Honda 175 AHRMA Racer

slowguy

New Member
Having raced a mostly stock CB175 AHRMA racer, I've decided to leave the old bike alone and build something a little faster. I'm building a new 175 vert based race bike using parts mostly from Motocicli Veloci, who I represent. Here's a mock up. Everything is not in it's final place, just a loose idea.
 

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Very interested so tell us about the upcoming upgrades!


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This one will be pretty mild. My best finish with the gold bike was a second at Road America in the 160 class. The engine on the gold bike is stock, with the exception of a fresh (1st over bore) set of pistons and rings. I ran stock carbs, and stock jets. The gold bike runs good, and everyone tells me that what I did was either wrong or impossible.

The new bike will run the stock cam. SS valves. Ti retainers. Bronze valve guides. New valve seats (with the correct press, unlike the factory did). Cylinder head has been flowed and ported by my top secret cylinder head geek. 55mm Arias pistons. Balanced rotating assembly. Lightened flywheel. 160 valve cover. Keihin PE24 carbs. Pertronix ignition. 4S RC battery. Borrani rims. Modified SL175 frame. 32mm Marzocchi forks. Honda CB125 Italia bodywork. Lengthened swing arm. Hand made Italian clip-ons. Amal style levers. Motocicli Veloci rear sets. Dunlop KR tires. Stoppy will be making the cables. I'll be machining the stuff that needs machining. Axle spacers will be 6061. Axles will be gun drilled like the gold bike.

Probably run some cheaper Hagon shocks. Might use a CB160 front brake or possibly a 210mm Fontana front brake.

Not sure on the grips yet.

Hopefully I can get the bike to be around 212-215lbs.

Not looking at going crazy, just want to do a little better than second place.
 
How much do you weigh? Did you epoxy the intakes on the stock bike? How much rotational mass did you remove from the stock bike engine? One of the clutch gears? Flywheel removed? Total loss? I see the starter is blocked off. How about gaskets? Did you increase the compression with different gaskets? Running a base gasket?

Not that you would do this but we have Uncle Pete Dalio in our family DNA and Jack Wilson (who built the Texas Ceegar) who completely dissembled a stock triumph and modified it and you couldn't tell they had touched a bolt on the engine.
They won the race the next day against a fierce rival shop against another "Stock" Bike. You see in Texas "Stock" has a different meaning. LOL




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The stock engine was as stated. Street engine with a fresh .25 (first overbore). I removed the rotor from the engine after setting the timing. I retained the stock carbs and jets. I did file the carbs out a little. I reused the original head and base gasket, but gave 'em a bit more torque (no, they don't leak). I did not degree my cam, just set it to the factory mark. No tricks at all. Of course I run total loss ignition. I weigh 145lbs. a little heavy.

I'm not from Texas and I don't have anything to prove, I just like ridding my motorbikes. I put this engine together as a spare the night before a race. The simple engine allows me to circulate the racing course. I call that fun.

The 160 valve cover is used to help brace the steering head. The wider spread of the 160 valve cover and its 2 (or 4, depending on how you want to view it) ad a little more rigidity.
 
slowguy said:
The stock engine was as stated. Street engine with a fresh .25 (first overbore). I removed the rotor from the engine after setting the timing. I retained the stock carbs and jets. I did file the carbs out a little. I reused the original head and base gasket, but gave 'em a bit more torque (no, they don't leak). I did not degree my cam, just set it to the factory mark. No tricks at all. Of course I run total loss ignition. I weigh 145lbs. a little heavy.

I'm not from Texas and I don't have anything to prove, I just like ridding my motorbikes. I put this engine together as a spare the night before a race. The simple engine allows me to circulate the racing course. I call that fun.

The 160 valve cover is used to help brace the steering head. The wider spread of the 160 valve cover and its 2 (or 4, depending on how you want to view it) ad a little more rigidity.
Cool! love these little bikes! As you know Texans like to tell tall stories so we find out what aTexan means when they say their motorcycle is basically stock. However when we know they have something to prove (like winning a race) we assume they are fibbing or they found a new way to make it faster within the rules. LOL Just last year I heard of a guy calling out my friend on the table so he put up the money to have him tear his engine down because he thought my friend was cheating. My friend also put up money for this guy (who lost to my friend) to tear his engine down. My friend wasn't cheating but the guy who lost to my friend who called fowl was LOL! Everything isn't bigger in Texas just the stories...lol. Sometimes if you are racing you have something to prove IMHO.


On our first bike a cb200 we kept everything stock and then changed a few things at a time on the bike just to see how the modifications would impact performance. We had .75 over Pistons and stock 18mm carbs and made 12 whp at the Dyno! (Basically what a stock 175 had stock)

After that we ported the exhaust ports, serdi cut the valves, change to copper gaskets and got a bump in compression it really came alive and we are still running a stock cb200 cam. At this time we are still running the rotor and the chain to the starter. That bike made 17.2 whp on the Dyno after we lightened the rocker arms and added 20mm mikuni carbs. We need to remove the rotor and starter chain and take it back to the Dyno. I think
that rotor is a kilogram/2.2 lbs off the rotational mass.

You have very fine taste in gas tanks. Love that cb200 tank!


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Texasstar said:
You see in Texas "Stock" has a different meaning.

Have you read the specifics in AHRMA's "Production" class rules?

ANYTHING GOES inside the engine, so long as it APPEARS stock from the outside. Carb bodies have to be stock, but they can be hogged out and jetted to suit a lumpy cam, stroked crank and the biggest pistons you can run without daylight peeking through the fins into the bores.

That class is a joke, but there is no way to police a tight "production" spec without teardowns, which nobody has time or money for. So, the racers "police" each other.
 
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