Old Guys Simplex moto-peddle bike

Wow lots of reply's yesterday and I'm pleased with that and again thanks to all for all. Steve is right this is a great forum! I'll do my best to address each of you through several posts and a few photos & my comments won't necessarily be linear in nature, though I hope they give some insight as to my thinking and know that your thoughts have my consideration.

Rick C.

Tom brought up the question of material strength & that should be a concern with any motorized bike, but as Pat pointed out application is highly relevant. I'd add to the conversation that todays steels are vastly superior to those available though out the classic period of motorcycling and roadways much improved and available. Standard clincher tires and other materials used in bike design and construction are vastly better. Still safety and quality go hand in hand and require the fabricators attention &appropriate selection.

Rick C.

PeteMcP said:

"Rollin, rollin, rollin...."
Hmmm, I'm betting maybe the fork isn't short. Possibly just the camera angle - and perspective being exacerbated by that longer temporary stem.

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Pete the last photos I posted are at a better angle for you and Pat to consider. That goose neck stem is really distracting and I'd have been better off not mounting the bars, till I could do it right.

My take is; the fork is actually short. Both you guys brought up good insights into what this means in the real world of riding and much goes back to application, type of riding, and feel. My use of the un sprung truss/girder style is as much for historic stylistic reasons as it is for function. I found it works well on another build & it's simple.

I checked the axle trail & found 1.5" positive trail on the Sportsman frame. now I'd allow .25" plus or minus on my trail number, but either way it's in the area I want for general riding. Pat's comment on short track forks running vertical is spot on, I'd add to that some run slightly negative trail metrics, for quick handling and track feel. My comments represent typical setup in the last century, lol. These bikes were fairly short wheel base machines running at comparatively slower speeds and radical riding attitude. High speed bikes tend to have longer wheel base and more positive axle trail & slightly more aggressive rake. A lot of factors enter into this other than the simple rake/head angle, and trail numbers.

Fenders I like on others bikes, but I don't build with fenders. The truss fork has 7/8" tire clearance and that's not enough for a fender, unless the drops are extended and that would radically change steering geometry. I did this when converting a truss fork to leaf spring for my Simplex, both wheel base and axle trail were extended and for my purpose it worked out, but I'd not want to alter the drops on my current build.

Early board track racers weren't as short in wheelbase as many photos suggest, and they didn't seem to follow a strict WB guideline. They probably just searched for that sweet spot. I measured the Sportsman wheelbase at 51" with axle forward and 52.5" adjusted mid drop seems about right & that surprised me with this fork. My Simplex is stretched to 53" as is my extended hybrid...the HD Peashooter is at 50". So this one is about where I've had good luck with other builds, though trail on each is different. The Simplex is 2.5" positive trail and is super stable, but not quick. Both the other two less than 2" trail. Handling is a fine line. ..a tight rope really. A small adjustment results in radical handling characteristic.

The controller, behind the seat tube will be mounted as high as possible to allow chain clearances on both pedal and motor drive sides.

3.5" clearance is really low.

Rick C.

sportscarpat said:

For me I see how close the front tire is to the down tube. Big difference from the forks I use. It will certainly make for a steeper steering angle as this lowers the front of the bike. Over time I have lengthened my forks to relax the steering geometry for more stability. This fork Rick has should still work but will have quicker steering. It will be interesting to see the bike sitting on its tires from a direct side view so I can see the angle of the top frame tube relative to the ground. I also need to keep in mind that the front part of the down tube on this frame is further forward. I lowered the loop and raised the upper bend higher just under the center tube which has also brought the down tube closer to the wheel. I have another frame just like this one with longer forks installed and can post a picture here if people want to see the difference.

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Pat please post the photos as an aid to understanding the differences that fork selection makes.

I'm discovering alterations that you've injected into this frame and I'm thankful for them. You've designed & produce the Sportsman series of frames for years & these encompass a broad range of riding uses, land speed racers to pedal bikes. So I value your willingness to alter what you know works and re-design important elements of your frames, for what I believed would be a one off custom frame. For you to participate in an open forum, regarding this special work, is to me an extraordinary opportunity to gain insight into your process. You took the time to think through my basic requirements and render them in steel & I value this.

Your Harley springer fork is a thing of beauty and a joy forever and I can't wait to see one mounted on the deep loop frame!

Rick C.

fasteddy said:

This build has it all. An incredible hand built period correct engine with a cleverly concealed electric motor with a brass carb that isn't real made from a brass T fitting made for tubing. A custom made Sportsman Flyer frame for it to sit in.

Tutorials on welding and a great amount of input from the builder and fellow viewers. What a grand forum this is.

Steve.

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Thanks Steve you long time old timers here on the forum have set high standards for content and the value of quality content and community rather than centering on drama and spiteful egos, and that's what marks a great forum ...dealing with any topic.

Rick C.

Lol, Mags. I was so beat last night that I'm surprised I found a bed, got up just after 3a.m. & started resizing, naming and sorting photos I took late yesterday afternoon. Still have some to finish and many to cull. I'm not very good with photos, but value their uses.

