Cheney Sonic Weld street tracker (father son tribute build).


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desert southwest, az
The YZ650 - Cheney Engineering rigid frame project (father/son tribute)

This project bike is based on the very rocky relationship I had with my stepdad of 30~ years (he died in 1999). He raced flat track in the 1950s and 1960s, and he of course taught me to ride and race. I'll post a more detailed explanation of all of that in post #2. So that way if you wish to skip all of that "Cats in the Cradle" crap from a 53 year old you can just roll right past post #2. :)

The Triumph below is probably pretty close to what I have in mind. Street legal, modern brakes and tires, shouldered Akronts, vintage vibe.


I'm basing this bike on a racing frame that was built specifically for hard core flat track racing by a company known as "Sonic Weld", all of which were rigid frame (aka "hard tail") designs much like a Speedway bike uses. It turns out that the rigid rear end is the cat's pajamas for getting around a dirt oval ~toot sweet~. So Sonic Weld designed and built hardtail flatrack frames up to 1968. In 1968 the AMA outlawed the used of aftermarket racing frames that had no rear suspension for flat track racing (aka "Class C"). The AMA felt that the bikes were becoming too much like "Class A" Speedway bikes and they wanted to keep a solid difference between the two racing types. That same year the proprieters of Sonic Weld parted ways over differences between them over which direction the company should take in the future. The two main fabricators at Sonic Weld ended up creating their own separate companies. Ray Hensley went on to create Trackmaster, and Ken Watkins went on to create Red Line.

The original Sonic Weld competition rigids had their geometry worked out by a fella known as Neil Keen. Neil was a dominator at Ascot in the early 1960s, winning a long string of main events. Neil ended up doing the material purchasing for Sonic Weld in the early stages of the company.

So the Sonic Weld competition rigids have a rich history in flat track, so much so that Cheney Engineering makes Sonic Weld ~type~ rigid frames for a number of different engine configurations, including the Yamaha XS650. The frame pictured below is the actual Cheney Sonic Weld tracker frame for the Yamaha XS650 vertical twin engine. Each frame is built around a set of design specs to suit the exact engine the end-user wishes to install. So you know you're not getting some sort of "one size fits all" set up.

Cheney Twin Cyl Sonic Weld frame - 1.jpg


In a nutshell the project bike will essentially be a hardtail street tracker, using a Sonic Weld frame hand made at Cheney Engineering and corrently configured to use the XS650 (as far as engine placement and relevant geometry is concerned). Yea, it's about $1,100 for the frame but it comes with CNC machined engine mounts, footpeg mounts, rear brake master cylinder plates, rear axle, rear axle plates with adjusters that offer 2 full inches of front/rear adjustment, Timkin steering head bearings and seals (with a headstock to fit any front end you wish). The frames are all made of 4130 CrMo, and are beautifully tank-blasted (a giant tank full of abrasive media that vibrates, like a rock tumbler sorta) that removes all welding slag and other little bits. When the frame arrives it is nearly ready for nickle plating. Also consider that with the rigid there is at least $1,000 in racing shocks that do not need to be purchased, as well as the swingarm and pivot bearings. In all the rigid works out to be about $2k less than a bike with rear suspension. So there's that.

I have no solid ideas on engine mods or rebuilding ideas. Same with front suspension and other details like that. That stuff will all come. The first thing was to work out the frame's details and decide on the XS650 engine (which was suggested to me by Jerry Cheney over the Harley engine due to the HD's engine is too heavy, too expensive, and not shaped properly to allow for the 49.5% front weight bias. The HD engine also requires more wheelbase to acomodate the physically larger Sportster engine. So he is unable to make a Sonic Weld frame with the prefered 54 inch wheelbase when using a Harley engine. Now, he'll build whatever the customer wants. So if I had wanted to stick with the HD engine Jerry would have obliged. He has a policy of making a suggestion just once. If the customer says that they'd rather stick with their own ideas then he'll oblige without any problems. But after he told me why he liked the Yamaha engine (many reasons) I looked into that engine and discovered he was absolutely correct. So here I am. :)

Cheney carries all of the hubs, brakes, brake levers, footpeg kits, and so on and so on. So, I can either go with caliper mounts and other brake components of my own choice or I can go with what they offer. They also have hubs, wheels, spokes, triple clamps, various CNC mounts and such, footbrake levers, discs, adapters, on and on. So a person can either use their stuff or stuff like that from any other source if one prefers it.

Ok, enough boring the hell out of you all. The pictures attached represent some Sonic Weld flat trackers, and a few pics are very close to what I wish to build here.

