Kimjon

Thanks, yes lead is 11.342g/cm3 so only an increase of 3.332g/cm3 over steel. I looked online and tungsten is much heavier, which was a surprise. Tungsten is 19.25g/cm3 so more than double the weight of steel. I ran the numbers again a few different ways and if I drill a hole right through both sides of the counterweight at the same radius of the big end pin, I need a 10mm hole to add exactly the amount of counterweight I need. So...I'm now on the lookout for about 24mm (2x 12mm long bits) of diameter 10mm tungsten.

This photo shows the issue I have trying to find places for bigger holes: The con rod boss/webb the pin is pressed into can't be drilled into, or it would weaken it too much. Those holes I've drilled (in the photo above) have maxed out that location already. So pretty limited space where I can put holes. if I drill it where the vivid circle is, it would be counterproductive, as it's on the side I need to keep weight on, or possibly even add weight. Remove material here and it would have a negative effect. There's just enough room to put another set of 6mm holes, but it's not ideal and won't achieve what I need...but I guess every little bit helps.

Did more math... Not looking good is the short answer... But I'm not giving up on using the FCC (full circle crankshaft). Just have to approach this problem from a different angle. I'll give it some absorption time to think it over...but likely to involve drilling out the bottom side, then adding lead to it to increase the weight on the counterweight side.

Okay, not quite turning out how I had hoped. I'm trying to get a balance factor in the ballpark of 55%. However I got 0% first try, as in neutral with no reciprocating mass added...cunt!!!! so I enlarged the holes to the maximum possible it could take which was 11.5mm...checked it...still no good...fuck!!! So added additional 6mm holes, which was once again the biggest I could go given the situation. mother fucker!!! Only achieved 22% balance factor...double cunt!!!

Playing with these full circle camshafts. They're renowned for not being balanced. Bit of a black art, but basically a single cylinder engine can't be truly balanced...so lots of people have come up with trial and error rule of thumb like a "balance factor". Something between 55% - 60% seems to be what the I interweb says...so that will do. Before After (well actually more during) Holes are drilled and each time the balance factor is checked to see if more material needs removal. It should be close according to what I've read online that others have done, but likely to need a bit more of a tweak later when I've got better information from actually results, but I'll leave it there as I may window my piston and that would throw my results out the other way. So call it done for now.

Carburetor test fit, looks sweet! And a dead sexy bracket to hold the expansion chamber. Mmmmmm sexy bracket...mmmmm.....

Added a silencer, mainly for the restriction as my "stinger" (outlet side of expansion chamber) was too large in diameter. The additional benefits of a silencer is ummmm....added silence;) pretty happy so far with what I've made.

Hell yes! Exactly the look I was trying to achieve, like a 90's MX bike (yz, cr, kx, rm125 etc...) So next up on the list: 1) Cut the top of the cylinder head off. 2) mill/lathe cylinder head to get right deck and compression ratio. 3) port the fuck out of it 4) fit s domed head kit to replace the top of the cylinder that's getting cut off 5) fit a much larger diaphragm carburetor Then pretty it up and ride!

Expansion chamber in the making. I want exaggerated proportions on this Goped. Trying to bias the bulk out one side to over inflate its looks. I took several (as in I've been fucking around for 2hrs) attempts just trying to find the best line for the exhaust to flow. I'm settling on this look, as I personally think it compliments the motor and look I'm going for.

Got a little bit done. Motor is now mounted, tacked together and sitting well. This Goped was never designed to use a chain, so I'm offsetting the centerline of the wheels by about 10mm to allow room for it to fit. Hopefully this won't be an issue, but theres only one way to find out?

V-twinstroke?

On a random side note, I did a mini spring clean of the shed today. I had accumulated a rather large pile of ever increasing junk taking up a bay for no good reason. Amongst this was a project I rarely look at...so I removed the covers to reveal it for a look... Fuck yeah...seriously...fuck yeah!!! Makes me wonder what the fuck I'm doing spending time on gopeds when I could be putting the finishing touches on this 99% finished harley? Someone kick me in the balls!!!

