money, provided the guides are in spec.

[wmajinw]

And what is your plan for repairing the plug hole thread? 

I suspect these some crossthreading, because the plug goes in easily until about half of it is screwed in and then it stop.

I'll try to use a tap to fix the thread, if that does not work then I'll look for a helicoil like solution.

[newday777]

And what is your plan for repairing the plug hole thread? 

I suspect these some crossthreading, because the plug goes in easily until about half of it is screwed in and then it stop.

I'll try to use a tap to fix the thread, if that does not work then I'll look for a helicoil like solution.

Using a tap from the outside is not a good plan for stripped spark plug hole threads. You won't get good results. If you are going to try to repair it in place then get a Back Tap.

[MRieck]

I can replace those guides and have them honed and the seats cut. The ports will have to be bead blasted as well. I'm pretty sure I have the OEM iron guides in stock too. I have back tap as well but make no guarantees without having the head in my hands.

[bryanj]

[Take Mikes offer and post it to him, his work is superb

[newday777]

I can replace those guides and have them honed and the seats cut. The ports will have to be bead blasted as well. I'm pretty sure I have the OEM iron guides in stock too. I have back tap as well but make no guarantees without having the head in my hands.

🙏

[wmajinw]

I can replace those guides and have them honed and the seats cut. The ports will have to be bead blasted as well. I'm pretty sure I have the OEM iron guides in stock too. I have back tap as well but make no guarantees without having the head in my hands.

I'd really like to take you on that offer, but the shipping costs and  the hassle woth my local customs when the parts are returned might cost more than the work itself.

If I somehow ruin it further and can't find some local help then I'll get in touch.

[grcamna2]

Either that or top end was mushroomed which means you have reamed out the guides oversize, check for side play with fitting valve, also inspect the guides closely for cracks

+1  you may have mushroomed ends on the tips of those valves;that's the first place to smooth off.

[MRieck]

I can replace those guides and have them honed and the seats cut. The ports will have to be bead blasted as well. I'm pretty sure I have the OEM iron guides in stock too. I have back tap as well but make no guarantees without having the head in my hands.

I'd really like to take you on that offer, but the shipping costs and  the hassle woth my local customs when the parts are returned might cost more than the work itself.

If I somehow ruin it further and can't find some local help then I'll get in touch.

No problem. You may be better off getting another head especially if the spark plug threads are compromised. There is a good chance the guides will be OK and all you will need ate new guide seals and valves. Don't grind the valve faces....you'll be lucky if they last 500 miles if you do.

[Tracksnblades1]

I can replace those guides and have them honed and the seats cut. The ports will have to be bead blasted as well. I'm pretty sure I have the OEM iron guides in stock too. I have back tap as well but make no guarantees without having the head in my hands.

I'd really like to take you on that offer, but the shipping costs and  the hassle woth my local customs when the parts are returned might cost more than the work itself.

If I somehow ruin it further and can't find some local help then I'll get in touch.

No problem. You may be better off getting another head especially if the spark plug threads are compromised. There is a good chance the guides will be OK and all you will need ate new guide seals and valves. Don't grind the valve faces....you'll be lucky if they last 500 miles if you do.

What happens if he doesn’t get all the valves back in their original holes..?

[wmajinw]

So my theory with sandpaper proved to be correct.

I took some 800 grit paper to the valve stem ends and now they're sliding in and out without any problem.

It was either some caked on residue or a bit of rounding at the ends and the fine grit paper fixed that quite well.

[rotortiller]

I took some 800 grit paper to the valve stem ends and now they're sliding in and out without any problem.

It was either some caked on residue or a bit of rounding at the ends and the fine grit paper fixed that quite well.

Good to hear, even with all the generous help here taking the personal approach certainly beat the keyboard diagnosis and saved you a chunk of money! A good lesson for others to try cleaning up parts first and looking closer at the situation.

[wmajinw]

I took some 800 grit paper to the valve stem ends and now they're sliding in and out without any problem.


It was either some caked on residue or a bit of rounding at the ends and the fine grit paper fixed that quite well.

Good to hear, even with all the generous help here taking the personal approach certainly beat the keyboard diagnosis and saved you a chunk of money! A good lesson for others to try cleaning up parts first and looking closer at the situation.

Thanks to all who replied to this thread as all of the advices on here helped me rule out other potential problems.

As the project goes, some other issues start coming around - i.e. when cleaning the head I didn't notice the valve spring seats and now one of the inner ones is missing... Now an evening will be spent trying to fit some random washer as paying 20+ eur for shipping for a part thats 1 eur is something else...