Pulled heads off my 1100 and surprise

[JSBail]

When I first got my 83 interstate it was locked up due to previous owner letting it set outside for too long. I was all set to tear it down but decided to see if i could break it loose and get it running before throwing too much money at it. To make a long story short I got it free but initial compression readings were of course dismal as in below 100 psi and it did smoke but the more it ran and the more I rode it the less it smoked to the point it doesn't smoke at all. That was about 15k miles ago and my curiosity got the better of me so I pulled the heads today to see what shape the cyl bores were in, besides I've been wanting to replace the head gaskets anyhow. Before pulling the heads I checked compression on all 4 cyls and had a high of 140, a couple other cyls had 130 and the last one had 125. Nothing outstanding but considering what those cyls had after I initially got it broke free I can't complain. The surprise was that only one cyl had evidence of rust pitting but what really stunned me was guess what compression that cyl had when I did the compression test? It was the #4 cyl and it's the one that had the highest compression yet was the only cyl that showed signs of rust damage. It was the first cyl I saw so I figured if that cyl had the highest comp and showed rust pitting then the other 3 must be even worse but nope the bores of the other 3 looked really good. I don't know how well the pic shows it but the pitting is down at the bottom of the bore just above the piston.

I've pulled the left cyl head apart and valves and seats do show some pitting but just how bad it is will have to wait while I clean the head and valves up and see how the pitting cleans up when I lap the valves. Wish me luck

[pidjones]

Don't lap the seats! The valves are stellite faced and you destroy it. You can have the seats ground and put in new valves (actually, they are pretty cheap). Valves are most likely your problem.

[JSBail]

Now that i have the left cyl head and valves cleaned up a bit and can take a closer look the valves do show pitting, nothing major however it's fair to assume that by the time it would take me to lap those pits out I would be taking the hard surface coating away in the process so new valves may be in order. I've been suspicious of the valves for some time, the reason is because when I first got the engine running I set the valve lash and was stunned to find all the valves had about twice the amount of lash they should've. I initially assumed the previous owner never bothered with them so I set them all to factory spec. About 3k miles later I checked them again and found I had zero lash. I'm very careful when setting valve lash so I was confused at how after 3k miles the valves had less lash than when I had set it. The only reasonable answer I could come up with was that the valves had crud or rust between the valve face and seat which wouldn't allow the valves to fully seat making it seem like it had way too much lash at the stem so after i set the lash and rode it for some miles that crud in between loosened up and thus closed up the lash I had set. With that said the pitting that I'm seeing now is actually what I was expecting to see.

[robin1731]

Don't lap the seats! The valves are stellite faced and you destroy it. You can have the seats ground and put in new valves (actually, they are pretty cheap). Valves are most likely your problem.

No, lapping the valves is fine. No way will you remove the coating just by lapping. I always grind the seats and clean the valves.

You can grind/cut the seats. You can lap the valves. You should not grind the valve face.

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[77Gowing]

No, lapping the valves is fine. No way will you remove the coating just by lapping. I always grind the seats and clean the valves.

You can grind/cut the seats. You can lap the valves. You should not grind the valve face.

.

Good to know

[JSBail]

No, lapping the valves is fine. No way will you remove the coating just by lapping. I always grind the seats and clean the valves.

You can grind/cut the seats. You can lap the valves. You should not grind the valve face.

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That's the rule of thumb I've gone by as well, I've lapped motorcycle valves before with no issues. The only time I had to replace the valves was on my cb750 but that had to do with the top of the valve stems being slightly indented by the lash screws which prevented me from setting lash correctly. Luckily I kept the old valves because I later found out those indentations can be ground away and lash caps put in to make up the difference and that's a good thing because 77 cb750 F2 valves aren't as easy to come by as earlier 750 valves are. So far it seems the valves on the 1100 aren't nearly as bad as I first suspected, I went ahead and lapped the valves on the left cyl head and the faces of the valves and the seats cleaned up nicely without much effort.

