Topic: Any AHRMA Racers in here? Questions...

[GroovieGhoulie]

I attended the Barber Vintage Festival and was enraptured with the vintage racing, telling myself, "I NEED to do this."  In keeping with my interests, I am planning a Honda Four-based roadracer, and have already started bouncing around ideas in my head for a 400F built up to a 500cc "giant-killer" like Kaz Yoshima's.

Problem is, I was reading the rulebooks last night that govern the classes and modifications and it seems like they have a decided bias against the SOHC Fours.  750s are limited to CR and RC-style mods only, and the smaller fours are heavily restricted as far as modifications and classes allowed.

Anyone know why?  It appeared that a bike built identical to Kaz's, despite being historically accurate and faithful (IE: such a bike DID exist and race back then), would have no class to run in and many of the mods he did back then would be disallowed under the current rules.  I sensed a major bias in favor of drum-braked bikes, twins, singles, two-strokes and British bikes of all makes.

WTF???  I wanna build a Honda Four that, (with either the right rider, or I get better), will positively whip ass like I know they can.

Anyone else identify this alleged "bias", or am I imagining things?

[mlinder]

Because a built 350f or 400f would dominate their class. Those little pistons can get moving REALLY fast. They also have disc brakes where many of the same era had drums.
I had to get a 350twin to race, as my 350f would not be allowed to race in a class it would be competitive in, for the same reason.
With the right parts, a 350 or 400f can probably do 16k rpm redline or more, giving them a pretty good advantage over other bikes in the class in the straights, while their extremely light weight makes them competitive with the twins of the same size in the corners.
If you wanna race, and do it on the cheap, run in the 350 twin class.

[GroovieGhoulie]

I recall reading somewhere that there is no higher praise in racing than when the sanctioning body outright bans your vehicle; IE, Porsche 917s (all variants) and the Audi Quattros.

I guess it's also a "praise" when they hamstring you to the point of non-competitiveness. 

Any other vintage racing bodies that are more open-minded, IE: better stomping grounds for killer Fours?

Might have to get a twin, but I REALLY prefer the Fours.

Come on, who WOULDN'T want to tear around on one of these:

[mlinder]

You could join ahrma, and make a request for a new class. 300 to 450cc 4 stroke multis. Can't really recall how many of those there are from other manufacturers, but it would be mostly 350f's and 400f's.
You'd have to get a lot of people behind it, though, which could be rough.

[gerhed]

Was once thinking of building a Sound of Singles AHRMA racer using a Honda XL600 motor.
Actually pulled the motor and stuck it in another frame.
Got a little discouraged when I found out the Super Mono's in the class did 180 !
The whole vintage racer scene does look like fun, though.

[ttr400]

I was recently at the Mid Ohio 07 event. I must say what an awsome event and I had a fantastic time, spoke to a few guys running 400F's.
As far as I know you have a few class choices.

1. 350 Grandprix class:  must be a full gp/rc replica 4-4 exhaust, full fairing, drum brakes. Std bore and stroke (0.5 over allowed) but the rest of the motor is open.

2. Formula 250: 350 and 400F's std bore and stroke (0.5 over allowed) Single disc front period type calliper, rear I'm not sure if a disc is allowed.

3. Formula 500: Up to 550 bore, Fully Gp kitted, twin front discs allowed.

So looking at those classes you could run a full house 400 56mm piston kitted in the Formula 500 class. you could also run a full race spec 400 with 2nd over pistons. Kaz style would work in both of these classes.

I also went up to Mosport for the 40th aniversary of the 67 GP the great Hailwood/ ago battle. I was invited to ride a 350 Jim Redman replica, what a blast did about 7 laps. took it easy in the corners as it was a new $30K machineand not mine..!

Man I think I need to make a pile of cash and take a year off and come over and race my Yoshi 400F.!!

Keep us updated.  PS I now have Close ratio g-boxes for the 400F motor. to order only.
Also looking at having 56mm slipper pistons manufactured but at a cost of +-$1200 a set!

Kevin

[GroovieGhoulie]

3. Formula 500: Up to 550 bore, Fully Gp kitted, twin front discs allowed.

So looking at those classes you could run a full house 400 56mm piston kitted in the Formula 500 class. you could also run a full race spec 400 with 2nd over pistons. Kaz style would work in both of these classes.

