Ok, so I've had a few posts about stretching to a 144", and think I have it figured out. I'll describe what I want to do, and I'd appreciate any input.
I love the RTX and the CK suspension, but the stock approach angle stinks, and the readily available 136" kits I've seen keep the same approach angle.
My plan is to use 136" rail extensions, a tunnel extension for a 144", and move the suspension back about 3". When I did a track changeout at the end of the year, I got a good view of the inside of my tunnel. The reinforcing brackets look like you could simply move them from one bolt hole to the next, using one of the original holes as a location template. Drill one new hole for the 8mm bolt, and re-rivet as necessary. I believe when I measured the center to center on the rear brackets is was about 4". Exactly what I need. By moving the whole skid back that same distance, I should wind up with a better approach angle, without modifying the suspension.
Has anyone tried this? I'd appreciate any input before I start tearing into the sled.
I'd say I ride 50% trail, and 50% boondocking, with a trip to the mountains about once every year or two. I want something that will work all around. I realize I will never have the best of both worlds, but there has to be a good comprimise there somewhere. I go about 275+ lbs in gear.
Anyone else as dissapointed as me in Yamaha's lack of a capable crossover sled. I even waited till the 08's came out, and didn't like what I saw. So I picked up an 07RTX end of year.
I love the RTX and the CK suspension, but the stock approach angle stinks, and the readily available 136" kits I've seen keep the same approach angle.
My plan is to use 136" rail extensions, a tunnel extension for a 144", and move the suspension back about 3". When I did a track changeout at the end of the year, I got a good view of the inside of my tunnel. The reinforcing brackets look like you could simply move them from one bolt hole to the next, using one of the original holes as a location template. Drill one new hole for the 8mm bolt, and re-rivet as necessary. I believe when I measured the center to center on the rear brackets is was about 4". Exactly what I need. By moving the whole skid back that same distance, I should wind up with a better approach angle, without modifying the suspension.
Has anyone tried this? I'd appreciate any input before I start tearing into the sled.
I'd say I ride 50% trail, and 50% boondocking, with a trip to the mountains about once every year or two. I want something that will work all around. I realize I will never have the best of both worlds, but there has to be a good comprimise there somewhere. I go about 275+ lbs in gear.
Anyone else as dissapointed as me in Yamaha's lack of a capable crossover sled. I even waited till the 08's came out, and didn't like what I saw. So I picked up an 07RTX end of year.
1CrazySledder
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You need to go back 4" not 3". I'm doing the same but with an Expert X on my 07 Attak. I to, wanted a better angle of approach. I had to go back 4" with a 136" skid and a 144" tunnel extension.
-Vince
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If you need a 136" or 144" extension ... I can help you out. See link to our website in my signature.
LazyBastard
TY 4 Stroke God
DO NOT DO THAT!!!!
Think about triangle geometry for a minute and it will make sense why relocating the suspension will not work.
In stock form, the track runs parallel to the front arm of the suspension. When you relocate the skid back 4 inches, this is no longer the case - you have a TRIANGLE between where the track SHOULD be, where the track IS, and the gap between them. As the suspension compresses, the ANGLE between where the track SHOULD be and the GAP will INCREASE. Because that angle increases, the LENGTH of the TRACK side of that triangle will ALSO increase. This means that the track will try to stretch. Now add on the fact that you'll also be extending the rails by 7.5", so you have the same problem at the back. The track doesn't stretch that much.
Now on an expertX suspension, you CAN relocate for this reason; the main arm of the suspension is set at a very low angle and the track is at a relatively steep angle, so a relocation will actually cause the track to run closer to parallel with the main arm.
Take a close look at the 136" mono suspension. You'll see that there is an extra set of wheels in the tunnel to keep the track running parallel to the rear arm. This approach can be used in conjunction with relocation to make a functional sled.
Now here's the thing about Yamaha suspensions; they tend to loosen a bit as they compress - thats why they ratchet under high transfer situations. You're extending by 7.5" and relocating by 4" for a total of 11.5". Add a set of wheels back somewhere between 7.5" and 9" (less than 11.5" to compensate for the yamaha-loosening thing), then you'll probably end up with a good working skid.
