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OMG! That's some serious racy bits! Tell us more about the bike and racing it!
 

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Wonderful work there, thank you for sharing these with us. I wonder, what is your total weight savings is so far? Have you made or thought about Ti tappet adjusters and nuts?
Would they help it to rev more freely?
 

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Discussion Starter #32
OMG! That's some serious racy bits! Tell us more about the bike and racing it!
It's a CL160 frame, and a CL175 engine. I started racing a CL160 in '06, up here in the PNW in the "Formula 160" class of vintage racing. Eventually swapped out the engine for a 175 to stay competitive, since everyone else was doing it. I "won" the class championship in '11, but I suspect it was because the same two fast guys who were trading the championship for years decided to sandbag and hand it to someone else, to keep hope alive for the rest of us.

We use the same skinny Bridgestone race tires originally made for the Dream 50. They are faster than the Avon race tires we used to run, and Bridgestone offers contingency money/vouchers for free tires to the top finishers. I can get about 2 years out of a set.

I like the bikes a lot. I have three race bikes built in various stages of tune. This one here is my primary race bike. In general, they are very light, nimble, communicative, and forgiving. Cheap to run. I liked them so much, that I restored one for street use. Quickly grew bored of slowly putting around surface streets with 15 HP. For me to have fun on these bikes, I need to be at the limit on a race track. So I sold that street bike. I have a KTM 525 SMR for street riding, and it scares me enough to keep things interesting.


Wonderful work there, thank you for sharing these with us. I wonder, what is your total weight savings is so far? Have you made or thought about Ti tappet adjusters and nuts?
Would they help it to rev more freely?
I've probably only saved a few pounds overall, not enough to make a big difference. I'm doing all this Titanium stuff because I can, relatively cheaply, and I enjoy it. There wouldn't be much benefit to the weight saved using Ti hardware in the rocker arms. Those bits are already so small, and I think they're high-strength, hardened fasteners. Not worth the effort, nor the risk of failure. I'd be more interested in Ti connecting rods, lightened wrist pins, and forged pistons. Maybe someday...
 

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Discussion Starter #33
End of another season, glad to still be racing despite the pandemic. Time for more small projects. Here's the Pertronix backing plate in CF, that I'll probably remake in aluminum which would be a better heat sink for the module.

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Discussion Starter #34
For the last 14 years that I've been racing this bike, I've used the rear brake just a handful of times. These small underpowered bikes rely on momentum, so the less braking, the better. Still, I have a really good front brake (Honda 160s have pretty large drums for a bike their size) and I can probably shave a second off my lap times with later, more aggressive braking on the one or two real braking zones these bikes experience on any given track.

On my bike, originally a CL160, had a rear brake cable. I adapted late model Suzuki GSX-R rearsets to my bike, and the rear brake cable adaption was never very effective. Too much travel, not enough leverage, too much friction in the cable setup. So I converted it to a 6mm rod setup. In titanium. Including the rear wheel brake stay, using spherical rod ends and 8mm titanium rod, with Ti bolt for the stay.

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Discussion Starter #35
Before I put the rear wheel back on, I couldn't stomach the fact that there was a chunk of steel hiding in the hub acting as a spacer between the bearings. So I made another spacer out of titanium.

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And I wasn't going to reattach the wheels without doing something with the bearings. Hadn't really inspected them in years, since the wheel seemed to roll fine. One of the bearings was gritty. So I replaced them both with ceramic hybrid bearings.

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The completed rear end, for completion's sake.
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Discussion Starter #37
WHO DID YOU INTAKE FLANGES FOR YOUR CARBS
I don't recall, probably Vicious Cycle in Portland, OR, a long time ago.

In addition to this bike, I also race a vintage car. I recently bought a bunch of used Magnecor ignition wires to cut down and adapt for that engine (an old Alfa), and had enough left over to make a pair for this bike. The bike has solid core wires (no resistance) and resistor caps that are 5K ohm. The Magnecor wires have about 1K ohm resistance per foot, but are completely shielded, which might be useful in case someday I convert to CDI. For now, I might run higher voltage and gap the plugs wider. Hopefully not burn out my coil or Pertronix. Like all my titanium bits, none of this may make a difference.

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I like to think that collectively all of your efforts make a difference.
And thanks for sharing with us.

I just totaled up the parts in this thread that you compared on the scale. You saved 683 grams, that's 1.5 lbs. Plus you upgraded to much stronger parts in the process. I think that adds to safety and you can better use that 1.5 lbs somewhere else like one liter of gasoline for instance.
 
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