Murray Explorer information, replacement parts list, and Predator 212 non-hemi modification resource

Coverfire

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Hello, I have recently been restoring and upgrading a Murray Explorer yard kart and wanted to say thanks to everybody in this community who helped me out with this project. There is not a ton of information out there on them and I often found myself frustrated with some aspects of working on them and trying to find correct replacement parts. So I wanted to make this post a master information/resource list on Murray Explorers so anyone who has one can come to this post to find out information and save themselves time and frustration. I'll post what I have learned so far and the correct replacement parts that I have used. This is an ongoing project so I will keep updating as I go along. Also, anyone who has any information, tips, part links, or anything else related to Murray Explorers please feel free to post here. I also upgraded the engine from the old beat up Tecumseh to a Predator 212 non-hemi and I will post all the modifications and parts I used on it as well since that seems to be the most common engine that people slap on go-karts as an inexpensive replacement.

KART PARTS

1. Front tires with wheels: 6" live axle assembly 145x70-6 tire. 1" bore with 1/4" key way https://www.gopowersports.com/145-x70-6-knobby-tire-1-live-axle-assembly/ I replaced the wheels because they were rusted through.
2. Brake pads (pucks) for manual brake caliper: https://www.gopowersports.com/brake-puck-manual-caliper/ I replaced these because mine were worn thin and cracking so the were not pinching the disc brake properly.
3. 3/4" 30 series 7" diameter Torque converter driven clutch: https://www.amazon.com/gp/product/B015UNQVUO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
4. 3/4" 30 series torque converter driver pully: https://www.amazon.com/gp/product/B076BSL5W3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 I replaced these because the original torque converter was worn out. These were a budget friendly replacement option from amazon but I ended up replacing them with higher quality products from gopowersports later. These worked just fine for a while but as I upgraded the Predator 212 to make more power I felt that it was wearing these parts out quick and I think there was some slipping starting to happen but it could just have been the belt being worn out.
5. 30 series comet replacement belt: https://www.gopowersports.com/30-series-comet-replacement-belt-common-on-murray-karts-203597/ I believe my Explorer came with the original belt and it was pretty worn out and skinny but still works to this day. I just replaced it so that it was reliable.
6. 3/4" 30 series 7" diameter Torque converter driven clutch from gopoersports: https://www.gopowersports.com/30-series-driven-7-dia-3-4-bore-murray-style/ It is actually cheaper now from gopowersports than it is from amazon. I'm not sure how much better quality this is compared to the Amazon version but I feel better about buying from gopowersports over Amazon
7. Super Series 30 Juggernaut driver: https://www.gopowersports.com/super-30-series-driver-the-juggernaut/ This is an awesome driver meant for modified engines that operate at higher RPM.
8. Axle 1 inch diameter 40 inches long: https://www.gopowersports.com/axle-1-diameter/ be sure to choose 40 inches as your option. I replaced the axle because unbeknownst to me my axle was bent when I purchased the kart. I'll add more notes about doing the axle swap down below.
9. Axle bearings 1 inch round: https://www.gopowersports.com/1-or-7-8-h-axle-bearing-manco-3941-3941h/ be sure to buy 2 and choose 1inch round option when purchasing.
10. 1 inch sprocket carrier hub: https://www.gopowersports.com/1-sprocket-carrier-sprocket-hub/ this hub is meant for a split sprocket which I would recommend in case you want to change gear ratios down the road. You won't have to disassemble the axle which can be a huge pain in the ***.
11. 60 tooth split sprocket (to go with above carrier hub): https://www.gopowersports.com/split-sprocket-41-420/ be sure to select 60 tooth when ordering if you want the same gear ratio as original Explorer WITH a jack shaft. Also be sure to tighten hub to axle before you tighten bolts on the split sprocket. If not the hub will not lock onto the axle and will remain loose. I used 2 1 inch axle locking collars to be on the safe side since I did not feel like the hub locked onto the axle as tight as I would have liked. I'll mention this again in the notes below.
12. #40 5feet chain: https://www.gopowersports.com/40-chain-choose-length/ be sure to select 5 feet when purchasing. This chain does come with a master link for easier install and removal. You will still need a chain break tool to size down the chain.
13. Chain break tool: https://www.gopowersports.com/chain-breaker-for-3-8-1-2-and-5-8-pitch-chain/ This is a pretty cheap version but worked just fine for me.
14. 8 inch brake disc: https://www.gopowersports.com/8-brake-disc/ this doesn't come with the set screw/bolt so be sure to keep the bolt from your original brake disc as it fits the pre drilled hole on this replacement brake disc. If you don't have the original be sure to buy two 1 inch axle lock collars to hold new disc brake in place. I'll list the link below.
15. 1 inch axle lock collars: https://www.gopowersports.com/axle-lock-collar-1/
16. 1/4 inch key way: https://www.gopowersports.com/1-4-key-1-1-4-long-az8435-6123/ I'm just listing this because some of my keyways were rusted into the old axle and I had to replace them.
17. 3/4" shims for torque converter https://www.ombwarehouse.com/3-4-shims-for-torque-converters-and-clutches.html I bought these and had to use all 5 to make the juggernaut driver and 7 inch driven pully line up perfectly. Worth the money because I went to ACE hardware and could not find anything as good as these. All I found were some heavy brass, stainless, and zinc washers that were heavy and despite being "3/4" of an inch were too loose and just spun off center.
18. Header Wrap: https://www.amazon.com/gp/product/B012C5FOLK/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 I wrapped the header just because when I work on it, test drive it, then work on it more I have accidentally burned the crap outta myself several times. The wrap is still hot as balls but it takes away the sizzle.

