Frame Building - race bike for next season

Hey guys. Had a great experience getting my water-cooled-head gila in order and having a competitive bike in NY Moped GP (see other thread). I'm retiring the maxi frame and want something that is more thought out and based on my body and demands of small tracks with tight turns.

I have a bicycle frame jig, brazing and tig setup at my disposal and friends with lathes/bridgeports.

I havent settled on a frame design, but will be starting with reading Tony Foales Motorcycle Chassis and Frame Design book. Ill also be using some of his software for the tube mitering etc.

Ill be updating this thread throughout the winter. Im looking for any and all advice from people who have built frames. Pictures welcome, PM's too.

The end goal:

1. Lightweight, stiff, thin wall DOM steel frame. Style/form TBD.

2. Geometry scaled to my body.

3. Monoshock with adjustable suspension settings.

If anyone's on the east coast and has gone down this road and wants to share some info in person, I'd love to visit and buy you a beer.

Re: Frame Building - race bike for next season

Here for info

Re: Frame Building - race bike for next season

> corduroy Swoop Wrote:

> -------------------------------------------------------

> Here for info

Yup, was liatening to moped Monday podcast and they noted people arent making build threads very often. Hopefully this info can help other people looking to take a bite out of building.

Re: Frame Building - race bike for next season

Joe Schuitema /

When I designed and built my frame, I had no intentions of racing, so I kept the rake and trail conservative at 26 degrees and 2.75". Wheelbase is 48", about 7" longer than stock. Those numbers gave me great stability and confidence when going 60+mph, but when I brought it to a tight kart track, I was more pushing it around the track than riding. I was still able to be competitive and have fun, but its not what the bike likes. What are your intentions with the bike? Planning on a trellis, ladder style frame or something more simple with a large backbone? although a mono-shock may be a better, more modern way, I stuck with a twin shock so I didn't have to modify the subframe.

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Re: Frame Building - race bike for next season

> Joe Schuitema Wrote:

> -------------------------------------------------------

> When I designed and built my frame, I had no intentions of racing, so I

> kept the rake and trail conservative at 26 degrees and 2.75". Wheelbase

> is 48", about 7" longer than stock. Those numbers gave me great

> stability and confidence when going 60+mph, but when I brought it to a

> tight kart track, I was more pushing it around the track than riding. I

> was still able to be competitive and have fun, but its not what the bike

> likes. What are your intentions with the bike? Planning on a trellis,

> ladder style frame or something more simple with a large backbone?

> although a mono-shock may be a better, more modern way, I stuck with a

> twin shock so I didn't have to modify the subframe.

> >

Nice frame!! I need mine to have a twitchier rake and shorter wheelbase for the track.

I can go monoshock because im running an e50, so no subframe woes.

Re: Frame Building - race bike for next season

Look at how the little gp pocket bikes are designed, may help you in the design, they are capable and purpose built for kart track style racing

Re: Frame Building - race bike for next season

> river 2strokes Wrote:

> -------------------------------------------------------

> Look at how the little gp pocket bikes are designed, may help you in the

> design, they are capable and purpose built for kart track style racing

Yep those are typically monocoque or trellis frame style. I'm keeping that in mind, I may as well model after full size street bikes since they are scaled down

Re: Frame Building - race bike for next season

Triangulation my friend...

Stiff is great but too stiff is really bad. Every great frame has flex intentionally built in for the type of suspension, use case and rider preference. Gotta give somewhere...might as well make it intentional.

I’ll take some pictures of the two frames I’ve done in Solidworks once I’m at the shop tomorrow. One is for AHRMA USCRA GP200 and the other is for a BMW R100 motor.

I’m also building up my Derbi Variant for NEMA since I’ve been bored and wanted to play with a moped again.

Larry -

Re: Frame Building - race bike for next season

I can't offer any advice to help you out, but I can't wait to see you get started based on your last build thread. Maybe copy the Kreidler Van Veen bikes, as they seemed to work?

Re: Frame Building - race bike for next season

> Ryan Graeme Wrote:

> -------------------------------------------------------

> I can't offer any advice to help you out, but I can't wait to see you

> get started based on your last build thread. Maybe copy the Kreidler Van

> Veen bikes, as they seemed to work?

Ive looked at these. The frame style is great, but the geometry is designed for longer sweepers instead of the tight turns and chicanes on go kart tracks.

The kriedlers overall height and hip to rear axle distance will be taken into account

Re: Frame Building - race bike for next season

Kids dirt bikes and tiny gp bikes dominate kart track racing. At 6' I find the ovales, metrakits, and even nsr50s pretty hard to ride but other people seem to manage them.

The kx65 is a dream though. Fresh12" grippy tires are really confidence inspiring. Doesn't even feel possible to low side(edited)

Re: Frame Building - race bike for next season

Van Veen Kreidlers were built for actual racing tracks and speeds exceeding 100mph. For a kart track small frames are way more preferantial.

