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My '29 Bitsa is coming together.

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CmdBentaxle Avatar
CmdBentaxle Silver Member Dave D
Federal Way, Washington, USA   USA
1950 CycleKart Italian "1950 Ferrari 166 F2"
Bryan, any chance you might make it up to Stanwood on the 9th?
Same question for anybody else.

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Smoky Avatar
Smoky Silver Member Don Schmok
Salmon Arm, BC, Canada   CAN
Hi Dave,

I'd like to join you guys at that track, but it's the same day as I enter our Fall Fair parade and display, and I have company coming for the event.

It's also a long trek to do solo and justify the time and expense. Next year there may be another CK or two in the area, and a couple of us could bring down two CKs and share the driving.

I didn't think this circle track stuff would be much fun, until I saw the video, anytime you can get that much time with the backend out, I wanna race it!

Have fun, wish I was there,

Smoky



1929 Riley Bitsa

CmdBentaxle Avatar
CmdBentaxle Silver Member Dave D
Federal Way, Washington, USA   USA
1950 CycleKart Italian "1950 Ferrari 166 F2"
I admit I didn't expect much out of it either, but it really is great fun. And with a bunch more cars
involved you would have your hands full on that little track. Plus, as has been said already,
the C/Ks just look right in that setting. I can't see anyone being let down by the experience.

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Smoky Avatar
Smoky Silver Member Don Schmok
Salmon Arm, BC, Canada   CAN
Had a good day installing a new chain. I don't have a chain breaker, so have to do it the hard way. ( I'll be getting a breaker, and you should too.) Even made a cool custom tool to help thread the chain, works like a charm.

I un-keyed the left wheel, as it was adding a new variable to my Stage One upgrade, and brake improvements.

Discovered my exhaust had cracked in two, cleanest break you ever saw, looks like it was laser cut! And it didn't break at a weld, much to my surprise, and anyone else who has seen me weld!

So my question is, is the break due to exhaust mount too rigid, or too loose?

I ran it as an open pipe for my test drive, nice extra power, power slides on pavement are real easy, can't tell for top speed, as I don't have the room, but need to get hard on the brake at the end of my street, and I didn't need to before the upgrade.

I need the quick turning for the upcoming parade, so the key stays out until that event is over.

So a good day with pleasing results, I'll repair the exhaust tomorrow.

Smoky



1929 Riley Bitsa

Woodysrods Brian Woods
Westbank B.C., Canada   CAN
Hi Don
How close to the weld did it break? I is common for things to break right next to the weld.
My guess is that your exhaust ridged mounted as it was wanted a little movement, same as that on a real car, even though we think our CK motors are mounted solid, they are still vibrating.
Glad to hear you are having fun.
I too have made some small steps forward on my CK, as I have been trying to steal some time to work on it before we leave on our next Teardrop adventure.
Good Roads
Brian

Denny Graham Silver Member Dennis Graham
Sandwich, Illinois, USA   USA
Most likely to rigid Don. I can relate a tale from when I was flying.
I built a single place Pitts special aerobatic airplane from plans back in the early 80’s
sticking to every detail religiously, cept for the tail pipes.
I build my own 321 SS exhaust headers according to the prints but when it came to
fitting up the short (18”) tail pipes the plans called for a real loose sloppy fit.
With my machinist background I wasn’t having any of that so I gave them a nice snug
fit and tightened the split up so they were tight to the end of each header.
Shortly after I got her airborne I was flying off the test time to find if any bugs might be
hiding. After a few days of testing on takeoff, right about the time I left the end of the
runway I heard what sounded like a loud bang then a deafening open exhaust sound
and suddenly could feel a lot of heat in the cockpit. I wasn’t sure if it was an engine fire
so I pulled up hard and rolled into a tight Immelmann turn to get it back on the ground as
soon as I could.
That rigid tailpipe had cause one of the headers to crack a few inches from the
exhaust port and was blowing exhaust right at the .020” SS fire wall. Would have made
a great cockpit heater on a cold winter morning, but not to welcome on a hot summer day.
After making a new header I fit the new tailpipes up so they rattled like a baby’s toy.
Put about 300 hours on that Lycoming IO-320 before I sold it and never had another
problem with the exhaust.
Denny Graham
Sandwich, IL



Edited 1 time(s). Last edit at 2017-08-29 08:52 PM by Denny Graham.