Predator 212 non-hemi (69730) and modifications:

1. Governor and oil sensor delete:
(also replace flywheel with billet ARC flywheel when removing governor for safety. Links below #3)
2. 18Lb valve springs: https://www.gopowersports.com/18lb-valve-springs/ VIDEO:
3. ARC Billet flywheel: https://www.gopowersports.com/arc-billet-flywheel-212cc-non-hemi-predator/ Video: (same as above)
4. ARC Billet Rod: https://www.gopowersports.com/predator-performance-billet-connecting-rod/ Video: (same #3,4, and 5) You will also want a torque wrench to get this install correct. Very important to torque rod bolts to spec. https://www.amazon.com/gp/product/B01LX4ND65/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 and sockets https://www.amazon.com/gp/product/B01JMIPVJU/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1
5. MOD2 camshaft: https://www.gopowersports.com/mod2-camshaft-212cc-non-hemi-predator/ Video: (same as #3, and 4)
6. Mikuni 22mm carburetor: https://www.gopowersports.com/22mm-genuine-vm22-133-mikuni-carburetor/ or cheaper Chinese version: https://www.ombwarehouse.com/mikuni-round-slide-22-mm-carburetor-gas-small-body-chinese.html which I don't have any experience with. Video:
and
7. Header pipe: https://www.gopowersports.com/go-kart-parts/performance-parts/header-pipes/?sort=featured&page=1 I can't be much of a help here because I bought one that was included with a stage 2 kit that didn't fit over the back of the frame so I cut it and lined it up so it would fit and then took it to a machine shop and had them weld it up for me. I'd recommend calling gopowersports and asking if they know which header pipe would fit the Explorer. The guys there know their stuff and probably know which direction to send you in.
8. Exhaust muffler/silencer:
9.




MORE WILL BE POSTED ASAP I have a lot more to add. I will add some notes and all my engine modifications soon but I just ran out of time today.

More helpful videos:
1. Throttle linkage for stock carb with governor delete:

2. Kill switch install on Predator 212: https://www.youtube.com/watch?v=DPORw5I9X1g&list=PLA34PnySmKdadXjMYEt_TCbIrs6_jwWtM&index=8

 
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madprofessor

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You missed a free and good opportunity with that billet rod, it's a stock replacement.
Same price to choose a version .020" over stock length. Moves the piston closer to the head for free increase in compression, more power.
Also, for increased compression from the other direction, a hi-perf head gasket (mine's .012", stock's about .050") moves the head closer to the piston. While the valve cover's off, you can just take out the 4 head bolts to make the change.
I bought an entire hi-perf gasket set for $14.95 that included it, and valve cover, intake, exhaust, side cover gaskets.
If you followed RBG's video to remove governor, you did it the hard way. That way's for folks who aren't changing the flywheel like you listed.
When the flywheel's off, you're looking at the backside of the shaft that the plastic governor gear spins on. You just hold a punch or even a nail up to it, and punch it right into the block in a one piece assembly, just don't forget any washer that's stuck to the case. 5 seconds, not 5 hours.
 
