OK, another 350X question. Sorry

[Hoosier_Daddy]

I took off my head. The cylinder looks great. The piston look great and seems to be tight and in tolerance. I nmeasure the bore and it is still the stock bore and in spech. I don't hink i have a reason to rebuild it. I mainly want to replace all the orings and gaskets from the head on upo including the valve seals.

I didn't have a 12 mil adapter to check compression but it ran strong so i don't think it's a factor.

The only problem I see, may not be a problem. After cleaning all the carbon off the valves, 2 valves have a little bit of pitting on them, the other two are perfect. Is this going to be ok or is this a sign I should replace those valves? Other wise the inside is clean, and stock and in spec. I think it's safe to say, that I'm the first to tear into this far.

Any advice is welcome as always. You guys are the best at giving great advice.

[Macs]

On the valves just regrind the valve surfaces with compound, replace the valve seals etc and throw it back together. why did you take it apart for if it was running good?

[Dirtcrasher]

How exactly did you measure the bore??

I've seen allot of Honda four pokes that look real good inside, but still need rings at the least. Quick, whats the ring end gap, NO CHEATING!! :lol:

[JohnR.]

+1

There is no way to eyeball that sort of thing. At the very least you should have the cylinder honed and install new rings. The machinist you are bringing the head to will be able to tell you what you need as far as the valves go.

John

[Russell 350X]

While you got it apart, you might as well go through, at least put new rings in. Valves don't cost to much for it, might as well get new ones, and seals. What kind of shape is the cam in?

[Hoosier_Daddy]

How exactly did you measure the bore??

I've seen allot of Honda four pokes that look real good inside, but still need rings at the least. Quick, whats the ring end gap, NO CHEATING!! :lol:I took the head off and haven't taken off the cylinder yet. I was considering a ring job. The way I measured was using an inside diameter caliper and it read around 80.54+\- in every area I could reach. So I don't have an answer to the question about ring clearance. I can do that if i pop off the cylinder.

[Hoosier_Daddy]

I can't rememvber the exact number now but according to the manual and my calipers, the cam is spot on in check as well.

[Dirtcrasher]

I took the head off and haven't taken off the cylinder yet. I was considering a ring job. The way I measured was using an inside diameter caliper and it read around 80.54+\- in every area I could reach. So I don't have an answer to the question about ring clearance. I can do that if i pop off the cylinder.

I'm sure you've read where allot of us say that cylinders wear "egg shaped" and dial calipers can only measure the top and bottom so thats a terrible indicator. You'd need an inside telescopic gauge that is accurate and the right size micrometer to measure the mic. I've done lots of machine work and I myself don't dick with it, I take it to the shop. They will measure it in different places and different axis's and figure out whats up.

The cam too, a micrometer is best to measure it...

Dial calipers are a great tool for getting within a couple thousandths of a given size, but operator error plays into that also. Honestly, for most people, dial calipers are good for scribing lines on things before you chop them into pieces on your band saw :lol:

EDIT, and as far as ring end gaps go, what happens when rings are stuffed into different areas of a worn cylinder? Different end gaps...................... Normally end gaps are checked after a fresh bore to ensure there in spec and not too tight. Assembling and aligning those rings correctly is something allot of people do not know how to do either.....

[fabiodriven]

You're probably measuring the ridge above where the rings actually contact (and wear) the cylender hoosier. If you're going to have the thing all apart, at the very least you should hone it and re-ring it. I really can't see why you would tear it all down and not do that.

[smvorndran]

Rob, I've got my telescoping gages & mics at home right now. Seriously, bring over your cam, cylinder, and piston, and let's get it done. Just up from the high school in town, where I've always been. I'm going to hone my cylinder later this week at the shop in Brimfield. Get up with me, as we're doing the same thing on similar top ends. Mefferd is only charging like $10-15 to regrind the valves & seats on the Red. I can kiss in the cylinder and head on a surface grinder if needed. I'm going to grind mine to make them fresh. The head I bought had a small groove in the mating surface, so I'm going to grind it out. Kissing the top of the cylinder off is easier than cleaning off the old gasket, and it makes it shiny! I use sandpaper on a granite plate sometimes too.

smvorndran

[Dirtcrasher]

Should? we grind our valves? I've been told they are coated.....

