Extending 05/06 Monoshock skid to 136 using rail extensions

[VX1R]

Last year I had heard and read from numerous sources that Yamaha had suggested not to extend the 121" Monoshock skid to 136" using rail extensions due to geometry changes and loads to the shock.

I've noticed that the 136" Monoshock skid used in the Attak and Rage this year uses the same tunnel mounting points as the 121" versions, although the upper track carrier wheels on the 136" skids use a separate shaft to support the wheels on the 136" skids.

I've also noticed that Hartman Inc. (www.hartmaninc.com) is selling a set of extensions to lengthen out the 121" Monoshock skid on the Apex models to a 136".

I'm wondering if anyone had tried this set up yet, and how it's worked out. Anyone care to chime in with their thoughts?

 

[SIMMER]

Re: Extending 05/06 Monoshock skid to 136 using rail extensi

Last year I had heard and read from numerous sources that Yamaha had suggested not to extend the 121" Monoshock skid to 136" using rail extensions due to geometry changes and loads to the shock.

I've noticed that the 136" Monoshock skid used in the Attak and Rage this year uses the same tunnel mounting points as the 121" versions, although the upper track carrier wheels on the 136" skids use a separate shaft to support the wheels on the 136" skids.

I've also noticed that Hartman Inc. (www.hartmaninc.com) is selling a set of extensions to lengthen out the 121" Monoshock skid on the Apex models to a 136".

I'm wondering if anyone had tried this set up yet, and how it's worked out. Anyone care to chime in with their thoughts?

Funny you say this....I would like to extend the Mono as well but I am thinking of finding a take-off 2006 136" Mono instead. I looked at a M-10 but the top end loss and lack of transfer doesn't really appeal to me for a $1700 skid... :? ....If you can indeed extend the 121" Mono-Shock, then that would be the ticket

 

[LazyBastard]

The upper rear wheels are the key to extending the skid. By keeping the angle of the back of the track steep, you are maintaining the original geometry. Unfortunately, the rear arm also has to be modified in order to clear that rear shaft (see pics on yamaha-motor.com).

As for hartman... they're HACKS. Just because they sell it doesn't mean it works. I learned this the hard way - with their 144" relocation and extension kit. It caused the track to try to stretch out by about 3 inches, which is more than it can ever stretch. Result is that the suspension can't compress, and there are much greater stresses on pretty much every component. Extending the 121 mono to 136 without putting up those wheels will do the same thing, just not quite as drastic.

 

[apexer]

Check out Bender Racing. They sell a retrofit mono shock upgrade for the Pro Action sleds maybe some parts out of their kit will help they have a 121 and 136 version.

 

[VX1R]

Thought I'd bring this back up to see if anyone's actually tried Hartman's extension set up and what kind of results they're seeing.

 

[suprfst]

I did the extension to mine check out the link

http://www.ty4stroke.com/viewtopic.php? ... highlight=

 

[bret151]

i did the tracks usa 136 extension and it works great.found a 121 mono and put it all together works like a charm. ride is awsome

 

[sxray]

i did the tracks usa 136 extension and it works great.found a 121 mono and put it all together works like a charm. ride is awsome

X2. Did my son's Apex this way. Works great.

 

[wkeggenhoff]

track extension

Did a 121 to 128 tracks USA, Works awsome. Also allowed me to add anextar set of 135mm to the rear to stop slider wear

 

[Bradford]

The upper rear wheels are the key to extending the skid. By keeping the angle of the back of the track steep, you are maintaining the original geometry. Unfortunately, the rear arm also has to be modified in order to clear that rear shaft (see pics on yamaha-motor.com).

As for hartman... they're HACKS. Just because they sell it doesn't mean it works. I learned this the hard way - with their 144" relocation and extension kit. It caused the track to try to stretch out by about 3 inches, which is more than it can ever stretch. Result is that the suspension can't compress, and there are much greater stresses on pretty much every component. Extending the 121 mono to 136 without putting up those wheels will do the same thing, just not quite as drastic.

I had a similar problem with the 121 ~ 144 extensions from TracksUSA. To figure out how loose my track needed to be to prevent binding when the skid was compressed, I removed the skid springs, re-installed the skid and collapsed it until it rested on all 4 bump-stops then adjusted the track until it was slightly tight. I found that any tighter than 1.25" of free sag is too tight.

 

[Miskow]

does your gearing on your sled have to change as a result of lengthening?

 

[maim]

last reply to this thread is over 10 years old. pls start a new thread to get your question answered.