Hey guys, I’m rebuilding the top end on my 03 Foreman 450. The piston and rings are done, and the cylinder was scarred a little. I honed out the scratches in the cylinder and it now measures 3.566". The service limit is 3.547" which puts it .019" over. After looking in the book, it says that a .50mm over piston is .020" over spec. I just ordered a .50 over piston and rings set, but I’m not sure if I want to hone any more out of the cylinder until they come in. Are the advertised measurements that accurate that I can finish honing the cylinder now or should I wait until it comes in to finish it? Also do these measurements sound right to any of y’all? I’m an ex-machinist so I’m pretty famililar with a mic and calipers, and feel pretty good about my measurements. Also, the book says clearance between the piston and cylinder is .0015" to .0022". If I go a little over that while honing, what would be the worst that would happen? I’d lose a little compression, or worse?

I have a 2015 420 rancher fa6! It has power steering and today i went through some water and now it is jerking to the left by itself….

So this thing went from hero to zero. Was running great and then wouldn’t start one day. Compression test showed 30psi so I pulled the engine out to do the top end and discovered this hole… Is this a huge problem? It doesn’t appear to be losing oil from that hole and the engine didn’t spit parts out or blow up.. Worry about it or move on?

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So this thing went from hero to zero. Was running great and then wouldn’t start one day. Compression test showed 30psi so I pulled the engine out to do the top end and discovered this hole… Is this a huge problem? It doesn’t appear to be losing oil from that hole and the engine didn’t spit parts out or blow up.. Worry about it or move on?

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So i have been away for quite a while, and had to put my restoration project on hold. I am picking up after a while, and here is where i am stuck.

So here goes:
Crunch time is here, Back to work on the differential:
1. After FIRST calculating the proper number (addition of two spacers (left + right of ring gear)) to get an easy spin of ring gear (non-binding BUT NOT tight either)

I came up with 3.18mm as optimal (3.22mm bound the gears/3.14mm had too much side-to-side play)

2. I then proceeded to move the ring gear left OR right to eliminate the "backlash" (by adding 0.04mm to one side of the ring gear and simultaneously subtracting 0.04mm from the other side of the ring gear)

(I did this because "Checking for Backlash" comes first in the Honda Manual)

I was able to decrease it to minimum spec. of 0.003-0.007 in. by swapping the ring gear shims (Ended up with the smallest ring ("A" 1.26mm) on the case side and the largest ("L" 1.92mm) on the cover side).

3. I then checked the "Gear Tooth Contact Pattern Check". I added thicker or thinner shims to try to change where the pattern contacted the ring gear teeth (Instruction said coat the "pinion gear teeth").

Thicker shims moved the pattern transferred to the ring gear away from the pinion gear toward the center of the ring gear (axle shaft).
I was mostly concerned with the "Drive" side pattern (turn the pinion shaft CCW) rather than the "Reverse" side pattern (CW). (How far do we drive in reverse?)

I couldn’t get the pattern to hit the center of the ring gear teeth. I could move it up and down (contacting less or more of the ring gear tooth/material "face" or "flank" respectively from the manual) in the relative same place, but it was always toward the "heel" (outside of the ring gear) (as opposed to the pattern being toward the "toe" (inside portion of the ring gear nearest the axle)).

In desperation, I swapped the two ring gear shims (now having "A" on the cover side and "L" on the case side).

Low and behold, the pattern was exactly center on the ring gear, but now I had @ 0.015 in. off backlash even with the largest shim ("G" 2.18mm). Using TWO SHIMS ("B" 1.88mm + "C" 1.94mm = 3.82mm) JAMS the pinion gear tail/tip INTO the aluminum case through the pin bearing. At THIS point I’m down to the minimum "Service Limit" of 0.010 in. and I’m starting to run out of space until I start grinding (hit) the needle bearing (there is still "visible" air space between them).

Obviously I’m trying to get down to 0.003-0.007 in.

