Raised tunnel

spencer_murphy · Nov 29, 2009

Hello everyone! I am new to this and only 2nd year snowmobiling. I have a 2001 snowcheck polaris rmk 800. I would like to raise my tunnel a little do to the deep snow we get here. So my question is, Is there a way to raise the tunnel? Any suggestions would help.

bannockrider · Nov 29, 2009

You can rasie it a little by mounting the skid lower on the tunnel (there are usually different mounts that come factory)

spencer_murphy · Nov 29, 2009

thanks. if i lower the skid is there any adjustments that i need to make?

550iq · Nov 29, 2009

It is all in the geometry of the rear suspension. Drop the back and it kills the front, etc. There are numerous posts on this subject (see Drop Brackets). Lots of folks trying and doing what you have in mind. My only advice is to take a good look at the stock set up and understand how it works, then make small changes at a time. Have fun with it, because that what it is all about anyway.

rdr99 · Nov 29, 2009

Without doing a drop and roll, any suspension movement will make the sled a trenching monster. Dropping the suspension down will increase the angle of approach. Which will make the track want to trench, rather than 'hop' up onto the snow.

Snodawg · Dec 6, 2009

Either do a drop and roll on the chaincase or disassemble the entire sled, buy a 2" raised tunnel, modify the top part of the bulkhead by raising it 2", and then reassemble. Piece of cake...not really

rmking600 · Dec 6, 2009

what size track are you running? use a drop braket to drop the suspention to lift the tunnel

Snodawg · Dec 6, 2009

Drop brackets will change the track/suspension geometry and will not allow the sled to jump up on the snow. Hope you like getting stuck.

skis_n_skid · Dec 6, 2009

Dropping the skid just for the sake of making the sled taller is counterproductive IMO. As others have already said, it will increase the attack angle which will negatively affect deep powder performance. If you drop the skid you have to drop the back more than the front to maintain ski pressure (unless you raise the front as well).

You might want to consider trying something like this: http://www.slp.cc/catalog.cfm?pageID=detail&catalogID=3&catID=47&productID=138

The xtra lite RMK skid I put in my wife's sled has one of those installed and so far it seems to work pretty well. I haven't tried it in dry powder yet, but it works well in deep wet snow.

manowar · Dec 6, 2009

the thing is if you want it to shed snow better then relocating the skid will do nothing. you need more clerence from the driver to the bulk head. if you want to get the sled up then you can raise the rear suspenion but only a little without wrecking the way it works after then you are going backwards . the way you worded your post it sounds like a drop & roll kit will be the easiest and most cost effective way to get what you are after. the thing is get one from some one that does not require the foot pockets to be re worked then it is a week end job not a head ach. what this will do is drop the drivers down and back an inch or two then re mount your skid in relation to the driver change to gain more tunnle clerence. pm me for more info or help if you need i can give you my number and explain better over the phone.

PLUMR · Dec 6, 2009

My experience is with the edge chassis, but should apply to a gen II. If you do drop brackets, also do a suspension set back to retain you track attack angle. won't do anything for track to bulkhead space, but will help keep the running boards out of the deeper snow. I dropped mine 3 inches and set back 2 inches. works good for me. adds more ski pressure, but you can adjust that to where you want it with front track shock, limiter straps and ski shock pre-load. takes a bit of tuning, but it works.

skis_n_skid · Dec 6, 2009

PLUMR said:
My experience is with the edge chassis, but should apply to a gen II. If you do drop brackets, also do a suspension set back to retain you track attack angle. won't do anything for track to bulkhead space, but will help keep the running boards out of the deeper snow. I dropped mine 3 inches and set back 2 inches. works good for me. adds more ski pressure, but you can adjust that to where you want it with front track shock, limiter straps and ski shock pre-load. takes a bit of tuning, but it works.

Just curious how you set the skid back 2 inches without a longer track. Did you D&R the chaincase?

spencer_murphy · Dec 6, 2009

Im running a 156x2 track. I am new to this and have not done anything to my sled except pull the sway bar. what does it mean to drop and roll the chaincase and how diffficult is it. I have been seaching the web and have not found any d&r for a gen 2 chassis.

Snodawg · Dec 6, 2009

There are couple of ways to do a drop & roll.

One: Poor mans D-n-R. Using the stock chaincase you relocate the both the jack shaft (upper shaft that is attached to secondary clutch) and drive shaft (lower shaft that drives track). You locate the jack shaft under the bulkhead inside the tunnel. You must pay close attention to the distance between the clutches (sometimes a longer belt is needed).

Two: The jack shaft remains where it is and a longer chaincase is used to lower and slide back the drive shaft. There used to be several companies that sold a kit to do this with templates and such. Don't know if they are still available or not.

Both will accomplish the same thing...moving the drive shaft back and down allowing more room between the drive shaft and tunnel and changing the approach angle. The first one is quite a bit more work but requires less money because you don't need to buy a chaincase. Neither one is what you would call a "simple" job (bolt on ), but if you are an able mechanic/fabricator it isn't extremely difficult.

If all you are trying to do is gain more clearance between the track and tunnel at the drive shaft area, you might just try to go to a smaller driver size. You would probably have to change your chaincase gearing ratio, too.

Hope this explains things for ya' ...Good Luck

rdr99 · Dec 6, 2009

You move the chaincase down, then back. Some kits put the jackshaft in the tunnel, some do not. I have done several, this is a fairly labour intensive job along with needing the right tools. Good summer project.

spencer_murphy · Dec 6, 2009

Right now my sled tracks good on the snow. Maybe something i will just leave alone. If it aint broke dont fix it! I think thats how i will leave it. Thanks all for the input.

PLUMR · Dec 7, 2009

sns, used the MMP two wheel kit and flipped it to the shorter side to accept the track.

mr. 12 valve · Jan 24, 2010

skis_n_skid said:
Dropping the skid just for the sake of making the sled taller is counterproductive IMO. As others have already said, it will increase the attack angle which will negatively affect deep powder performance. If you drop the skid you have to drop the back more than the front to maintain ski pressure (unless you raise the front as well).

You might want to consider trying something like this: http://www.slp.cc/catalog.cfm?pageID=detail&catalogID=3&catID=47&productID=138

The xtra lite RMK skid I put in my wife's sled has one of those installed and so far it seems to work pretty well. I haven't tried it in dry powder yet, but it works well in deep wet snow.

i have a 01 800 rmk with a 144 and last year i put a 153 attack track under it. when i did i moved my skid back so would that throw off my approach angle and my ski pressure

tahoermk · Jan 24, 2010

slp front track shock mount

the SLP front track shock mount listed above is a cheap mod that really makes a difference. It made my 01 rmk 144 track do much better in the deep snow, also better skis, like powder pros will help.

Raised tunnel

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