More to come soon. I'm ordering the frame either this week or next week. After that I'll figure out how I wish to proceed (do I buy cases and build an engine up, do I buy a running engine, do I buy an entire bike that I can remove the engine from and eBay off the rest???, bla bla bla. Sometimes opportunities arrise that can change your plans, we bought a Yamaha XJ650 Maxim that needed a little work for forty bucks once! We only needed the engine so we eBay'd the rest of the bike and made a nice little bit of cash to use for the project bike). Thanks! :)


(BELOW) That's one sweet ass Honda CB450 hard tail flat tracker!



Below is a Cheney Sonic Weld frame with a Triumph engine. I'm guessing the frame for the XS650 will look similar to this one.



After the frame arrives here in my shop I'll need to TIG weld on some various tabs and brackets for minor stuff (ignition box, seat mounts, and so on). The plan is to eventually Nickel plate the frame once the fabbing is finished. Paint scheme? Who knows just yet. There are many details that will need to be worked out. The main thing was getting the frame/engine combination decided upon. All of that other stuff will work out easily enough. :)
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Oh, and by the way, I am in no way connected to Cheney Engineering either professionally or personally. I'm simply a soon-to-be customer of theirs.
Neil Keen #10, used to come in the dealership I worked at regularly back in the early 70's. Super guy. I like the looks of this and I'll be following your build. Good luck!
Neil Keen #10, used to come in the dealership I worked at regularly back in the early 70's. Super guy. I like the looks of this and I'll be following your build. Good luck!
Thank you. It will move a bit slowly until the frame arrives (roughly one month lead time). I'm very excited about this one.

PIC = Neil Keen. He won a string of eleven consecutive main events at Ascot in 1961.



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How hard is it to register an aftermarket frame in AZ?

There are a couple of ways to get it done. One method involves purchasing a headstock (with the VIN plate on it) and a clear title. You then have that VIN put on the aftermarket frame and register the bike as whatever the headstock tube was. You then destroy the old headstock tube so there is only one VIN in existence with that number sequence. Places such as Cheney Engineering will put any serial number you want on the new frame.

You can also buy an old frame with clear title and do the same thing. However if you can convince the eBay seller to just hacksaw off the headstock tube and send it to you, you won't have to pay to ship an entire frame to you just to cannibalize the VIN.

If questioned at DMV you simply tell them the original frame was damaged beyond repairability and had to be replaced.

As long as you do not elongate the original frame or "chop" it then a replacement frame is legal as well as completely insurable. I know it sounds weird (as well as pretty unenforcible if you ask me) but I don't make the rules.

Basic insurance on this bike will run me about $125 per year. I used a 1975 Yamaha XS650 as the model when I checked the cost of insurance and registration. Total cost of ownership per year will be less than two hundred and fifty bucks. I'm not worried at all about registering it here. There are no vehicle inspections here, no smog tests either (knock on wood).

I have a 1980 Yamaha XJ650J Maxim frame with clear title, and a 1982 (same make-model) with clear title. I'll most likely use one of those frame's VINs and titles to register this bike. This will save me from having to buy another frame/title, as well as save me from having to try to sell motorcycle frames on the internet. It just kinda worked out that way, we had the two frames and titles from previous projects. They are the leftovers, in fact the 1980 frame came on a bike that we paid only forty dollars for the entire running bike!
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Will be watching your build...looking forward to it this should be good. Yes, Neil just past away he was one hell of a racer. All the guys that did get to race Ascot are getting up there in their years for sure, really miss that place. All good information to know on the VIN's and frames. Keep us posted Jeeter
Here is a few pictures of a Sonic Weld 500 Triumph frame that I repaired and put it back to original for a customer. Frame had been cut and rear stays extended for a hillclimber. Someone really did a number on this frame, but I made it right. Neil Keen and Albert Gunter were very good racers and engineers during their time. Neil Keen was even part of the Yamaha Factory Dirt Track team for a time. RIP both of them. Thanks Curtis


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Here is a few pictures of a Sonic Weld 500 Triumph frame that I repaired and put it back to original for a customer. Frame had been cut and rear stays extended for a hillclimber. Someone really did a number on this frame, but I made it right. Neil Keen and Albert Gunter were very good racers and engineers during their time. Neil Keen was even part of the Yamaha Factory Dirt Track team for a time. RIP both of them. Thanks Curtis
HA! I already have all of your pictures that you've posted here in my photo archives! :) I'd seen your webpage and that restoration project some weeks ago.

