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  #1  
Old 11-14-2019, 08:20 PM
Voodoo Rufus Voodoo Rufus is offline
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Default Invader restoration and Murray Kilowatt

I made some more progress on my Invader restoration project this past weekend. It goes slowly since I keep it at my parents place (acreage to run it). It got a new axle, wheels, brake caliper, disc, tires and chain. The original axle was bent. I also bought a Tillotson 212E and new Max Torque clutch for it.. I have new, larger tie rods yet to be installed. I think it does need new spindles but need to measure them. There's a fair amount of frame rust now, but I'll get to painting or powder coating it eventually. I just want to get it running for now. I would re-drill the tie rod holes closer to the pivot, but steering is already limited by the mounts. My brother chopped the frame in half to lengthen the wheelbase in the past, so it's not as nimble or drift happy as it used to be. I have found out that the Invaders were made with Chromoly tubing, so I'm a little disappointed in the alteration because I'm certain the added tubing is not up to the same spec. We're also much 'bigger' kids now compared to when I bought this 20+ years ago. I'm tempted to pick up another one in stock form just to keep the factory wheelbase. Looking forward to getting it really under it's own power around Xmas. If it doesn't have enough motivation, I suppose I could always add a 30-series TC to it.

On to the Murray. I got the original owner to drop their price to something more reasonable, so I grabbed it locally. As you can see in the pics, the tires are far larger than the originals. The rears are 22", and the fronts are 21". The Predator 6.5 works fine, and the TC appears to work fine. The shocks are blown. The rears are reservoir shocks with the reservoirs removed, so I have springs but no damping. The driven pulley is a 7", but with those 22" rear tires, I don't think it gets up more than about 20mph. The engine never appears to hit the governor and feels like it's working pretty hard. The kart is far heavier than the Invader for obvious reasons, too. It also needs some touch up paint. My options here are to reduce the tire size back to 18" or attempt a Predator 420cc and Series 40 TC swap. I would likely go with slicks or turf tires to try to get some dirt drift action into it.

Open to comments and suggestions. I want to get these going well enough for myself, my fiance and my brother to enjoy whenever we visit home.

Sorry for the non kart-modeling quality of the photos. Still, that little Tillotson is one good looking motor!
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  #2  
Old 12-30-2019, 01:07 PM
Voodoo Rufus Voodoo Rufus is offline
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No new pictures for now, but I do finally have results.

The Murray is usable but slow. I'm going to be swapping out the 22" knobbies for 18-9.5-8 turf tires to get the gearing back into spec. It can't go fast enough to get the driven pulley to change ratio.

The front shocks are 12" long with 1/2" bolt holes. I'm having a hard time finding replacements for these.

The rear shocks are 3/8" holes and 12.5" long. These seem to be standard enough.

The front wheels seem to have a 3.5" diagonal spacing for the hub on an 8" rim. I want to swap out these tires as well. The current tires are 21x7x8".

The Invader has been a pleasant surprise. After getting the throttle cable sorted, new clutch and chain on, it was time to break in the motor and have some fun. It has turned out to be very torquey. It hit the governor way too fast and abruptly, so I move the spring outwards on the adjustment holes. I did the same on the Murray but to no effect. Now the 212E hits the governor more softly, but still gets there easily. It feels like it wants to rev even higher. I didn't speed check it, but the kart should be breaking into the 30s with ease. It's also a massive drift monster on the soft grass and wet dirt. I didn't expect this since my brother and I are way bigger than we were as kids and with the lengthened chassis, but this thing feels as fast and drifty as when we were kids. It's a total hoot! I do want to know what it'll take to safely let it rev freely.

I do need new spindles for it, and the rear disc brake is snug but soft on action. I see why people move to hydraulic brakes now. The next task is to get the Invader down to my home so I can get the chassis refinished.

I'll fix up the Murray, but since everyone seems to like the speed and playfulness of the Invader, I expect I'll be selling the Murray to pick up another Invader. The Murray would definitely benefit from a 420cc and series 40, but I don't see the cost to benefit ratio as being good enough.
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Old 02-07-2020, 11:55 AM
Voodoo Rufus Voodoo Rufus is offline
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Last weekend I swapped the 22" knobbies for 18" turf tires on the Murray. Definitely helped acceleration and no longer feels like it's bogging, and also turns much better. Lower CG feels more confident. Top end feels about the same, probably in the low 20mph range. Still can't hit the governor. Both ends of the 30-series seem to function properly.

