GT5A / Skyhawk Clone build - slowest build in recorded history.

Preamble to this - I have had a basic straight kit-build in the past decade, and an aborted build that was much higher grade, that had i lost interest in/evolved into the build being documented right now.. over a 5 year time-span.

I had stopped 'building' .. but i didn't stop monitoring/buying up parts to progress on another possible build. As such, in putting it all together when the project came back on the bench, i had minimum needed to buy, more a matter of pick and choose. In my frustration over my aborted build, i had built a higher-end eMTB - and some components of that, have also being able to filter down to this project. I have, in all truthfulness, already found my 'regular' ride in the Downhill eMTB. I am doing this project, for an occasional use neighborhood pavement-plonker.

In the meanwhile, the project had idled, as other projects jumped the project queue.. i did get a work bench into the garage, and organized parts so that i could find them, whatever project it might be awaiting... until several months ago being newly inspired, it hopped onto the workbench in this state... a collection of parts flying together in loose formation.

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In addition to the Belt Drive pulley option - one of the last things i had picked up, was 3 or 4 different variations of the 36 tooth sprocket/rotor adapter combo, but for the life of me i couldn't make it work.. I'm going to call that, my own cognitive issue. When i got it on the bench, i was looking at my drive-train options again, i laid them out.. and got a bit of a brainwave on the Belt Drive Pulley. See, i was never really happy with it, in Theory.. it's got no shouldering for belt retention. If alignment or tension is off, you aren't going to have belt retention! I just so happened to have a few 203mm rotors sitting on the bench at the same time, and my mind's eye made a visual connection.

Let us start putting a couple of these things together..

Now, along with a 255mm rotor that i had from Bicycledesigners.com...

This is the renewed Impetus for my Project. I couldn't make it work with 203mm/36 tooth combo, but i'm making the principle work in a way i haven't seen elsewhere... This is all a creative experiment, at this point, using what i have accumulated, minimum additional to purchase. I've already done several donations to Bike Cooperatives, in cleaning the garage of spare parts.. .

 

[Frogslayer]

Your going to have like 5 mile range with that battery bro. Might be alright though with the 2 stroke on there. Honestly going straight electric could be torqier and lighter.

 

[HackD]

Your going to have like 5 mile range with that battery bro. Might be alright though with the 2 stroke on there. Honestly going straight electric could be torqier and lighter.

I've got a full-on eBike build already. This is a mechanical experimentation exercise, with the driving factor being to augment my own diseased hips with a method, to get that 2 stroke running at speed. No need for a battery of larger capacity on this one.

I've got a Weird Johnny Gear-Loose thing going on, with this hybrid gas/electric build.

This one isn't all that lightweight, considering - it's a BBSHD 1000W build with a 48v12.5ah battery.. good for about 30km range, by my usage.

 

[HackD]

Project de Jour was the exhaust Stinger/Silencer, and securing down of same. This worked out beautifully - i actually was over-complicating what i was doing, thinking that i wouldn't have clearance on the top tube and would have to offset bracket it - instead, the PERFECT direct, adjustable fit. The shouldered bolt acts as a 'jackshaft', to fine-tune the distance that the exhaust sits out from the frame, and then lock-nutted and pinched in position on the modded frame bracket.

LHS inside of frame, tight and high against the seat post weld.

This aligns the repurposed Roll Bar light clamp bracket, well clear of the gas tank, and the canister from the seat stay, as well. Going to be no rattling, rubbing or creaking back there, from a poorly strapped down exhaust.

Final Product looks sanitary enough in presentation, for me.

 

[gary55]

Project de Jour was the exhaust Stinger/Silencer, and securing down of same. This worked out beautifully - i actually was over-complicating what i was doing, thinking that i wouldn't have clearance on the top tube and would have to offset bracket it - instead, the PERFECT direct, adjustable fit. The shouldered bolt acts as a 'jackshaft', to fine-tune the distance that the exhaust sits out from the frame, and then lock-nutted and pinched in position on the modded frame bracket.

LHS inside of frame, tight and high against the seat post weld.

View attachment 101771

This aligns the repurposed Roll Bar light clamp bracket, well clear of the gas tank, and the canister from the seat stay, as well. Going to be no rattling, rubbing or creaking back there, from a poorly strapped down exhaust.

View attachment 101772

Final Product looks sanitary enough in presentation, for me.

View attachment 101773

This has worked good for me at the flange to pipe connection. Easy to remove for cleaning out the muffler. 7/8" ID high tenp silicone.HPS - Manufacturer of High Temp Reinforced Performance Silicone Hoses , Aluminum Tubing & Stainless Steel Clamps


View media item 61262

 

[HackD]

This has worked good for me at the flange to pipe connection. Easy to remove for cleaning out the muffler. 7/8" ID high tenp silicone.HPS - Manufacturer of High Temp Reinforced Performance Silicone Hoses , Aluminum Tubing & Stainless Steel Clamps


View media item 61262

Mine is now 'permanently' riveted as an assembly. For what it's worth, i don't really plan on using the project all that regularly, for coking up of the exhaust system to become a pressing issue.

However, good tip for the future, as i had not done a 2 stroke exhaust before, much less cobbled one together.

 

[HackD]

A few complications cropped up, on the Build front.

Last night i removed the cranks/bottom bracket, and discovered that i needed an eccentric bottom bracket adapter.. 68mm x 54.8mm to be precise, so ordered and inbound. The TSDZ2 installation is stalled, and awaiting that part now.

