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Old 05-09-2019, 10:37 AM
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Default Torque converter behaviour

Hey all

On my Pred. 420 setup I noticed during fast / hard cornering the engine wants to bog down and would even stall because the torque converter is (presumably) still in high speed mode as it enters the corner and the rapid decel happens too quick for the converter to change to low speed. When it did this when me and my buddy were riding it we'd have to get out, push the cart a little bit to "unlock" the converter and get back to it.

I also noticed the converter is wildly inconsistent at idle. Sometimes the converter is semi engaged and wants to push the cart past the brakes (belt squealing for mercy while sitting on the brake at idle). Sometimes its fine.

I have a cover over the converter right now but I was pretty **** sure I had the belt as aligned as possible. Could the mid corner problems be related to the engine governor?

Video

https://youtu.be/gfIffjxr8T0
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Old 05-09-2019, 11:05 AM
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How old is it?
Have you used a wet lubricant?
Have you ever rebuilt it?
Are you using a 40 series?
Are the roller bearing in the driver free and clean if it’s a 40 series?
Is it completely aligned?

Now for the engine,
Is the cable lubricated?
Is the throttle arm getting jammed?
Do you have a govoner?
If so does it work correctly?

Post some pictures of tc and throttle setup
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  #3  
Old 05-09-2019, 11:28 AM
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Quote:
Originally Posted by Konnorbye1 View Post
How old is it?
Brand new

Quote:
Have you used a wet lubricant?
No lube. If it needs lube, where is it needed? I imagine not anywhere near the belt...

Quote:
Have you ever rebuilt it?
New

Quote:
Are you using a 40 series?
Yes

Quote:
Are the roller bearing in the driver free and clean if it’s a 40 series?
Should be...

Quote:
Is it completely aligned?
I will double check but I'm sure it is.

Now for the engine,

Quote:
Is the cable lubricated?
No, but the linkage is.

Quote:
Is the throttle arm getting jammed?
No

Quote:
Do you have a govoner?
Engine is bone stock


Quote:
Post some pictures of tc and throttle setup
Will do

---------- Post added at 01:28 PM ---------- Previous post was at 01:17 PM ----------

I assume this is good:



Comet says to use a dry film moly type lube, and it appears only on the inside of the drive side.

Looks like I will start there

Quote:
Indicators of a torque converter system requiring cleaning and lubrication are erratic or jerky engagement upon acceleration and a tendency to apparently "lock" into a particular speed (a second cause of jerky engagement is an excessively loose drive chain). If either one of these conditions exist service the unit immediately. Both driver and driven pulleys should be disassembled and cleaned. SEE ILLUSTRATION BELOW. (use this guide for Comet 20, 30 Series and Max Torque Systems).
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Old 05-09-2019, 11:46 AM
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Yes so use the dry lube as comet specified that is correct.
Do you have any photos of YOUR own setup? In the current state?
Make sure everything is Greeley moving and lube up your cable while your at it, wd40 should work to break apart grime.

Other than that you might have to scan he your driving style ie: let of gas’s going into a turn and back on it when you Exit the turn. Break early if you need to, don’t hold both break and gas
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Old 05-09-2019, 01:13 PM
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This specific torque converter mounts the opposite of how comet specifies, as discussed here

also FYI there are more shaft collars on there now to keep stuff from sliding around...
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Old 05-09-2019, 02:13 PM
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Do you have a picture of the inside of the driven, as in taking it apart and take a picture, post pictures of all of it taken apart so we can diagnose the issue
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Old 05-09-2019, 05:58 PM
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no need..
three rollers and three springs interconnecting the rollers
(or more precisely pins the rolelrs rotate around) running in three tracks..
the tracks need the dry lube (as does the inside of the bell)

and that's about all the lube it ever needs.

BEST series40 maintenance video ever:
https://youtu.be/a3FCcLlR-sg

when ran dry the rollers tend to create flat spots that can affect the shifting process,
but usually it's the idle of the engine creating the issue.. so turn the idle speed down.
especially since your unit isn't that old

a too short belt can also cause issues, so measure center to center again and tell us both CTC distance and belt number

[EDIT]
Oh alright... backplate
you flipped the driver, nice,
make sure it does not float on the crankshaft, with zero play!
It must sit tight on the crankshaft shoulder.
mabye needs a washer to not lock the bearing outer race..