My Dad raced during the Joe Leonard days (1953 to about 1962 I think). He also spoke highly of Al Gunter as well. Dad raced in Class C (that sortof sportman's division that the AMA conjured up in the 1950s), mostly rode Harley KRs (if he's to be belived, haahaa!). He stuck around the southern California region for the most part (Ascot, Perris, and so on). He was issued national number 57 in 1954 in the Class C division. He always said that I rode like Bart Markel ... haahaa. :)

This damned FLU has been screwing us out of what is probably the best winter weather we've ever seen out here (I've lived in the desert southwest since 1973). It was friggin NINETY DEGREES yesterday .... 90! So it's been this ideal winter for building a bike, and this danged FLU has had me grounded (on and off) since Thanksgiving of 2013!

Anyhow ....

I'm wanting to order the Cheney frame this coming week. I am pretty well set on the design aspects that Jerry (Cheney) will require to build the frame. As it stands, here's how I am wanting to configure it:

* Fifty Five inch wheelbase.
* Girder front fork system (by Durfee Girder).
* 21 inch front wheel assembly.
* Modern type front brakes.
* Yamaha XS650 engine.
* "Competition hardtail" design.
* Rake - Trail - Offset to be determined at the time of ordering (a short telecon to confirm these ideas will be all Jerry needs to decide on rake, trail, and offset.). I'm gonna guess it will be somewhere in the region of about 28 degrees of rake (or so) with about 4 inches of trail (or so) and whatever offset that Durfee and Cheney decide is the best to go with to make the bike turn in easily without making it squirrelly.

That said, I think I am about ready to order the frame.

I'll post more information on the girder type front end soon, it is a very intersting front suspension design that is all too often taken for granted. I mean, just imagine some insanely cool looking Racetech type coil-over reservoir shock nested within the girder, nickel plating on the girder's tube-works to match the nickel plated frame (by the way, we contacted our local chroming shop, they quoted us $125 to polish and double nickel plate the Cheney frame. One layer of copper, and a second layer of nickel).


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Hey Jeeter:
Mind me asking where in Arizona you are from?
The lower southwest corner, near the California-Arizona-Mexico border.

Sorry I didn't reply sooner. I spent seven days in the hospital with an 8mm kidney stone. Still goofing with that thing (it's my thirteenth kidney stone) for now, have an 18 inch stent, hard antibiotics, y'know, that whole hassle. Puking every night (antibiotics), pain meds every 4 hours. Screw this shit man, I just wanna ride.
Sorry to hear Jeeter. I have a friend with similar problems. They know him so well that when he walks into the ER, they just grab a gurney & start hooking him up with morphine. Hope you get it straightened out, I know it's painful. Love the last pic. I used to have a K model.
Sorry to hear Jeeter. I have a friend with similar problems. They know him so well that when he walks into the ER, they just grab a gurney & start hooking him up with morphine. Hope you get it straightened out, I know it's painful. Love the last pic. I used to have a K model.
Thanks. We'll see how it goes.

I think a KR750 engine would make for a fun street tracker if they weren't so rare. They had that sortof ~soft~ power delivery that made them so easy to ride. My first Harley streetbike was like that, it was a 1984 XLX61 (1000cc Sportster, stripped to the essentials). It only had about 50hp, and it had that ~soft~ power delivery so you could literally ride the living shit out of that bike and have an incredibly great time on it without worrying about accidently doing 165+mph, or the rear end stepping out drastically due to unsavory power delivery characteristics. Very forgiving bike. The XR750s of the 1970s had the power delivery worked out really well, at least those that were made into twingles (mine was). They were just far more "of the shark" than the KR750 was. Even Mert Lawill used to pine after the old KR750s over the XR750s due to that wonderful soft power delivery. Made the bike so well mannered on the track.

Then of course the Shell Thuett Yamaha XSs showed up, and a little sawed-off nobody ameteur rider wearing the yellow number 80y came along, and before too long he was wearing number 80 on a white plate, then not long after that he wore number 1 on a white plate. I think his name was Kenny something ;)
Just got off the phone with Jerry Cheney (he is currently en route to Daytona Bike Week, said he had not missed one in like 17 years). I was prepared to order the frame for this project today. However I needed to discuss the girder front end idea with him, he liked it and said there'd be zero troubles tweeking the Sonic Weld frame to suit the installation of a girder type front end.

Before I can order the frame he needs me to do some homework first. Jerry needs the basic offset dimension between the stem line and the axle center. But he'd really like a full set of dims from the girder builders. So I need to contact Durfee (I know of no other custom girder builder ... any help here?) and discuss my intentions to get this front end figured up.