I get sick of wondering who knows what! Can we lap them or not? Can we grind them or not? I'd think any coating would be toast in short term??!!

Also been told that if they don't leak if you flip it over and fill the dome with gas, don't mess with them. Just make certain the valve guides are good and change the valve seals.

This has ALWAYS worked for me, I'm curious to know what you guys have experienced...........

If I bent a valve, I bought another OEM valve.

WHO has lapped and or ground worn stock Honda valves and still got 25 years out of it??

The manual only shows proper seat grinding.....

[fabiodriven]

Should? we grind our valves? I've been told they are coated.....

I get sick of wondering who knows what! Can we lap them or not? Can we grind them or not? I'd think any coating would be toast in short term??!!

The manual only shows proper seat grinding.....

If you really want an answer, DC, I've got a couple guys I can ask.

[Hoosier_Daddy]

If you really want an answer, DC, I've got a couple guys I can ask.

If you could get na answer, I'm just as interested in it as DC.


Scott, when you taking your cylinder in for a hone? You still at B&J?

[smvorndran]

Yes, I am. I'll probably do it it Thursday after work. I've lapped quite a few valves on Hondas to bring the compression back. This Big Red top end I received had a few small pits in the seat that wouldn't have been lapped out, so the shop is grinding the valves & seats, then I'll give them a final lap. As for 25 years more service, I can't attest to that, because I'm only 32, and I wasn't lapping valves at 7.:lol: :lol: :lol:

smvorndran

[fabiodriven]

OK, I sent the question to the expert. I'll be home at 4:30 and I'll see if he wrote me back.

[Dirtcrasher]

^ thanks bud....

I'm sure grinding and lapping them does help them seat, I just wonder if it cuts the lifespan.

[fabiodriven]

OK, I got this from one of the smartest guys I know. He did motorcycle machining, boring, sleeving, and just about any other kind of work on motorcycles, dirtbikes, and ATV's out of his own shop for years (Wright Machine- Superior Sleeving).

John,
I've always used light or med grit valve grinding compound to get the valves to seat properly. Regrinding the valves is right out!!

Here's what Honda has to say...

INTAKE AND EXHAUST VALVE REFACING - NOT RECOMMENDED

The intake and exhaust valves in some Honda engines have a bimetal head and stem. A hard stellite facing is welded to the valve face and the end of the valve stem to provide a long wearing surface. This hard surface is thin and can be destroyed if the valves are ground. If a valve is burnt, warped, or worn excessively, replace the valve; do not attempt regrinding the valve face or stem.

On the other hand, the intake and exhaust valve seats in the cylinder head can be recut as often as necessary, provided the valve seat still makes contact with the center of the valve face. Refer to the applicable shop manual for valve seat width specifications.

When installing a new valve in a used cylinder head, the valve seat should be recut and the valve lapped to the seat, to obtain a perfect seal.

AMERICAN HONDA MOTOR CO., INC.
9-725 Motorcycle Service Department

[Hoosier_Daddy]

Forgive my ignorance but i read a lot about lapping valves. Waht does that mean?

[fabiodriven]

I think you put the valve in the seat along with some compound on the face where it contacts, and spin it back and forth with a little suction-cup looking doo-hickey.

[smvorndran]

I agree with Fabiodriven in post 17. My seats were pitted, not the valves, so I'm not sure what the shop will do to them. I'm not worried if they do kiss in my valves though. Both my valves had thick heads on them. I don't think Honda welded the valves though. If anything, they hard-coat the valves with a surface treatment, usually by heat or cryogenics.

smvorndran

[The Goat]

hmmmm... got the old wheels turning. how are these valves cut? I'm confused.

and if running a retardedly high lift cam... what do try cut and how?

[smvorndran]

what do try cut and how?

WHAT?

smvorndran

[The Goat]

lol iPhone keyboard while driving and not looking.

I meant... when running a high lift cam... many times I see "requires shortened something..."

what are they shortening, the guides? if so... are they just cutting and removing burs?

[SWIGIN]

for some high lift cams the retainer will hit the guide.....so you shorten them how ever much you need for clearence.

i'v done this in the past and its simple to do and figure out.