STRETCHING MY APEX

[bigdog_mike]

Well a month ago I started a thread asking about stretching my 2006 Apex GT 121" into a capable dual use 144" that can be converted into a 2-up sled when needed and back to a single rider that can go off trail without getting buried, several of you said that going with Tracks USA or Muffin Works and you can't go wrong so after choosing the Muffin Works long track conversion I had to decide what length and style of rails, my buddy Big Blue Dave said to go with the 144" tip-up rails style as it would handle the corners like a 121" yet bridge the bumps like a long track 144". He also said to go with the Ice Cobra 1.6" paddles. Then on the last ride before doing the conversion when he was riding it he heard a backfire when he let off the throttle one time so while I was doing all this work to the chassis and skid frame I may as well replace the exhaust donuts with the copper donuts that I purchased right after I replaced the last donuts, then with all the parts torn down that far I may as well replace the spark plugs that were still the original ones and do an oil and filter too, and since the sled was going to be used at times as a 2-up sled it would be a good idea to rebuild the Ohlins rear shock and upgrade the coil springs to handle the extra weight of 2 riders...so after sending the shock out to Hygear to rebuild and upgrade the shock springs to dual rate Eibach springs...well let the pics show you how this project came about...

This was the Apex 121" with the 2-up Kimpex seat jack that I had to fab up custom brackets as the Apex seat was 5" higher than stock for my old tired knees...that's my Viper LTX on the other side

Got the Apex up on the lift ready to tear down, you will notice the carving up I had to do to the exhaust covers to allow the 2-up seat bracket to fit as the seat was made for 2011 and up Apex sleds which tuck in the exhaust pipe ends and the 2006 sit out wide on the tunnel...fab up covers for the exhaust when riding solo...

Now starts the tunnel conversion and dry fit up of the extension...

Now the tunnel extension is mounted up and ready for the next step...rail extensions

After installing the rails and new dupont hyfaxes and looking closely at the old hyfax there was a large wear area between the front 2 outer boogie wheels and the back boogie wheel that I installed to lesson the wear of the hyfax, so I decided to add another set of boogies next to where the rear wheels use to fit and move the wheel in front of it up another inch forward to spread the load out more evenly...all boogie wheels are over sized 5.35" to help extend hyfax life, yeah they are polaris wheel from kimpex...

Then I had the Ohlins shock rebuilt by Hygear suspensions and upgraded the Eibach dual springs to carry the load of 2-up riding I also upgraded the rear shock mount track bearings from my good buddy Dave at Percision Spindle with high performance spindle bearings

Had two 800# springs on the shock previously and upgraded to 1200# tender spring and 1000# main spring

Upon tearing down the sled to replace exhaust donuts I discovered one of the flex pipes was cracked which was why the sled backfired but all the donuts were all good but I replaced them with copper donuts so I won't have to worry about them ever again...

Then after the delay of a few days ordering a new flex pipe I was able to finish the exhaust and replace the spark plugs as they were original 10,000 miles old plugs

Then it was time to replace the wind screen after the girlfriend was trying out for the gymnastics team doing rollovers with the Apex...LOL...but I still love her...with 5" higher seat I had to use an extra tall wind screen just to keep the frigid wind off your chest...

Finally got the skid frame installed but not without my nephew and his buddy coming by to help me to re-install the jack shaft as this old fart may still be out in the garage trying to get it installed...

Finished it just in time for 68 degree Michigan temps this week...!$%@&...

 

[steiner]

Very nice.
You may want to install a cross shaft in the rail ext area just behind where the old axle was located. There is a lot of force on the rails.
I do it to my 136 rails. Had two rails crack on me before I figured out what was causing it. Added a cross shaft and have not cracked another rail yet.

 

[PowderFalcon]

Looks good!! I did the exact same kit you did, except i got my tunnel extension powder coated black to match my black tunnel. How did you like removing the structural rivets from the track adjuster brackets?! What a job that was! Something for you to consider also for slider wear... run your dupontes backwards so the inserts run along the tip up. I did on mine and my sliders are wearing beautifully. I also added an extra set of wheels where you did which also helped. I did not add a shaft as steiner mentioned, but maybe not a bad idea. I ride my sled hard and luckily have not had any issues with cracked skid rails.

