1 3/4 exhaust valves in an ironhead

[hubbard]

Know of any drawbacks to this? I'm trying to keep from having to put seats in it.

[garyajaz]

will dig out my old set of racing heads in a bit.
i have huge intakes XLR and i think a tad bigger ex.  although with the pressure generated by combustion not really needed.
iron heads dont take seats.  the seat is the iron head. no insert.
do you mean yours is ruined and cant grind/cut/or lap in??

pix?

[garyajaz]

 rowe site saying stock ex is 1.562 head size.
havent measured mine yet.  they kinda buried..
so will .19" clean it up? 
if so and can find them would probably be much cheaper than machining heads for seats that may fall out.
p.m. me if need help.  i have done a few...
p.s.  info only .  i not trying to sell anything or do any work...
lol..
how bad are they??

[garyajaz]

black diamond valves showing a 1.75 for the XLR.

[hubbard]

The seat in the head is to deep according to the valve stem gauge. I'm just going to put seats in it. From what I can tell without doin the math I would have to unshroud 'em anyway so might as well just put 'em back like they were. I was just bein lazy. They won't fall out, the ones I put in my pan and shovel have plenty of miles on 'em without any trouble.

[Hillside Motorcycle]

Lot's of folks ran that size back in the day.
We have a set in here now that Branch did, yeeeeeears ago.
1.940" in, 1.750 ex.
These are on a 74"er.
Scott

[garyajaz]

scott comes through again.
lol.
mine same numbers.  but ported by C R Axtell in 1976 for my 1974 xlch..
it was 77 inches with stroke before bore that took it to 80"
still runs well (when i can kick it over)

[rhino]

one trick I learned is that volkswagon seats will fit in ,I had a machine shop cut the heads and install the unleaded seats many years ago and has not given me any problems.

[Hillside Motorcycle]

And steel seats can be readily manufactured if need be.
Scott

[tomfiii]

Inletting the exhaust valve only a small amount will have no effect on it's running ,as I can't remember what drag racers tuners used to say by how much,but slight shrouding of valve actually increased output.