Jerry is all about my idea of using the girder front end with the 21 inch front wheel on this street tracker, he is most definitely diggin' on it. He says he'll easily be able to combine the front end components I wish to use, be able to make the bike handle as I expect it to (pretty much like any fun track-inspired streetbike, kinda like a "motard" would be ridden). 55 inch wheelbase, 27-or-so-degrees rake, a couple of inches of offset, 4-or-so inches of trail, and enough ground clearance to produce lean angles that will make my nards run away and hide. Rough seat height will be about 26 inches, perhaps 27.

So, I need to get to designing that girder front end and get with Durfee on getting it made up. Jerry at Cheney Engineering will need as many engineering dims as I can provide to get this frame right.

Damn, I am most certainly AMPED!


What I am seeing in my mind's eye is this sortof hybrid flattracker (hybrid in the true sense of the word, not the modern slang that refers to the electric/internal-combustion propulsion designs intended to use less hydrocarbon fuels). It is taking all of the best parts of most of the ~best~ flat track eras. The purpose-built competition rigid frame from the "KR750 era" (1950s and 1960s), the 21 inch front wheel and girder forks of the 1950s "Class A Prototypes" (aka Speedway bikes, impossibly fast machines for getting around a groomed dirt oval), the Yamaha XS650 engine from the Shell Thuett/Roberts "HD is my bitch" era, and the basic look of the 1950s and 1960s Triumph and HD KR750 bikes (the double seat setup, shouldered Akront type rims, and the essential look/feel). And lastly modern type brakes front and rear, as well as a modern Racetech (or?) type reservior single rear shock used on the girder front end.

So it's a mix of many eras, many technologies, all hopefully put together in a tasteful manner that will please the eye, tease the memory, and be an absolute gas to ride. Oh, and cheap to own as well.


Durfee girder front end. I think I'll nickel plate mine, and imagine some sick-ass looking Racetech type single rear shock with an onboard reservior, adjustable everything at the rider's fingers, and the spring powdercoated to compliment whatever paint scheme I end up chosing.

Durfee Girder front end.jpg

Here's that Godden 1000cc "long track" bike again, no transmission (direct drive), rigid frame, and that 21 inch front wheel on that thing looks fairly righteous. The profile and basic shape is pretty bitchen. Since the 21 inch is only about 1/2 taller than the 19 inch is (due to tire profiles) the 21 isn't too awfully difficult to fit-up.

