[fishfiles]

Fourtrax300BigRed = as per our conversation I started a thread on the 300 rear end replacement modification , attach your pic to this thread -----------

there are thread about this on the site with pics of how to do it , the differentials of all the mentioned model and year rear ends are the same , the axle tubes are what is different , and what has to be done depends on which set up you get

here are a couple of pics of a 86 TRX250A rear end being modified to put in the 300 , the mounting bracket is welded to the tube , the lower shock steel bushing has to be cut flush with the rubber to fit inside the shock mount , on some models I have to replace the rear foot brake cable with one longer , not always , depending on rims you may need wheel spacers to clear the muffler , 1 1/2 -2 inches will do it , the 85 you mentioned should be the same as this one unless it is the ATC and not a TRX , post your pics

 

[Fourtrax300BigRed]

Right on i think the one i was looking at gettings not available anymore anyway , would a 1986 350 fourtrax work at all or is it completely different?

 

[fishfiles]

yes , the 86 350 will work for you , there is just one extra step to do , the 350 has 2 shocks , one on each side , where the 250 and 300 has one in the middle , so you need to weld a shock mount onto the axle tube in the middle , the welding of the mounting bracket for the swing arm connection is the same 250 or 350 --------

 

[Jeepwm69]

So am I correct that you got one of these.

Honda 4x4 TRX 300FW 300 Rear Axle Carrier Pipe Tube | eBay

Cut it off around the shock mount, then spun it around so the plate is closest to the diff, and welded it onto the 250 axle?

 

[fishfiles]

an easy way to do it if you have the 300 center section , cut the shock mount off the tube and leave 1/2-34 of an inch all the way around the shock mount , so what you have is a saddle to mount over the 250/350 tube , makes it alot easier to weld -----much like in this pic of how I repair frame weldments for the bumpers , fender stays and such

 

[Jeepwm69]

an easy way to do it if you have the 300 center section , cut the shock mount off the tube and leave 1/2-34 of an inch all the way around the shock mount , so what you have is a saddle to mount over the 250/350 tube , makes it alot easier to weld -----much like in this pic of how I repair frame weldments for the bumpers , fender stays and such

What do you mean "leave 1/2-3/4 all the way around the shock mount"?

Cut the shock mount off the tube.
Cut the tube in half?

Looking at the pics it looks like you cut the tube, then halved the part you use, sandwiched the 250 tube with the halves, then welded them back together.

Sorry for my lack of understanding here. I'm sure I'm making it harder than it is.

 

[Manny]

cut the shock mount off the tube and leave 1/2-34 of an inch all the way around the shock mount

this is what I do as well. much easier when your doing the swaps. makes the lower shock mount much more square and uniform.

 

[fishfiles]

an easy way to do it if you have the 300 center section , cut the shock mount off the tube and leave 1/2-34 of an inch all the way around the shock mount , so what you have is a saddle to mount over the 250/350 tube , makes it alot easier to weld -----much like in this pic of how I repair frame weldments for the bumpers , fender stays and such

What do you mean "leave 1/2-3/4 all the way around the shock mount"?

Cut the shock mount off the tube.
Cut the tube in half?

Looking at the pics it looks like you cut the tube, then halved the part you use, sandwiched the 250 tube with the halves, then welded them back together.

Sorry for my lack of understanding here. I'm sure I'm making it harder than it is.

I think I confused you with two separate things , yes for the swing arm mount , I cut the center section of the 300 rear end and then cut that piece in half and sandwich the axle tube --------------but what I was trying to explain with the shock mount is basically the same think but only use the half of tubing that has the shock mount on it , it makes welding much easier and it is easier to get it all lined up , the pic I showed is of a front bumper mount which broke off the frame and I was repairing it using the same process , I don't have a pic of the 350 A or D shock mount mod , basically making a saddle with the shock mount still welded to it , and it can be clamped right on the axle tube ----makes any sense

 

[Jeepwm69]

Ahhh, that makes sense now. So you use a bit of the 300 rear tube with shock mount attached and saddle the new tube with it, weld it into place

AND

You cut the flange with some pipe from the 300 section and sandwich the new tube with it for the swingarm mounting.

On my 2wd 250TRX rear the existing shock mount will work, right? These instructions about the shock mount are for a 350D?

A buddy is picking up a complete-ish 350D today for $200 with a good rear end in it, and we're going to put the rear end in his 300.

 

[Fourtrax300BigRed]

So theres no way to swap a different differntial itself other then a 300 diff ?

 

[fishfiles]

So theres no way to swap a different differntial itself other then a 300 diff ?

so what I get out your question " is there any other differential that will fit into a 300 rear end " , if that is the question then , No!

 

[Gundy]

Hi, I want to know if a 1987 trx 350d rear will work on a 2000 trx300 2x4 for this swap? Thanks for any info.