Murray Explorer Rebuild

[River3]

My son and I bought a Murray Explorer as a project. "Project" Lol. This thing had been hacked on quite a bit by previous owners. We stripped it down to the frame. The po had flipped the axel to run the 60t sprocket to a clutch. Luckily the jack shaft plate and jack shaft came with it and after getting all the seized bearings etc off it it, polished up nicely. I've ordered new bearings for the jack shaft and a new jack shaft sprocket. I found a 30 torque converter that is advertised as an oem replacement and its on the way. I've also ordered new bearings, sprocket (60t), brake disc etc for the axle and tires. It had 20"x9.5-8 on it and factory was an 18. (most answers on parts were found here) Thanks! Now to the questions I can't seem to find answers for, 1. The engine sandwiches the jack shaft plate and bolts to the frame mounting plate. How do I know what the correct tension is on the belt? Once that's all solidly bolted down, do I then line the axle sprocket to the jack shaft sprocket and make the chain needed for proper fit? My problem is that it seems I have two things, the torque converter to jackshaft and the jackshaft sprocket to axle sprocket that will both need to be adjusted. We've cut out wrecked sections of roll cage and welded in newly bent pipe, realigned the steering, deleted the governor and low oil shutoff, reworked the throttle for pedal control and a few other things. Thanks in advance for yalls help.

 

[BigWes]

you should have seen the mess mine was in...least I didn't have to flip the axle though. The cage was gone. Still no seat cushions. I kinda had to guess on all of it.

Ok, the following text is a reply I gave to a guy on FB post buying a junk explorer...I just copied and pasted it here...use any helpful information you can get from it and disregard the rest as it was intended for him. It was supposed to help him know what to look for.

Scrap the Tecumseh. It is a Murray explorer. It should have a 30 series T/C setup on a jackshaft with a true 7 inch driven pulley on a 3/4 inch shaft...not 5/8. The sprocket for the chain to the live axle should deploy from the right rear side. It should have a comet style disc brake on the left side. The role cage is sketchy at best. Most get removed or broken with age. It's not really structural. The front end has a simple spring suspension on the spindles. Actually fairly effective for the most part for minor bumps. I suggest inspecting the frame all over for cracks. These karts are robust but got abused over the years. Murray made ****** mowers but these karts are great. The seat should be mounted on sliding adjustable rails. I am 6'2" and mine will go back far enough that I can almost not reach the pedals.I have a 212 on mine with governor still installed, stage 1, and it will exceed 40 mph easily. The location of the drive sprocket makes it easy to swap out and experiment with. The large steering wheel makes it very easy to drive and it has a smooth predictable ride. The neighbors kids love to drive it. Any more questions feel free to ask. I hope this reply wasn't too lengthy.

 

[River3]

Thanks for the reply Big Wes. After reading hear, I've decided to scrap the roll cage. It's not in bad shape but I don't plan to add a high back seat and harness so I'd rather not have my son get his arm or something else between the cage and ground. It came with a running ironton 212. We removed the governor and the low oil cut off. It runs well sitting on the shop floor lol. Waiting on a pile of parts this next week. Should make significant progress. Took the seat sliders off today and with pb blaster and more back and forth since I was 14 they are free and functional. Really curious as to how to adjust the engine and jack shaft plate at the same time but I guess it'll explain itself once parts arrive. Looking forward to maiden ride.

 

[BigWes]

I responded to your PM. Yeah, adjusting the engine around is kinda tricky. What I did was slightly loosened the bolts and adjusted the chain tension first, then kinda slid the engine opposite way to get my belt tension. Then tighten it down. It's not easy but extra hands help.

 

[BigWes]

digging around in my files on my PC. found a few pics that might help give you an idea what my kart has.

these pics are old and I have made some improvements since then...

the first pic is a top down view. shows I bought and replaced the original
brake assembly. Also notice under the axle there is a long spring.

this spring goes back to the rear frame. I forget where I got it.
It basically is a return spring. it's nice to have and helps pad life.



Another top down view, just further back. You can probably make out that I have the spring held onto the frame with a zip tie. Yeah, it's maybe silly, but it's still there. My intent was to make and weld on a proper metal bracket. Just haven't gotten around to it yet. Good zip ties are tough...but they have to be good ones.

Ensure you keep your spring off the disc if you install it in this manner. see how I have the spring slightly offset to prevent contact? Keep the little things like this in your thoughts at all times. You will read this again.



In this next picture you can see what replaced the factory attachments. I didn't install this the PO did. I did however drill a new hole further back to use with the current brake assy. I also replaced the bolts in the mounting bracket as well.

For whatever reason every single person in the world thinks you need to use grade 8 bolts on a go-kart. this is simply not true. These are grade 5 from tractor supply and for this application they will never fail. I honestly can't think of any place on a kart where you need a grade 8 bolt except maybe suspension or hubs and on the engine itself.

OK, back to what I wrote earlier. Attention to little things like clearance. Notice our brake control rod. As we put input into our rod and it comes forward it could come in contact with the lower caliper assembly bolt. If this happens you ain't stopping this kart. If you should be able to muster enough push in a fit of fright to get it past the bolt it will certainly seize up...stopping your fun.

So there are several ways to prevent this. I just had a bolt long enough to put a few washers between the lever and the rod to provide space for clearance. You could just put a slight 'z' bend in the rod as well. Whatever it takes to have working brakes. Make sure you don't over tighten your bolt or it won't even move. This is why I like the washers. Also either use a self locking nut on the outside or some other locking device so it doesn't come off.