Re: Frame Building - race bike for next season

Check out the Dejager bikes from the 60's-70's. I keep thinking about building something like this.

dejager.jpg

Re: Frame Building - race bike for next season

> baird co Wrote:

> -------------------------------------------------------

> Check out the Dejager bikes from the 60's-70's. I keep thinking about

> building something like this.

Love that. The spine style is great for the way moped engines mount.

Re: Frame Building - race bike for next season

If you have TIG access why not do some aluminum box?

Offers proper flex and rigidity if properly designed - in all honesty if you want GP style design look at the NSR and RS chassis - perimeter aluminum box frame, engine mount spars and swingarm all have millions upon millions of dollars of research and development by HRC so what you’d learn from them would put you on the correct path

Re: Frame Building - race bike for next season

> river 2strokes Wrote:

> -------------------------------------------------------

> If you have TIG access why not do some aluminum box?

>

> Offers proper flex and rigidity if properly designed - in all honesty if

> you want GP style design look at the NSR and RS chassis - perimeter

> aluminum box frame, engine mount spars and swingarm all have millions

> upon millions of dollars of research and development by HRC so what

> you’d learn from them would put you on the correct path

I have tig access but have not done aluminum. For my first frame I am going to stay away from it for any stress parts. Chain guard/dash? Ya ill try that. Headtube and gussets? Eek not yet. I'd have to send the frame out for heat treatment too..

As I dig into frame design its clear that the standard twin spar / box frame takes the cake. Every company uses it ona bike. Thats for bikes with HEAVY engines relative to frame weight though..4 cyl 200 pound engines. My bike is 112 pounds right now.

My e50 has three NARROW mounting points. I'm working backwards from the engine and tire contact points. From there ill have a better idea of what the frame will physically look like.

Re: Frame Building - race bike for next season

> Lawrence Au Wrote:

> -------------------------------------------------------

> Triangulation my friend...

>

first of all, its pretty great that Larry commented and hopefully he has some more tips as the build progresses. He's a humble guy but has a lot of experience in motorcycle racing, his word is the gold standard.

I'm not even close to the same league but i have done some AHRMA racing experience and modified some vintage bikes for racing, not to mention dirt stuff that is probably more topical.

For my own race moped, i chose a pinto frame because i wanted something lightweight and tube, then i welded on a custom rear seat/shock subframe out of cr-mo tubing which pitched the entire frame forward effectively tightening up the rake because i didn't want to cut the neck and weld- the stock frame is very thin wall and its professionally coped and welded, i didn't trust myself to get it right in my garage, then i used Magnum forks with a 16 inch front wheel mostly because that was stuff i had around and the magnum forks are lighter than other forks and have hydraulic damping.

the tighter rake and trail makes it turn in really nice, it rides very similar to a mini-moto like a kx65 or XR100. i have medium wide MX bars with a mid rise so they end up about 4-5 inches above seat level. Raising up the seat was huge because it lets you get your weight high and forward like a dirtbike or mini.

the thing everyone fucks up with moped racing (i haven't actually done a moped gp event, so take this with a grain of salt) but it seems like people just want to make smaller versions with the same proportions as a motoGP road racing bike. at low speeds and tight stuff, in my experience riding supermoto and dirt, you're better off getting on top of it, just because of how tight everything is on a moped, plus getting the suspension to work right with limited options for parts puts you in a very compromised window.

anyhow, my advice is- start with the rider triangle and work your way back into a design. When i did mine i took photos of the frame and made measurements on the picture to see where i would end up, then i filled in the blanks with the parts i needed to use for practical purposes (forks, wheels, shocks) then i just 'connected the dots' between those parts. My bike looks weird as shit but it works well, hopefully next summer i'll get my program sorted out and make it to a moped GP track to actually compete against people.

Re: Frame Building - race bike for next season

> Graham Motzing Wrote:

> first of all, its pretty great that Larry commented and hopefully he has

> some more tips as the build progresses. He's a humble guy but has a lot

> of experience in motorcycle racing, his word is the gold standard.

>

> I'm not even close to the same league but i have done some AHRMA racing

> experience and modified some vintage bikes for racing, not to mention

> dirt stuff that is probably more topical.

Uh...I'm no gold standard Graham. Maybe by some moped standards cause I take showers, replace every part I think sucks and make things I want to ride and deem safe haha.

And correct, we aren't even close to the same league. YOU are way higher. You're the one who's been making heads and stuff for the community for years. I left for like 7 years and came back to MA and you're still kicking. But you and me are starting to get old. We've been doing bike things for a long time.

I completely forgot to reach out to you last time I came to Milwaukee for the Mama Tried show. That was one sketchy drive out last time me and Keino did it. I'm not sure if I'm going again this year, but we should link up soon. I got some fun ideas we should bounce back and forth...I want to elevate the moped game to the same level of the motorcycles I take to Handbuilt show in Austin and The Brooklyn Invitational. Partially because I'm getting a little tired of how serious the motorcycle game is, especially when it comes to the high dollar race bikes (new and old). But that doesn't mean I'm going to roll around on a rusty bike with original tires...you know me better than that.

