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Probly not the proper forum for this but couldn't find a better one either so what the hell...

So I got this kids ATV from my neighbour for free so couldn't turn it down, upon closer examination it was quickly quite clear it would cost me more to fix this than to buy a slightly used but working one so I decided to chop this one up and make a crosskart out of it for my and my sister's boys to arse around in the field at my mom's.


Here's the frame stripped bare. Looks like somebody has had fun with it, not a straight bit on it.



A very rough test of how long it needs to be for the driver's feet to clear the front tires at full lock. Looking at around 70cm of added tube minus the overlay so the actual stretch would be somewhere around 40:ish cm. The first question I have is how much will it affect the performance of the rear shock to be mounted almost vertical instead of in a 45° angle as it was before? Will it be harder or softer? The pivot point on the rear shock isn't that much higher from the hinge point so I don't reckon it should cause it to go limp near full compression if the pivot point would be moving more forward than upward.

First bigger decision to make is will I split the front suspension in half to make the thing wider and shorter or leave it as is. It's sort of narrow-ish for being so long but I suppose within reason. My main fear is if I widen the front I'm gonna have to widen the rear too and since that's nothing more than a single axel on a swingarm making it awfully wide could make this thing too hard to turn for small kids.
 

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Bit on the narrow side for the length... Might have to split the front end in half to make it wider... Need to do some sandrail frame design studying.
 

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Breaking shit...
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neat stuff. subbbrd
 

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Yea gonna have to split the front, not difficult just a lot of work. Not in a rush tho deadline for next spring, this is probly gonna be one of those builds that move in bursts of inspiration with months of crickets in between :D
 

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re-tarded
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I agree about widening the front. Rear seems less important.

With the shock at 45, for each inch the mount goes up the shock compresses about .7". It varies some because the shock angle changes with suspension compression, but somewhere around there. With it at 90, an inch is an inch.

Compressing the shock more requires more force, so it should be stiffer (but with less travel) with it vertical. A ballpark estimate is 1.4x as stiff (1/.7), .7x the travel. Why .7? sin(45*).

The angle that really matters is shock vs swingarm. If they're parallel, the shock does nothing. If they're perpendicular, the shock is stiffest. Between there it varies.
 

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Gonna cut out the entire old subframe and weld the new bottom frame rails straight to the swingarm mounts, this lets me fit the shock mount wherever I please so gonna be having the shock at around 45° as it was. Going to split the front end and already have a pretty good game plan on how to do it, Just don't have time to do nothing to this for a while so that's gonna have to wait.
 
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The garage is still a heaping mess bad enough to not be able to even get the bike in but managed to get this thing forward a little bit today by buying this:







Brand spanking new crate engine, never run straight off the shelf, 6.5hp and 196cc, way too much for the lemmings but shouldn`t be too hard to make a governor, it has both a ripcord and a 12v starter just need to peruse through the manual about what to hook and where as I don`t currently see any loose wire ends to hook up to a battery. It`s physically bigger than the 160cc I went to get but they were all out of those and this was the next cheapest thing to get anywhere at 199e. Now I need to order a centrifugal clutch to go with it to get the chain alignment, tried it on a bit and it will sit a wee bit to the right but since it`s a four wheeler off-road vehicle I don`t suppose that will be an issue at all.
 
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^ think ive actually watched some of those but subbed just in case.
 

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test run done, motor works, ordered a centrifugal clutch, should receive it sometime next week. Still need to clear up the garage but right now my main goal is SMASH next weekend so probly not a whole helluva lot happening to this for a while still.

Oh, also bought a Bahco pipe cutter and four rods of 22x1.5mm pipe.
 

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Clutch came today, fits the axel like a greased glove but it didn't come with the fixing bolt, tried a normal m8 bolt but the hole appears to be fine thread, the problem is the manual doesn't specify the pitch but I reckon it's probly 8x1, can't be arsed with it right now though as SMASH is one day away. Went with the ten tooth version even though 14 would have been cheaper but trying to limit the top speed for the meerkats as the engine already is 6.5hp which will send a couple fire extinguisher sized brats flying if left unrestricted.
 

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V four honda whore
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So we can expect for power wheelies?
 

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heh yea probly not this type of clutch tends to slip like hell so I`d honestly be impressed if this can fling dirt at takeoff at all.
 

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Did a thing today! Can`t seem to get to do anything to this at home so as my wife was going in to sleep for the third night shift in a row I packed the pieces up to the van and headed to my homeplace, dumped the lemmings onto grandma for a few hours and went to town with the angle grinder. Had to take apart the entire front suspension to be able to split the front end in two but eventually had it in pieces. Apparently the factory doesn`t bother with stuff like tension release treatment as the two pieces basically shot apart when I got the last part holding them together cut. Now that I look at the parts more closely the entire thing seems welded together somewhat haphazardly. The weld seams themselves are withing acceptable but symmetry wise the whole thing looks like it`s slapped together without a jig. Anyway the front end will be seeing an additional 16cm of track width which directed my attention to an another problem. I had noticed before that the rear swing is asymmetrical but had not paid enough attention to quite how much, so it might well be I need to extend the rear axel a little from at least one side but that is something that can be done after everything else is sorted no problems.
 

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Now that the bike is off the table (and hopefully keeping off too!) I figured I'd slap the front wheels back onto this thing to have a peek of the dimensions. The front is only about one tire width wider than the back so I don't think that is gonna cause any issues. Now just gotta try to find time to start gluing sticks together to start forming a frame. And trying to find a suitable seat. And longer tracking rods (though I suppose I can just cut em and weld a pipe in between...)
 

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V four honda whore
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if you ever consider bodywork
 

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The thought did cross my mind but I've never been good with panel beating besides it's a lot of work for little gain. And I need to make a roof in case the boys manage to roll it so going for the sandrail buggy look.
 

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Got a huge inspiration to start welding this right after I got the garage empty, actually got a few bits done til I had to call quits when a stray spark found a very delicate place to land on...
 

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Few bits more spit welded on, cut up the old front fairing for a looksie, needs work but usable, gotta pop into the hardware store to get a few rods of tube tomorrow, goal for the weekend is to sort the rear suspension mount, then I can start fabbing up the main cage. This is fun :D not stressing about shit being nidentical to the millimeter and stuff, basically just eyeballing it and going yeea that's close enough :D best stress release since SMASH.
 

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Tried to notch the ends of that tube with a drill cutter thingy (don`t remember what`s it called) and failed miserably, could probly have made it neater if I had set a pack of wolves to maul it into shape so had a go with the drill press, much much better.



A few shock mounts from a 6mm piece of scrap, way overkill but hey it was free.





Aaaand we have a rolling self supporting chassis. Well, the bottom part of it anyway... Left that pole too long on purpose to be cut into shape later, probly gonna bend it back above the shock mount to make more room for the driver seat (which I still have no idea where to get from)
 
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