 

[PowderFalcon]

Before i added the extra set of wheels...

 

[bigdog_mike]

Yeah adding a cross shaft would be a good idea as I like to run the sled hard through our always rutted and mogul field we lovingly call our Michigan trail system...LOL...just so happen to have a piece of aluminum round stock that I can cut to size and have my buddy Meilke drill and thread the cross shaft.
Hey Steiner, do you have any pics showing where you mounted the cross shaft, I see the area just behind the old rear shaft mount that look like a logical position to mount the shaft, should the position be centered between the top of the rail and the hyfax or down low???

 

[steiner]

I did not add a shaft as steiner mentioned, but maybe not a bad idea. I ride my sled hard and luckily have not had any issues with cracked skid rails.

The wheels past the rear pivot add pressure to the rail and the rail wants to twist.

Looks good!! I did the exact same kit you did, except I got my tunnel extension powder coated black to match my black tunnel.

If you want to make the ext black you could get a piece of vinyl wrap from an auto detail shop or signage shop. When done it looks like it was painted.

 

[steiner]

I would add it where the red circle is. The rails like to bend out at the bottom slightly as the wheels hold the sled up. This was the best place to install this shaft in this white skid. I used an existing hole on the rails.
Not everyone has problems here but I have twice.

 

[bigdog_mike]

Thanks for the pics and your input to place the cross shaft, to answer the question about removing the rivets it was a pain in the butt as I used a cutoff grinder then an air chisel to drive the rivets out...

 

[steiner]

I had no issues getting the rivets out. I first take a small punch and knock out the steel pin inside the rivet. Then a new sharp drill bit. They drill out nicely for the most part. If they start to spin I wedged the surfaces apart to add tension on the rivet.

 

[actionjack]

Cool thread. I keep dreaming of setting my 136 mono back for 141 or 144 to get a better angle of attack for the track.

 

[maim]

kimpex made a shaft set-up for the enticer trappers to add a shaft and extra wheels. when we did the muffinworks extension from 136" to 151", i added one between the rails on the rear most of the lower adjuster bolt holes on my brothers rx war. it was just holding the plastic off of the floor at the kickup and he has not broken it yet.

 

[PowderFalcon]

Food for thought.... I am not sure what you've got for a rear heat exchanger or if you have one at all, but I had to relocate mine into the tunnel extension as my 1.75" track would slap it when my suspension would fully compress. It actually pulled the rivets through the mounting brackets on the exchanger and popped the left side flex hose off the side exchanger dropping my coolant on the trail!! TWICE!! Although my 1.75" track clears the tunnel no problem, it would still tag my exchanger if i came in hot into a sucker hole ... you could see approx 1/4" black marks on it from my track! To ensure it didn't happen again, I made up some aluminium brackets to mount the exchanger on the bottom my tunnel extension. I had to cut and re weld the pipes going into the exchanger so the overall width was narrow enough to fit inside the extension because in stock form, it exits out each side of the tunnel. I then got some stainless tubing mandrel bent to run through the tunnel and re-attach to the side exchangers with the OEM flex hoses. Kind of hard to describe in words, check out my pics. You can see my exchanger was tweaked a bit from when my track hit it, but i had it leak tested and it's all good!

 

[bigdog_mike]

In the process of fabing up the cross shaft and put together the plumbing to move the rear heat exchanger back on the tunnel extension but my welder is busy at the moment so I have to wait to chop and shorten the rear heat exchanger to fit inside the tunnel extension, when finished I will post pics of the completed project...

 

[hereismylife]

Did you ever finish this? How did it run?

 

[bigdog_mike]

Yes I did and the relocated heat exchanger worked out great, also before the first ride I has the front GTYR shocks rebuilt as they had never been serviced before and what a difference it made, over all it was the best decision to upgrade and extended to 144" with tip up rails. Will work on making more pics available to show the finish product in my next post