I only had a few minutes at the shop tonight after work then had to run home to start dinner. So I couldn't take any good pics of the custom frame bikes. But you can peak in a pic in the background the Seeley inspired Honda frame in the background. I only had a chance to snap a pic of my Derbi frame I did and the hoarding of Revolution motors I've been doing, but you can see the difference between Vapor Blasting vs Steel Wool vs Dirt & Mud. Maybe I'll start a build thread on here of it. Who knows...I don't even think people really care.

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Re: Frame Building - race bike for next season

Continued

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Re: Frame Building - race bike for next season

I hope you do a build thread here , Larry .

I don't know you or your work , but for the few pics you posted above . You seem rather 'devoted' and that's generally what it takes to produce quality .

Re: Frame Building - race bike for next season

> P D Wrote:

> -------------------------------------------------------

> I hope you do a build thread here , Larry .

>

> I don't know you or your work , but for the few pics you posted above .

> You seem rather 'devoted' and that's generally what it takes to produce

> quality .

Hah!

Thanks man.

I see from your profile you're in Sioux Falls.

Do you know my friend Brian Klock from Klockworks? He's not too far from you in Mitchell. I only say it as he's my only reference of location in SD, haha. Really really good man that one...

Larry -

Re: Frame Building - race bike for next season

http://www.eurospares.com/

what is your opinion on the bidalot rs or malossi mvr frame design?

stick with silicon bronze for GTAW on thin stuff. super easy to work with.

Re: Frame Building - race bike for next season

> Lawrence Au Wrote:

> -------------------------------------------------------

> > P D Wrote:

>

> > -------------------------------------------------------

>

> > I hope you do a build thread here , Larry .

>

> >

>

> > I don't know you or your work , but for the few pics you posted above

> .

>

> > You seem rather 'devoted' and that's generally what it takes to

> produce

>

> > quality .

>

> Hah!

>

> Thanks man.

>

> I see from your profile you're in Sioux Falls.

>

> Do you know my friend Brian Klock from Klockworks? He's not too far from

> you in Mitchell. I only say it as he's my only reference of location in

> SD, haha. Really really good man that one...

>

> Larry -

You're welcome , Larry . :)

South Dakota is our domicile state for legal purposes . We are full time RVers and live in our motor home . Currently , we're at Wappapello Lake , Missouri and leaving for Arkansas in the morning , on our way to Texas for the Winter .

I don't know Brian Klock , but Klockworks sounds familiar .

Re: Frame Building - race bike for next season

Here's my race bike I built for the motorized bicycle races (which are often frowned upon by moped guys because it's not a "traditional" moped.)

24" bmx frame stretched and modified for a V1. Weighs just under 70lbs and geared for the track will hit 55mph. (10-42 gearing.)

Posting it so you get ideas to think outside of the box. If you're building your own frame, you don't have to conform to "but it's not a real moped" mentality.

IMG_20190326_142800.jpg

Re: Frame Building - race bike for next season

ha ha well now, we might find ourselves in a good old fashioned minnesota nice-off if we aren't careful.

I dunno if you caught it through the grapevine or what but i worked for Harley for the last two years doing powertrain design, got to meet a lot of really good folks through there, ended up quitting that gig and bought a lil' farm up north wisconsin and now i design trailer hitches, haha, little change of pace.

some of these people, you can catch for a 5 minute watercooler conversation and learn more than reading 5 books. my buddy Wes (second place in 500 at Barber this year) and my other buddy Andy (first place in the same race) gave me some really good tips for 'flat out friday' at mama tried two years ago where i built that bike to compete on a flat track concrete oval covered with sticky soda syrup.

alas, my wrist pin needle bearing didn't like 11,000 rpm on 13x45 gearing when i was doing test and tune down the block and i didn't even get a chance to run that bike.. bummer. its a shame because it was wicked fast and the handling from the little bit that i got to ride it felt damn good...

next year for moped GP i'll try to throw together this stroker athena AJH dmp clone kit that has been on my shelf for too long and see what i can do in single speed class.

Re: Frame Building - race bike for next season

Anonymous User /
scootertrash

The BMX turned out awesome! Gangster

PD I’m 2 hours north.(edited)

Re: Frame Building - race bike for next season

> Ana L. of the Aurora Roras Wrote:

> -------------------------------------------------------

>

> PD I’m 2 hours north.

Ha . We were at Carlyle Lake the week before . Went well around St Louis .

We try to stay away from big towns and freeways . A lot less stress .

Currently we're in Kensett , Arkansas . Only about 5 hours South .

Re: Frame Building - race bike for next season

bump

Re: Frame Building - race bike for next season

Is Nick Leeflang still making VanVeen frames?

> Bas Autowas Wrote:

> -------------------------------------------------------

> Van Veen Kreidlers were built for actual racing tracks and speeds

> exceeding 100mph. For a kart track small frames are way more

> preferantial.

Re: Frame Building - race bike for next season

No prototype made yet. I've been working on my GTI and dialing in my 3d printer for the model (mounting plates for the e50)

Also learning Fusion 360 for modeling.

I'll be sending the dimensions to larry for some solidworks stress testing too.

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