Final Drive gear and shaft in 400/450 engine

[AKATV 691]

Well embarrassed to say this is the first time I noticed this-

Split and tore down a foreman 400  engine today to swap out a burned up crankshaft

(ever see a piston so bonded to the small end end of a crank you could hammer nails with the piston and it wont move.....? )

Anyways, i was buttoning it all back up and after dropping in transmission and all that, I went to place the final drive gear down

into the case and noticed the two sides are different slightly, I went back and forth several times and does not SEEM to be any difference

Service manual makes no mention of paying attention to a particular side and I cant glean anything from the parts blowups enough to tell anything

I ended up putting the one side that had worn shiny against the bearing as the side that butts to the final shaft would not wear that way

you would think if it did not matter the two sides would be the same

Any thoughts on this?

 

Also for a laugh, I was spinning crankshaft by hand after tightening down case bolts as I had just had put the crank in and buttoned up the cases (with no other parts put on yet)

I heard this funny buzzing sound, like the crank gear was making noise driving the crank balancer  whirrrrrr-rwhirrrrrr-whirrrr- thats not good......

this weird grindy buzz noise like gears not meshing cleanly. I wasnt happy and thought I was going to have to tear it open tomorrow-I  tilted it on side -no buzzing, set it upright- buzzing

What the *&&%%^!  spin the crankshaft while it was buzzing and turn motor around to find cam slider arm bouncing and rubbing on the timing chain teeth on crank....

Lifted up slider, spun crankshaft and silence..............time to go in the house.....

 

[jeepwm69 6,601]

12 hours ago, AKATV said:

Well embarrassed to say this is the first time I noticed this-

Split and tore down a foreman 400  engine today to swap out a burned up crankshaft

(ever see a piston so bonded to the small end end of a crank you could hammer nails with the piston and it wont move.....? )

Anyways, i was buttoning it all back up and after dropping in transmission and all that, I went to place the final drive gear down

into the case and noticed the two sides are different slightly, I went back and forth several times and does not SEEM to be any difference

Service manual makes no mention of paying attention to a particular side and I cant glean anything from the parts blowups enough to tell anything

I ended up putting the one side that had worn shiny against the bearing as the side that butts to the final shaft would not wear that way

you would think if it did not matter the two sides would be the same

Any thoughts on this?

 

Also for a laugh, I was spinning crankshaft by hand after tightening down case bolts as I had just had put the crank in and buttoned up the cases (with no other parts put on yet)

I heard this funny buzzing sound, like the crank gear was making noise driving the crank balancer  whirrrrrr-rwhirrrrrr-whirrrr- thats not good......

this weird grindy buzz noise like gears not meshing cleanly. I wasnt happy and thought I was going to have to tear it open tomorrow-I  tilted it on side -no buzzing, set it upright- buzzing

What the *&&%%^!  spin the crankshaft while it was buzzing and turn motor around to find cam slider arm bouncing and rubbing on the timing chain teeth on crank....

Lifted up slider, spun crankshaft and silence..............time to go in the house.....

 

 

What do you mean by "cam slider arm"?

 

And as for bonded up pistons, I had one in a 500 recently that was completely welded to the rod.  I messed with it for about 30 minutes and thought to myself "this is a waste of time, this rod is ruined anyway" so I took out my cut-off wheel, cut the end of the rod off, and dropped it in a box going to Mr Crankshaft for a rebuild.

[AKATV 691]

Guess this post was kind of useless- without pics☺️

First pictures are the two  different sides on a Foreman 400 final output shaft gear that I just noticed was differently sided for the first time- which placement is correct?

Manual just said to slap it in there....haha not really but there is no specifics noted in the manual

I also just looked at a foreman 450 final gear and they appear to be more "equal sided"

 

Third picture was the "weird noise" maker when I was spinning crankshaft- I should have called it the cam chain slider arm, not cam slider arm -anyways it was bouncing off the teeth and making a noise you dont want to hear after you just swapped crankshafts.

I usually wire it up, as have actually put a crankshaft in and bolted cases and found it dropped down UNDER the crankshaft...grrr -

 

Last picture is the ""amazing and magical self leveling connecting rod" -lol

when I realized how bad it was stuck, I figure it was ruined, so I even tried an air hammer on the the wrist pin and it did not budge- I heated the upper rod so hot I would not want to reuse it anyways. It was a first time seeing one friction welded

owner said he let some kid ride his wheeler and it did this the next day.......