After much thought, I'm going to put a CAG 49cc motor on it. My main reasoning for this was, I'd have to destroy a perfectly good pocket bike to put a C1 polini (replica) water cooled motor on it. I just dont have the heart to ruin a working bike just to get the motor - when I have two CAG motors sitting there in bits. So, I made a start... Here's the goped. Purchased as is, missing the motor. CAG motor getting a 6mm thick steel plate attached to the bottom of it. This will enable me to weld a strong pivot point to it. Close up of the OEM engine mount. This pivot held the motor, there was no clutch as in a centrifugal clutch. However the wire cable tensioner literally pulls the motor directly onto the tyre and transmits power via a friction drive spindle. To start, you push it to about a walking pace and then tension the motor down to contact the tyre...then you can stop pushing and the motor takes over. Pretty clever low tech solution. I'm going to do away with the friction drive system and transmit the power to the rear wheel using a chain drive via a centrifugal clutch. This has a number of advantages over the friction drive, and also solves the main problem with my motor spinning the opposite way to the OEM motor. I'm going to weld my steel mounting plate to this OEM pivot. I'll cut it to a suitable size to lower the motor down to provide a strong engine mount. I'll replace the cable with a spring and this will provide a constant chain tension. So that's the plan...

Those are very good reasons. I just work on the theory that accidents happen to other people and not me...so I should be sweet as:)

They're breeding like rabbits! Plus another one on the bench as a "work in progress". Waste of money you say - can't argue with that...but some people gamble or smoke that amount in a month, so there's worse habits out there I guess?

Shit hot! Just carjamed it and first registration was 22 May 1964...sweet!!!

Thanks. Yeah confusing eh... Think I don't need them, may have to double check registration dates, as it may have lapsed then been put back on etc...

Seatbelts? I've googled but end up with complicated tables of rules I don't understand. I was under the impression that pre 1972??? You don't need rear seatbelts if the vehicle never came with them? Is this right? Or kind of right?

Made this today, put together out of left over parts that have accumulated over the years doing other projects. It's been sitting in a pile of bits for almost a year on my work bench getting in the way everytime I try to do something... Pretty happy with it, making something out of nothing. Still needs a rear wheel, but I started it up and it sounds wicked!

Got it going with new gear ratio. It sheds the wheels spinning them with ease! Definitely worth the extra work to gear it at 6:100 in T8f. I need to raise it with thicker sleeves as I've bottomed out the chain a couple times on my driveway. Another 10mm ground clearance will make a world of difference. But hey, for 39cc it shreads!!!! Pretty happy with this one.

Had another visualizing session, just trying to balance it out as much as possible. Also found some solutions... Boy racer spec bonnet spacers...JDM as fuck! And my throttle system to operate twin motors simultaneously... I've thrashed my Ebay account once more - buying up a storm of cheap Chinese parts. Normal 6 week delivery time. So I'll grab some steel on Monday and start welding shit together, do as much as I can in the meantime for the win!

Very crudely. I only did a basic calculation with 100kg hanging on the hoop. Ignoring a heap of things just to get a feel for it. If you gave it a high stress value on the less than ideal welded joint, and a high shock value on the load being applied...it will still easily hold 25 people hanging on it (ignoring that the ground would fail first).

I brought my son this tempered glass basketball backboard for his birthday this week. Problem is I had no idea how monstrous it was in size/weight at the time of purchase (online). Slapping it up on a bit of 2" pipe wasn't going to happen. So: Trademe to the rescue again. An ex stadium spotlight pole at a whooping 180mm diameter, 10mm wall thickness and 5.9m length... "honest truth officer, I'm only moving it just down the road" Some "School-C" level mathematics and equivalent drawing talents soon had a design in place. Let's just say it has a generous factor of safety when I did the calculations for bending stress... And many hours later...cut and fitted, v notched for multiple weld passes...and shitted together using an arc welder. Not my finest work, I certainly wont be sitting any gasline or food grade welding tickets this week that's for sure... but I'm pretty confident it's not going to brake anytime soon. That's as far as I got today. Been up since 4.00am and just sat down now, so 14hrs of picking up and getting shit done today. Must be beer o'clock???

Okay, some progress... Mocking it up - will look similar to this. Yes that's right...and no you don't have double vision. Yup...twin motors...fuck yeah!!! Still lots to figure out and actually do in order to turn a collection of parts on the shed floor into a working trike, but progress is progress.

I chucked the new T8f sprocket in the lathe and took a 0.3mm skim off each side to bring it's thickness into spec. This was part of the deal when I ordered it. Here it is loosely mounted up. Luck of the Irish...everything clears where it needs too. Considering the first sprocket was almost half this size and that's what my design was tailored around - this was just dumb luck. But fuck it...I'll take dumb luck anyday, as I get my fair share of the opposite all to often. Ground clearance is tight, but it clears. I can put thicker sleeves on to raise it 10mm or so if this is really a problem? But think it'll work fine as is. Waiting on a chain breaker to arrive and then I'll sort the last steps out.