So I’m thinking two choices:
1. Grind down the tip of the pinion gear tip so it no longer bottoms out into the case and see if I can get it any closer (thicker pair of shims until I have no "visible air gap" between the needle bearing and bottom of the pinion gear teeth collar) and call it a day with wherever I end up with "backlash"…OR
2. Take a shim to a local machine shop and mill it down to an "as yet to be determined" size until the pinion no longer bottoms out against the case.

Comments at this point?

So i have been away for quite a while, and had to put my restoration project on hold. I am picking up after a while, and here is where i am stuck.

So here goes:
Crunch time is here, Back to work on the differential:
1. After FIRST calculating the proper number (addition of two spacers (left + right of ring gear)) to get an easy spin of ring gear (non-binding BUT NOT tight either)

I came up with 3.18mm as optimal (3.22mm bound the gears/3.14mm had too much side-to-side play)

2. I then proceeded to move the ring gear left OR right to eliminate the "backlash" (by adding 0.04mm to one side of the ring gear and simultaneously subtracting 0.04mm from the other side of the ring gear)

(I did this because "Checking for Backlash" comes first in the Honda Manual)

I was able to decrease it to minimum spec. of 0.003-0.007 in. by swapping the ring gear shims (Ended up with the smallest ring ("A" 1.26mm) on the case side and the largest ("L" 1.92mm) on the cover side).

3. I then checked the "Gear Tooth Contact Pattern Check". I added thicker or thinner shims to try to change where the pattern contacted the ring gear teeth (Instruction said coat the "pinion gear teeth").

Thicker shims moved the pattern transferred to the ring gear away from the pinion gear toward the center of the ring gear (axle shaft).
I was mostly concerned with the "Drive" side pattern (turn the pinion shaft CCW) rather than the "Reverse" side pattern (CW). (How far do we drive in reverse?)

I couldn’t get the pattern to hit the center of the ring gear teeth. I could move it up and down (contacting less or more of the ring gear tooth/material "face" or "flank" respectively from the manual) in the relative same place, but it was always toward the "heel" (outside of the ring gear) (as opposed to the pattern being toward the "toe" (inside portion of the ring gear nearest the axle)).

In desperation, I swapped the two ring gear shims (now having "A" on the cover side and "L" on the case side).

Low and behold, the pattern was exactly center on the ring gear, but now I had @ 0.015 in. off backlash even with the largest shim ("G" 2.18mm). Using TWO SHIMS ("B" 1.88mm + "C" 1.94mm = 3.82mm) JAMS the pinion gear tail/tip INTO the aluminum case through the pin bearing. At THIS point I’m down to the minimum "Service Limit" of 0.010 in. and I’m starting to run out of space until I start grinding (hit) the needle bearing (there is still "visible" air space between them).

Obviously I’m trying to get down to 0.003-0.007 in.

So I’m thinking two choices:
1. Grind down the tip of the pinion gear tip so it no longer bottoms out into the case and see if I can get it any closer (thicker pair of shims until I have no "visible air gap" between the needle bearing and bottom of the pinion gear teeth collar) and call it a day with wherever I end up with "backlash"…OR
2. Take a shim to a local machine shop and mill it down to an "as yet to be determined" size until the pinion no longer bottoms out against the case.

Comments at this point?

Ok, I’ve tried everything! Cleaned carb. Swapped jets, different carb. This is what my plugs look like after 30-40 min..

New top end, valves and cam chain..

What’s going on??Attachment 25203

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Attachment 25199
I’m probably second guessing myself but if you’ve had to reinstall this before you’d know… I used new o rings. Even with bolts sighed it has a bit of wiggle

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Hi everyone im rebuilding my 1985 Trx 125 subtransmission and after a month and a half finally found all the parts i need. What i cant figure out is where this little wooddruff key type piece goes. Does anybody have any ideas?
Any help is greatly appreciated.

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I went out for a little ride. Bike felt a little sluggish.No smoke from exhaust. Pull in the shop check oil. EMPTY. Not my bike, not a chance. I’m vigilant about checking everything all the time! Air box is coated with oil. I pull carb boot and it’s loaded as well. Upon further inspection I find the motor has retained all the oil. I think its a bad oil pump but I never heard of this issue on a 400 ex. Any input?