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Coverfire

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You missed a free and good opportunity with that billet rod, it's a stock replacement.
Same price to choose a version .020" over stock length. Moves the piston closer to the head for free increase in compression, more power.
Also, for increased compression from the other direction, a hi-perf head gasket (mine's .012", stock's about .050") moves the head closer to the piston. While the valve cover's off, you can just take out the 4 head bolts to make the change.
I bought an entire hi-perf gasket set for $14.95 that included it, and valve cover, intake, exhaust, side cover gaskets.
If you followed RBG's video to remove governor, you did it the hard way. That way's for folks who aren't changing the flywheel like you listed.
When the flywheel's off, you're looking at the backside of the shaft that the plastic governor gear spins on. You just hold a punch or even a nail up to it, and punch it right into the block in a one piece assembly, just don't forget any washer that's stuck to the case. 5 seconds, not 5 hours.
Thanks for your input madprofessor. I actually did the governor and oil sensor delete a while before I upgraded the flywheel and rod. I was just careful not to push it hard. I wanted to put out the safe way to do it for others because it was dangerous the way I did it and I didn't want to promote it. I also intentionally put in the stock length rod because it was my first build and I didn't know if the longer rod affected clearances or anything like that. So you're saying that with the .020 extended rod and with a high performance head gasket that all the clearances are still good and no other modifications have to be done to accommodate it like a shorter plug or anything? If so it sounds like ill have to experiment with my next build to see if I can squeek out a bit more power. I've seen people shave the head to accomplish the same thing but I didn't feel confident enough to try it. Is this the rod you're talking about? https://www.gopowersports.com/predator-performance-billet-connecting-rod-020/. Could you please include a link to the head gasket kit you used for us too?
 
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Coverfire

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You said it has a #40 chain. It's also reffered to as a 420 chain.
Hey, Solo, thanks for replying! I'm not an expert so I just listed the chain that I went with. However, from my understanding #40 and #420 chain are not exactly the same. I believe they have the same 1/2 inch pitch but the 420 is not as wide from side plate to side plate as the 40. I think the 40 chain also has beefier side plates. In most cases I think that you can use 420 in place of the 40. If I'm wrong please correct me.
 

madprofessor

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That GPS link to the .020"-over rod is the exact same ARC (Amundsen Research Corp.) rod I used. With that .020" and about .038"? of the head gasket, there's a huge compression increase but no clearance issues on mine with the plug or valves.
I can tell you that even before the changes, when a piece of welding slag not quite as big as a .177" BB (as in BB gun) fell into the cylinder from a temporary muffler, that turning the crank slowly would make it hang up at TDC, had to give it a headstart to make it go on around.
Picture the (flattop) piston/head proximity going from that to my new higher compression setup, the space at TDC is practically nonexistent. Yet and still, no clearance issues. Note: I'm too afraid of shaving the head anyway, but Jerry has advised me against it without going to the larger stainless valves and keepers on a full 3-angle valve grind.
The "Cars and Cameras" guys on youtube have a video where they got some Play-Doh and used it to do a "mush test" to check clearance of the valves, real good idea that.
Don't know how to do the link thing, but go to ebay and type in the search bar "Predator 212 cc HEMI 60363 Hi Performance Gasket Set" to see my set for 13.99 w/ free shipping from Jerry at "diy performance".
He's my only source for hi performance parts and advice because he's the absolute best motor builder around. Direct quote: "Other people are building time bombs. I'll only sell you what's right for you."
 

Coverfire

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Thanks, I like the quote! I'll look him up. My Predator is a non-hemi so I'll see if he has the performance gaskets for it.
EDIT: I saw the instructions said to put in the comments when ordering to specify if you want the non-hemi version. Thanks for the information. Here is a link for those interested: https://www.ebay.com/itm/114660407287
 
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madprofessor

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Saw that he's got a 3-pack of my 212cc performance .012" head gaskets for $14.99 w/free shipping, non-specific for hemi or other.
Good reason for that 3-pack, they're stainless steel gaskets that will "crush" tight when torqued. Reusable, but new recommended each time.
Sent him a note to ask if he's got the performance full gasket set for the non-hemi, will let you know.
 

Solomonster212

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Hey, Solo, thanks for replying! I'm not an expert so I just listed the chain that I went with. However, from my understanding #40 and #420 chain are not exactly the same. I believe they have the same 1/2 inch pitch but the 420 is not as wide from side plate to side plate as the 40. I think the 40 chain also has beefier side plates. In most cases I think that you can use 420 in place of the 40. If I'm wrong please correct me.
Hmm. When I did a centrifugal clutch swap on my Explorer I bought a 420 clutch and it worked perfectly with the stock chain.
 

Coverfire

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Hmm. When I did a centrifugal clutch swap on my Explorer I bought a 420 clutch and it worked perfectly with the stock chain.
I'm sure it did work fine. It was just a slight bit tighter of a fit for the sprocket between the side plates of the chain.
 
