Help with Murray explorer

Lyricrex

Lyricrex

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I just picked up this Murray for my kids. It has a Honda GX270. It starts and runs but drives rough as hell.
im beginner at this, so im not that experienced. I only know some things from reading and YouTube.

I think the jack shaft is bent. It makes a knocking/banging sound when I accelerate. It struggles going up hill and I’m seeing sparks coming from the clutch.
I was told I should switch to a belt drive torque converter. Should I go with a 30 or 40 series? Should I change the sprockets?
Not sure what parts I need to get, if you someone can provide links. IMG_5359.jpegIMG_5376.jpegIMG_5380.jpegIMG_5357.jpeg
 
Hellion

Hellion

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You definitely have a driveline issue, sprockets wrong, parts bent (it appears).

For that kind of kart, it needs a Comet Torq-A-Verter or a CVT (continuously variable transmission). It will give you the power/torque you desire.
Probably a 30-series TAV : https://www.cometclutches.com/products/torque-converters/tav2-torq-a-verter/#productTab|1

Boy I sure would like to know what the standard configuration is on a factory new Murray Explorer.

Tell us what the tooth count is on every sprocket you have. Sparking or smoking clutch tells us something is very wrong....
 
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Hellion

Hellion

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Hellion said:
Tell us what the tooth count is on every sprocket you have.
Click to expand...

The tooth count will help for determining the gear ratio. Jackshaft assemblies do work but I, personally, am not a fan of the dual chains.
 
Lyricrex

Lyricrex

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Hellion said:
The tooth count will help for determining the gear ratio. Jackshaft assemblies do work but I, personally, am not a fan of the dual chains.
Click to expand...
10T and 60T sprockets. I was able to remove the jack shaft, which it looks to be straight. I think the problem was the 20T sprocket on the clutch side.
Given it has a 1inch shaft, should I go with the 40 series or 30 series.
 
Hellion

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Denny said:
40 series for the 1” shaft but it probably had a 20 or 30 series stock.
Click to expand...

There's many in the Comet lineup that (appear) to facilitate a 1" shaft, "There are four kits available, 3/4" and 1" bore drive clutch with either a 10 tooth, 40/41 pitch sprocket or a 12 tooth, 35 pitch sprocket..." blah blah blah. <---That's the specs from a TAV2 which handles up to 9 HP (GX270).

Many seem to suggest the next biggest CVT size but are we hampering it (the kart) with more weight (and more parasitic drag) and for example, more expensive spare parts, i.e. "overkill"? I want Denny to write a deep dive thread on the subject of torque converters with 200 photos, and schematics along with an example of each type installed on the typical application (instead of the limited parts photos that Comet provides). I want it in 48 hours!
:roflol:
 
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panchothedog

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Lyricrex said:
10T and 60T sprockets. I was able to remove the jack shaft, which it looks to be straight. I think the problem was the 20T sprocket on the clutch side.
Given it has a 1inch shaft, should I go with the 40 series or 30 series.
Click to expand...
If the engine is relatively stock ( thinking 8 to 9 horsepower ) you can get away with a 30 series torque converter. Most all the kits you see advertised are for a 3/4" output shaft.But drivers are available for a 1". You might have to purchase it separately. Use the plate system, where the whole thing bolts directly to the engine. 10 X 60 tooth will work perfectly. Get rid of the jack shaft assembly and go straight from the torque converter to the axle.
 
Edwin Spangler

Edwin Spangler

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panchothedog said:
If the engine is relatively stock ( thinking 8 to 9 horsepower ) you can get away with a 30 series torque converter. Most all the kits you see advertised are for a 3/4" output shaft.But drivers are available for a 1". You might have to purchase it separately. Use the plate system, where the whole thing bolts directly to the engine. 10 X 60 tooth will work perfectly. Get rid of the jack shaft assembly and go straight from the torque converter to the axle.
Click to expand...
But his axle sprocket is on the wrong side? He would either need to fab something to swap the caliper or sacrifice the rear brake.
 
Hellion

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Edwin Spangler said:
But his axle sprocket is on the wrong side?
Click to expand...

It would appear to be factory located. I'm not sure what series CVT these had but it was not the all-in-one plate style, it was the separated or individual sheave style for factory jackshaft. It may have had a "backing plate" but it only served as the mounting surface for the plastic cover, if I understand correctly.

The previous owner took the CVT off and turned it into a chain driven fixed jackshaft assembly. That's going backwards in functionality and fun.

Here's an intact one I believe, with original OHV Tecumseh...

Image 40.jpeg
 
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panchothedog

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His axle sprocket could sit right in line with where left side of the jack shaft sprocket sits now. I know some are easier than others, but I've never looked at moving an axle sprocket as a major project stopping issue.
 
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Denny

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Hellion said:
There's many in the Comet lineup that (appear) to facilitate a 1" shaft, "There are four kits available, 3/4" and 1" bore drive clutch with either a 10 tooth, 40/41 pitch sprocket or a 12 tooth, 35 pitch sprocket..." blah blah blah. <---That's the specs from a TAV2 which handles up to 9 HP (GX270).

Many seem to suggest the next biggest CVT size but are we hampering it (the kart) with more weight (and more parasitic drag) and for example, more expensive spare parts, i.e. "overkill"? I want Denny to write a deep dive thread on the subject of torque converters with 200 photos, and schematics along with an example of each type installed on the typical application (instead of the limited parts photos that Comet provides). I want it in 48 hours!
:roflol:
Click to expand...
Man! Everybody knows I can’t write and my spellin is even worser.
 
Hellion

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I want to see more of the OP's kart and that muffler! What a big honker chonker -- wonder if it is as quiet as it is big?
 
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