I make sure the bikes are clean before they come inside and never after lubricants and fuel are added. I've done this for the last ten years and not damaged or soiled my home once!

I've come up with some pretty good design ideas while eating a meal and pondering a half built bike, like this one.

Rick C.

PeteMcP said:

Rick, with this build's major parts to hand, I'd also have been unable to break off from working on it or to grab some sleep till I had the 'money shot' with engine mated to rolling frame. Maybe I'm guilty of over-using the phrase 'the dog's danglers' - but this aptly describes the bike I'm seeing in your latest shots. So excited for you I could use a cigarette - and I don't even smoke!
Fork rake looks spot on to me in that side-on view. Nailed it.

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Pete I appreciate it and this forum has more than a few builds that actually qualify for your defining description.

I couldn't break off without taking a few pics& the photos were shot before I lost light and found sleep yesterday.

Rick C.

sportscarpat said:

Man, that fork is short.
I see two engine mounts. Are you planning a third? Heads to center tube.
I see some discussion ablove about .120" wall DOM. In my experience it is seriously strong, and heavy. For the lighter duty applications, like electric bikes, I use .090" wall ERW as it's more than strong enough and I prefer to save a few pounds. I prefer .120" wall for the motorcycle tire applications.
Pat

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Pat I'll be adding a "bridge" mount attached to both heads and anchored to the tank straddle tube with another Harley tube clamp. These HD clamps are ridiculously strong.

Also the motor case actually sits on the frame loop which is also cupped to hold the motor case from twisting, even if the other three motor supports are unattached the motor can't move enough to even tilt enough to notice side to side or front to back.

Rick C.

FOG said:

Can I push the like button twice?

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Thanks FOG and I do quite often, just on account of I can and they deserve it!

Rick C.

And looks great as well Pat. The photos clearly show both clearance and fork to frame geometry change. I love these forks!

Rick C.

I agree Pete. Thumbs up on the scissor damper, but with or without this is a great looking fork. I'd say the longer length makes it more suitable for a variety of completed looks. There is no doubt in my mind that the extra length noticeably changes handling as was previously described. Now that's not a criticism, just what I'd term as a realistic observation. Coupled with the availability of differing spring rates and adjustable damping the fork can be tuned to suit. Obviously it works well with the other Sportsman frames and this deep dish frame just provides an opportunity to tune another to suit.

My use of the truss fork is basically a one trick pony, at it's current length though I could lengthen the drops as I did on the truss fork I based my Simplex leaf fork on (photo below). This allowed mounting larger tires and provided plenty of room for suspension travel. It also modified the axle trail and the change in suspension geometry is noticeable, It also increased wheelbase. I like the results, but hindsight tells me I lucked out rather than designed in handling that works. I'd advise keeping both the mind and eyes wide open when scratch building any style fork, testing with great caution on varying road surfaces before adding a little more speed and repeating.

Like Pat posted building frames is relatively easy compared to forks. The real trick, I'd submit, is to do both and get them to work together. Pat's observation about the short truss fork was a subtle reminder for me to check my premises and verify it's use with the new frame and I will and am grateful for bringing this to my attention. Just because I think it will work, and has on past builds, doesn't mean it will perform well on my current project!

Rick C.

Thanks Tom & I'm certain Pat will be pleased with your input as well. I greased the wheel but he built it, as well as the HD style handle bars and I hope to be able to use his tank to hold my battery pack also. My input on his frame was just the need for more space to mount the motor and to drop the center of gravity. I provided dimensions and weight that the frame would carry and he suggested material that would do the job. How he arrived at my requirements I left up to his experience with his frames. Along the way we corresponded with 4 pages of private mail on various bike topics and he followed my e-V-twin motor case posts in this thread, so to say he took an interest in what I was doing is quite an understatement of the reality. Communication and understanding my needs allowed him to design a frame that would really benefit my project. He went the extra mile!

Does the frame suit me? Absolutely. Does my motor case fit perfectly? It does, though routing my drive chain will be more eccentric than normal, what with jackshaft built in the case and motor output shaft located so low in the frame. We'd already discussed this so it came as no shock to me, and as problems go it's not a big deal. The motor case design is on me not Pat and this is where I confess to the bike build itself being a cycle assembled of bits purchased from a couple of guys I trust and have some history with. My selection and $$ are pretty much all I'm providing on this platform, other than final assembly.This frees me up to work on the electric V-twin motor cases and the associated controls and battery packs. The electronics I'm just learning about and they too will be purchased. The battery packs I will eventually build myself.

There's still a part of me that want's to fabricate each individual part, but that's just ego talking crap, so I'm concentrating on what I really want to work on and that's vintage e-V-twin motor cases, with variations; including a dual e-motor case and drive

Rick C.

sportscarpat said:

Deep Dish by Pat Dolan, on Flickr

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Pat I'm so excited by your enthusiasm to get started on a bike built on the "deep dish" frame and it looks great to this point. Will this mount an electric or a large gas motor? Either way it'll be a beauty.

What's the wheel base & trail with the pictured fork?

Rick C.