I'll get some more pics up tomorrow. I never did paint this old kart. And it still needs new tires on the back. I just ride it The neighbors kids like it the best of all my karts because it is smooth and predictable. It steers easy too. I think you will be happy when you get it set up and going. Mine was an old beater I got for cheap. When I first got it I was a little disappointed but the more I got it back together the more I liked it.

 

[BigWes]

on a side note, I have been thinking about moving my linkage to the bottom hole on the brake lever and attaching the spring directly to the linkage. I just haven't gotten around to it yet.

 

[River3]

Thanks a lot for the pics and explanation. Very helpful. Is that the comet caliper? Those things are made of gold from what I've found online!

 

[BigWes]

Thanks a lot for the pics and explanation. Very helpful. Is that the comet caliper? Those things are made of gold from what I've found online!

No, that is just one I got from gopowersports.com

It fit right in place. I can't remember if I had to swap sides with the lever or not but it's easy to do. I have the OEM parts somewhere but the pads are shot and it won't stay locked down. The jam nut engagement is different. Honestly it's not worth the hassle of trying to take it back entirely like new. It's not cost effective or productive. And the OEM brake setup as I stated earlier was ineffective to say the least. Every one changed it to work better. Folks wanted the thing to stop!

 

[River3]

Good deal. That's what I wanted to hear. Not really excited about spending $60+ on a comet. On another note, the po gave me a donor predator 212 for parts and said it was locked up. Well...it was full of water but took it apart, flushed it out, took carb off running engine and it fired right up.

 

[BigWes]

Good deal. That's what I wanted to hear. Not really excited about spending $60+ on a comet. On another note, the po gave me a donor predator 212 for parts and said it was locked up. Well...it was full of water but took it apart, flushed it out, took carb off running engine and it fired right up.

Good job. I love to read stories of folks bringing dead engines back to life, even Tecumsehs. I just don't run them on my karts. Those 212s are tough guys for sure. I brought a 208 back to life in the same condition. Watch for some more reports of it coming soon. I had it up in the engine section but the thread got closed.

 

[mckutzy]

Thanks a lot for the pics and explanation. Very helpful. Is that the comet caliper? Those things are made of gold from what I've found online!

Its a Tolomatic/Airheart mechanical caliper.... Comet make a very similar one, but their actuation lever is adjustable radially on the outside, this only has 2 vairiants, 3/9 and 6/12 o'clock positions, push or pull....

 

[River3]

I'll post some pics of our progress tomorrow.

 

[BigWes]

So I told you I would take a few pics for you.

Rode it around the block a few time as well.

So mine is nothing special, just a red rust bucket that still needs plenty of work.

 

[landuse]

Good job. I love to read stories of folks bringing dead engines back to life, even Tecumsehs. I just don't run them on my karts. Those 212s are tough guys for sure. I brought a 208 back to life in the same condition. Watch for some more reports of it coming soon. I had it up in the engine section but the thread got closed.

If you want it opened again, just let me know what the link is and I can get it done. Threads close automatically after 6 months of inactivity. We did that because people would post on years old threads thinking that they were still current

 

[BigWes]

If you want it opened again, just let me know what the link is and I can get it done. Threads close automatically after 6 months of inactivity. We did that because people would post on years old threads thinking that they were still current

I'll consider it sir. It's no big deal really. It's no fault of anyone but my own. It was I that didn't update the thread. Actually, life has a way of doing that. I had to pull out from social media with my small engine stuff. I didn't stop doing it. I just didn't want media to cause me to be jaded and self absorbed. It was actually a good thing for me to get away. You know that silly little junk clone engine I was working on has really impressed me. Not my skills mind you. But the fact that the thing just wants to run if you will! So with that in mind I have decided to do something I normally don't do and that is to spend some money on it. And when I say spend money I mean go a bit above and beyond. I still have all my pictures and stuff. So who knows. It was my thread on the Briggs 9.50 series in the engine section. I was going to put it on a chopper bike. But later decided against it due to issues with the frame of the bike. I ordered a cam and rod for it. I am going out on a limb here because there is not much info on the Briggs 9.50 series. I hope I have made the right call on parts. We shall see.

Wes

 

[Wilson_Engine_Shop]

I've been working on my Explorer for a while now. It has a Stage 2 212 on it w/out the Govenor. I got it up to 53mph a couple times before my older brother wanted to drive it, got some huge air on accident and bent my brand new axle. I'm sure I got a pic somewhere. I also made my first modification to the frame by adding a pedal stop (for when I swap to a Mikuni)

 

[BigWes]

Cool, do you know the numbers on your cam?

 

[Wilson_Engine_Shop]

Cool, do you know the numbers on your cam?

Its got a Hot .265 Cam, billet rod, flywheel and valve spring retainers, 26# springs, SS Valves and chromoly pushrods.

I can only get to 5,500 rpm at 50mph, there's more in it but the 30 series TAV wont let it rev any further

 

[madtom]

Its got a Hot .265 Cam, billet rod, flywheel and valve spring retainers, 26# springs, SS Valves and chromoly pushrods.



I can only get to 5,500 rpm at 50mph, there's more in it but the 30 series TAV wont let it rev any further

Pop a juggernaut on there and that motor will scream.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Wilson_Engine_Shop]

My GPS cart already has $300 in parts lol. It'll take me a month or so to get enough $$ for it all