[JamesPal]

Stellite coating is a weld process. It has been around for a long time, WW1 or so. People say the same thing about the CB450 valves, "they are Stellite coated, don't grind the faces! You will be sorry!" Valves for the old DOHC engines are a little harder to come by the the GL valves. I know a guy who actually had CB450 valves made and uses them exclusively for his rebuilds.
When I did the 450 my machinist said my valves had been lapped a lot. There were groves in the faces. He went ahead and ground them just to see if they would clean up without going through the Stellite. They did clean up and they have about 2500 miles on them and the bike runs great. As long as there are valves available at a reasonable price, replacing them would be the best. This is what Honda put in the CB450 Factory Shop Manual:

Stelite CB450 Valve jpg.jpg (53.77 KiB) Viewed 390 times

[robin1731]

There have been guys even on here that said they did grind the valves. They said they did not have an issue. Who knows how long though they ran the engine after that. Be interesting to see the results after 50,000 miles or more.

I will say if anyone lapped the valves so much that they put grooves in them they should never have touched that engine/head. Can't imagine how long that would take lapping valves by hand.

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[robin1731]

Getting valves for any engine is not really that hard. There are companies that make valves with all kinds of dimensions. I buy blank valves to do race engines. They then need the face machined down to the size I need. Also the length needs to determined and then they are cut down. Then the keeper grooves are machined in to them.

Engines that use rocker arms directly on the valve then either need to be hardened on the end of the stem or you have to use valve lash caps.

All of that works gets expensive and time consuming. But the option is out there.

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[JSBail]

I will say if anyone lapped the valves so much that they put grooves in them they should never have touched that engine/head. Can't imagine how long that would take lapping valves by hand.

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Agreed, If the valves were pitted enough that I knew I'd end up with grooved faces trying to lap the pits out I wouldn't waste my time on them. Fortunately mine have cleaned up quickly so far.

As far as valves for my 750 yeah there are options but most were beyond my budget, I did however find a set from CycleX that so far have worked well and were within my budget

[JamesPal]

There have been guys even on here that said they did grind the valves. They said they did not have an issue. Who knows how long though they ran the engine after that. Be interesting to see the results after 50,000 miles or more.

I will say if anyone lapped the valves so much that they put grooves in them they should never have touched that engine/head. Can't imagine how long that would take lapping valves by hand.

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The old Honda twins are the budget classic bike. People have to start somewhere. I have seen people actually use a drill motor to lap valves.

[JamesPal]

Getting valves for any engine is not really that hard. There are companies that make valves with all kinds of dimensions. I buy blank valves to do race engines. They then need the face machined down to the size I need. Also the length needs to determined and then they are cut down. Then the keeper grooves are machined in to them.

Engines that use rocker arms directly on the valve then either need to be hardened on the end of the stem or you have to use valve lash caps.

All of that works gets expensive and time consuming. But the option is out there.

.

My friend wants around $300 for a set of four CB450 valves. I have an extra set of good condition used valves for the 450. I would rather have them faced and reset to my head that pay that much money. People don't think much about lapping being a metal removal process. If the existing valve face is square to the stem then not much material must be removed to clean them up.

[ancientdad]

I will say if anyone lapped the valves so much that they put grooves in them they should never have touched that engine/head. Can't imagine how long that would take lapping valves by hand.

Forever and a day, no doubt. I've lapped valves until my hands and arms were tired and barely made a "dent" in them

I have seen people actually use a drill motor to lap valves.

and we know that's a no-no, don't we Jim? it's the lazy man's method, though I have seen people get away with it. those people were generally going to sell the bike anyway so what did they care...

[JSBail]

I have seen people actually use a drill motor to lap valves.

and we know that's a no-no, don't we Jim? it's the lazy man's method, though I have seen people get away with it. those people were generally going to sell the bike anyway so what did they care...

Yeah I've read some heated debates on that on other sites and I myself prefer to do it by hand rather than use a drill but it's a debate I steer clear of.

[JamesPal]

I will say if anyone lapped the valves so much that they put grooves in them they should never have touched that engine/head. Can't imagine how long that would take lapping valves by hand.

Forever and a day, no doubt. I've lapped valves until my hands and arms were tired and barely made a "dent" in them

I have seen people actually use a drill motor to lap valves.

and we know that's a no-no, don't we Jim? it's the lazy man's method, though I have seen people get away with it. those people were generally going to sell the bike anyway so what did they care...

My machinist told me if the grind job was done correctly lapping is not required. So far he is right.