Keystone Flyer

[sportscarpat]

Detail shot of the various bits to complete the frame. I have yet to find a good source for cast pieces for the seat tabs so I fabricated them, then brazed onto the frame. I am thinking this frame will get a good bead blast then clear powder coat. I did that once before and the frame came out with a metallic graphite type finish, then when you looked close you could see all the gold color braze joints. Figure a clear powder and my raw stainless tanks for a durable finish. This bike will see lots of abuse so no pretty paint job on this beast.


Keystone Flyer by Sportsman Flyer, on Flickr

 

[chainmaker]

Pat,
Will the Keystone be a production bike?

 

[sportscarpat]

My brother dropped by yesterday with an engine for the Keystone. Rich has been building all our engines lately and he says this one has the best of everything. Stroker crank, billet rod, big valve head and massive porting. Oh, and a nice big fat cam. Should be the most powerful engine to date. I believe Rich said it should be 236cc. Bet it makes a solid 25 hp. Also important is THE ENGINE FITS! This is the first mock up to check engine to frame fit and it came out exactly like the drawings.

Keystone by Sportsman Flyer, on Flickr

Quite the frame/engine package! I hope it lives up to our expectations. I also hope those crazy Keystone plates don't drag on the ground.......

Keystone by Sportsman Flyer, on Flickr

 

[sportscarpat]

The Keystone is starting to come together. Lot's of little bits on this build. Steering stops, steering stabilizer, fender.

Sportsman Keystone by Sportsman Flyer, on Flickr

It definately feels like a solid machine. It will probably be 140 pounds when finished.

Sportsman Keystone by Sportsman Flyer, on Flickr

Front crown detail for the springer fork. Still needs bushings pressed in.

Sportsman Keystone by Sportsman Flyer, on Flickr

Not sure what I will do for the drive system. I may do a narrow BB shaft and no pedal crank arms. Thinking about some rear sets and maybe something different for the handlebars.

 

[sportscarpat]

Here is a similar fork out of the same fork jig. This one is finished up in gloss black.

Bonneville Forks by Sportsman Flyer, on Flickr

Underside seat detail showing the mounting hardware and nice heavy stitching on the bottom of my saddle. This saddle is trimmed down a little and padded differently. Nice soft padding and leather. Because of the split in the seat pan this seat actually flexes between the two sides. The thick leather then ties both sides back together but allows give. Anyway, it's a comfortable saddle.

Sportsman BTR Seat by Sportsman Flyer, on Flickr

 

[MotoMagz]

Awesome work ...again!

 

[Allen_Wrench]

I love how it's even got friction-disc dampers on the springer fork.

 

[sportscarpat]

Here it is sitting on the ground for the first time.

Keystone Flyer by Sportsman Flyer, on Flickr

Here is another one. Man, this engine sits low!

Keystone Flyer by Sportsman Flyer, on Flickr

 

[hsvmick]

g'day there PAT,
this Machine look's "Amazing"
cant wait to see bar's and waiting to see the paint and bet the decal's will say it all ,the mounting of the engine Geometry is outstanding and thanks alot i couldnt sleep last night thinking of riding one one day

 

[Seanery]

Pat,
What's the benefit of this frame style? Well, other than the cool factor? Does it stiffen the frame?

Tanks
-sean

 

[sportscarpat]

Pat,
What's the benefit of this frame style? Well, other than the cool factor? Does it stiffen the frame?

Tanks
-sean

My understanding is that early motorcycle manufacturers wanted to lower the engine further in an existing frame design for racing purposes. This allowed easy head removal with the engine still in the chassis, lowered the center of gravity for better handling, and allowed for the engine to drop straight out the bottom of the frame. All these reasons applied to my situation as well. Also, from a practical standpoint, it simplifies the down tube considerably and really opens up the frame for bigger engines. I can now just build a different plate system for different engines. I am messing around with a Briggs Keystone system for this same chassis. Oh, and like you mentioned it looks cool! As far as making the chassis stronger, well, it appears to be stiffer but I have yet to determine if it is actually stronger.

 

[silverbear]

One I can see is that it makes a really secure way of anchoring the engine and tying it in to the frame of the bike. The other is that it drops the engine as low as possible making for a low center of gravity. And yes, there's definitely that cool factor.
SB

 

[sportscarpat]

Not sure if I shared this picture of the frame without the plates bolted in. You can see the lug on the down tube is pretty stout. Also how the tabs are located on the bottom bracket.

Keystone Flyer by Sportsman Flyer, on Flickr

This picture I did share before. The whole Keystone mount is a complete assembly all welded together. Probably overbuilt, but very strong.

Keystone Flyer by Sportsman Flyer, on Flickr

 

[Ragnarok]

The frame looks straight and proportions are right too.must be one heck of a cam and head work to get it to breathe well enough to get that kind of power! So did you make the forks a bit wider to accomodate a wheel that has a hub for that kinda torque?

 

[Bruce Lee]

Pat if you REALLY want to test the frame just take it to the Escondido car and bike show.

 

[hsvmick]

How you going Pat,
the machine look's amazing and the framing i cant put a word to the art work you have done ,i would of liked to seen a different tank on this build,
the tank Ritchy come out with on his bike would of been insane but i guess he would not of let you take that design lol ,not that i saying your tank looks bad at aLL as it looks the best made tanks i have seen
if someone was to order a machine like this could a Ritchy tank come with it

 

[fasteddy]

A work of art indeed. The interchangeable cradle for different motors is genius and would work for racers as well as someone who want's to change one motor for another just to ride for the day.

Steve.

 

[sportscarpat]

Forks and engine mounts finished up. Drive chains installed.

Keystone Flyer by Sportsman Flyer, on Flickr

Keystone Flyer by Sportsman Flyer, on Flickr

 

[sportscarpat]

Just a quick picture showing that the starter BARELY fits. Adding a starter to the GX200 really increases the physical size of the whole package. This bike will be electric start only, with no backup starting system. That's one way to make a system functional and reliable. If it breaks I'm pedaling home. No easy chore on a 130 pound machine! Now if I can just get those new handlebars installed and the intake and exhaust built I can get this beast fired up for a shake down run.

Keystone Flyer by Sportsman Flyer, on Flickr

 

[Ragnarok]

Pat I know how busy you must be....sent you a pm when you can find the time please.