custom MotoTrax upgrades

[eric82930]

This is a thread to discuss positive upgrades please do not flame mtx failures and customer service issues.
That being said this is my latest mtx project I've been spring riding a bunch the last month a and got it working as good or better than my super mod timersleds I've built.

This one is the original scout model which is basically the same as the new ones but has a steel backbone and a disc brake on the jackshaft. the only complaint I have so far is the overzealous tilting but is really no worse than camso and once I got used to it I really like it. It will wash out easier on side hills but so does the camso just pick lines accordingly and have a blast.
This one like all the dedicated bikes in my fleet has had the backbone shortened to move the track 4 inches closer to the rider. You can see I moved as much weight as I could to the back as well. after doing this I still felt like it had a little more weight on the front end than I am used to especially compared to my timbersled sx two stroke.
to get the front end lighter I tied 10 wraps of climbers rope to couple the rear slider to carry more weight on the front of the rails. This is working really well. I tried 4 wraps before but it stretched the rope beyond its limit and lost tension. climber's rope is stretchy like a bungee and 10 wraps creates a lot of force but still will Flex when needed to.Some guys have put a spring on the front of the slide coupler but I'm not sure the spring was stiff enough to carry any weight. As you can see the rope is carrying all the weight without a rider. It rides more neutral than my ts. I can still lift the front when I need to but it doesn't lift under throttle unless I want it to. the timber sleds I've built with light front ends always lift under throttle because of the force of the center shock and location of the swing arm.time will tell how it will work in pow. I will probably put a spring rear bushing to dampen any rearward rocking at some point when I can test it in deep snow next fall.

 

[dooman92]

Mtx

Eric, good idea with the rope. Any idea how long it would last? I used a fairly stiff spring on my '17 kit, sometimes the spring could use some help. But, definitely an improvement over stock. Do you have any photos of mod to backbone to move forward?

 

[eric82930]

Not sure how long it will last. It's just cheap rope I got from a ranch supply store but it's not chafing or rubbing on anything. I've used it on my ski for 2 seasons to keep the tip from folding up too easy.
All my dedicated bikes I ditch the strut rod and gut the top of the backbone and use 1/2 square tube for the subframe/strut rod. It's lighter and way stronger and super easy to cut and weld angles. Gives way more room for fuel tanks brake covers intakes tunnel coolers or anything else you might need to fit under the seat. The last pic is my ts sx frame. I even cut part of the frame on the bike away to move the paddles closer to the engine block. The chain adjusted is the bomb and brakes never ice up.
If you have to keep the strut rod set up then you need to mount it to the track frame far enough back so it still has some angle for strength. My buddy is going to try it on his new mtx this summer. He is going to shorten the aluminum plates between the swingarm bolt and the backbone. One thing to consider If you end up mounting strut somewhere behind the telescoping chain adjuster then adjusting the chain will require also adjusting the strut if you want to keep the same ride height. Mine doesn't have a telescoping backbone so it was easier.

 

[Norma Stitz]

Isn’t your rope pulling the back up and the spring they offer pushes it down so that opposite force?
Oh and I have their spring and it’s so light I doubt it does anything at all in practice.

 

[dooman92]

Mtx

Isn’t your rope pulling the back up and the spring they offer pushes it down so that opposite force?
Oh and I have their spring and it’s so light I doubt it does anything at all in practice.

You got it! Another indication original mtx guys didn't test much. If they tested they would have found that the front of the rails needed additional down pressure not lifting as Randy's spring idea does. Mine was much much better with more down pressure on the front of rails.

 

[eric82930]

Yes the mtx spring upgrade was to put some down force on the back of the rails to limit trenching by creating float. On sleds that seemed to work well at higher speeds on steeper climbs but you have to get moving first.
My goal was to make my ski feel lighter like my sx. It probably won't float as well but runs more in what I call snowcat mode where all the weight is on the track so with throttle control its less likely to get stuck. The ski drags in snow like a brake or anchor.. Snowcats don't float or go fast but rarely get stuck unless they drop the plow on the front. I used to jack my center shocks and let out limiters on my older sleds to keep from getting stuck but they would not float and go as fast as the typical chute climber setups. It was really obvious in crusty snow with a softer base the guys who got on top went twice as fast.
I will probably put something on the back too. I think a stiff short spring that only contacts when the rails tip past the level position would be ideal then it won't counter any of the force I'm trying to put on the front of the rails.