Motorcycle Building Tools

[John Noonan]

Watch out for the people that build a chassis based solely on "looks" and not geometry..can't cheat physics or mother nature..

What may work at 75 mph may not work the same way at 175 mph.

John

[sockjohn]

----first you need a plan -the more you can work out on paper the less mistakes and redoes you will have later on---

I would add, full scale mockups with PVC pipe and cardboard can sanity check a lot of paper screw ups.  It's been a while since I've screwed up by drawing one solid object "through" another, but it's better to catch it before the tube is cut and frame welded together.  A scrap pile of PVC pipe costs less and takes less time than the "real deal"

Regarding geometry, anyone know of a better book or a book to add to Tony Foale's?

[Calkins]

I would add, full scale mockups with PVC pipe and cardboard can sanity check a lot of paper screw ups.  It's been a while since I've screwed up by drawing one solid object "through" another, but it's better to catch it before the tube is cut and frame welded together.  A scrap pile of PVC pipe costs less and takes less time than the "real deal"

Great idea!  I'll try that, Thanks

[willieworld]

John  would you please elaborate on the geometry thing im sure everyone would like to know     willie buchta

[John Noonan]

Willie,

Geometry regarding angles, rake, trail etc.

Design regarding length, strength, support, cockpit structure, distance from rear axle to swing arm pivot on a chassis with a swingarm/shock design.

Material thickness, what may be strong enough in a 72" chassis may not be as strong in a 96" chassis

What works at 50 mph may not work the same at double the speed, same thing with Boost or Nitrous fueling and timing.

Looks regarding wings for down force, engine/turbo placement that is a bad aero design.

Now I need to go get some PVC for the new bike..


John

[willieworld]

thanks john     now tell us about the new bike      willie buchta

[bak189]

You want a good and safe chassis (frame) contact BAKKER FRAMEBOUW in the Netherlands....................
Nothing but the best..............been building M/C frames since the early 1960's for the likes of Freddy Spencer, and many other top-line GP-Riders..........now if you are interested in a sidecar chassis.........
those are build right here in the USA by BAKKER MOTORSPORTS..........been building chassis for the likes of 3 times AMA National Sidecar Roadracing Champion and many times record holder in LSR................... Larry Coleman...

And...Yes, mild-steel is O.K....BUT... if you are building a small displacement M/C you might want to use
.039 CM and Tig.

[754]

It always seems to me that if you cant figure out how to build a frame jig or fixture, you probably should be very careful, before you  test your frame on the track.

I used to supply lots of small parts to a couple of framebuilders, mounts, bungs, that sort of thing..

 If you are really good you can build some frames without a jig.. if you are really bad, you might never build one, even with a jig..

 We got a guy over on the sohc4 forum that built a really killer spine frame, just on a bike bench..

 whatever you do, research SOONER, not Later.. and GOOD LUCK..

[Constant Kinetics]

What is the compuss/angle finder tool for front end geometry called?

Protractor.

[Constant Kinetics]

IMO, your best bet is to find a used frame from a salvage yard that has room for your engine and is STILL STRAIGHT. 1/100th of an inch out of square could cause all kinds of problems at land racing speeds, not to mention not all metals act the way you're used to when it comes to assembly. You may get everything square all tacked together just to watch it tweak itself out of shape during welding. If you use cro-moly tubing for your frame, will you use it for motor mounts too? If you use steel or aluminum for motor mounts, do one or both metals need to be pre-heated before welding? Should the welds  be allowed to cool naturally or cooled with oil/cold water? All it takes is one little thing being off just a hair and all that work is for naught. I admire what you're trying to do, but by the time you get all the bugs worked out you really aren't saving time or money.

[1212FBGS]

kinetics
you'll find most of the people on this board don't care about time or money.... its more about making and building exactly what you want

Noonan...post #19....you forgot 1 very important measurement.... crank to rear axle

Kent

[Constant Kinetics]

True enough. Pulled out my 401k early for my build and don't expect to run at least until 2011, and all because no one had quite what i was looing for.

[wobblywalrus]

Justin, probably the best way to learn to build a frame is to become a decent welder by taking night classes at the local community college.  Then maybe you can watch and help a good builder in your area.  Those chopper guys on TV can be bad tempered, but most folks will teach someone who wants to learn and has taken the time to master the basic skills.