Rebuilding rear end in my Monster Big Red

[Mondexbrute]

So I am in the process of a much needed rear end rebuild in my Big Red. I have everything torn apart, & started cleaning the rust, mud & water outta the axle tube. I guess that what happens when u ride in the Florida swamps!

I have been wondering if a diff. or the diff. gears out of a Honda TRX 300 will work? Basically I need a lower gearing setup for turning 28" Mud tires. Any input or ideas would be great thanks.

[cattle-dog]

the 250sx is a little better

[86'250sx]

The rear end out of a 250sx is a higher gear ratio than the big red. I think the trx 300 is the same gear ratio as the big red? what year trx 300?

[Mondexbrute]

Yeah ive been told that the 250sx is slightly higher, TRX 300 im not sure, think all years are the same.

[86'250sx]

The gears are the same in all year trx 300 but the housings changed. I wasnt sure if you wanted to use the whole trx rear end or just the gears. The ratio of the big red is the same as the trx if I remember right. I put a BR rear end in my sx last year and it has a lot more bottom end. Then a buddy blew the rear end in his trx 300 and it was the same ratio as my BR rear end. So the gears should work but it wont be any lower.

[TheRealFatShady]

Get a cam or gear reduction for more low end.

[Big Mike]

Dont have any insight to add to this thread, but wanted to say that is a sweet Big Red man. I want to build one like that.

[tri again]

boy, you'd think the spec sheets either
owners manuals
shop man
or sales brochures would mention gear ratios.

Pretty sure they're all avail on 3www here somewhere

[Mondexbrute]

Ok good to know, I would love to do a gear reduction, have any more info on that?

[TheRealFatShady]

I think the clutch on a 300 has 5 springs, and the 250 has 4 or vice-versa. But pretty much used a 300ex primary gear and clutch basket + about $150 worth of machining a few guys do on highlifter.com. Lowers the gearing for more torque.

[Mondexbrute]

here is what I have been up to...
http://i779.photobucket.com/albums/yy78/crazyquadrider83/DSCF2635.jpg
http://i779.photobucket.com/albums/yy78/crazyquadrider83/DSCF2633.jpg

Just have one problem, how the hell do I get this apart, the manual says that it takes special tools and for the dealer to do it.
http://i779.photobucket.com/albums/yy78/crazyquadrider83/1296585447020.jpg

[Mondexbrute]

another pic, anyone know how to get this apart?

http://i779.photobucket.com/albums/yy78/crazyquadrider83/2011-02-01154212.jpg

[Mondexbrute]

I need some help here, I know someone has had their rear diff apart to put new bearings in.

[Mondexbrute]

???????????? Still dont know what to do here!

[tx200m]

Do you have the factory manual? Looks a lot like doing bearings in a car differential, but u gonna need special tools, no doubt.

[Dirtcrasher]

That is the outer pinion locknut/holding nut, the smaller nut has to be taken out 1st with an impact gun or put it back together and jam a penny in it for the 17/19MM?? pinion center nut. You can make, buy a tool or just have the dealer remove that part. Many guys make a tool for it........

As long as you shim the ring gear the same as it was when you took it apart, you don't have to check the mesh like a 4x4 truck diff.

Stay out of the water and it won't need rebuilding again :D

[Mondexbrute]

thanks for the info, but I will never stay out of the mud & water lol.

[cosmohawk]

I was going to replace my rear-end bearings in my BR...even have the parts...but not sure if I'm going to get into it now...looking at those pics!

I think I'm going to stick with the "if it ain't broke don't fix it: for now. Really depends on the "special tool" required to do the job. If it's something that can be homemade...try and make it...otherwise, rather than get retardedly frustrated, take it to a dealer, and get them to swap out things out, or at least take it apart. You clean it up, replace the parts, and get them to put it back together. Sometimes there's no real way around it.

I am surprised that no one on here has chimed in on how to do this, because both you and I know someone has done this before? Or maybe not? Who knows...but I'll be curious to see what the solution is.

Best of luck!

[Woodsrider]

I would think if you were to get a big nut that fits inside the large pinion nut, and then just weld that to a properly sized socket, or build it up with more nuts welded together(maybe decreasing in size a bit until one of your sockets fits it), that would be the way to go. I have one of those large rings in a pile of parts that I bought once, and it was obviously removed with a screwdriver and hammer, but I wouldn't have the heart to do that to a piece of machinery...unless it was an emergency.

[Tecate Karl]

I took one apart about 12 to 13 years ago and I wish I could remember what I did to get it apart but I think I made some kinda tool. wish I could be of more help but I havent got to my SX yet or I would have built another tool so you would know what you needed.

[86'250sx]

Do you know what happens when that pinion bearing goes. Say bye bye to some teeth and a good chunk of change to replace em.

[tri again]

???????????? Still dont know what to do here!

Are the bearings bad?
Prob a silly question from the looks of that air intake.
They say the 86-87 rears are sealed a little better.
DC has surely done those...so on that note an airgun and penny jam technique. and then figure out how to get it back together and torqued correctly and double check backlash of ring and pin in case spacers, bearing dimensions are off a little.

I had a ring gear bearing pressed off and new one on and spent many hours trying to get it back together so I took it back to the machine shop and saw what looked to be my .020" SPACER sitting next to their press.

It was supposed to be between the bearing and gear.

aaaah backlash flashbacks.

and my adhd kicks in and I need to know where you got that muffler.

Thanks

[trikes4life]

i looked through my repair manual, nothing on getting that bearing out. throw it in the oven on high for a few hours should pop right out.

[mustangman1990]

Well I did a SX but didnt take any picks. I made a tool to do it. I have to do my Big Red next so if yall are still needing info I will document it. Just let me know. Here is some good info I found on another site but it is for a TRX 300 which is a little different. Please note that in the directions he states to use a 26mm socket. !!!THAT IS NOT THE RIGHT SIZE FOR A BIG RED OR SX REAR END!!! After much trial and error I found that a 36mm deep well impact socket which I found at O'Reillys worked great! When I built the SX the pinion bearing was totally trashed which let the pinion ride up and ground down the teeth on the end. Dont fret thinking you will have to drop a ton of money to find a pinion, when you get everything clean and new bearings installed the backlash is perfect. The main stress on the gears are higher up where there is still plenty of teeth mesh left. I though id just give it a shot and it has been working great without problem for several months. Was kinda leary about how it would do if I actually pulled anything but moving trailers around and pulling hoods around in the snow should have been a good enough test. NO problems it does awesome!:w00t: So just let me know if yall need any help.

http://www.atfreeforum.com/httpwwwhondafou/viewtopic.php?t=117&mforum=httpwwwhondafou

[Mondexbrute]

Yes the bearing were bad. But its all back together now, took it to a local shop & the mechanic had the old bearings out & the new ones in and put all back together in about an hour. I bolted the diff. back to the swingarm & hope to get the rest of the rear end put back together tomorrow.

[Mondexbrute]

Well finished her up today, test rode and everything seems to be good, nice & tight and no play in the rear end! Wow that sounds dirty lol.