XS11 and XJ1100 valves

[Geezer]

I found a supplier that lists valves for Japanese bike by specs. Anybody know the specs for XS11 and XJ1100 valves? None of my books have this info.

Geezer

[81xsproject]

Tony, do they have any options like SS valves? Or are you just trying to find another bike that uses the same valves?

[dpotter58]

for an sf

this is from my supplementary manual

intake
head diameter 36 +/- 0.2 mm
face width 2.26 +/- 0.57 mm
seat width 1.1 +/- 0.1mm
margin thickness (min) 1.2 +/- 0.2 mm

stem diameter 7 -0.0010 mm
-0.0025
exhaust
head diameter 31 +0.2 mm
face width 2.26 +/- 0.57 mm
seat width 1.1 +/- 0.1mm
margin thickness (min) 1.2 +/- 02mm

[Geezer]

Do you know what year these specs are for?

Geezer

this is from my supplementary manual

intake
head diameter 36 +/- 0.2 mm
face width 2.26 +/- 0.57 mm
seat width 1.1 +/- 0.1mm
margin thickness (min) 1.2 +/- 0.2 mm

stem diameter 7 -0.0010 mm
-0.0025
exhaust
head diameter 31 +0.2 mm
face width 2.26 +/- 0.57 mm
seat width 1.1 +/- 0.1mm
margin thickness (min) 1.2 +/- 02mm

[81xsproject]

Since he owns 2 '81's and mentions that it is from the 'supplementary' manual, it is probably for the late model/80/larger valve heads. Which, of course, would be the most important valves to source

[DiverRay]

He stated that it's for the SF, a 1979 Engine.
The specs for the '81 are as follows:
Intake:
38mm head diameter
2.26 -+0.57mm face width
1.1-+0.1mm seat width
0.7mm minimum margin
7mm -0.010 to -0.025mm stem O.D.
Exhaust:
32mm head dia.
2.26 -+0.57 face
1.1-+0.1mm seat
0.7mm min. margin
7mm -0.025 to -0.040mm stem O.D.
This is from LIT-11616-XS-13 The "H" manual with the previous manuals included.

[Geezer]

OK, if I can get stem length, I can see if we can get them. I would be nice if I could get the specs on the earlier engine's valves without pulling the head off one of my engines...

Geezer

[psycoreefer]

for an sf

it's in the "title"

so now you have both early and late....

[Geezer]

Once I have the lengths, I'll see what I can do...

Those 38mm intakes are going to be tough but the later valves are available from CRC anyway.

Geezer

[tinman905]

If it helps I believe the FJ1100/1200 use the same valves .

[Geezer]

The FJ's have 4 valves per cylinder. If FJ head would transplant onto an XS11, I'd already be working on it... The XS11 and XJ1100 only being 2 valve per cylinder bikes is one of my pet peeves. Yamaha had the technology to do it but decided not to...

Geezer

[Yahman]

Once I have the lengths, I'll see what I can do...

Those 38mm intakes are going to be tough but the later valves are available from CRC anyway.

Geezer

I can check the lengths of some from a 79. I'll post them later on today. I have to dig them out first.

Any other measurements that you want me to take?

Larry

[trbig]

The FJ's have 4 valves per cylinder. If FJ head would transplant onto an XS11, I'd already be working on it...

I remember Dan Hodges posted a pic of a 4-valve head that was designed and would work on our bikes. He listed who sold it, but unsure of a price since I remember him saying something about "If money wasn't an option".

That being said, the valves on our bikes can move more air/fuel than even the biggest bore possible would need. Up to 1500cc if I remember right.


Tod

[Yahman]

The 4 valve design keeps the velocities of the air/fuel mixture in a higher range, which keeps the mixture suspended in the air flow. It also helps throttle response.

Larry

[Geezer]

I can check the lengths of some from a 79. I'll post them later on today. I have to dig them out first.

Any other measurements that you want me to take?

Larry

Nope, just length. I now have the other specs.

Geezer