After lots of pissing around, I finally got a spacer machined to put the Supertrapp on the Ryca kit elbow. Whatever '80s aluminum Supertrapp can that is, it fits perfectly and sounds the business. That on, the fueling was still overly rich, so it meant time for a trip to the Dyno.
That's Nels Byersdorf running my bike on his Dyno. He's a super cool guy and the price is right, $50 a run. I have a 47.5 pilot and a 152 main in right now. Even after fiddling with the fuel screw it ran terribly rich. The first run it didn't even register on his air/fuel ratio. He recommended dropping down to like a 35 pilot and 135 main - I was saying WTF!!! He wisely noticed maybe the Ryca provided K&N filter is restricting air flow too much. He noted that filter is sized for a scooter or something. We popped it off and ran again and power jumped from 27.89 (with K&N) to 32.53 (open). Needless to say, that filter is useless on this bike. It's obvious Ryca uses it because it's the only thing that fits in that tiny space between the battery box and the carb. I rode home with a big grin, a 20% jump in power and a much better performing bike. To keep it from bogging when coming to a stop, the idle is set up around 1600 RPM I believe.
My next objective was to get a decent air filter on it. My velocity stack looks cool, but, like a set of Firestone Champions, it's all show no go. It will go well with a big filter over it, but, no space until I redo the battery box to make room. I don't want to go filterless.
I wanted a Uni after seeing how light and simple they are. I went to Bent Bike in Lynnwood an found this PERFECT rubber intake manifold in the parts bin. My carb O.D. is 57.1mm or 2.25". Amazingly, loads of the intake rubbers are 2.25".
So I went to the filter aisle and found this 7" x 2.25" Uni filter.
Just a foam sock over a coil spring, brilliant. It sticks out behindmy leg just like a dirt tracker, even better. Soaked it in motor oil,
rung out the excess and popped it on. It ran like a top. And with
the deep POP-POP-POP bark from the Supertrapp,
it sounds like a KTM barreling down the road. I love it. To top it off, it (barely) clears the regulator/rectifier on the front of the battery box.
The Supertrapp was a bit of work. I had to get raw aluminum stock for my buddy to machine, but, turning it down was easy and fast. I alodined everything like a nerd to minimize potential corrosion. I kept the 6 discs and put an open flow disc on the end as seen below. "COMPETITION USE ONLY"
This also meant my rear brake rod wouldn't fit around the exhaust, so I flipped the arm up and bent it a bit so it wouldn't interfere with the shock.
Still plenty left to do. For starters, my gearing is tall enough to run 150 mph if I just had the power. I have the stock belt drive with a 2" larger diameter rim and a bigger tire to boot. With the chain installed and my 18/45 gearing, she should hoist the front end pretty handily. I changed the grips from the Ryca kit ones. Again, like Firestones, they look the business, but, are not practical. I like to ride in traffic with a finger or two on the brake and clutch and I had the bars bounce out of my smallish hands more than once with those HUGE vintage grips. I got some $5 Scott motocross grips. Vibes are just not a problem on this bike, unlike my old ZRX1100...
Speaking of harsh, the front end feels like it has about 2" of travel. I need to get some proper length springs, I seem to be bottoming them out on any bump at all. I assume the overly-long (after putting in a 2" spacer in the forks) spring coils are just bottoming out on themselves. I need to get the forks apart to find out.
The proof is in the pudding, red line is with no air filter and the blue one is with the K&N moped filter. You can see the run below, it was a cool day, about 53 degrees, so she's still a hair rich, but, not enough to worry about (and for a total of $50, cheers Nels!):
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