I received my replacement Tektro HD-E710 front brake (needed for brake sensor).. go to install it, and find out that Tektro used a non-standard post spacing adapter for that brake model. What. The. Hell. So i guess i need to re-sort my front brake setup to accommodate that.. and the brake line is far too long for a front brake, even though it's a front brake...

So, back up to Ebay, and ordering an adapter component to bring that in from Australia.. oy vey.

As far as the photo goes - a couple of things going on here. The tail-light assembly is now finished and mounted, ready for wiring I switched and swapped LED modules out from another assembly. Also, just below the seat post clamp, can be seen a billet aluminium clamp, as normally used as the rear mount for the engine. It required significant conformal filing to fit the tube, and clear the seat post/tank weld, even though it was originally meant for that diameter tubing. This mount point will serve as the base mount for a tool-bag 'tray', with a two-point mounting setup, to hold the battery behind the seat. Additionally, i'll likely be adding another mount point for a small rechargeable battery pack for the lighting system, onto that tray, wrapping around the side of the seat-post downtube.

When the battery tool-bag shows in next day or so, the tray will be my focus, until the other parts come in.

 

[HackD]

This project is an ongoing exercise in frustration. I thought i had an industry standard BMX type 66mm bottom bracket on this, and had ordered an eccentric bottom bracket insert for it.

Either the bottom bracket is undersized by ~2mm, or the bottom bracket eccentric adapter is oversized by ~2mm in diameter.

I've got a long-assed while behind a file, ahead of me. I hope to get it down to tolerance enough to loose press fit in place, perhaps with assistance of tape to act as a soft-shim, prior to assembly of the Tongsheng motor. on the bottom Bracket - once together, any slip, will be entirely irrelevant.

Edit: what i needed, essentially, was a 51.2 mm eccentric bottom bracket, unthreaded. That appears to not exist, pretty much. This is a 54.5 mm eccentric bottom bracket. Essentially, what i need to do, and have been doing for the past 7 hours, is shaving 1.3 mm off of the bottom bracket - essentially, making the inside lines of the bottom bracket outer diameter, disappear.

No wonder my shoulders are wearing out in the joints..

~10 hours later, and making machined lines disappear. This was the hardest part, being full-width solid and at the outer point of the eccentric, needing planing down with broad-file. The rest should go quicker from here.

Update - Update - 20 hours of profile refiling total, i get to the required Tolerance.. BUT, i am going to need to do further work - looks like i need to improvise a 2 piece eccentric adapter, which will require bisecting this down to size - there is a machined line inside of the bottom bracket for the individual crank spindle and bearing cup inserts of the original crankset, therefore my modified 1-piece eccentric adapter, won't go straight through.

Out comes the hack-saw.. tomorrow.

 

[HackD]

Another photo flood and project report.

I bisected the eccentric bearing spacer, removing the Lobes of the 'Cam' that i had in effect created. The discarded centre was tossed in the spare spacers bucket. I will need to find appropriate thin-wall tubing to create an appropriate length floating spacer, to keep the two eccentric lobes from crushing in on each other under tightening torque of the electric motor spindle Jesus-nut, but these should be good.

What isn't working, is this. I'm fully a 1/2" short, of my seated goal on the motor spindle. Close, but no cigar. It's a tight fit on the bottom bracket, close to the motor spindle base.

This bike project is seemingly determined to try to reject this motor - but i am equally determined to make it work. It's my Rubik's Cube of the Present Moment.

I was able to clean up excess casting on the forward portion of the motor case on the left hand side bracket mount, which allowed the motor to slide in freely on the eccentrics.. but not enough reach/clearance. I will need to locate and carefully machine out about 2-3mm off of the bottom portion of the bottom bracket, in order to 'slot in' on two castings that are located on the motor case spindle base, that are otherwise unreachable - and those castings might also have a purpose underneath to protect something else, so I'm not going to mess with them. Should be worth an hour or two's worth of patience, on the Dremel.

Once everything is lined up with the soon to be fabricated centre floating spacer, eccentrics to final specs, and everything in place, i might also drill and tap both bottom bracket and eccentrics to take a 5mm bolt, to in order to 'Lock' those eccentrics in place, once everything is tightened down.

I WILL get this to mate together, fully.

Edit: After poking around in the metal pile in the back of the garage - seems i didn't need to go far. I have about 60 feet of T6061 that i had squirreled away for a project aluminium frame at one point, that i had forgotten about. I'm sure i can give up two inches. Being a packrat, comes in handy.

 

[HackD]

Now, THIS is a stonking great e-bike center stand!

My 1200cc motorcycle is less stable on it's center stand, than this!

Definitely has my recommend, if anyone is looking for Stability in their life!

Also, as can be seen in photo - the e-bike motor is now in. It was certainly a challenge, overall to get it to work with the Bottom Bracket.

Ursus Jumbo Double Leg Kickstand : Amazon.ca: Sports & Outdoors

Ursus Jumbo Double Leg Kickstand : Amazon.ca: Sports & Outdoors

www.amazon.ca

 

[HackD]

Toolbag, aka my 48v6ah battery bag came in today. The PERFECT fit!

Now that i have it in hand, i can produce the battery bracket/tray to support in position behind seat. I'll also be doing some leather sewing on this one, to fasten quick detach buckles on the back.