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#Post#: 1000--------------------------------------------------
Re: Bugatti Type 37 Build - stability
By: StefanN Date: July 9, 2019, 3:35 am
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Stretton was the first real test of the Bugatti and it felt a
bit unstable at speed and definitely tippy/unpredictable in
corners. So the search for stability starts. I'll create a
topic thread in the Tech Forum for the general discussion. I'm
going to double check the toe-in and castor.
One difference between my CK and many others is that my spring
is clamped to a perch on top of the beam axle, rather than
hanging below. The rest of the front geometry means that the
chassis rail is level - ie, this is not making my ride height
higher than intended. Given it is all bolted together and the
beam drops, I can't see this making any difference, but I'd be
interested to hear alternative theories on this question.
#Post#: 1006--------------------------------------------------
Re: Bugatti Type 37 Build - alternative pull cord positions
By: StefanN Date: July 9, 2019, 9:53 am
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Rather than make another hole in the Bugatti tail. I'm thinking
about routing the starter cord to somewhere else - either below
the side rail so its under the tail, or forwards to the gap
between my back rest and seat cushion, or possibly to the side
wall just in front of the tail. Obviously I'll need to remove
the metal cover and create a new hole for the cord to exit from
but will be removing that anyway to fit a Hall effect sensor.
Any thoughts?
#Post#: 1013--------------------------------------------------
Re: Bugatti Type 37 Build
By: chrisenamels Date: July 9, 2019, 10:31 am
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When you remove the pull start, you'll find you can reposition
it so that the it faces forward without any problem. There are
six holes in the pull start housing and at least three threaded
bushes in the fan housing. Just remove the bolts and rotate the
pull start housing to the position that suits you.
#Post#: 1016--------------------------------------------------
Re: Bugatti Type 37 Build
By: RhysN Date: July 9, 2019, 12:05 pm
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All of mine have had the cord through the back rest using what
Chris has suggested.
#Post#: 1079--------------------------------------------------
Re: Bugatti Type 37 Build - diet
By: StefanN Date: July 21, 2019, 1:59 pm
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Having weighed the Bugatti and given that I wanted to lower the
seat to drop the centre of gravity, I stripped down the seat
cushion, took out some foam, pretty much removed the rails and
drilled some lightening holes. Incredibly, that removed just
about 1.2kg. I've dropped the driver position about about
100mm. Now just need somewhere to test what different that
change has made.
#Post#: 1080--------------------------------------------------
Re: Bugatti Type 37 Build - rear wheel to hub improved
By: StefanN Date: July 21, 2019, 2:39 pm
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I took the lip off the inside face of the pit bike wheel SDG
hub. This means the hub from Gemini and the inside face of the
wheel hub sit flush to each other - a better solution I think.
#Post#: 1081--------------------------------------------------
Re: Bugatti Type 37 Build
By: RhysN Date: July 21, 2019, 2:56 pm
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I agree that's a much better idea. It only takes a few minutes
with a flap disc on the grinder too. Do you have a support for
the axle at the outboard side of the wheel Stefan?
#Post#: 1082--------------------------------------------------
Re: Bugatti Type 37 Build
By: StefanN Date: July 22, 2019, 5:37 am
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[quote author=RhysN link=topic=3.msg1081#msg1081
date=1563739011]
Do you have a support for the axle at the outboard side of the
wheel Stefan?
[/quote]
Both inside and outside. My original thought was to only drive
one wheel. I couldn't find 35mm OD/25mm ID bearings (except v
expensive ones) and given the freewheel only moves a bit
relative to the axle I made up Oilite bushes to replace both the
bearings. These hold the wheel nicely on the axle. The Gemini
wheel hub helps to prevent the wheel from sliding along the axle
and also transfers the rotational torque to the wheel.
I have been considering how to improve this set-up, although so
far what I've got seems to be working. The central bore on the
SDG hub tapers to a 25mm hole (sometimes just under) and the
outside of that section is roughly parallel at approx 40mm
diameter. Unfortunately the inside is a cast finish and so not
a surface it would be easy to mate up against.
#Post#: 1083--------------------------------------------------
Re: Bugatti Type 37 Build
By: RhysN Date: July 22, 2019, 6:01 am
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I just spent a lot of time with files, dremels and such to go
right through. My outside bushes for Kim were steel as I never
intended one wheel drive, mounted where the bearings would
normally seat. Because the axle (ex hire kart) was 30 mm it took
a lot of time, and turned out unbelievably true when the bushes
were installed.
I do think the axle needs to go right to the outside to support
the wheel more positively, and then the hubs are really left to
only support the inside, and to drive.
On the outside I drill and tap into the end of the axle, then a
heavy washer (or my cast knock offs) can be tightened against a
lock collar inboard of the hub. Belts and braces.
#Post#: 1212--------------------------------------------------
Re: Bugatti Type 37 Build - Bonnet hinge
By: StefanN Date: August 20, 2019, 3:07 am
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I couldn't find a bonnet hinge in the right size at a reasonable
cost so made one out of 50mmx40mm pieces of 1mm aluminium. The
rod is 6mm.
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