Also: make sure the compression spring and guid bushings are installed correctly,
and are free to move in the moveable sheave
(bushing spring bushing) if the spring expands during compression it will lock the moveable sheave;
so test with the driver off, remove the outer bell, and push the moveable sheave against the fixed sheave by hand, if it's "sticky" once depressed, the spring is causing your issue.

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  #8  
Old 05-10-2019, 12:03 AM
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I skimmed through this thread, but you mentioned the engine wants to die on cornering. Have you disconnected your low oil sensor. That will make the engine want to cut out on cornering because the oil in the case gets pushed to the one side and the sensor then thinks there is no oil and cuts the engine
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Old 05-10-2019, 04:16 AM
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If you put in heavier springs in the drive unit that might help force it back into position. Iirc they are red springs.

One trick to keep it from stalling is to flip the kill switch to off just for a second until the engine idle goes down enough to make the drive unit go back to resting position.

This is if you can’t fix it with cleaning. I’ve gotnone 40 series that does this and I just flip the kill switch for an easy fix.
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Old 05-10-2019, 05:02 AM
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Quote:
Originally Posted by itsid View Post
no need..
three rollers and three springs interconnecting the rollers
(or more precisely pins the rolelrs rotate around) running in three tracks..
the tracks need the dry lube (as does the inside of the bell)

and that's about all the lube it ever needs.

BEST series40 maintenance video ever:
https://youtu.be/a3FCcLlR-sg
I found some WD-40 brand dry PTFE lube at autozone last night

This stuff

Is that acceptable?

Quote:
when ran dry the rollers tend to create flat spots that can affect the shifting process,
but usually it's the idle of the engine creating the issue.. so turn the idle speed down.
especially since your unit isn't that old
mmk

Quote:
a too short belt can also cause issues, so measure center to center again and tell us both CTC distance and belt number

[EDIT]
Oh alright... backplate
you flipped the driver, nice,
make sure it does not float on the crankshaft, with zero play!
It must sit tight on the crankshaft shoulder.
mabye needs a washer to not lock the bearing outer race..
Which bearing?

Quote:
Also: make sure the compression spring and guid bushings are installed correctly,
and are free to move in the moveable sheave
(bushing spring bushing) if the spring expands during compression it will lock the moveable sheave;
so test with the driver off, remove the outer bell, and push the moveable sheave against the fixed sheave by hand, if it's "sticky" once depressed, the spring is causing your issue.

'sid
Will do

---------- Post added at 07:02 AM ---------- Previous post was at 07:00 AM ----------

Quote:
Originally Posted by landuse View Post
I skimmed through this thread, but you mentioned the engine wants to die on cornering. Have you disconnected your low oil sensor. That will make the engine want to cut out on cornering because the oil in the case gets pushed to the one side and the sensor then thinks there is no oil and cuts the engine
Its not like it cuts in and out (video shows exactly what happens). Its just a rapid decel and the torque converter doesnt react quick enough to compensate.

Based on the symptoms, and what I've been reading, I think the driver just needs lubed up.
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Old 05-10-2019, 08:32 AM
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crankshaft PTO side bearing, nevermind I just looked at the manual and it's behind an oil seal..
IDK how much of a shoulder the 420 has..
so in your case make sure the oil seal is not getting chewed up by the driver instead

Unfortunately your videos shows NOT exactly what happens..
if the engine cuts out it doesn't sound that much different really as long as it's engaged and turned over by the wheels.
And since sound is all we can go by... NO, unfortunately the video is not much of a help

Especially since you cannot restart the engine (no even trying to fire, not a single pop)
which to me sounds like either a wet plug or a shortened out ignition coil.
Going by that I'm with landuse and pointing you towards the low oil sensor.
if you removed it, and have not used it's wire as a kill switch yet..
maybe it's dangling around and shorting out against the chassis in tight corners?
[maybe even if you attached a killswitch]

*shrugs*

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Old 05-10-2019, 09:28 AM
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Quote:
Originally Posted by itsid View Post
crankshaft PTO side bearing, nevermind I just looked at the manual and it's behind an oil seal..
IDK how much of a shoulder the 420 has..
so in your case make sure the oil seal is not getting chewed up by the driver instead