Nearly-A-Speedway bike - 1.jpg

Nearly-A-Speedway bike - 2.jpg

Nearly-A-Speedway bike - 3.jpg

~~~~ The AMA wanted to keep the prototype class very separate and distinct from the Class C production bikes and the Grand National factory backed bikes. So the "big wheeled, rigid framed" Class A bikes were relegated to Speedway racing, and the 19 inch front wheeled, suspended framed Class C and GN bikes to traditional 1/2 mile and 1 mile dirt ovals as well as TT tracks. But just imagine what would have happened if there were a flat track class that allowed big-displacement 2-cyl streetbike engines such as the XS650, XR750, Triumphs, BSAs, Nortons along with rigid frames, larger front wheels and so on .... wow ~~~~

That is sortof the heart and soul of this project I suppose.

Now, I am not totally and unbendingly set on the girder + 21 inch setup. I mean if a street tracker is properly set up with a 37mm telescopic fork and 19 inch front wheel they can look and perform like a seriously pissed off beast. I mean there is no more intense machine than the handbuilt flat track bikes built with streetbike engines. Those motorcycles took serious stones to ride at their peak output. I mean just look at how insanely intense this dirt racing machine is, holy cats that thing is a monster. Keep in mind that it is a friggin "dirt bike"! So I am not totally set on the girder/21 setup. I'm still keeping the telescopic/19 setup on the stove....


EARTH TO JEETER, EARTH TO JEETER .... ok, I think I got a little lost here.

I got to thinking (uh oh, can you smell the smoke from the shorted synapse?). The racebikes that Dad and I built were never these nickel plated "obviously sponsored" machines. They were basically development bikes in the sense that we were always changing them. And we didn't have a large racing budget either. My first racebike was a modified Yamaha JT1 Mini Enduro that we set up for TT and scrambles tracks (pretty cool machine, I put a Hooker pipe on it among other mods, never seen a Hooker pipe quite like it since. He and I also "corked" the crankcase, installed a cut rotary valve, foam sponge air filter without an airbox, Carlisle tires, and a little trick used by us JT1 riders - the choke on those bikes was actually an additional fuel passage. So we'd install what looked like a compression release lever that was actually connected to the choke actuator rod. On straight-aways in a full tuck I'd begin to creep that "compression release" lever inward adding fuel to the air/fuel charge which gave me several hunderd more RPM.).

Here's my little TT bike, I took the pic in October of 1972.


So anyhow, with the premise of this project being as if he and I were to have built this bike ourselves for some imaginary racing series, it seems best if I were to keep the "foo foo" to a minimum. Black painted frame and pipes, less high polish on aluminum parts, and so on. More the look of a privateer's bike that is raced every Saturday afternoon at Perris or DeAnza. Sortof like these here:


1960s - Pheonix Az - Beardsley TT track - Jon Sellars.jpg

This looks like a fun short track bike (below)


This choice also gives me the luxury of making changes to the frame (such as adding or removing various brackets or tabs for changes in seats or perhaps gas tanks or whatever.) It also allows me some lateral room to have Cheney make changes to the frame should I decide I want something ~big~ changed that required remove-and-reweld of some hunk of the frame. Sure the frame can be de-nickeled, welded on, then re-nickeled again. However I certainly do not have that kind of money.

Other than some cosmetic changes this decision doesn't really affect anything important or significant in this project. Everything pretty much stays the same, except it will look more like what Dad and I built for me a few times rather than a solidly sponsored bike built in a bike shop. And of course this decision also permits saving a pretty good bit of cash on the project, or the redirection of that money that was slated for plating into more important issues like making the front brakes just a little bit better than previously chosen.

The other thing I'm still unsteady on is the girder front end, and the 21 inch front wheel. I just need to research it all more, knowledge is power.

I located another girder builder, these look pretty sharp.

The Durfee girder is made from 4130 Chrome Moly, and TIG welded. The Spitfire is made of DOM Mild Steel (seamless tubing) and all TIG welded.

I think the DOM is fine, and another thing is the Durfee starts at $1,800 (ouch) however the Spitfire starts at $849. Before I learned about the price difference between the two designs I had already picked the Spitfire over the Durfee. The Spitfire just looks ~more trick~ (forgive me for this .... but it looks more "Hi Zoot" ... or if I really want to inflict pain, I could have said they're simply "Zoot Capri" ... shudder)

So since I've discovered the Spitfire girder I'm re-enthused about the use of the 21 inch front wheel and the girder front end. In case I have not already said so, this front end will be set up with the same rake/trail/offset as any standard hydraulic telescopic front end would have. It will also be no longer than any ~tracker~ front end. Just sayin'.

Here's some more things about the Spitfire (quoting their webpage here):

"The new Spitfire Girder front end is made from the highest quality American DOM tubing. All of the parts on this front end are CNC machined for a precise assembly. They are available in 2-inch length increments from -2″ to + 12″. We have designed this front end with two 300-lb coil-over damped shocks to maximize performance.

Comes complete with 3/4-inch axle and chrome hardware. Can be ordered with brake mount for 00-07 caliper CCI p/n 640263 Left or 640264 Right (must use 11.5″ rotor on late model narrow glide hub). Also available are 3 & 6 degree rake top link kits. Headlight sold separately. Like all of our products, this front end is made in our facility in Rancho Cucamonga, California USA. Price $849."

Yea, so if you look at the pics carefully you'll see a pair of what appear to be some half-decent short-stroke shocks. They might be sufficient for a while, I can have Racetech or Works Performance build up a set of fully adjustable reservoir shocks with 2-stage coils. Overkill? Yea, but that's ok. To be honest this entire bike is an indulgence, y'know?



And it appears that I can actually ask for dual-front-calipers/disks without any whining from them about it being "custom" or "super special order" or whatever. It's set up to use stock Harley calipers and 11.5" disks (I'll see if there are other caliper options, I mean one would think that there are aftermarket calipers that fit stock late model Harleys, which implies that those aftermarket parts will fit the Spitfire front end.

Best I can tell (so far) the girder front end ends up weighing in almost exactly the same as a standard telescopic/hydraulic front end does (with triple clamps - both front ends ready to install end up weighing about 30 pounds). The girder is far more rigid than a set of (let's say) 37mm, and perhaps 39mm. The popular choice of using the 43mm conventional telescopic front ends from early-2000s Yamaha R6 sportbikes (before Yamaha went to USDs on the R6) is fine and well supported by any number of suspension vendors. But the 43mm outweighs the girder by a chunk. Yea, see, I think the girder would be a well balanced match with the rest of this rigid framed street tracker. With some modernizing of the shocks, modern type brakes and tire, combined with the older engineering and design should make for an interesting construct.


Spitfire Girder Front End - 1.jpg

Spitfire - girderSlider-GeorgesBike.jpg