What sprocket are you using on axle and jackshaft?
Murray Explorer Rebuild
- Thread starter River3
- Start date
What sprocket are you using on axle and jackshaft?
Wilson_Engine_Shop
Supporter
I'm using the stock 10t jackshaft sprocket (i have a 12t in my parts box) and a 60t split sprocket for 420 chain with adapter hub from GoPowerSports
Wilson_Engine_Shop
Supporter
That is correct. I don't think i'll lose much low end acceleration with the cam that I have
I'm waiting on a couple of those cams to arrive myself. One for a 212 and one for a clone. I have one of the GPS two piece sprockets that I just ate the teeth up with a strong hemi. The engine in question also breaks chains and lifts the front wheels. It'll snatch your arm out of the socket too if you ain't careful. So I'm gonna try gearing it differently and see if that doesn't help. I'm just not entirely sold on aluminum sprockets yet. Let me know how yours works out with a strong engine. Also has does your engine feel coming off the bottom with the hot265 cam in it?
Wilson_Engine_Shop
Supporter
My 420 chain and split sprocket has been fine so far. I've been doing donuts, small hill climbs and several top speed runs. The Hot .265 feels great off the line as long as the belt is cold. When my belt gets hot I lose a lot of performance in the low end and mid range. The Juggernaut should fix that
Bearings for jackshaft arrived today. Got that put back together with a little anti-seize on inner bearing surface. Now I need to check parts diagram for missing washers etc. Hopefully they'll address the lock nut size too.
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Wilson_Engine_Shop
Supporter
Where did you get the jackshaft bearings? I've needed some for a while now for both my Murray karts. That looks like a new jackshaft too, or it was kept in good shape
https://www.ebay.com/itm/152681448268
The jack shaft looked rough. I wire wheeled it quite a bit. Turned out good. The po had removed the jackshaft plate, swapped the axle so sprocket was drivers side and was running a clutch. On 20x9.5-8 heavy tires. The bearings are weird. Metric od and thickness but standard 3/4 id
The jack shaft looked rough. I wire wheeled it quite a bit. Turned out good. The po had removed the jackshaft plate, swapped the axle so sprocket was drivers side and was running a clutch. On 20x9.5-8 heavy tires. The bearings are weird. Metric od and thickness but standard 3/4 id
Wilson_Engine_Shop
Supporter
Are you sure those are the correct jackshaft bearings? I'm just double checking before I order some.
Thanks for the link!
My buddy Solomonster212 also ran a centrifugal clutch on his Explorer just for kicks and giggles. It was fast but didnt have much low end
Thanks for the link!
My buddy Solomonster212 also ran a centrifugal clutch on his Explorer just for kicks and giggles. It was fast but didnt have much low end
That is weird, but not surprising though.
You can get those small hubs from TSC and weld 40 series sprockets on there to fit that 3/4 shaft. I think I have a 14t somewhere. The bottom end sucks but I got high 40s from a stock engine with the governor still installed...just took a long stretch of road to get there.
They seem to be a perfect fit. Cleaned the jack shaft plate pipe ends with a small wire wheel on a screw gun and wire wheeled the shaft on a bench grinder. They didn't drop into the tube easily. We set them in place and then my son used a hammer while I held a clean piece of 3/4 ply on bearing to seat them. Put a little anti-seize on inside of bearing, used a screwdriver to line up spacer tube and tapped shaft into place. No play at all. One thing I found odd was that there's a small land on the inside of the pipe for stopping the bearing from just falling inside but they call for snap ring bearings? Redundant I guess. Either way snap ring fits flush to pipe and it all looks good.
I hooked up the throttle cable to the pedal rod bracket and it operates the throttle to wot and returns to idle but the pedal only travels about 1" to go from idle to wot. Doesn't seem right. Any ideas from you guys with explorers? Pedal and rod assembly appears factory per the diagram. Return spring works.
Wilson_Engine_Shop
Supporter
On my Explorer with a Stage 2 and no Govenor, my throttle pedal travel is around an inch, maybe a inch and a half. I didn't like it at first but I like it now that i've driven it for a while. I just barely push on it to start going
So do you have a pedal stop to avoid torquing the throttle plate assembly? My concern was someone getting on it and putting their toenails through the floor and bending the throttle assembly or breaking the cable. I can weld or bolt a pedal stop onto it to limit pedal travel.
Wilson_Engine_Shop
Supporter
Yes. I fabricated up a pedal stop so anyone can ride mine but it's really for a Mikuni swap that will be happening soon lol. I have some pictures too. I got my idea from RedBeardsGarage. I found a piece of 3/16" steel and drilled a hole in it just big enough for my bolt to slide through with a jamb nut on either side of it. It works great and is adjustable
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I just adjusted the spring collar at the throttle rod where the cable connects at the back. That's kinda what it's for anyway. Move the collar and spring on the rod towards your stopping point. You'll get spring feedback and a pedal stop.