Attachments:
Pitts S1D Exhaust Header 02.jpg    42.2 KB
Pitts S1D Exhaust Header 02.jpg

Pitts S1D Exhaust Header 03.jpg    40.6 KB
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Smoky Avatar
Smoky Silver Member Don Schmok
Salmon Arm, BC, Canada   CAN
Denny,

I had the muffler mounted on a stout rubber flex mount, sized for a truck, and trimmed smaller. It was pretty solid. I will trim some off, weld up the pipe, and put it back together.

Pitts special aerobatics airplane? Doesn't that sound like fun!

Woody,

The break wasn't near a weld, I think it was a fatigue from vibration. I'll build something with more "give" in it.

Smoky



1929 Riley Bitsa

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Denny Graham Silver Member Dennis Graham
Sandwich, Illinois, USA   USA
More fun that I've ever had or ever will have, but......all that's left
of that life are the memories. Besides, flying isn't meant for a
75 year old retired blue collar class dude like me. Cyclekarts
are more inline with the budget and my capabilities now a days.

I think what Brian was pointing to was that the heat effected zone
just adjacent to the weld is a highly stressed area and even though
you have a good solid weld, the parent metal at that point can fail.
I took a look back thru the thread and didn't see any pictures of your
engine with the exhaust mounted. From you're description it sounds
like you've used a support because of a rather long pipe?????
You haven't mentioned the type of material that you used for the
pipe. Black iron pipe is prone to fatigue cracking at low cycle of
vibratory stress, also fatigue failure from resonant vibration
can be a contributing factor. It you're hitting the right note,
that can greatly decrease the fatigue life of a structure.
It might help to use a wrap on the pipe to dampen out the
vibration.
All that being said, I'm quite surprised that we do not hear
of exhaust cracking more often. The rather long exhaust
pipes used on most of the Cyclekarts looks to me to be
a weak spot and a recipe for failure. But......unless no one
is talking about it, they seem to hold up quite well.
Take note that none of the utility engines ever have long
exhaust, instead it's always kept to a minimum even
where there is room for a remotely mounted muffler.
Denny Graham
Sandwich, IL

Smoky Avatar
Smoky Silver Member Don Schmok
Salmon Arm, BC, Canada   CAN
Here's my exhaust when it was new. Old 3/4" is on the floor. It is a 1" header kit with lovely slip joints. Easy to weld, and made a very strong exhaust system. It broke about 2 inches below the last slip joint, in the photo just above the bolt holding the exhaust hanger to the frame.

I'll weld it up, and go for a drive.

Smoky



1929 Riley Bitsa

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Attachments:
IMG_5603.JPG    54.9 KB
IMG_5603.JPG

Denny Graham Silver Member Dennis Graham
Sandwich, Illinois, USA   USA
SHAZAM! That's a lot of exhaust pipe Don.
Ya might want to think about shortening it up
by rerouting it to the other side?.
dg

Smoky Avatar
Smoky Silver Member Don Schmok
Salmon Arm, BC, Canada   CAN
My original 3/4" exhaust was on that side, exited between the brake and the sprocket. That was a lot of heat and clutter on that side of the Kart.

So when I built the 1" version, I extended it to the other side of the car, for several reasons this is a better design.

Perhaps the longer length contributed to the failure.

We shall see.

Smoky



1929 Riley Bitsa

CmdBentaxle Avatar
CmdBentaxle Silver Member Dave D
Federal Way, Washington, USA   USA
1950 CycleKart Italian "1950 Ferrari 166 F2"
That much might even be a power sap.

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