Unfortunately your videos shows NOT exactly what happens..
if the engine cuts out it doesn't sound that much different really as long as it's engaged and turned over by the wheels.
And since sound is all we can go by... NO, unfortunately the video is not much of a help

Especially since you cannot restart the engine (no even trying to fire, not a single pop)
which to me sounds like either a wet plug or a shortened out ignition coil.
Going by that I'm with landuse and pointing you towards the low oil sensor.
if you removed it, and have not used it's wire as a kill switch yet..
maybe it's dangling around and shorting out against the chassis in tight corners?
[maybe even if you attached a killswitch]

*shrugs*

'sid

I guess that's true, but the engine not starting without using the choke (even after its warm) has also been a problem since day one. So that would be why it wouldn't even "pop".

Combined with the torque converter literally locked up requiring me to push the cart it to loosen the driver, makes me believe it has nothing to do with the oil sensor.

Like I said the engine is bone stock I have modified nothing except extend the wires for the control until to the dash to be remote started/killed.

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Old 05-10-2019, 10:28 AM
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CVT's are normally have a smooth automatic function.
Problems with downshifting can be caused by:
Binding, broken parts.
Dry, dirty moving parts.
Engine idle too high.
Holding the throttle during braking. As in one foot on brake, one foot on throttle.
Too sudden of deceleration. As in slamming on the brake. The CVT does need a moment to spin to be able to downshift. Locking up the brake essentially locks the shifting.

If the brake is locked up during the time that the drive pulley's clutch function is engaged then the brake is also locking up the engine for a instant. If your low speed/idle is questionable than the instant engine lockup could be enough to stall it to the point where it cant catch.

Also you might want to remove that spare key and save in a safe place. I've had key ring stuff turn the ignition on hard landings.
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Old 05-10-2019, 03:29 PM
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Quote:
Originally Posted by LightningTeg View Post
I found some WD-40 brand dry PTFE lube at autozone last night

This stuff

Is that acceptable?
I'd say no. Dry moly lube would be more appropriate, but BlottoZone probably doesn't carry it(the ones here don't stock anything but inept clerks and even then...). I recently had to order some elsewhere.

A potential substitute might be door lock graphite.
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Old 05-10-2019, 04:29 PM
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Looks like NAPA sells the moly stuff. I’ll get some tomorrow
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Old 05-13-2019, 04:59 AM
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So I got the driver apart yesterday and it didnt seem like there was anything apparent. I resprayed the moving components and closed it back up. Upon running the motor I accidently left the driver bolt a tad loose and it must have allowed the driver to float to a happier place because I was able to run the engine and stop the axle without stalling it. It appears aligned right but I think one more washer on the crankshaft will get it proper. It looks like its riding slightly on the left side of the drum causing the belt to want to move at idle. You can see the witness mark from the belt in the top picture.



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Old 05-15-2019, 04:59 AM
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So I got to drive it today after adjusting my gas pedal and man what a difference. Just picks up speed like no other. Instant power in the corners, enough to trip the oil kill switch so time to remove that nonsense.The converter was definitely slower to react before.
Only issue still left is the belt alignment. I got a few different thickness washers to try shimming it so I'll continue to work on that.
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Old 05-15-2019, 06:10 AM
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Quote:
Originally Posted by LightningTeg View Post
So I got to drive it today after adjusting my gas pedal and man what a difference. Just picks up speed like no other. Instant power in the corners, enough to trip the oil kill switch so time to remove that nonsense.The converter was definitely slower to react before.
Only issue still left is the belt alignment. I got a few different thickness washers to try shimming it so I'll continue to work on that.
Glad to hear it!!!!
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Old 05-17-2019, 08:51 AM
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Starting to think the backplate is flexing as no matter how I shim it doesn't seem to be happy. Time for actual jack shaft on pillowblocks?

Might try an in between and make some kind of mount to the frame for the drive side.
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Old 05-20-2019, 08:48 AM
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Was able to install a stiffer idle return spring and it has helped a bit. The kart will not move but the belt still squeaks and hates life.

Is it possible I could get the next size up belt (203786) and solve this issue?
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