Ordered a new drive belt as the current one I don't know is the right one or not. Also finally got new shocks on the way.

Any ideas for the Predator 212 and top end? Granted the Murray is pretty heavy compared to the Invader.

I'm tempted to make it a guinea pig and tear it apart to do flywheel/cam/valve springs and air/fuel upgrades. Although it may be more tempting and easier to just do a 420cc and 40-series upgrade. Kind of expensive to do, though.
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Old 02-07-2020, 06:56 PM
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gegcorp2012 gegcorp2012 is offline
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Quote:
Originally Posted by Voodoo Rufus View Post
...
Although it may be more tempting and easier to just do a 420cc and 40-series upgrade. Kind of expensive to do, though.
I agree on the 420 upgrade being on the expensive side. There was a sale at the first of the month on the HF 420 for just $ 299 and that was the best price I have seen in 6 mos of watching. I may try one some day after brakes and full cage upgrades.

The Invader looks really nice.



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  #5  
Old 02-08-2020, 12:09 PM
Voodoo Rufus Voodoo Rufus is offline
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$300 for the motor wouldn't be bad at all. The other sticky point is how much a 40 series TC costs. It's more than the motor! The Murray is a pretty heavy kart with the two-level chassis and full cage. The Invader is really light in comparison and a drift monkey on grass.
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Old 02-24-2020, 09:39 PM
Voodoo Rufus Voodoo Rufus is offline
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More work done on the Murray a weekend ago.

New shocks:
Standard duty on the front. Required swapping the metal bushings from the old ones to new ones to mount with the bolts on the kart.
Rear heavy duty shocks. Bolts fit fine. I need to use my die grinder on the lower mounts to prevent any binding but there's not much movement as is. Changed out the hardware on the upper mounts to Grade 8 since the old bolts were nearly frozen. Cheap upgrade.

New drive belt from GPS. Side by side comparison with the belt that came off is night and day. The GPS unit is much beefier, wider, thicker and has coarser teeth. Almost makes me wonder if the old belt was some random asymmetric belt that belonged on a lawn mower or something.

16x6.5x8 front turf tires. The old tires were way too tall and caused a lot of spindle wobble when turning hard.

Verdict:
The kart acclerates as it should! Actually feels like it approaches a governed top speed, perhaps around 30mph. Fast enough.

Suspension with actual damping is a huge improvement on ride quality. No more rear axle hop. It should be noted that the rear geometry is not optimal. I think the kart would be better served with shocks that acted more vertically.

Turning is far better now with proper tires all around. Sits a little lower so driving confidence is higher.

Can almost get it to drift on grass, but not quite. Still could use some more grunt, so I'm pondering options. Might swap the Tillotson 212E to it and put a 225RS on the Invader if I'm feeling particularly nuts. or just pick up a second 212E and behave myself.

I would like to tighten up the action on the spindles and front A-arms, but not sure how to do that or if it's possible. Way too much wiggle. But then again, this isn't a precision instrument, either.

Also swapped the engine mount hardware to Grade 8 on the Invader since it wiggled loose and cleaned the mounting plate top and bottom. No more issues.

From what I've been able to gather, the jackshaft is 5/8". I wonder if there's enough room to put a proper 40 series driven on that, or if I might need to get a longer shaft. Either way, if it's possible it would make the upgrade to a 420-460cc class engine far easier. The way that Cars and Cameras did it with a double-chain setup seemed distinctly....not engineered.
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  #7  
Old 03-17-2020, 08:07 PM
TennesseeVol TennesseeVol is offline
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Nice Murray! I've got the same kart. I'm planning on cutting the rear shock mounts on the frame and moving them to a more vertical position. Doesn't seem like they are in the optimal position for dampening. I'll let you know if it helps.
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  #8  
Old 03-17-2020, 08:35 PM
Voodoo Rufus Voodoo Rufus is offline
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Please do, thanks!
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