I am currently racing a '72 350 Sprint in WERA Road Racing but have been toying with the idea of building and Iron Head Sportster for AHRMA's production heavyweight class.
Who are the best resources for info on building an Iron Head race engine? Reliability will be the number one priority,
Thanks,
Brad

If ya want to race a Ironhead
I think YOU would be the best choice for building what you want
S&S sells carbs , stroker kits , cams
there is lot of others , Andrews for one
you will need a strong trap door w/ a good clutch
in 77/78 Harley made the XLCR
I would look for one of those
or are you wanting a specificaly built frame / chassis
what ever good luck
:smoke:smoke:smoke:smoke

a reliable Ironhead ?
what rules will you have to conform to ?
:smoke:smoke:smoke:smoke:smoke:smoke

I think you should re-think this if reliability is your number one priority. Ironheads are great bikes but, they are 25 years or older.

Will an Ironhead fit in the Production Heavyweight class? I'm thinking 750cc is the limit, but I may be wrong. I'd just make sure the motor's built right and concentrate on COOLING. Oil coolers, carb shrouding, etc. Ironhead engines have trouble shedding heat, and heat is the enemy of power and reliability.

That's a good question. I have contacted Tim Lile at AHRMA and I am going to submit a request for eligibility form.
I can't see the iron head 883 having any power advantage of the
CB750.
Brad

Here are the rules and eligible biked for Novice Historic Production HEavyweight.
10.6.4 REQUIREMENTS AND MODIFICATIONS FOR HISTORIC PRODUCTION
a) CARBURETORS: Must be OEM and same type (e.g., if CV, must use CV), no larger
than the original OEM bore size. (Restrictors may be introduced to ensure parity of
performance.)
b) EXHAUST SYSTEMS: All Historic Production motorcycles must use OEM exhaust
pipes & mufflers as fitted on that motorcycle. Pipes may be tucked in and mufflers
raised for ground clearance.
c) BRAKES: Front and rear may be upgraded to Sportsman 750 specifications.
d) RIM SIZES: WM3 (2.15 inches) maximum front, WM4 (2.5 inches) maximum rear.
Replacement rims must be of the same material as OEM.
e) Side stands and center stands must be removed.
f) FOOTRESTS: Must remain in the original OEM location fore and aft. NO REARSETS.
Footrests may be raised or modified for ground clearance.
g) Lighting equipment must be removed or totally taped over to the tech inspector’s
requirements.
h) FAIRINGS AND BODYWORK: Fairings of any type are NOT allowed. Gas tank, seat
and fenders must be OEM equipment or period replacements. NO modern “GSXR
style” bodywork will be allowed.
i) NUMBER PLATES: 10-inch by 12-inch rectangular. White background with red numbers.
Also see rule 9.5.
j) Specialty machines such as Rickman, Dunstall are not eligible.
k) Historic Production machines are NOT allowed to bump up into any other AHRMA class.

BMW R75/5
BSA, all 650 and 750 two- or three-cylinder
Ducati 750 round-case Sport or GT (no Desmos)
Honda 750 four-cylinder
Honda 500T two-cylinder
Kawasaki 500 two-stroke
Laverda SF750 (SFC must compete in Formula 750)
Moto Guzzi 750 (V7 Sport must compete in Formula 750 or Sportsman 750)
Norton, all 650/750 (except short stroke)
Suzuki 500 two-stroke
Triumph, all 650/750 two-valve head, two- or three-cylinder
Yamaha RD series 350/400 air-cooled two-stroke
Yamaha R5

Cowboy Way....If it gets built, I will build it. I am just looking for all the info I can come by.
My current race bike is a 1970 Aermacchi Harley-Davidson Sprint 350. I built if from the ground up with a lot of help from a good friend and fellow racer. No part of it was untouched.

Oh, by the way, the engine rules are interpreted to mean; any internal engine mods with stock intake and stock TYPE exhaust. The mufflers to not have to be OEM.

Harley Davidson's AINT on that list:smoke

Yes CW, that is why I am submitting a request for eligibility form.

I've road raced some Jap bikes in my day and I can't see a 900cc or 1000cc Ironhead beating the Honda 750cc. That was the Superbike of it's day. Even the Ducati would be hard to beat. The 1000cc Sportster only has about 55 HP, but more torque. They also weigh about 500 lbs. They are also top heavy. A great flat track bike by all means. It would be fun though.

I realize the 883 is the underdog here but while the class does contain a few CB750s, the do not dominate the class.
This years results so far:
Triumph 750 4 -wins, 3 -2nd,
Honda CB750 3 -wins, 4 - 2nd,
Yamaha XS650 0 -wins, 1 -2nds, 2 -3rds

The point is, we just want to do this. If we can compete great, if not we
will have fun trying. The internals of the engine can be changed. We just need to stay at 883cc and use a stock carburetor. Seems worth giving it a go.

gives you the goahead
cheat
until you get cought
stroke it / bore it what ever it takes to win:smoke

Jon Dillingham ran an xlcr back when the Ama had a Bott production class. He won the Loudon National in the rain but they had great difficulty keeping it running on anything with much of a straight. Reliability will be a major challenge at best. I am not sure what it would take to keep one running, but would love to hear of your progress.

Has a decision been made on weather or not to go forward with this project?

All I can say is I wish you the best with the Iron head, man those things run hot, you may need two oil coolers..........Maybe you could sneak by with the extra large finning of XR1000 jugs but I don't know you'd mount the heads.....

Thanks for all the input guys. No, AHRMA has not given me an answer as of yet. This bike belongs to a friend who asked me to race it. We may just build it for WERA and run it on occasion. I currently race a 1970 Aermacchi/ H-D 350 Spring in WERA.

I saw a Iron head XL racing in AHRMA classic 60's today, he finished both races, not too high up, but he did finish....... I also saw a XR1200 in BOTT F-2, and an assortment of Buells ( air & watercoooled ) in different classes...............