Valve Length?

[blue giant]

Thanks TC. There is more than 1 mm difference in length.

Terry, I'll measure both valves tonite and let you know, thanks!

Paul

[79XS11F]

Paul, the jugs and pistons your getting, are they from an 80 model? If not will these larger DIA valve heads clear the relief's in the tops of the pistons.
I am guessing they will or all your valves would have been bent in your engine but this should be confirmed. If they will clear the tops of the pistons on all earlier model years, is there any chance the valve got bent because of heavy carbon buildup on the piston tops and in the relief's?
Rob

[blue giant]

That is a possibillity Rob, it was #4 ex valve that was bent and #4 piston top was the only piston with excessive carbon build up on it. I'm waiting on an answer as to the model year of the spare head I have.

[Big Daddy Funk]

New Valve

I checked back and I actually got it from the Yamaha dealer without problem.
Blue Giant, if you still need one give us the head and length dimensions. I'm sure someone will have one for you. Rick

[Firefighter46]

I'm sure I could be driving a new bike for what I've spent on this thing!

Harley Demo ride this sunday in Kingston! I think the Good Time center still has that Vulcan!

[blue giant]

I'm sure I could be driving a new bike for what I've spent on this thing!

Harley Demo ride this sunday in Kingston! I think the Good Time center still has that Vulcan!

Go away!

[blue giant]

I checked back and I actually got it from the Yamaha dealer without problem.
Blue Giant, if you still need one give us the head and length dimensions. I'm sure someone will have one for you. Rick

Thanks Rick, I found out the spare head is off an 80G. I think mine might be an 80 bottom end with a 79 top!

[Guy_b_g]

80 valves are shorter than the 78s, I have both heads and took them apart at the same time. 1/8th inch sounds about in the ballpark as far as the difference.

They sunk the valves into the head farther on the 80 and the valves are bigger...about as big as you would want to go in these heads.

The bigger exhaust and intake valves are very close together in the 80, and had to be set deeper in the head to avoid interference...thus putting them closer to the camshaft...and thus requiring a shorter stem (and higher domed pistons to make up the lost compression from the inset valves, which create more volume in the combustion chamber). No free lunch with the bigger valves...

[blue giant]

Thanks Guy, you're my new hero. You just told me what it's taken me all day to figure out!

The engine in my bike is indeed a 1979 engine and the spare head is a 1980. Exhaust valve length in 1978-9 = 3-3/4 inches. Exhaust valve length in 1980-1 = 3-11/16 inches.

Sorry TC I didn't realize you were giving me the diameter of the intake and exhaust valves for 78-9 and 80-1

Paul

[79XS11F]

OK, now that's making some sense. I was wondering what was going on.
Rob

[blue giant]

OK, now that's making some sense. I was wondering what was going on.
Rob

Ya learn something new everyday eh?

Got a good 79 exhaust valve rolling around in the bottom of your toolbox?

Paul

[Firefighter46]

Go away!

Either way, Fix it or buy a new one so we can get out and ride!

[blue giant]

Either way, Fix it or buy a new one so we can get out and ride!

Don't you have a hockey game to go and watch!

[79XS11F]

Ya learn something new everyday eh?

Got a good 79 exhaust valve rolling around in the bottom of your toolbox?

Paul

Hey Paul, the only valves i have are installed in the 79 special head. Andrea is sending me some junk tomorrow perhaps he has one and can throw it in with my stuff.
Rob

[Axel]

Hmm

Sorry to hear you are having trouble , Paul . I didnt know you had your bike apart . Good to see father and son posting ! You will overcome !