Think about triangle geometry for a minute and it will make sense why relocating the suspension will not work.
In stock form, the track runs parallel to the front arm of the suspension. When you relocate the skid back 4 inches, this is no longer the case - you have a TRIANGLE between where the track SHOULD be, where the track IS, and the gap between them. As the suspension compresses, the ANGLE between where the track SHOULD be and the GAP will INCREASE. Because that angle increases, the LENGTH of the TRACK side of that triangle will ALSO increase. This means that the track will try to stretch. Now add on the fact that you'll also be extending the rails by 7.5", so you have the same problem at the back. The track doesn't stretch that much.
Now on an expertX suspension, you CAN relocate for this reason; the main arm of the suspension is set at a very low angle and the track is at a relatively steep angle, so a relocation will actually cause the track to run closer to parallel with the main arm.
Take a close look at the 136" mono suspension. You'll see that there is an extra set of wheels in the tunnel to keep the track running parallel to the rear arm. This approach can be used in conjunction with relocation to make a functional sled.
Now here's the thing about Yamaha suspensions; they tend to loosen a bit as they compress - thats why they ratchet under high transfer situations. You're extending by 7.5" and relocating by 4" for a total of 11.5". Add a set of wheels back somewhere between 7.5" and 9" (less than 11.5" to compensate for the yamaha-loosening thing), then you'll probably end up with a good working skid.
gerald1588
Newbie
for someone that refers to himself as a lazy bastard, you sure did your homework on that one, but it makes perfect sense as to why it wont work, but there has to be some type of solution for it...
I am going to stretch my Attak to 144 as well here in a month or so. The approach angle has been a real concern of mine. You have the gears working to see if it possable.
Powder Pounder
Pro
I see why you think it woudn't work, but there are LOTS of guys out there doing this, and I haven't herd of any problems.
LazyBastard
TY 4 Stroke God
No, there is NOBODY out there doing this and having it work. Unless you can figure out a way for the track to stretch out by over 2" every time the suspension compresses, it will cause the suspension to BIND.
On an ATTAK or other 136" sled; no problem. The transfer gap causes the track to loosen as the skid compresses, so shift it by 4" and it'll tighten, but within the realm of possible. 121" and it just doesn't work. The track will definitely go, and you'll get fine flotation, but hit a bump and it'll knock your brains loose because the suspension will BIND.
On an ATTAK or other 136" sled; no problem. The transfer gap causes the track to loosen as the skid compresses, so shift it by 4" and it'll tighten, but within the realm of possible. 121" and it just doesn't work. The track will definitely go, and you'll get fine flotation, but hit a bump and it'll knock your brains loose because the suspension will BIND.
schmeg
Expert
LB is right. When I first started reading his posts, I took him wrong, but he really knows what he is talking about. When I stretched my 121 this year, I talked to Tom Hartman about going to 144 and he gave me the same reasons why it won't work as LB states. The geometry just won't allow it going from 121 to 144. The Attak has different numbers which will allow 136 to 144. Tom can sell you a lightweight skid for mid 2000's that will bring out your Apex to longer lengths. BTW, great analogy LB. Jay.
A relocation by sliding the skid back 4" on my attak should work then. This should really reduce the approach angle quite a bit, and you guys are sure it should give me full suspension travel?
LazyBastard
TY 4 Stroke God
Just don't overtighten your track and you'll be fine. Point to note; if it ratcheted at all before, then with the relocation, you'll be able to run the track looser and it won't ratchet.
I planned on changing over to extravert drivers at the same time. The only thing I should have to do will extend the mono cable, and maybe build some kind of different rear axle mount. Havn't looked at my machine since we started this discussion. Has anyone else tried this yet? I think I will start in a month or so.
680
680
LazyBastard
TY 4 Stroke God
You definitely WILL NOT need external drive sprockets.
Powder Pounder
Pro
LazyBastard said:
Whatever you want to think is fine with me. But I RIDE with guys that have done this to their doos and Polarises, WITHOUT any problems in 1000-3000 miles.
LazyBastard
TY 4 Stroke God
Except that their suspensions don't compress.....
