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Brantley Foreman

1996 Honda Fourtrax 300 FW 4x4 Shudder at low rpm

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Posted (edited)

Hope everyone is doing well today.

 

I am trying to diagnose the issue on my mint 1996 Honda Fourtrax 300 FW 4x4

 

It is all stock except for having 25" tires on 12" rims. The tires are stock maxxis tires from a foreman. I also added a Warn 424 6 or so years ago and a highlifter yellow spring in the back with the stock shock to help sag.

 

Nothing has ever been done to this bike.

 

Issues:

 

When I am cruising at low rpms (0 to 1/2 throttle) in all gears there is a shudder or shake of the entire four wheeler but seems to be from mid line to back. When I put it on my atv jack it shakes a bunch at same rpms. The swing arm doesn't move when I jack it up and shake it. The intermediate axle from output to transfer case is tight. There are not shavings in the rear differential. The rear wheels don't have any play in the bearings and the axles seem straight.

 

When I go full throttle the issues is not present. I have adjusted the clutch on the side cover to spec and also to only 1/8 clockwise and the issue is still present.

 

No carb issues. Starts easily and donesn't bog due to fuel issues.

 

What would y'all start with now?

Edited by Brantley Foreman

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Hi: Big Welcome Here -- have you checked the rear universal?

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I think I would get all 4 off the ground and see if I could pin point something     

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2 hours ago, Melatv said:

Hi: Big Welcome Here -- have you checked the rear universal?

 

Took off swing arm and the u joint is great. It looks like it did the day it came off the assembly line.

 

Swing arm bearings are tight and good. Pinion it tight and the shaft from pinion to u joint is great as well as the pinon cup of the shaft.

 

Fighting with the axle now. It is stuck in the differential and my 20 ton press won't even push it out.

300 u joint.jpg

press.jpg

shaft.jpg

shaft pinion side.jpg

shaft splins.jpg

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1 hour ago, Fishfiles said:

I think I would get all 4 off the ground and see if I could pin point something     

I had it off the ground on my atv lift in both 2wd and 4wd (warn 424). It still does the same thing without load on the tires.

 

If I use the original solid shaft it still does the same thing with low rpm and in each gear. It will almost shake it off the jack.

 

No play in the out put shaft from the read of the engine either.

 

I am stumped.

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pull bolts out of diff, split it, remove the left side cover up off the axle, this will give you a better look at the ring gear and axle splines, not to mention see how much rust is in there.

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There is no water in the diff. The teeth of the ring gear nor pinion gear are not rusted. See pictures showing how good the internals are.

 

The only rust is between the ring gear splines and the axle splines.

 

All of the rear drivetrain is good and working smoothly.

 

I guess it is either in the transmission or clutch.

 

Would y'all think clutch plates or clutch weights are worn?

 

Is there anything else to check to hone in on which clutch could be the culprit? Any more adjustment to see where the deficiency is?

 

 

splines.jpg

pinion splines.jpg

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run it without the tires on it, see if it still shakes ?.

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Posted (edited)

if it still does it with wheels off, then you Rule out Bent rim, Out of balance tires 

 

 

Edited by Goober
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Posted (edited)

How long since you mounted those tires has this quad been running with no problems? Fishfiles can probably tell you if your front tire setup will make a difference. TRX300 stock setup is 23 in tires front and 24 in back—you went 25 all round. 
i wonder if this wears on the driveline 

Edited by Goober

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4 hours ago, Goober said:

How long since you mounted those tires has this quad been running with no problems? Fishfiles can probably tell you if your front tire setup will make a difference. TRX300 stock setup is 23 in tires front and 24 in back—you went 25 all round. 
i wonder if this wears on the driveline 

with it up on jacks, no load, tires wont affect the drive line, but if a rims is bent, or the weight throws it off ?, then yes..it will. i want to know if it still shakes with the wheels all off ?.

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up on jacks without tires no problems. i guess it is either, larger tires, same size tires all around, bent rim or unbalanced!

 

Any thoughts?

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52 minutes ago, Brantley Foreman said:

up on jacks without tires no problems. i guess it is either, larger tires, same size tires all around, bent rim or unbalanced!

 

Any thoughts?

as i figured, the prob is the tires, rims, or both !.

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11 minutes ago, shadetree said:

as i figured, the prob is the tires, rims, or both !.

It's crazy, I know bunches of folks that run 25" tires on 300 without gear reduction with no problems. Also the tires and rims were brand new from honda....never used until this machine and it started from day one.  You think its just too much tire for a stock gear ratio?

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18 minutes ago, Brantley Foreman said:

It's crazy, I know bunches of folks that run 25" tires on 300 without gear reduction with no problems. Also the tires and rims were brand new from honda....never used until this machine and it started from day one.  You think its just too much tire for a stock gear ratio?

if rims are new ?, then i blame the tires, rims never go bad unless they get bent ?, tires on the other hand do come to us defective !. i have run itp mudlite at's with all my trx300fw's, and not one problem from them. i do however try to stay stock size, i can not remember if i went one 1 inch bigger or not when i bought them many yrs ago ?.

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On 5/22/2021 at 12:00 PM, Brantley Foreman said:

Hope everyone is doing well today.

 

I am trying to diagnose the issue on my mint 1996 Honda Fourtrax 300 FW 4x4

 

It is all stock except for having 25" tires on 12" rims. The tires are stock maxxis tires from a foreman. I also added a Warn 424 6 or so years ago and a highlifter yellow spring in the back with the stock shock to help sag.

 

Nothing has ever been done to this bike.

 

Issues:

 

When I am cruising at low rpms (0 to 1/2 throttle) in all gears there is a shudder or shake of the entire four wheeler but seems to be from mid line to back. When I put it on my atv jack it shakes a bunch at same rpms. The swing arm doesn't move when I jack it up and shake it. The intermediate axle from output to transfer case is tight. There are not shavings in the rear differential. The rear wheels don't have any play in the bearings and the axles seem straight.

 

When I go full throttle the issues is not present. I have adjusted the clutch on the side cover to spec and also to only 1/8 clockwise and the issue is still present.

 

No carb issues. Starts easily and donesn't bog due to fuel issues.

 

What would y'all start with now?

 

Make sure motor mounts are tight.  The issue seems to be throttle/ engine speed related vs driveline related, based on the above in bold (at least in my mind)

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Even though your pinion of the diff looks pretty clean in the pic above , the axle being stuck in the diff where a 20 ton press didn't move it tells me either water got into the diff and rusted the splines to the diff and might have messed up some bearings or you were trying to push the axle out the wrong way as it only comes out one way , the axle only comes out to the right side 

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