I found the oil screen all sucked up and clogged with goop, so it was probably oil starvation, cam and lifters were good- cylinder and piston were all galled up and shot too

Edited May 22, 2020 by AKATV

[shadetree 5,448]

and this is WHY i do not mix and match parts from diff models !..lol.

[AKATV 691]

8 hours ago, shadetree said:

and this is WHY i do not mix and match parts from diff models !..lol.

 

No mixing or matching going on......

Both those pictures of the final drive gear for a TRX 400 Foreman are the same gear- showing 2 different side depths

My point was if there are 2 different sides which one is the correct one to face the final shaft?

The manual does not indicate a particular orientation, so I was trying to see if it really does not matter or was 

an omission in the manual

Edited May 23, 2020 by AKATV

[shadetree 5,448]

9 hours ago, AKATV said:

 

No mixing or matching going on......

Both those pictures of the final drive gear for a TRX 400 Foreman are the same gear- showing 2 different side depths

My point was if there are 2 different sides which one is the correct one to face the final shaft?

The manual does not indicate a particular orientation, so I was trying to see if it really does not matter or was 

an omission in the manual

ok, then which ever side is NOT shinny ?, it should face up. reason: the shinny side spins against that bearing, where is the side that slides onto the shaft bottoms out on the shaft, and does not wear.

[AKATV 691]

Thanks for the confirmation Shade- that was my thinking too and I had already buttoned the cases up

but I just kept thinking about it wondering why it had 2 different sides and was not mentioned in the manual-so it was bugging me

but, as you all have probably found thru the years the Honda Manuals are top of the line (my opinion) but I am aware of finding a few omissions

and  a few questionable steps -not many but a few....

Maybe we should start a post on that LOL

I would be interested to hear what you all have noted or found thru the years

 

Well I have 4 top ends to put on after my local machine shop called last nite, working on 3 that were sunk- x2 Foreman 400,  x1 Foreman 450ES

and and Arctic Cat 400 FIS (yeah yeah boo-hisss) with the Suzuki engine that was smoking from regular wear

Been a long week with 3 Honda bottom end teardowns and crank swaps, but engines are clean inside now and will last a long time- till someone sinks them again-sigh

Going to take a break after that and take it easy the rest of weekend and put something on the grill and take a  long ride

Hope you all have a great Memorial Weekend

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[shadetree 5,448]

1 hour ago, AKATV said:

Thanks for the confirmation Shade- that was my thinking too and I had already buttoned the cases up

but I just kept thinking about it wondering why it had 2 different sides and was not mentioned in the manual-so it was bugging me

but, as you all have probably found thru the years the Honda Manuals are top of the line (my opinion) but I am aware of finding a few omissions

and  a few questionable steps -not many but a few....

Maybe we should start a post on that LOL

I would be interested to hear what you all have noted or found thru the years

 

Well I have 4 top ends to put on after my local machine shop called last nite, working on 3 that were sunk- x2 Foreman 400,  x1 Foreman 450ES

and and Arctic Cat 400 FIS (yeah yeah boo-hisss) with the Suzuki engine that was smoking from regular wear

Been a long week with 3 Honda bottom end teardowns and crank swaps, but engines are clean inside now and will last a long time- till someone sinks them again-sigh

Going to take a break after that and take it easy the rest of weekend and put something on the grill and take a  long ride

Hope you all have a great Memorial Weekend

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

haha..i could write a book on stuff i've learned through the 29 yrs i've been doing this !. your right, oem honda service manuals are top notch, but !!!, they tend to go strictly by the book !. some things i've learned to by pass, and do it regardless of what the manual says !. for instance, it says to use a clutch puller tool to remove the centrifugal clutch ?, nope..good ole hammer..and its off ( don't try this at home folks ! )...lol. 

[Fishfiles 17,097]

 You can put a 400 head on top a 450. Everything is identical except the combustion chamber of the 400 is smaller on a 400 than a 450 so it increases compression if the 400 head is on top a 450.  You wouldn’t want to put a 450 head on a 400 as it would decrease compression. Add in a 500 sleeve into a 450 jug , 500 piston custom made to fit the connecting rod and bore , hmf muffler , 34.5 % reduction and a jet kit and it will breath fire.