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Coverfire

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Saw that he's got a 3-pack of my 212cc performance .012" head gaskets for $14.99 w/free shipping, non-specific for hemi or other.
Good reason for that 3-pack, they're stainless steel gaskets that will "crush" tight when torqued. Reusable, but new recommended each time.
Sent him a note to ask if he's got the performance full gasket set for the non-hemi, will let you know.
Awesome, thanks man. Just out of curiosity do you think that the smaller head gasket makes a noticeable difference in performance. I know every little bit helps but just curious if you think it is noticeable?
 

madprofessor

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It's absolutely noticeable! One of the cheapest mods for the greatest gain you can do. No figures on it, but I'd say it's good for at least another horsepower, probably a little more.
 

madprofessor

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Heard back from Jerry at diyperformance about his performance gasket sets. Like you saw, you just order from the hemi performance set description and specify in the comments it's for a non-hemi.
He says the hemi and the non-hemi both use the exact same head gasket, you just don't use the head dowels anymore. So ordering a pack of head gaskets only wouldn't even require specifying which 212 engine.
Pro Quip advertises their performance head gaskets as all paper, or paper with a stainless ring, in .010" thickness. Jerry's are all stainless completely, and the only part that compresses is the raised bead.
Whoever decided a paper gasket could be certified .010" thick didn't think it important to say that's nothing you can depend on after squishing it with 4 highly torqued head bolts. They also decided a paper gasket with a metal insert will squish an equal amount under that torque.
What's really disturbing is where they say (in all capitals).............."Yes it is ok to stack them to get proper quench".
Scary stuff.
 

Coverfire

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Heard back from Jerry at diyperformance about his performance gasket sets. Like you saw, you just order from the hemi performance set description and specify in the comments it's for a non-hemi.
He says the hemi and the non-hemi both use the exact same head gasket, you just don't use the head dowels anymore. So ordering a pack of head gaskets only wouldn't even require specifying which 212 engine.
Pro Quip advertises their performance head gaskets as all paper, or paper with a stainless ring, in .010" thickness. Jerry's are all stainless completely, and the only part that compresses is the raised bead.
Whoever decided a paper gasket could be certified .010" thick didn't think it important to say that's nothing you can depend on after squishing it with 4 highly torqued head bolts. They also decided a paper gasket with a metal insert will squish an equal amount under that torque.
What's really disturbing is where they say (in all capitals).............."Yes it is ok to stack them to get proper quench".
Scary stuff.
Thanks is for the info! I placed an order for them and I can't wait to install it. I definitely hear where you are coming from with the cheap paper gaskets. When I installed the 22mm Mikuni it came with a paper gasket to go between the exhaust port and the carb adapter. It got shredded when I torqued down the bolts unbeknownst to me. I had a hell of a time trying to tune the carb and get rid of backfire and engine running really rough. I thought I was crazy. So when I stripped down the motor I discovered that stupid gasket was shredded and figured that was the issue and sure enough . . . I threw some gasket maker on there, torqued it up slapped it back on the kart and it ran perfectly.
 
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madprofessor

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Gasket maker is some problem-solving-grace stuff. However, let me give you one caution about it....................
If you split your case to do anything inside, use only a sidecover gasket to close it up, no gasket maker. Your shaft seal has to be made snug enough not to have endplay in the crankshaft. They make all kinds of shims just for the purpose of filling an endplay gap, and it's important.
Gasket maker will squish down to basically metal-to-metal contact, and not be consistent enough for you to gauge your endplay correctly.
 

Coverfire

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Gasket maker is some problem-solving-grace stuff. However, let me give you one caution about it....................
If you split your case to do anything inside, use only a sidecover gasket to close it up, no gasket maker. Your shaft seal has to be made snug enough not to have endplay in the crankshaft. They make all kinds of shims just for the purpose of filling an endplay gap, and it's important.
Gasket maker will squish down to basically metal-to-metal contact, and not be consistent enough for you to gauge your endplay correctly.
Thanks for the heads up. I did use it one time when I didn't have a crankcase gasket but it wasn't on there long before I replaced it with a gasket. I got lucky that there is no endplay because that had not occurred to me. This is my first build so I'm learning so much! I really appreciate all the help I get here!
 

madprofessor

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Check RBG videos on youtube, (Red Beard's Garage), he does a good job explaining about shimming for endplay on one where he goes inside the case. New rod, governor delete, whatever it was.
 

Coverfire

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Check RBG videos on youtube, (Red Beard's Garage), he does a good job explaining about shimming for endplay on one where he goes inside the case. New rod, governor delete, whatever it was.
Thanks! I'll go look. I love RBG! Him and cars and cameras are my two favorites/go to on youtube
 
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