Subframe Strengthening Plate (finished)

[YamaMTX]

The subframe is a pretty big job! I would have a second person helping you get it back together as getting things lined back up is a pain.

 

[grizztracks]

The subframe is a pretty big job! I would have a second person helping you get it back together as getting things lined back up is a pain.

I'd consider this as being a fairly simple replacement. I've replaced two of these frames and It takes me just over 2hrs. It's a lot easier than it looks but I was a diesel mechanic for many years before becoming an engineer. I still work at the shop when I'm bored but that hasn't happened much since I bought a Nytro.

 

[YamaMTX]

I would agree that after you do one it is easy, but when I was doing my first I was told it would take about 4 hours. I guess I had expectations and the first time you don't know how everything comes apart and back together so I tend to be slow and careful. So what I expected that would be 4 hours turned into about 12-14 hours with building the supports and painting. I just don't want to tell a guy it is a piece of cake and have him frusterated. If I had to do it again I think I could swap one in 3-4 hours.
Just like the track swap it took me many hours to swap the first time, now that I have done it 3 times I can do it in about 1.5 hours with adjusting the Avid drivers.

 

[grizztracks]

My question is how much work is it to get the subframe out?? I don't really want to be welding on it with it still in the sled.

The subframe can be replaced with minimal ability and no special tools are required. If your going to repair the frame use the pry bar method and straighten it before you remove it. It can be welded on without removing it (disconnect the ECU first) but it's much easier with it out on the floor. I straightened my 09 frame with a pry bar then removed it and took some measurements off the a-arms back to the rear of the frame. I compared it to the 2010 frame and found that I really didn't need a new frame. I'm going strengthen both and probably sell the reinforced 09 frame.

 

[**sj**]

what kind of hits or impact is causing this a ski or a arm impact? or direct subframe impact? how beneficial is a skid plate?

 

[YamaMTX]

I would say a normally a one ski impact to give you that torsion twist to the subframe.

 

[grizztracks]

I finished installing a subframe support plate in my 09 frame. I ordered 12 gauge 4130 alloy steel to make another for my 2010 frame. http://s589.photobucket.com/albums/ss33 ... %20gusset/

 

[DeerHuntr]

Looks real good grizz, should help allot!! Have you put any thought into strengthening the top in someway?? i haven't dug into mine to have a look yet.

 

[grizztracks]

I don't think there is a need to reinforce the top. The lower a-arms take most of the impact which is why they are so much larger than the upper ones. I didn't see any evidence in the two frames I bent that there's inadequate support in the upper portion of the frame or in the rear where Yamaha added the plating in 09. I believe the new support plate addresses the areas that need strengthening and should help reduce bending. If I hadn't already bought the 2010 frame I would be reinstalling the reinforced 09 frame. I believe it's considerable stronger with the support plate than a new 2010 frame.

 

[multi sled]

grizz could you show or tell where exactly the frame is bending?is the thing twisting or is the tube right behind the lower a arm attachment point buckling.

 

[grizztracks]

From what I see it's flexing the lower a-arm mounts. I really can't see or measure anything out of place as far as the tubing. The rear mount takes the majority of the force and has little to support it. The mounting tower is welded to the frame at the bottom and supported at the top by the steering pivot support. I think that due to the height of the mount with no vertical support the lower a-arm forces rotate around the upper steering pivot. Keep in mind it only takes a slight movement at the mounts to cause a noticeable offset at the end of the a-arm.

This is all speculation on my part but I don't think I'm to far off.

 

[cawcislo]

Does someone have a write up or a photo of the "right" technique on the pry bar bending. My left a-arm is a little tweaked back and I'd like to straighten it, but I want to see what's the best way of "fixing" it. Will this added reinforcement plate work on an 08 subframe? Would I also need to add some plating to the bottom of the subframe as this topic is about a reinforcement plate that is higher up since Yamaha added some reinforcement to the bottom of the subframe in 09.

 

[grizztracks]

I use a 3-4' long truck tire bar at the ends of the a-arms. Insert the bar between the arms, get positioned behind the ski with your foot against the spindle and pull toward the rear of the sled. Use a few rags between the a-arms and pry bar so you don't scratch things up. It doesn't take much.

The support plate will fit the 08 frame. The center plate that Yamaha added in 09 may not be needed with this plate but wouldn't hurt. I would be more concerned about the larger gusset added in 09 to the rear of the frame. I made a template of that gusset so I can fabricate them to update 2008 frames.

Lower frame gusset update for 2008 frames

 

[cawcislo]

What type of skis are on your nitro. Looks like you got two sets of carbines on them?

 

[eightpilot]

The subframe is a pretty big job! I would have a second person helping you get it back together as getting things lined back up is a pain.

I'd consider this as being a fairly simple replacement. I've replaced two of these frames and It takes me just over 2hrs. It's a lot easier than it looks but I was a diesel mechanic for many years before becoming an engineer. I still work at the shop when I'm bored but that hasn't happened much since I bought a Nytro.

Lol... The nytro has a way of taking up all your free time and spare cash by having to fix all the $hit that Yamaha refuses to address.