I also went up to Mosport for the 40th aniversary of the 67 GP the great Hailwood/ ago battle. I was invited to ride a 350 Jim Redman replica, what a blast did about 7 laps. took it easy in the corners as it was a new $30K machineand not mine..!

Man I think I need to make a pile of cash and take a year off and come over and race my Yoshi 400F.!!

Keep us updated.  PS I now have Close ratio g-boxes for the 400F motor. to order only.
Also looking at having 56mm slipper pistons manufactured but at a cost of +-$1200 a set!

Kevin

Now for the 500 class, when you say "fully GP kitted", does that mean with one of those fairings?  I HATE fairings, but if it's the only way to get the bike I want on the track, I might have to take one for the team on that one.

As far as your gearboxes and pistons, we WILL be talking.  This will be a "no-cost-spared" totally trick engine.

Now to track down one of those RSC 350 magnetos...

[ttr400]

Fully GP kitted, Yes they would prefer a full fairing, but I am sure you could run without a fairing, you could talk to them to allow it to be passed etc.

Magneto system you ask....! watch this space....I am busy developing a magneto ignition set up (no battery) only for a race motor. will be doing the same set up for the 750 motor as well.

Kevin

[mlinder]

Not having a fairing is the difference between 110mph and 145mph top speed.

Yer gonna want a fairing if you want to be competitive.

[GroovieGhoulie]

Not having a fairing is the difference between 110mph and 145mph top speed.

Yer gonna want a fairing if you want to be competitive.

Will the bike even pull 145 with airport gears?

[mlinder]

Not having a fairing is the difference between 110mph and 145mph top speed.

Yer gonna want a fairing if you want to be competitive.

Will the bike even pull 145 with airport gears?

Dunno. with long enough straight-away, yes.
Yoshi wasn't beating kawi 1000's with a 40hp 400. If youa re saying "no expense spared' engine, You are looking at at least 50rwhp, and probably more.
Not only does the fairing effect your top speed, but how quickly you GET to your top speed.
Drag increases exponentially. Faster you go, harder it is to go fast.

You'll want a fairing, believe me.

[mlinder]

By the way, the high end cb350 racers here in Portland are pushing somewhere between 47 and 50 rwhp.

[GroovieGhoulie]

By the way, the high end cb350 racers here in Portland are pushing somewhere between 47 and 50 rwhp.

That's awesome for a 350!! 

I read that the 400F based racers in the day were making up to the low 70s at the rear wheel, with one bike making 78.  The 78hp bike ran the longest before needing rebuild or grenading too.  They think the stars lined up just right when that one went together since it shared specs with the low-70s/high-60s bikes.

[Uncle Ernie]

I'm not familiar with all the classes, but for the most part, they want everything as stock as possible.  Just adding a fork brace can cause a stir.  Building a one-off replica is not in the spirit of things. 

I would dig deep into the rules and contact the AHRMA folks. 

[GroovieGhoulie]

I'm not familiar with all the classes, but for the most part, they want everything as stock as possible.  Just adding a fork brace can cause a stir.

That's weird.  Why do they run like that?  Bizarre.

Building a one-off replica is not in the spirit of things.

That's ridiculous.  Is it just because of the costs?  They don't wanna start "cash wars" with the racing?

I would dig deep into the rules and contact the AHRMA folks. 

I do believe I will. 

I mean, it's the American HISTORIC Racing Motorcycle Association.  What could be more historic than Kaz's little Honda 400F "Z-1 Killer"?

[ttr400]

It is not that they want to keep stock bikes, they want period looking race bikes..! sure they have stock classes, but realy stock bikes are not race bikes.
If you look at the rules and the different classes you can see there are many mods allowed as long as it fits in with the period.

Kevin

[Uncle Ernie]

Yeah, that's more of what I was trying to say.  I do think, also, they want to emphasize skill over HP, but that is probably an unspoken thing...

[gerhed]

Pic from afew years ago of Team Obsolete pits at AHRMA in Daytona.
The often misunderstood Mr. Knobby Clark can be seen, I think.
<a href="http://i170.photobucket.com/albums/u251/gearheaded_photos/obsolete3.swf" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://i170.photobucket.com/albums/u251/gearheaded_photos/obsolete3.swf</a>